/**
 * MetonaEditor Core — MarkdownEditor class (TypeScript)
 * @module core
 * @version 0.2.0
 */

import { generateId, escapeHTML, isBrowser } from './utils';
import { DEFAULTS, ICONS, THEMES } from './constants';
import type { EditorOptions, EditMode, ToolbarItem, RenderEnv, ThemeName } from './constants';
import { injectStyles } from './styles';
import { t as i18nT, getCurrentLocale, getLocaleDirection, createInstanceI18n } from './i18n';
import type { InstanceI18n } from './i18n';
import { parseMarkdown } from './parser';
import { presetPlugins, topologicalSort } from './plugins';
import { resolveTheme, getThemeConfig, setThemeVariables, createInstanceTheme } from './themes';

const MODES: EditMode[] = ['edit', 'split', 'preview'];
const TOAST_ICONS: Record<string, string> = { success: '✓', error: '✗', warning: '⚠', info: 'ℹ' };
const BRACKET_PAIRS: Record<string, string> = {
  '(': ')', '[': ']', '{': '}', '"': '"', "'": "'", '`': '`', '*': '*', '_': '_',
};

const resolveThemeName = (theme: string): string => {
  if (theme && theme !== 'auto') return theme;
  return resolveTheme('auto');
};

export class MarkdownEditor {
  static _hooks = new Map<string, Array<(editor: MarkdownEditor) => void>>();

  static on(name: string, fn: (editor: MarkdownEditor) => void): () => void {
    if (!this._hooks.has(name)) this._hooks.set(name, []);
    this._hooks.get(name)!.push(fn);
    return () => this.off(name, fn);
  }
  static off(name: string, fn: (editor: MarkdownEditor) => void): void {
    const list = this._hooks.get(name);
    if (list) this._hooks.set(name, list.filter((f) => f !== fn));
  }
  static trigger(name: string, instance: MarkdownEditor): void {
    const list = this._hooks.get(name);
    if (list) list.forEach((fn) => { try { fn(instance); } catch (e) { console.error(`MeEditor hook "${name}" error:`, e); } });
  }

  id!: string;
  container!: HTMLElement;
  config!: EditorOptions;
  el!: HTMLElement;
  toolbarEl!: HTMLElement;
  bodyEl!: HTMLElement;
  editorPane!: HTMLElement;
  editorInner!: HTMLElement;
  previewPane!: HTMLElement;
  dividerEl!: HTMLElement;
  textarea!: HTMLTextAreaElement;
  previewEl!: HTMLElement;
  gutter!: HTMLElement;
  statusEl!: HTMLElement | null;

  _value!: string;
  _mode!: EditMode;
  _history!: string[];
  _historyIndex!: number;
  _cleanups!: Array<() => void>;
  _plugins!: any[];
  _listeners!: Record<string, Array<(...args: any[]) => void>>;
  _renderRaf!: number | null;
  _historyTimer!: ReturnType<typeof setTimeout> | null;
  _fullscreen!: boolean;
  _destroyed!: boolean;
  _lastRenderedValue!: string | null;
  _shortcuts!: any[];
  _contextMenuItems!: any[];
  _customActions!: Record<string, (...args: any[]) => void>;
  _outlineTimer!: ReturnType<typeof setTimeout> | null;
  _zenMode!: boolean;
  _wordWrap!: boolean;
  _syncing!: boolean;
  _zenMouseHandler!: ((e: MouseEvent) => void) | null;
  _ariaLive!: HTMLElement;
  _renderFn!: (md: string, env: RenderEnv) => string;
  _highlightFn!: ((code: string, lang: string) => string) | null;
  _themeCtx: any;
  _i18nCtx!: InstanceI18n;
  _floatingToolbar!: HTMLElement | null;
  _selectionTimer!: ReturnType<typeof setInterval> | null;
  _floatingEnabled!: boolean;

  constructor(container: string | HTMLElement, options: EditorOptions = {}) {
    if (!isBrowser()) {
      this._destroyed = true; this._value = options.value || ''; return this as any;
    }
    this.id = options.id || generateId();
    this.container = typeof container === 'string' ? document.querySelector(container) as HTMLElement : container;
    if (!this.container) {
      console.error('MeEditor: container not found:', container);
      this._destroyed = true; return this as any;
    }
    this.config = { ...DEFAULTS, ...options };
    if (options.style && typeof options.style === 'object') {
      this.config.style = { ...DEFAULTS.style, ...options.style };
    }
    this._value = this.config.value || '';
    this._mode = MODES.includes(this.config.mode!) ? this.config.mode! : 'split';
    this._history = []; this._historyIndex = -1; this._cleanups = []; this._plugins = [];
    this._listeners = {}; this._renderRaf = null; this._historyTimer = null;
    this._fullscreen = false; this._destroyed = false; this._lastRenderedValue = null;
    this._shortcuts = []; this._contextMenuItems = []; this._customActions = {};
    this._outlineTimer = null; this._zenMode = false; this._wordWrap = true; this._syncing = false;
    this._zenMouseHandler = null;
    this._floatingToolbar = null; this._selectionTimer = null;
    this._floatingEnabled = this.config.floatingToolbar !== false;

    this._renderFn = (typeof this.config.render === 'function') ? this.config.render : parseMarkdown;
    this._highlightFn = (typeof this.config.highlight === 'function') ? this.config.highlight : null;

    MarkdownEditor.trigger('beforeCreate', this);
    injectStyles();
    this._buildDOM();
    this._themeCtx = createInstanceTheme(this);
    this._i18nCtx = createInstanceI18n(this);

    if (options.theme && typeof document !== 'undefined') {
      document.documentElement.setAttribute('data-md-theme', resolveTheme(options.theme));
    }
    const resolvedThemeConfig = getThemeConfig(this.config.theme!);
    setThemeVariables(resolvedThemeConfig, this.el);

    this._buildToolbar();
    this._updateModeButtons();
    this._bindToolbarKeyboard();
    this._initAriaLive();
    this._bindEvents();
    this._bindContextMenu();
    this._trackOutlineScroll();
    if (this.config.floatingToolbar !== false) this._initFloatingToolbar();

    this.textarea.value = this._value;
    this._pushHistory();
    this._render();
    this._updateWordCount();

    if (Array.isArray(this.config.plugins)) {
      const plugins = this.config.plugins.map((p: any) => {
        if (typeof p === 'string') return { ...presetPlugins[p], _isStringRef: true };
        return p;
      }).filter(Boolean);
      const sorted = topologicalSort(plugins);
      sorted.forEach((p) => this.use(p));
    }

    if (this.config.autofocus && !this.config.readOnly) this.focus();
    if (typeof this.config.onCreate === 'function') {
      try { this.config.onCreate(this); } catch (e) { console.error('onCreate error:', e); }
    }
    MarkdownEditor.trigger('afterCreate', this);
  }

  _buildDOM(): void {
    const wrapper = document.createElement('div');
    wrapper.className = `me-wrapper me-theme-${resolveThemeName(this.config.theme!)}`;
    if (this.config.readOnly) wrapper.classList.add('me-readonly');
    wrapper.dataset.id = this.id;
    wrapper.setAttribute('role', 'application');
    wrapper.setAttribute('aria-label', i18nT('edit'));
    if (this.config.className) {
      this.config.className.split(/\s+/).filter(Boolean).forEach((c) => wrapper.classList.add(c));
    }
    const h = this.config.height;
    wrapper.style.height = typeof h === 'number' ? `${h}px` : (h || '400px');
    if (this.config.style && typeof this.config.style === 'object') {
      Object.entries(this.config.style).forEach(([k, v]) => { if (v) (wrapper.style as any)[k] = v; });
    }
    const toolbar = document.createElement('div'); toolbar.className = 'me-toolbar'; toolbar.setAttribute('role', 'toolbar');
    const body = document.createElement('div'); body.className = `me-body me-mode-${this._mode}`;
    const editorPane = document.createElement('div'); editorPane.className = 'me-editor-pane';
    const editorInner = document.createElement('div'); editorInner.className = 'me-editor-inner';
    const gutter = document.createElement('div'); gutter.className = 'me-gutter';
    if (!this.config.lineNumbers) gutter.style.display = 'none';
    editorInner.appendChild(gutter);
    const textarea = document.createElement('textarea'); textarea.className = 'me-textarea';
    textarea.spellcheck = !!this.config.spellcheck; textarea.readOnly = !!this.config.readOnly;
    textarea.style.tabSize = String(this.config.tabSize || 2);
    textarea.placeholder = this.config.placeholder || i18nT('placeholder');
    textarea.setAttribute('aria-label', i18nT('edit'));
    editorInner.appendChild(textarea);
    editorPane.appendChild(editorInner);
    const divider = document.createElement('div'); divider.className = 'me-divider'; divider.setAttribute('role', 'separator');
    const previewPane = document.createElement('div'); previewPane.className = 'me-preview-pane';
    previewPane.setAttribute('role', 'region'); previewPane.setAttribute('aria-label', i18nT('preview'));
    const preview = document.createElement('div'); preview.className = 'me-preview'; previewPane.appendChild(preview);
    body.appendChild(editorPane); body.appendChild(divider); body.appendChild(previewPane);
    wrapper.appendChild(toolbar); wrapper.appendChild(body);
    let statusbar: HTMLElement | null = null;
    if (this.config.wordCount) { statusbar = document.createElement('div'); statusbar.className = 'me-statusbar'; wrapper.appendChild(statusbar); }
    this.container.appendChild(wrapper);
    this.el = wrapper; this.toolbarEl = toolbar; this.bodyEl = body;
    this.editorPane = editorPane; this.editorInner = editorInner; this.gutter = gutter;
    this.previewPane = previewPane; this.dividerEl = divider;
    this.textarea = textarea; this.previewEl = preview; this.statusEl = statusbar;
    // Restore divider position if saved
    this._restoreDividerPosition();
  }

  _buildToolbar(): void {
    const tools = this.config.toolbar;
    if (!tools || !Array.isArray(tools) || tools.length === 0) return;
    const modeActions: string[] = [];
    tools.forEach((item) => {
      if (item === '|') { const sep = document.createElement('span'); sep.className = 'me-toolbar-sep'; this.toolbarEl.appendChild(sep); return; }
      if (item === 'edit' || item === 'split' || item === 'preview' || item === 'fullscreen') { modeActions.push(item); return; }
      this.toolbarEl.appendChild(this._createBtn(item));
    });
    if (modeActions.length) {
      const group = document.createElement('div'); group.className = 'me-toolbar-group';
      modeActions.forEach((item) => {
        const btn = this._createBtn(item);
        if (item === 'edit' || item === 'split' || item === 'preview') { btn.dataset.mode = item; if (item === this._mode) btn.classList.add('me-active'); }
        group.appendChild(btn);
      });
      this.toolbarEl.appendChild(group);
    }
  }

  _createBtn(item: string): HTMLButtonElement {
    const btn = document.createElement('button'); btn.type = 'button';
    btn.className = `me-btn me-btn-${item}`; btn.dataset.action = item;
    const label = i18nT(item) || item; btn.title = label; btn.setAttribute('aria-label', label);
    btn.innerHTML = ICONS[item] || `<span>${escapeHTML(item)}</span>`;
    return btn;
  }

  _bindEvents(): void {
    const ta = this.textarea;
    const onInput = () => {
      const oldValue = this._value;
      this._value = ta.value;
      MarkdownEditor.trigger('beforeChange', this); this._emit('beforeChange', oldValue, this._value);
      this._scheduleRender(); this._scheduleHistory(); this._updateWordCount();
      this._renderGutter(); this._updateOutline();
      this._emit('input', this._value); this._emit('change', this._value);
      if (typeof this.config.onInput === 'function') { try { this.config.onInput(this._value, this); } catch (e) { console.error(e); } }
      if (typeof this.config.onChange === 'function') { try { this.config.onChange(this._value, this); } catch (e) { console.error(e); } }
      this._emit('afterChange', this._value); MarkdownEditor.trigger('afterChange', this);
    };
    ta.addEventListener('input', onInput);
    const onKeydown = (e: KeyboardEvent) => {
      if (e.key === 'Enter' && !e.shiftKey && !e.ctrlKey && !e.metaKey) this._handleSmartEnter(e);
      this._handleKeydown(e);
    };
    ta.addEventListener('keydown', onKeydown);
    const onKeypress = (e: KeyboardEvent) => this._handleBracketAutoClose(e);
    ta.addEventListener('keypress', onKeypress);
    const onCursorActivity = () => { this._updateCurrentLine(); };
    ta.addEventListener('click', onCursorActivity);
    ta.addEventListener('keyup', onCursorActivity);
    const onScroll = () => { this._syncScroll(); };
    ta.addEventListener('scroll', onScroll);
    const onPreviewScroll = () => {
      if (!this.config.syncScroll || this._mode !== 'split') return;
      if (this._syncing) return; this._syncing = true;
      const pmax = this.previewPane.scrollHeight - this.previewPane.clientHeight;
      if (pmax <= 0) { this._syncing = false; return; }
      const ratio = this.previewPane.scrollTop / pmax;
      const tmax = ta.scrollHeight - ta.clientHeight;
      ta.scrollTop = ratio * tmax;
      if (this.gutter) { const gmax = this.gutter.scrollHeight - this.gutter.clientHeight; this.gutter.scrollTop = gmax > 0 ? ratio * gmax : ratio * tmax; }
      requestAnimationFrame(() => { this._syncing = false; });
    };
    this.previewPane.addEventListener('scroll', onPreviewScroll);
    const onFocus = () => {
      this._emit('focus'); if (typeof this.config.onFocus === 'function') { try { this.config.onFocus(this); } catch (e) { console.error(e); } }
    };
    const onBlur = () => {
      this._emit('blur'); if (typeof this.config.onBlur === 'function') { try { this.config.onBlur(this); } catch (e) { console.error(e); } }
    };
    ta.addEventListener('focus', onFocus); ta.addEventListener('blur', onBlur);
    const onPreviewClick = (e: MouseEvent) => {
      const a = (e.target as HTMLElement).closest('a'); if (!a) return;
      const href = a.getAttribute('href'); if (!href || href.startsWith('#')) return;
      e.preventDefault(); this._emit('linkClick', { href, text: a.textContent });
      if (typeof this.config.onLinkClick === 'function') { try { this.config.onLinkClick(href, a.textContent, this); } catch (_) {} return; }
      window.open(href, '_blank', 'noopener');
    };
    this.previewEl.addEventListener('click', onPreviewClick);
    const onToolbarClick = (e: MouseEvent) => {
      const btn = (e.target as HTMLElement).closest('.me-btn') as HTMLElement; if (!btn) return;
      const mode = btn.dataset.mode; if (mode) { this.setMode(mode as EditMode); return; }
      const action = btn.dataset.action; if (action) this.exec(action);
    };
    this.toolbarEl.addEventListener('click', onToolbarClick);
    const onDividerDown = (e: PointerEvent) => this._bindDividerDrag(e);
    this.dividerEl.addEventListener('pointerdown', onDividerDown);
    this._bindDragDrop();
    this._cleanups.push(() => {
      ta.removeEventListener('input', onInput); ta.removeEventListener('keydown', onKeydown);
      ta.removeEventListener('keypress', onKeypress); ta.removeEventListener('scroll', onScroll);
      this.previewPane.removeEventListener('scroll', onPreviewScroll);
      ta.removeEventListener('click', onCursorActivity); ta.removeEventListener('keyup', onCursorActivity);
      ta.removeEventListener('focus', onFocus); ta.removeEventListener('blur', onBlur);
      this.toolbarEl.removeEventListener('click', onToolbarClick);
      this.dividerEl.removeEventListener('pointerdown', onDividerDown);
    });
  }

  _handleKeydown(e: KeyboardEvent): void {
    if (e.key === 'Tab') { e.preventDefault(); this._handleTab(e.shiftKey); return; }
    if (this._shortcuts.length) {
      for (const sc of this._shortcuts) {
        const ctrlOk = sc.ctrl ? (e.ctrlKey || e.metaKey) : !e.ctrlKey && !e.metaKey;
        const shiftOk = sc.shift ? e.shiftKey : !e.shiftKey;
        const altOk = sc.alt ? e.altKey : !e.altKey;
        if (e.key.toLowerCase() === sc.key && ctrlOk && shiftOk && altOk) {
          e.preventDefault();
          if (typeof sc.handler === 'string') this.exec(sc.handler);
          else if (typeof sc.handler === 'function') { try { sc.handler(this); } catch (err) { console.error('Shortcut error:', err); } }
          return;
        }
      }
    }
    const mod = e.ctrlKey || e.metaKey; if (!mod) return;
    const key = e.key.toLowerCase();
    const shortcuts: Record<string, string> = { b: 'bold', i: 'italic', k: 'link', u: 'underline', e: 'code', '1': 'h1', '2': 'h2', '3': 'h3', q: 'quote' };
    if (key === 'z' && !e.shiftKey) { e.preventDefault(); this.undo(); }
    else if ((key === 'z' && e.shiftKey) || key === 'y') { e.preventDefault(); this.redo(); }
    else if (key === 's') { e.preventDefault(); this._emit('save', this._value); if (typeof this.config.onSave === 'function') { try { this.config.onSave(this._value, this); } catch (err) { console.error(err); } } }
    else if (shortcuts[key]) { e.preventDefault(); this.exec(shortcuts[key]); }
  }

  _handleTab(shift: boolean): void {
    const ta = this.textarea; const start = ta.selectionStart; const end = ta.selectionEnd;
    const tabSize = this.config.tabSize || 0; const tabStr = tabSize > 0 ? ' '.repeat(tabSize) : '\t';
    if (start === end) {
      ta.value = ta.value.slice(0, start) + tabStr + ta.value.slice(end);
      ta.selectionStart = ta.selectionEnd = start + tabStr.length;
    } else {
      const lineStart = ta.value.lastIndexOf('\n', start - 1) + 1;
      const block = ta.value.slice(lineStart, end); const lines = block.split('\n');
      let newBlock: string;
      if (shift) { newBlock = lines.map((l) => l.replace(/^(\t| {1,4})/, '')).join('\n'); }
      else { newBlock = lines.map((l) => tabStr + l).join('\n'); }
      ta.value = ta.value.slice(0, lineStart) + newBlock + ta.value.slice(end);
      ta.selectionStart = lineStart; ta.selectionEnd = lineStart + newBlock.length;
    }
    this._value = ta.value; this._pushHistory(); this._render(); this._emit('change', this._value);
  }

  _bindDividerDrag(e: PointerEvent): void {
    if (this._mode !== 'split') return; e.preventDefault();
    const startX = e.clientX;
    const editorWidth = this.editorPane.getBoundingClientRect().width;
    const totalWidth = this.bodyEl.getBoundingClientRect().width;
    if (totalWidth <= 0) return;
    const divider = this.dividerEl;
    const onMove = (ev: PointerEvent) => {
      const dx = ev.clientX - startX;
      let newW = editorWidth + dx;
      const min = 80; const max = totalWidth - 80 - divider.offsetWidth;
      newW = Math.max(min, Math.min(max, newW));
      const pct = (newW / totalWidth) * 100;
      this.editorPane.style.flex = `0 0 ${pct}%`;
      this.previewPane.style.flex = `1 1 ${100 - pct}%`;
    };
    const onUp = () => {
      window.removeEventListener('pointermove', onMove);
      window.removeEventListener('pointerup', onUp);
      this._saveDividerPosition();
    };
    window.addEventListener('pointermove', onMove); window.addEventListener('pointerup', onUp);
  }

  _saveDividerPosition(): void {
    try {
      const epFlex = this.editorPane.style.flex;
      if (epFlex) localStorage.setItem('metona-editor-divider', epFlex);
    } catch (_) {}
  }

  _restoreDividerPosition(): void {
    try {
      const saved = localStorage.getItem('metona-editor-divider');
      if (saved && this._mode === 'split') {
        this.editorPane.style.flex = saved;
        this.previewPane.style.flex = '1 1 auto';
      }
    } catch (_) {}
  }

  _scheduleRender(): void { if (this._renderRaf) return; this._renderRaf = requestAnimationFrame(() => { this._renderRaf = null; this._render(); }); }

  _render(): void {
    if (this._mode === 'edit') return;
    if (this._lastRenderedValue === this._value) return;
    this._lastRenderedValue = this._value;
    MarkdownEditor.trigger('beforeRender', this); this._emit('beforeRender', this);
    let html: string;
    try { html = this._renderFn(this._value, { highlight: this._highlightFn || undefined, locale: getCurrentLocale() }); }
    catch (err: any) { console.error('MeEditor render error:', err); html = `<p style="color:#ef4444">${i18nT('renderError')}: ${escapeHTML(err.message)}</p>`; }
    if (typeof this.config.sanitize === 'function') { try { html = this.config.sanitize(html); } catch (e) { console.error('sanitize error:', e); } }
    this.previewEl.innerHTML = html; this._renderGutter();
    MarkdownEditor.trigger('afterRender', this); this._emit('afterRender', this);
  }

  _renderGutter(): void {
    if (!this.config.lineNumbers || !this.gutter) return;
    const lines = this._value ? this._value.split('\n').length : 1;
    const current = this.gutter.children.length;
    if (current === lines) return;
    if (current < lines) {
      // Add new line numbers
      let h = '';
      for (let i = current + 1; i <= lines; i++) h += `<div class="me-gutter-line">${i}</div>`;
      this.gutter.insertAdjacentHTML('beforeend', h);
    } else {
      // Remove excess line numbers
      while (this.gutter.children.length > lines) {
        this.gutter.removeChild(this.gutter.lastChild!);
      }
    }
  }

  _updateCurrentLine(): void {
    if (!this.gutter) return;
    const pos = this.textarea.selectionStart;
    const lineNum = this._value.substring(0, pos).split('\n').length;
    const prev = this.gutter.querySelector('.me-gutter-active'); if (prev) prev.classList.remove('me-gutter-active');
    const cur = this.gutter.children[lineNum - 1] as HTMLElement; if (cur) cur.classList.add('me-gutter-active');
  }

  _handleSmartEnter(e: KeyboardEvent): void {
    const ta = this.textarea; const start = ta.selectionStart;
    const val = ta.value; const lineStart = val.lastIndexOf('\n', start - 1) + 1;
    const line = val.slice(lineStart, start);
    const listMatch = line.match(/^(\s*)([-*+]|\d+\.)\s(.*)/);
    if (listMatch) {
      const indent = listMatch[1]; const marker = listMatch[2]; const content = listMatch[3];
      if (!content.trim()) { e.preventDefault(); ta.value = val.slice(0, lineStart) + '\n' + val.slice(start); ta.selectionStart = ta.selectionEnd = lineStart; this._value = ta.value; this._pushHistory(); this._renderGutter(); this._emit('change', this._value); return; }
      let nextMarker = marker;
      if (/^\d+\.$/.test(marker)) { const num = parseInt(marker, 10); if (!isNaN(num)) nextMarker = (num + 1) + '.'; }
      e.preventDefault(); const insert = '\n' + indent + nextMarker + ' ';
      ta.value = val.slice(0, start) + insert + val.slice(ta.selectionEnd);
      ta.selectionStart = ta.selectionEnd = start + insert.length;
      this._value = ta.value; this._pushHistory(); this._renderGutter(); this._emit('change', this._value); return;
    }
    const quoteMatch = line.match(/^(\s*>+\s?)(.*)/);
    if (quoteMatch) {
      const prefix = quoteMatch[1]; const content = quoteMatch[2];
      if (!content.trim()) { e.preventDefault(); ta.value = val.slice(0, lineStart) + '\n' + val.slice(start); ta.selectionStart = ta.selectionEnd = lineStart; this._value = ta.value; this._pushHistory(); this._renderGutter(); this._emit('change', this._value); return; }
      e.preventDefault(); const insert = '\n' + prefix;
      ta.value = val.slice(0, start) + insert + val.slice(ta.selectionEnd);
      ta.selectionStart = ta.selectionEnd = start + insert.length;
      this._value = ta.value; this._pushHistory(); this._renderGutter(); this._emit('change', this._value);
    }
  }

  _handleBracketAutoClose(e: KeyboardEvent): void {
    if (!this.config.autoBrackets) return;
    const ta = this.textarea; const key = e.key; const close = BRACKET_PAIRS[key];
    if (!close) return;
    const start = ta.selectionStart; const end = ta.selectionEnd;
    if (start !== end) { e.preventDefault(); const selected = ta.value.slice(start, end); const wrap = key + selected + close; ta.value = ta.value.slice(0, start) + wrap + ta.value.slice(end); ta.selectionStart = start + 1; ta.selectionEnd = start + 1 + selected.length; this._value = ta.value; this._pushHistory(); this._emit('change', this._value); return; }
    const nextChar = ta.value[start] || '';
    if (key === close) { if (nextChar === close) { e.preventDefault(); ta.selectionStart = ta.selectionEnd = start + 1; return; } if (/\w/.test(nextChar)) return; }
    e.preventDefault(); const pair = key + close; ta.value = ta.value.slice(0, start) + pair + ta.value.slice(end); ta.selectionStart = ta.selectionEnd = start + 1; this._value = ta.value; this._pushHistory(); this._emit('change', this._value);
  }

  _bindDragDrop(): void {
    const ta = this.textarea; if (!ta) return;
    const onDragOver = (e: DragEvent) => { e.preventDefault(); if (e.dataTransfer) e.dataTransfer.dropEffect = 'copy'; };
    const onDrop = (e: DragEvent) => {
      e.preventDefault();
      const files = e.dataTransfer?.files;
      if (files && files.length) {
        Array.from(files).forEach((file) => {
          if (file.type.startsWith('image/')) { const reader = new FileReader(); reader.onload = () => { this.insert(`![${file.name}](${reader.result})\n`); }; reader.readAsDataURL(file); }
          else if (file.type.startsWith('text/') || /\.(md|txt|js|ts|json|css|html|xml|yml|yaml)$/i.test(file.name)) { const reader = new FileReader(); reader.onload = () => this.insert(reader.result as string); reader.readAsText(file); }
        }); return;
      }
      const text = e.dataTransfer?.getData('text/plain'); if (text) this.insert(text);
    };
    ta.addEventListener('dragover', onDragOver); ta.addEventListener('drop', onDrop);
    this._cleanups.push(() => { ta.removeEventListener('dragover', onDragOver); ta.removeEventListener('drop', onDrop); });
  }

  _buildOutline(): void {
    if (!this.config.outline || !this.previewEl) return;
    const old = this.el.querySelector('.me-outline'); if (old) old.remove();
    const headings: Array<{ level: number; id: string; text: string }> = [];
    const headingRe = /<h([1-6])\s+id="([^"]+)"[^>]*>(.+?)<\/h\1>/gi;
    let m: RegExpExecArray | null;
    while ((m = headingRe.exec(this.previewEl.innerHTML)) !== null) {
      headings.push({ level: parseInt(m[1], 10), id: m[2], text: m[3].replace(/<[^>]+>/g, '') });
    }
    if (!headings.length) return;
    const panel = document.createElement('div'); panel.className = 'me-outline';
    panel.innerHTML = `<div class="me-outline-title">${i18nT('outline') || '大纲'}</div>`;
    const buildTree = (items: typeof headings, minLevel: number): string => {
      let h = '<ul>'; let i = 0;
      while (i < items.length) {
        const item = items[i]; if (item.level < minLevel) break;
        h += `<li class="me-outline-l${item.level}"><a href="#${item.id}" data-line="${item.id}">${escapeHTML(item.text)}</a>`;
        const sub: typeof headings = []; let j = i + 1; while (j < items.length && items[j].level > item.level) { sub.push(items[j]); j++; }
        if (sub.length) h += buildTree(sub, item.level + 1);
        h += '</li>'; i = j > i + 1 ? j : i + 1;
      }
      return h + '</ul>';
    };
    panel.innerHTML += buildTree(headings, 1);
    this.el.appendChild(panel);
    panel.addEventListener('click', (e) => {
      const a = (e.target as HTMLElement).closest('a'); if (!a) return; e.preventDefault();
      const id = a.getAttribute('href')!.slice(1);
      const target = this.previewEl.querySelector('#' + CSS.escape(id));
      if (target) { target.scrollIntoView({ behavior: 'smooth', block: 'start' }); const idx = this._value.indexOf(target.textContent || ''); if (idx !== -1) { this.textarea.focus(); this.textarea.setSelectionRange(idx, idx); } }
    });
  }

  _updateOutline(): void { if (!this.config.outline) return; if (this._outlineTimer) clearTimeout(this._outlineTimer); this._outlineTimer = setTimeout(() => this._buildOutline(), 300); }

  _trackOutlineScroll(): void {
    if (!this.config.outline || !this.previewPane) return;
    let ticking = false;
    const onScroll = () => {
      if (ticking) return;
      ticking = true;
      requestAnimationFrame(() => {
        ticking = false;
        if (!this.el) return;
        const panel = this.el.querySelector('.me-outline');
        if (!panel) return;
        const headings = this.previewEl.querySelectorAll('h1, h2, h3, h4, h5, h6');
        let activeId = '';
        const scrollTop = this.previewPane.scrollTop + 80; // offset for better UX
        headings.forEach((h) => {
          if ((h as HTMLElement).offsetTop <= scrollTop) {
            activeId = h.id;
          }
        });
        panel.querySelectorAll('a').forEach((a) => {
          a.classList.toggle('me-outline-active', a.getAttribute('href') === '#' + activeId);
        });
      });
    };
    this.previewPane.addEventListener('scroll', onScroll, { passive: true });
    this._cleanups.push(() => this.previewPane.removeEventListener('scroll', onScroll));
  }

  _scheduleHistory(): void { if (this._historyTimer) clearTimeout(this._historyTimer); this._historyTimer = setTimeout(() => this._pushHistory(), this.config.historyDebounce || 400); }

  _pushHistory(): void {
    const cur = this._history[this._historyIndex]; if (cur === this._value) return;
    this._history = this._history.slice(0, this._historyIndex + 1); this._history.push(this._value);
    const limit = this.config.historyLimit! > 0 ? this.config.historyLimit! : 100;
    while (this._history.length > limit) this._history.shift();
    this._historyIndex = this._history.length - 1;
  }

  undo(): this { if (this._historyIndex <= 0) return this; this._historyIndex--; this._applyHistory(); return this; }
  redo(): this { if (this._historyIndex >= this._history.length - 1) return this; this._historyIndex++; this._applyHistory(); return this; }
  canUndo(): boolean { return this._historyIndex > 0; }
  canRedo(): boolean { return this._historyIndex < this._history.length - 1; }

  _applyHistory(): void {
    this._value = this._history[this._historyIndex]; this.textarea.value = this._value;
    this._render(); this._renderGutter(); this._updateWordCount();
    if (this.gutter) this.gutter.scrollTop = this.textarea.scrollTop;
    if (this.previewPane && this.config.syncScroll) this.previewPane.scrollTop = 0;
    this._emit('change', this._value);
    if (typeof this.config.onChange === 'function') { try { this.config.onChange(this._value, this); } catch (e) { console.error(e); } }
  }

  exec(action: string, ...args: any[]): this {
    const actions: Record<string, () => void> = {
      bold: () => this._wrapSelection('**', '**'), italic: () => this._wrapSelection('*', '*'),
      strikethrough: () => this._wrapSelection('~~', '~~'), underline: () => this._wrapSelection('<u>', '</u>'),
      code: () => this._wrapSelection('`', '`'), h1: () => this._toggleLinePrefix('# '),
      h2: () => this._toggleLinePrefix('## '), h3: () => this._toggleLinePrefix('### '),
      quote: () => this._toggleLinePrefix('> '), ul: () => this._toggleLinePrefix('- '),
      ol: () => this._toggleLinePrefix('1. '), indent: () => this._handleTab(false),
      outdent: () => this._handleTab(true), hr: () => this._insertBlock('\n---\n'),
      link: () => this._insertLink(), image: () => this._insertImage(), table: () => this._insertTable(),
      undo: () => this.undo(), redo: () => this.redo(),
      edit: () => this.setMode('edit'), split: () => this.setMode('split'),
      preview: () => this.setMode('preview'), fullscreen: () => this.toggleFullscreen(),
      zen: () => this.toggleZen(), wordwrap: () => this.toggleWordWrap(),
      formatTable: () => this._formatTable(),
    };
    const fn = actions[action];
    if (fn) { (fn as Function).apply(this, args); return this; }
    if (this._customActions && typeof this._customActions[action] === 'function') {
      try { (this._customActions[action] as Function).apply(this, args); } catch (e) { console.error('custom action error:', e); }
    }
    return this;
  }

  _wrapSelection(before: string, after: string): void {
    const ta = this.textarea; const start = ta.selectionStart; const end = ta.selectionEnd;
    const selected = ta.value.slice(start, end); const text = selected || 'text';
    const inserted = before + text + after;
    ta.value = ta.value.slice(0, start) + inserted + ta.value.slice(end); ta.focus();
    if (selected) { ta.selectionStart = start + before.length; ta.selectionEnd = start + before.length + text.length; }
    else { ta.selectionStart = ta.selectionEnd = start + before.length; }
    this._value = ta.value; this._pushHistory(); this._render(); this._updateWordCount(); this._emit('change', this._value);
  }

  _toggleLinePrefix(prefix: string): void {
    const ta = this.textarea; const start = ta.selectionStart;
    const lineStart = ta.value.lastIndexOf('\n', start - 1) + 1;
    const lineEndPos = ta.value.indexOf('\n', start); const lineEnd = lineEndPos === -1 ? ta.value.length : lineEndPos;
    const line = ta.value.slice(lineStart, lineEnd);
    const existingMatch = line.match(/^(#{1,6}\s*|>\s*|[-*+]\s*|\d+\.\s*)/);
    let newLine: string;
    if (existingMatch && existingMatch[0] === prefix) newLine = line.slice(prefix.length);
    else if (existingMatch) newLine = prefix + line.slice(existingMatch[0].length);
    else newLine = prefix + line;
    ta.value = ta.value.slice(0, lineStart) + newLine + ta.value.slice(lineEnd); ta.focus();
    ta.selectionStart = ta.selectionEnd = lineStart + newLine.length;
    this._value = ta.value; this._pushHistory(); this._render(); this._updateWordCount(); this._emit('change', this._value);
  }

  _insertBlock(text: string): void {
    const ta = this.textarea; const start = ta.selectionStart;
    const before = ta.value.slice(0, start); const needNL = before && !before.endsWith('\n');
    const insert = (needNL ? '\n' : '') + text;
    ta.value = ta.value.slice(0, start) + insert + ta.value.slice(ta.selectionEnd); ta.focus();
    const pos = start + insert.length; ta.selectionStart = ta.selectionEnd = pos;
    this._value = ta.value; this._pushHistory(); this._render(); this._updateWordCount(); this._emit('change', this._value);
  }

  _insertLink(): void { const ta = this.textarea; const start = ta.selectionStart; const end = ta.selectionEnd; const sel = ta.value.slice(start, end) || i18nT('link') || 'link'; const url = 'https://'; const insert = `[${sel}](${url})`; ta.value = ta.value.slice(0, start) + insert + ta.value.slice(end); ta.focus(); ta.selectionStart = start + sel.length + 3; ta.selectionEnd = ta.selectionStart + url.length; this._value = ta.value; this._pushHistory(); this._render(); this._emit('change', this._value); }
  _insertImage(): void { const ta = this.textarea; const start = ta.selectionStart; const end = ta.selectionEnd; const sel = ta.value.slice(start, end) || i18nT('image') || 'image'; const url = 'https://'; const insert = `![${sel}](${url})`; ta.value = ta.value.slice(0, start) + insert + ta.value.slice(end); ta.focus(); ta.selectionStart = start + sel.length + 4; ta.selectionEnd = ta.selectionStart + url.length; this._value = ta.value; this._pushHistory(); this._render(); this._emit('change', this._value); }
  _insertTable(rows = 3, cols = 3): void { const header = Array.from({ length: cols }, (_, i) => `${i18nT('tableCols') || '列'}${i + 1}`).join(' | '); const sep = Array.from({ length: cols }, () => '---').join(' | '); let md = `| ${header} |\n| ${sep} |\n`; for (let r = 1; r < rows; r++) md += `| ${Array.from({ length: cols }, () => ' ').join(' | ')} |\n`; this._insertBlock('\n' + md); }

  _formatTable(): void {
    const ta = this.textarea;
    const start = ta.selectionStart;
    // Find table boundaries around cursor
    const before = ta.value.substring(0, start);
    const after = ta.value.substring(start);
    const blockStart = before.lastIndexOf('\n\n');
    const blockEnd = after.indexOf('\n\n');
    const tableStart = blockStart === -1 ? 0 : blockStart + 2;
    const tableEnd = blockEnd === -1 ? ta.value.length : start + blockEnd;
    const tableText = ta.value.substring(tableStart, tableEnd);
    const lines = tableText.split('\n').filter((l) => l.includes('|'));
    if (lines.length < 2) return; // need at least header + separator
    // Parse columns
    const splitRow = (r: string) => r.replace(/^\s*\|?\s*|\s*\|?\s*$/g, '').split(/\s*\|\s*/);
    const allCells = lines.map(splitRow);
    const colCount = Math.max(...allCells.map((c) => c.length));
    // Calculate max width per column
    const colWidths: number[] = Array(colCount).fill(3);
    allCells.forEach((cells) => {
      cells.forEach((cell, ci) => {
        colWidths[ci] = Math.max(colWidths[ci], cell.trim().length);
      });
    });
    // Rebuild table
    const pad = (s: string, w: number) => { const padLen = w - s.length; return s + ' '.repeat(Math.max(0, padLen)); };
    const formatted = allCells.map((cells) => {
      const padded = [];
      for (let ci = 0; ci < colCount; ci++) {
        padded.push(pad((cells[ci] || '').trim(), colWidths[ci]));
      }
      return '| ' + padded.join(' | ') + ' |';
    });
    // Replace in value
    ta.value = ta.value.substring(0, tableStart) + formatted.join('\n') + ta.value.substring(tableEnd);
    this._value = ta.value; this._pushHistory(); this._render(); this._emit('change', this._value);
  }

  setMode(mode: EditMode): this { if (!MODES.includes(mode) || mode === this._mode) return this; const taS = this.textarea.scrollTop; const pvS = this.previewPane.scrollTop; this._mode = mode; this.bodyEl.className = `me-body me-mode-${mode}`; this._updateModeButtons(); if (mode !== 'edit') this._render(); this.textarea.scrollTop = taS; this.previewPane.scrollTop = pvS; this._emit('modeChange', mode); this._announce(`${i18nT(mode) || mode} mode`); if (typeof this.config.onModeChange === 'function') { try { this.config.onModeChange(mode, this); } catch (e) { console.error(e); } } return this; }
  getMode(): EditMode { return this._mode; }

  _updateModeButtons(): void {
    const isPreview = this._mode === 'preview'; const isReadonly = this.config.readOnly;
    this.toolbarEl.querySelectorAll('.me-btn').forEach((b) => {
      const btn = b as HTMLButtonElement; const mode = btn.dataset.mode; const action = btn.dataset.action;
      if (mode) { btn.classList.toggle('me-active', mode === this._mode); btn.disabled = false; return; }
      if (action === 'fullscreen') { btn.disabled = false; return; }
      if (isReadonly) { btn.disabled = !(action === 'undo' || action === 'redo'); return; }
      if (isPreview) { btn.disabled = !(action === 'undo' || action === 'redo'); return; }
      btn.disabled = false;
    });
  }

  toggleFullscreen(): this { this._fullscreen = !this._fullscreen; this.el.classList.toggle('me-fullscreen', this._fullscreen); const fsBtn = this.toolbarEl.querySelector('.me-btn-fullscreen') as HTMLButtonElement; if (fsBtn) fsBtn.title = this._fullscreen ? (i18nT('fullscreenExit') || '退出全屏') : (i18nT('fullscreen') || '全屏'); this._emit('fullscreen', this._fullscreen); if (typeof this.config.onFullscreen === 'function') { try { this.config.onFullscreen(this._fullscreen, this); } catch (e) { console.error(e); } } return this; }
  isFullscreen(): boolean { return this._fullscreen; }
  exitFullscreen(): this { if (this._fullscreen) this.toggleFullscreen(); return this; }

  toggleZen(): this {
    this._zenMode = !this._zenMode; if (this.el) this.el.classList.toggle('me-zen', this._zenMode);
    if (this._zenMode && this.toolbarEl) {
      this._zenMouseHandler = (e: MouseEvent) => { this.toolbarEl.style.opacity = e.clientY < 40 ? '1' : '0'; this.toolbarEl.style.pointerEvents = e.clientY < 40 ? 'auto' : 'none'; };
      this.toolbarEl.style.transition = 'opacity 0.2s'; this.toolbarEl.style.opacity = '0'; this.toolbarEl.style.pointerEvents = 'none';
      document.addEventListener('mousemove', this._zenMouseHandler);
      if (this.statusEl) this.statusEl.style.display = 'none';
    } else {
      if (this._zenMouseHandler) { document.removeEventListener('mousemove', this._zenMouseHandler); this._zenMouseHandler = null; }
      if (this.toolbarEl) { this.toolbarEl.style.opacity = ''; this.toolbarEl.style.pointerEvents = ''; this.toolbarEl.style.transition = ''; }
      if (this.statusEl) this.statusEl.style.display = '';
    }
    this._emit('zenChange', this._zenMode); return this;
  }
  isZen(): boolean { return this._zenMode; }

  toggleWordWrap(): this { this._wordWrap = !this._wordWrap; if (this.textarea) this.textarea.style.whiteSpace = this._wordWrap ? 'pre-wrap' : 'pre'; return this; }
  setWordWrap(on: boolean): this { this._wordWrap = !!on; if (this.textarea) this.textarea.style.whiteSpace = this._wordWrap ? 'pre-wrap' : 'pre'; return this; }
  isWordWrap(): boolean { return this._wordWrap; }

  _initFloatingToolbar(): void {
    if (typeof document === 'undefined') return;
    // Inject floating toolbar CSS once globally
    if (!document.getElementById('me-float-style')) {
      const style = document.createElement('style');
      style.id = 'me-float-style';
      style.textContent = `.me-float-toolbar{position:absolute;z-index:25;display:flex;gap:4px;padding:4px 6px;background:var(--md-toolbar-bg,#f8f9fa);border:1px solid var(--md-border,rgba(0,0,0,0.1));border-radius:8px;box-shadow:0 8px 24px -8px rgba(0,0,0,0.2);opacity:0;transform:translateY(4px);transition:opacity .15s,transform .15s;pointer-events:none}.me-float-toolbar.me-visible{opacity:1;transform:translateY(0);pointer-events:auto}.me-float-toolbar .me-btn{width:28px;height:28px}`;
      document.head.appendChild(style);
    }

    if (!this._floatingEnabled) return;

    const ta = this.textarea;
    const show = () => {
      if (this._destroyed || this.config.readOnly || !this._floatingEnabled) return;
      const start = ta.selectionStart; const end = ta.selectionEnd;
      if (start === end) { this._hideFloatingToolbar(); return; }

      if (!this._floatingToolbar || !this._floatingToolbar.parentNode) this._buildFloatingToolbar();

      // Position the toolbar near the selection (toolbar is absolute inside editorPane)
      const taRect = ta.getBoundingClientRect();
      const paneRect = this.editorPane.getBoundingClientRect();
      const textBefore = ta.value.substring(0, start);
      const lines = textBefore.split('\n');
      const currentLine = lines.length - 1;
      const lineHeight = parseInt(getComputedStyle(ta).lineHeight, 10) || 22;
      const paddingTop = parseInt(getComputedStyle(ta).paddingTop, 10) || 16;
      const scrollOffset = ta.scrollTop;

      // Line top relative to viewport
      const lineViewportTop = taRect.top + paddingTop + currentLine * lineHeight - scrollOffset;
      // Convert to editorPane-local coordinates
      const lineLocalTop = lineViewportTop - paneRect.top;
      const toolbarHeight = 36;
      const gap = 4;

      // Try above first
      let top = lineLocalTop - toolbarHeight - gap;
      // If not enough room above, place below the selection
      if (top < gap) {
        top = lineLocalTop + lineHeight + gap;
      }

      // Horizontal: center near selection, in pane-local coords
      const selMidX = taRect.left + (ta.selectionEnd - ta.selectionStart) / 2 * (taRect.width / Math.max(1, ta.value.length || 1));
      let left = selMidX - paneRect.left - 80; // ~half toolbar width (5*28 + gaps)
      left = Math.max(4, Math.min(left, paneRect.width - 200));

      this._floatingToolbar!.style.top = top + 'px';
      this._floatingToolbar!.style.left = left + 'px';
      this._floatingToolbar!.classList.add('me-visible');
    };

    const hide = () => { this._hideFloatingToolbar(); };

    let lastSelStart = ta.selectionStart;
    let lastSelEnd = ta.selectionEnd;
    this._selectionTimer = setInterval(() => {
      if (this._destroyed || !document.body.contains(ta) || !this._floatingEnabled) return;
      const s = ta.selectionStart; const e = ta.selectionEnd;
      if (s !== lastSelStart || e !== lastSelEnd) {
        lastSelStart = s; lastSelEnd = e;
        const text = this._value.slice(s, e);
        this._emit('selectionChange', { start: s, end: e, text });
      }
    }, 500) as any;
    this._cleanups.push(() => { if (this._selectionTimer) { clearInterval(this._selectionTimer); this._selectionTimer = null; } });

    ta.addEventListener('mouseup', () => { if (this._floatingEnabled) setTimeout(show, 0); });
    ta.addEventListener('keyup', () => {
      if (!this._floatingEnabled) return;
      if (ta.selectionStart !== ta.selectionEnd) setTimeout(show, 0);
      else setTimeout(hide, 0);
      this._emit('cursorMove', this.getCursorPosition());
    });
    ta.addEventListener('blur', () => setTimeout(hide, 300));
    ta.addEventListener('click', () => { if (ta.selectionStart === ta.selectionEnd) setTimeout(hide, 0); });
  }

  toggleFloatingToolbar(): this {
    this._floatingEnabled = !this._floatingEnabled;
    if (this._floatingEnabled) {
      // Re-enable: restart the interval
      if (!this._selectionTimer) {
        const ta = this.textarea;
        this._selectionTimer = setInterval(() => {
          if (this._destroyed || !this._floatingEnabled) return;
          const s = ta.selectionStart; const e = ta.selectionEnd;
          if (s !== e) { /* will show via keyup/mouseup */ }
        }, 500) as any;
        this._cleanups.push(() => { if (this._selectionTimer) { clearInterval(this._selectionTimer); this._selectionTimer = null; } });
      }
    } else {
      // Disable: clear interval and hide toolbar
      if (this._selectionTimer) { clearInterval(this._selectionTimer); this._selectionTimer = null; }
      if (this._floatingToolbar) {
        if (this._floatingToolbar.parentNode) this._floatingToolbar.parentNode.removeChild(this._floatingToolbar);
        this._floatingToolbar = null;
      }
    }
    return this;
  }
  isFloatingToolbar(): boolean { return this._floatingEnabled; }

  _buildFloatingToolbar(): void {
    const bar = document.createElement('div');
    bar.className = 'me-float-toolbar';
    const actions = ['bold', 'italic', 'code', 'link', 'strikethrough'];
    actions.forEach((action) => {
      const btn = this._createBtn(action);
      btn.addEventListener('mousedown', (e) => {
        e.preventDefault(); e.stopPropagation();
        this.exec(action);
        // Keep selection after exec
        setTimeout(() => this.textarea.focus(), 0);
      });
      bar.appendChild(btn);
    });
    this.editorPane.appendChild(bar);
    this._floatingToolbar = bar;
  }

  _hideFloatingToolbar(): void {
    if (this._floatingToolbar) {
      this._floatingToolbar.classList.remove('me-visible');
    }
  }

  _bindToolbarKeyboard(): void {
    if (!this.toolbarEl) return;
    const onKeydown = (e: KeyboardEvent) => {
      const btns = [...this.toolbarEl.querySelectorAll('.me-btn:not(:disabled)')] as HTMLButtonElement[];
      if (!btns.length) return; const idx = btns.indexOf(document.activeElement as HTMLButtonElement); if (idx === -1) return;
      if (e.key === 'ArrowRight') { e.preventDefault(); btns[(idx + 1) % btns.length].focus(); }
      else if (e.key === 'ArrowLeft') { e.preventDefault(); btns[(idx - 1 + btns.length) % btns.length].focus(); }
      else if (e.key === 'Home') { e.preventDefault(); btns[0].focus(); }
      else if (e.key === 'End') { e.preventDefault(); btns[btns.length - 1].focus(); }
    };
    this.toolbarEl.addEventListener('keydown', onKeydown);
    this._cleanups.push(() => this.toolbarEl.removeEventListener('keydown', onKeydown));
  }

  _initAriaLive(): void { if (!this.el) return; const live = document.createElement('div'); live.className = 'me-sr-only'; live.setAttribute('aria-live', 'polite'); live.setAttribute('aria-atomic', 'true'); this.el.appendChild(live); this._ariaLive = live; }
  _announce(msg: string): void { if (this._ariaLive) { this._ariaLive.textContent = ''; requestAnimationFrame(() => { this._ariaLive.textContent = msg; }); } }

  _syncScroll(): void {
    if (this._syncing) return; this._syncing = true; const ta = this.textarea; if (!ta) { this._syncing = false; return; }
    const tmax = ta.scrollHeight - ta.clientHeight; if (tmax <= 0) { this._syncing = false; return; }
    const ratio = ta.scrollTop / tmax;
    if (this.gutter) { const gmax = this.gutter.scrollHeight - this.gutter.clientHeight; this.gutter.scrollTop = gmax > 0 ? ratio * gmax : ta.scrollTop; }
    if (this.config.syncScroll && this._mode === 'split' && this.previewPane) {
      const pmax = this.previewPane.scrollHeight - this.previewPane.clientHeight;
      if (pmax > 0) this.previewPane.scrollTop = ratio * pmax;
    }
    requestAnimationFrame(() => { this._syncing = false; });
  }

  _updateWordCount(): void {
    if (!this.config.wordCount || !this.statusEl) return;
    const text = this._value || '';
    const chars = text.length;
    const cnChars = (text.match(/[\u4e00-\u9fa5]/g) || []).length;
    const enWords = (text.replace(/[\u4e00-\u9fa5]/g, ' ').match(/[a-zA-Z0-9]+/g) || []).length;
    const words = cnChars + enWords; const lines = text ? text.split('\n').length : 0;
    const readingMin = Math.max(1, Math.ceil(words / 300));
    this.statusEl.textContent = [`${i18nT('characters')}: ${chars}`, `${i18nT('words')}: ${words}`, `${i18nT('lines')}: ${lines}`, `${i18nT('readingTime')}: ${readingMin} ${i18nT('minutes')}`].join('  ·  ');
  }

  getStats() { const text = this._value || ''; const cnChars = (text.match(/[\u4e00-\u9fa5]/g) || []).length; const enWords = (text.replace(/[\u4e00-\u9fa5]/g, ' ').match(/[a-zA-Z0-9]+/g) || []).length; return { characters: text.length, words: cnChars + enWords, chineseChars: cnChars, englishWords: enWords, lines: text ? text.split('\n').length : 0, readingTime: Math.max(1, Math.ceil((cnChars + enWords) / 300)), }; }

  getSelectedText(): string {
    if (!this.textarea) return '';
    return this._value.slice(this.textarea.selectionStart, this.textarea.selectionEnd);
  }

  getCursorPosition(): { line: number; column: number } {
    if (!this.textarea) return { line: 1, column: 0 };
    const pos = this.textarea.selectionStart;
    const before = this._value.substring(0, pos);
    const line = before.split('\n').length;
    const column = pos - before.lastIndexOf('\n') - 1;
    return { line, column: column < 0 ? 0 : column };
  }

  setCursorPosition(line: number, column: number = 0): this {
    if (!this.textarea) return this;
    const lines = this._value.split('\n');
    const clampedLine = Math.max(1, Math.min(line, lines.length));
    let pos = 0;
    for (let i = 0; i < clampedLine - 1; i++) pos += lines[i].length + 1;
    pos += Math.min(column, lines[clampedLine - 1]?.length || 0);
    this.textarea.focus();
    this.textarea.setSelectionRange(pos, pos);
    return this;
  }

  scrollToLine(line: number): this {
    if (!this.textarea) return this;
    const lines = this._value.split('\n');
    const clampedLine = Math.max(1, Math.min(line, lines.length));
    const lineHeight = 22; // approximate
    this.textarea.scrollTop = (clampedLine - 1) * lineHeight;
    if (this.gutter) this.gutter.scrollTop = this.textarea.scrollTop;
    return this;
  }

  selectLine(line: number): this {
    if (!this.textarea) return this;
    const lines = this._value.split('\n');
    const clampedLine = Math.max(1, Math.min(line, lines.length));
    let startPos = 0;
    for (let i = 0; i < clampedLine - 1; i++) startPos += lines[i].length + 1;
    const endPos = startPos + lines[clampedLine - 1].length;
    this.textarea.focus();
    this.textarea.setSelectionRange(startPos, endPos);
    return this;
  }

  selectAll(): this { if (this.textarea) { this.textarea.focus(); this.textarea.select(); } return this; }

  replaceAll(search: string, replace: string, caseSensitive: boolean = true): number {
    if (!search) return 0;
    const flags = caseSensitive ? 'g' : 'gi';
    const escaped = search.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
    const re = new RegExp(escaped, flags);
    const matches = this._value.match(re);
    if (!matches) return 0;
    this._value = this._value.replace(re, replace);
    this.textarea.value = this._value;
    this._pushHistory(); this._render(); this._updateWordCount(); this._emit('change', this._value);
    return matches.length;
  }

  replaceAllRegex(pattern: RegExp, replace: string): number {
    if (!pattern) return 0;
    const re = new RegExp(pattern, pattern.flags.includes('g') ? pattern.flags : pattern.flags + 'g');
    const matches = this._value.match(re);
    if (!matches) return 0;
    this._value = this._value.replace(re, replace);
    this.textarea.value = this._value;
    this._pushHistory(); this._render(); this._updateWordCount(); this._emit('change', this._value);
    return matches.length;
  }

  lineCount(): number {
    return this._value ? this._value.split('\n').length : 0;
  }

  getLine(line: number): string {
    const lines = this._value.split('\n');
    const idx = line - 1;
    if (idx < 0 || idx >= lines.length) return '';
    return lines[idx];
  }

  getValue(): string { return this._destroyed ? '' : this._value; }
  setValue(md: string, opts: { silent?: boolean } = {}): this {
    if (this._destroyed) return this;
    MarkdownEditor.trigger('beforeChange', this); this._emit('beforeChange', this._value, md);
    this._value = md || ''; this.textarea.value = this._value;
    if (!opts.silent) this._pushHistory(); this._render(); this._renderGutter(); this._updateWordCount(); this._updateOutline();
    if (this.gutter) this.gutter.scrollTop = 0; this.textarea.scrollTop = 0;
    if (!opts.silent) { this._emit('change', this._value); if (typeof this.config.onChange === 'function') { try { this.config.onChange(this._value, this); } catch (e) { console.error(e); } } }
    this._emit('afterChange', this._value); MarkdownEditor.trigger('afterChange', this);
    return this;
  }
  getHTML(): string { MarkdownEditor.trigger('beforeRender', this); this._emit('beforeRender', this); let html = this._renderFn(this._value, { highlight: this._highlightFn || undefined, locale: getCurrentLocale() }); if (typeof this.config.sanitize === 'function') { try { html = this.config.sanitize(html); } catch (e) { console.error(e); } } MarkdownEditor.trigger('afterRender', this); this._emit('afterRender', this); return html; }
  refresh(): this { this._lastRenderedValue = null; this._render(); return this; }

  copyAsMarkdown(): this {
    if (typeof navigator !== 'undefined' && navigator.clipboard) {
      navigator.clipboard.writeText(this._value).then(() => this._emit('copy', { type: 'markdown' })).catch(() => {});
    }
    return this;
  }

  copyAsHTML(): this {
    const html = this.getHTML();
    if (typeof navigator !== 'undefined' && navigator.clipboard) {
      const blob = new Blob([html], { type: 'text/html' });
      const item = new ClipboardItem({ 'text/html': blob, 'text/plain': new Blob([this._value], { type: 'text/plain' }) });
      navigator.clipboard.write([item]).then(() => this._emit('copy', { type: 'html' })).catch(() => {});
    }
    return this;
  }

  insert(text: string, opts: { replace?: boolean } = {}): this {
    const ta = this.textarea; const start = ta.selectionStart; const end = ta.selectionEnd;
    ta.value = ta.value.slice(0, start) + text + ta.value.slice(opts.replace ? end : start); ta.focus();
    ta.selectionStart = ta.selectionEnd = start + text.length;
    this._value = ta.value; this._pushHistory(); this._render(); this._updateWordCount(); this._emit('change', this._value); return this;
  }
  wrap(before: string, after: string): this { this._wrapSelection(before, after || before); return this; }
  focus(): this { if (this.textarea) this.textarea.focus(); return this; }
  blur(): this { if (this.textarea) this.textarea.blur(); return this; }
  enable(): this { if (this.textarea) this.textarea.disabled = false; if (this.el) this.el.classList.remove('me-disabled'); return this; }
  disable(): this { if (this.textarea) this.textarea.disabled = true; if (this.el) this.el.classList.add('me-disabled'); return this; }
  isDisabled(): boolean { return this.textarea ? this.textarea.disabled : false; }
  setReadOnly(readOnly: boolean): this { this.config.readOnly = !!readOnly; if (this.textarea) this.textarea.readOnly = !!readOnly; if (this.el) this.el.classList.toggle('me-readonly', !!readOnly); this._updateModeButtons(); return this; }
  isReadOnly(): boolean { return !!this.config.readOnly; }

  on(name: string, fn: (...args: any[]) => void): () => void { if (!this._listeners[name]) this._listeners[name] = []; this._listeners[name].push(fn); return () => this.off(name, fn); }
  off(name: string, fn: (...args: any[]) => void): this { const list = this._listeners[name]; if (list) this._listeners[name] = list.filter((f) => f !== fn); return this; }
  _emit(name: string, ...args: any[]): void { const list = this._listeners[name]; if (list) list.forEach((fn) => { try { fn(...args, this); } catch (e) { console.error(`MeEditor event "${name}" error:`, e); } }); }

  use(plugin: string | any, options: any = {}): this {
    let p = plugin; if (typeof plugin === 'string') { p = presetPlugins[plugin]; if (!p) { console.warn(`MeEditor: preset plugin "${plugin}" not found`); return this; } }
    if (!p || typeof p !== 'object') { console.warn('MeEditor: invalid plugin'); return this; }
    const merged = { ...p, ...options };
    if (typeof merged.install === 'function') {
      try { const result = merged.install(this, options); if (result && typeof result.then === 'function') { result.catch((e: any) => console.error(`MeEditor: async plugin "${merged.name}" error:`, e)); } }
      catch (e) { console.error(`MeEditor: plugin "${merged.name}" install error:`, e); }
    }
    this._plugins.push(merged); return this;
  }
  unuse(name: string): this { const idx = this._plugins.findIndex((p) => p.name === name); if (idx === -1) { console.warn(`MeEditor: plugin "${name}" not found`); return this; } const plugin = this._plugins[idx]; if (typeof plugin.destroy === 'function') { try { plugin.destroy(this); } catch (e) { console.error(`MeEditor: plugin "${name}" destroy error:`, e); } } this._plugins.splice(idx, 1); return this; }
  getPlugins(): any[] { return [...this._plugins]; }

  addToolbarButton(config: any): this {
    if (!config || !config.action) return this;
    const btn = document.createElement('button'); btn.type = 'button'; btn.className = `me-btn me-btn-custom-${config.action}`;
    btn.title = config.title || config.action; btn.setAttribute('aria-label', config.title || config.action);
    btn.innerHTML = config.icon || `<span>${escapeHTML(config.text || config.action)}</span>`;
    if (typeof config.onClick === 'function') { btn.addEventListener('click', (e) => { e.stopPropagation(); config.onClick(this); }); }
    else if (config.action) { btn.dataset.action = config.action; this._customActions = this._customActions || {}; this._customActions[config.action] = config.handler; }
    this.toolbarEl.insertBefore(btn, this.toolbarEl.querySelector('.me-toolbar-group') || null); return this;
  }

  registerShortcut(combo: string, handler: Function | string, description: string = ''): this {
    if (!combo) return this;
    const parts = combo.toLowerCase().split('+'); const key = parts.pop()!;
    const ctrl = parts.includes('ctrl') || parts.includes('cmd'); const shift = parts.includes('shift'); const alt = parts.includes('alt'); const meta = parts.includes('meta');
    this._shortcuts.push({ combo, key, ctrl, shift, alt, meta, handler, description }); return this;
  }
  unregisterShortcut(combo: string): this { this._shortcuts = this._shortcuts.filter((s) => s.combo !== combo); return this; }
  getShortcuts(): any[] { return [...this._shortcuts]; }

  configureToolbar(tools: ToolbarItem[]): this { if (!this.toolbarEl) return this; this.config.toolbar = tools; this.toolbarEl.innerHTML = ''; this._buildToolbar(); return this; }
  removeToolbarButton(action: string): this { if (!this.toolbarEl) return this; const btn = this.toolbarEl.querySelector(`.me-btn[data-action="${action}"], .me-btn[data-mode="${action}"]`); if (btn) btn.remove(); return this; }
  registerContextMenu(items: any[] = []): this { this._contextMenuItems = items; return this; }

  _bindContextMenu(): void {
    if (!this.el) return;
    const onContextMenu = (e: MouseEvent) => {
      const existing = document.querySelector('.me-context-menu');
      if (existing) existing.remove();
      this._showContextMenu(e);
    };
    this.el.addEventListener('contextmenu', onContextMenu);
    this._cleanups.push(() => this.el.removeEventListener('contextmenu', onContextMenu));
  }

  _showContextMenu(e: MouseEvent): void {
    e.preventDefault();
    const ta = this.textarea;
    const hasSelection = ta && ta.selectionStart !== ta.selectionEnd;
    const defaultItems: Array<{ label?: string; action?: string; shortcut?: string; sep?: boolean; disabled?: boolean; onClick?: () => void }> = [
      { label: i18nT('undo') || 'Undo', action: 'undo', shortcut: 'Ctrl+Z', disabled: !this.canUndo() },
      { label: i18nT('redo') || 'Redo', action: 'redo', shortcut: 'Ctrl+Y', disabled: !this.canRedo() },
      { sep: true },
      { label: i18nT('cut') || 'Cut', action: 'cut', shortcut: 'Ctrl+X', disabled: !hasSelection },
      { label: i18nT('copy') || 'Copy', action: 'copy', shortcut: 'Ctrl+C', disabled: !hasSelection },
      { label: i18nT('paste') || 'Paste', action: 'paste', shortcut: 'Ctrl+V', disabled: !!this.config.readOnly },
      { label: i18nT('selectAll') || 'Select All', action: 'selectAll', shortcut: 'Ctrl+A' },
    ];
    const items = [...defaultItems];
    if (this._contextMenuItems.length) {
      items.push({ sep: true });
      this._contextMenuItems.forEach((item) => items.push(item));
    }
    const menu = document.createElement('div');
    menu.className = 'me-context-menu';
    menu.style.left = e.clientX + 'px';
    menu.style.top = e.clientY + 'px';
    // Adjust if off-screen
    requestAnimationFrame(() => {
      const rect = menu.getBoundingClientRect();
      if (rect.right > window.innerWidth) menu.style.left = (e.clientX - rect.width) + 'px';
      if (rect.bottom > window.innerHeight) menu.style.top = (e.clientY - rect.height) + 'px';
    });
    items.forEach((item) => {
      if ((item as any).sep) { const sep = document.createElement('div'); sep.className = 'me-context-menu-sep'; menu.appendChild(sep); return; }
      const el = document.createElement('div');
      el.className = 'me-context-menu-item';
      if (item.disabled) el.classList.add('me-disabled');
      el.innerHTML = `<span>${item.label}</span>${item.shortcut ? `<span class="me-context-menu-shortcut">${item.shortcut}</span>` : ''}`;
      el.addEventListener('click', (ev) => {
        ev.stopPropagation();
        if (item.disabled) return;
        if (item.onClick) { item.onClick(); }
        else if (item.action) this._execContextAction(item.action);
        this._hideContextMenu();
      });
      menu.appendChild(el);
    });
    document.body.appendChild(menu);
    const close = (ev: Event) => {
      if (!menu.contains(ev.target as Node)) { this._hideContextMenu(); }
    };
    document.addEventListener('click', close, { once: true });
    document.addEventListener('keydown', (ev) => { if (ev.key === 'Escape') this._hideContextMenu(); }, { once: true });
  }

  _hideContextMenu(): void {
    const menu = document.querySelector('.me-context-menu');
    if (menu) menu.remove();
  }

  _execContextAction(action: string): void {
    const ta = this.textarea;
    if (!ta) return;
    switch (action) {
      case 'undo': this.undo(); break;
      case 'redo': this.redo(); break;
      case 'cut': document.execCommand('cut'); break;
      case 'copy': document.execCommand('copy'); break;
      case 'paste': document.execCommand('paste'); break;
      case 'selectAll': ta.focus(); ta.select(); break;
      default: this.exec(action); break;
    }
  }

  toast(message: string, opts: { type?: string; duration?: number; animation?: string } = {}): this {
    if (!this.el || typeof document === 'undefined') return this;
    const { type = 'info', duration = 3000, animation = 'fade' } = opts;
    const toast = document.createElement('div'); toast.className = `me-toast me-toast-${type} me-toast-${animation}`;
    toast.innerHTML = `<span class="me-toast-icon">${TOAST_ICONS[type] || ''}</span><span class="me-toast-msg">${escapeHTML(String(message))}</span>`;
    this.el.appendChild(toast); requestAnimationFrame(() => { toast.classList.add('me-toast-enter'); });
    const remove = () => { toast.classList.remove('me-toast-enter'); toast.classList.add('me-toast-leave'); setTimeout(() => { if (toast.parentNode) toast.parentNode.removeChild(toast); }, 300); };
    if (duration > 0) setTimeout(remove, duration); toast.addEventListener('click', remove); return this;
  }

  setLocale(locale: string): this { if (this._i18nCtx) this._i18nCtx.set(locale); return this; }
  getLocale(): string { if (this._i18nCtx) return this._i18nCtx.get(); return getCurrentLocale(); }
  t(key: string, params?: Record<string, any>): string { if (this._i18nCtx) return this._i18nCtx.t(key, params); return i18nT(key, params); }

  setTheme(theme: ThemeName): this { if (!theme) return this; this.config.theme = theme; if (this._themeCtx) this._themeCtx.set(theme); return this; }
  getTheme(): string { if (this._themeCtx) return this._themeCtx.get(); return this.config.theme || 'auto'; }
  getThemeContext(): any { return this._themeCtx || null; }

  getStatus() { return { id: this.id, mode: this._mode, theme: this.getTheme(), locale: getCurrentLocale(), fullscreen: this._fullscreen, readOnly: this.config.readOnly || false, disabled: this.textarea ? this.textarea.disabled : false, destroyed: this._destroyed, plugins: this._plugins.map((p) => p.name || 'custom'), }; }

  destroy(): void {
    if (this._destroyed) return;
    MarkdownEditor.trigger('beforeDestroy', this);
    if (this._renderRaf) cancelAnimationFrame(this._renderRaf);
    if (this._historyTimer) clearTimeout(this._historyTimer);
    if (this._outlineTimer) clearTimeout(this._outlineTimer);
    if (this._selectionTimer) { clearInterval(this._selectionTimer); this._selectionTimer = null; }
    this._cleanups.forEach((fn) => { try { fn(); } catch (_) {} }); this._cleanups = [];
    this._shortcuts = []; this._contextMenuItems = []; this._customActions = {};
    if (this._floatingToolbar && this._floatingToolbar.parentNode) this._floatingToolbar.parentNode.removeChild(this._floatingToolbar);
    this._floatingToolbar = null;
    if (this.el) this.el.querySelectorAll('.me-toast').forEach((t) => t.remove());
    this._plugins.forEach((p) => { if (typeof p.destroy === 'function') { try { p.destroy(this); } catch (_) {} } }); this._plugins = [];
    if (this.el && this.el.parentNode) this.el.parentNode.removeChild(this.el);
    this.el = null!; this.textarea = null!; this.previewEl = null!;
    this._destroyed = true;
    if (typeof this.config.onDestroy === 'function') { try { this.config.onDestroy(this); } catch (e) { console.error(e); } }
    this._emit('destroy'); this._listeners = {};
    MarkdownEditor.trigger('afterDestroy', this);
  }
  isDestroyed(): boolean { return this._destroyed; }
}

export { MarkdownEditor as Editor };
export default MarkdownEditor;