/**
 * MetonaEditor Plugins — plugin system v2
 * @module plugins
 * @version 0.2.0
 */

import { t } from './i18n';

// ============ Editor contract ============

/** The editor surface plugins may rely on. Keeps plugin code type-checked
 *  without importing the full MarkdownEditor class (avoids circular imports). */
export interface EditorLike {
  id?: string;
  value?: string;
  _value?: string;
  el: HTMLElement;
  textarea: HTMLTextAreaElement;
  config?: Record<string, any>;
  on?: (name: string, fn: (...args: any[]) => void) => (() => void) | void;
  off?: (name: string, fn: (...args: any[]) => void) => unknown;
  _emit?: (name: string, ...args: any[]) => void;
  _pushHistory?: () => void;
  _render?: () => void;
  _updateWordCount?: () => void;
  insert?: (text: string, opts?: { replace?: boolean }) => unknown;
  setValue?: (value: string, opts?: { silent?: boolean }) => unknown;
  getValue?: () => string;
  getHTML?: () => string;
  focus?: () => unknown;
  toast?: (message: string, opts?: { type?: string; duration?: number; animation?: string }) => unknown;
}

// ============ Plugin state keys (Symbols avoid property-name collisions) ============

const K_AUTOSAVE = Symbol('me-plugin:autoSave');
const K_SEARCH = Symbol('me-plugin:searchReplace');
const K_IMAGE_PASTE = Symbol('me-plugin:imagePaste');
const K_SHORTCUT = Symbol('me-plugin:shortcutHelp');
const K_FILESYSTEM = Symbol('me-plugin:fileSystem');

const pluginState = <T>(editor: EditorLike, key: symbol): T | undefined => (editor as any)[key] as T | undefined;
const setPluginState = <T>(editor: EditorLike, key: symbol, state: T): void => { (editor as any)[key] = state; };
const deletePluginState = (editor: EditorLike, key: symbol): void => { delete (editor as any)[key]; };

export interface Plugin {
  name: string;
  version?: string;
  description?: string;
  depends?: string[];
  priority?: number;
  install?: (editor: EditorLike, options?: any) => void | Promise<void>;
  destroy?: (editor: EditorLike) => void;
  [key: string]: any;
}

export interface PluginSchema {
  [key: string]: {
    type?: string;
    required?: boolean;
    default?: any;
    enum?: any[];
    validator?: (val: any) => boolean | string;
  };
}

// ============ Plugin Manager ============

export class PluginManager {
  plugins = new Map<string, Plugin & { enabled: boolean }>();

  register(name: string, plugin: Plugin): this {
    if (this.plugins.has(name)) { console.warn(`MeEditor: plugin "${name}" already registered`); return this; }
    if (!plugin || typeof plugin !== 'object' || (!plugin.name && !name)) { console.error(`MeEditor: invalid plugin "${name}"`); return this; }
    this.plugins.set(name, {
      version: plugin.version || '0.0.0', description: plugin.description || '',
      depends: plugin.depends || [], priority: plugin.priority || 0,
      ...plugin, name, enabled: true,
    });
    return this;
  }

  unregister(name: string): this { this.plugins.delete(name); return this; }
  get(name: string): Plugin | null { return this.plugins.get(name) || null; }
  has(name: string): boolean { return this.plugins.has(name); }
  getAll(): Plugin[] { return Array.from(this.plugins.values()); }
  getNames(): string[] { return Array.from(this.plugins.keys()); }
  enable(name: string): this { const p = this.plugins.get(name); if (p) p.enabled = true; return this; }
  disable(name: string): this { const p = this.plugins.get(name); if (p) p.enabled = false; return this; }
  isEnabled(name: string): boolean { const p = this.plugins.get(name); return p ? p.enabled : false; }
  destroy(): void { this.plugins.clear(); }
}

const defaultPluginManager = new PluginManager();

// ============ Topological sort ============

export const topologicalSort = (plugins: Plugin[]): Plugin[] => {
  const map = new Map<string, Plugin>();
  plugins.forEach((p) => map.set(p.name, p));
  const inDegree = new Map<string, number>();
  const adj = new Map<string, string[]>();
  plugins.forEach((p) => { inDegree.set(p.name, 0); adj.set(p.name, []); });
  plugins.forEach((p) => {
    (p.depends || []).forEach((dep) => {
      if (map.has(dep)) { adj.get(dep)!.push(p.name); inDegree.set(p.name, (inDegree.get(p.name) || 0) + 1); }
      else { console.warn(`MeEditor: plugin "${p.name}" depends on unknown "${dep}"`); }
    });
  });
  const queue: string[] = [];
  inDegree.forEach((deg, name) => { if (deg === 0) queue.push(name); });
  const sorted: Plugin[] = [];
  while (queue.length) {
    queue.sort((a, b) => ((map.get(b)!.priority || 0) - (map.get(a)!.priority || 0)));
    const name = queue.shift()!;
    sorted.push(map.get(name)!);
    (adj.get(name) || []).forEach((n) => { inDegree.set(n, inDegree.get(n)! - 1); if (inDegree.get(n) === 0) queue.push(n); });
  }
  if (sorted.length !== plugins.length) { console.warn('MeEditor: circular dependency detected, falling back to original order'); return plugins; }
  return sorted;
};

// ============ Config validation ============

export const validateConfig = (schema: PluginSchema = {}, config: Record<string, any> = {}): { valid: boolean; errors: string[]; patched: Record<string, any> } => {
  const errors: string[] = [];
  const patched = { ...config };
  for (const [key, rule] of Object.entries(schema)) {
    const val = config[key];
    if (rule.required && (val === undefined || val === null)) { errors.push(`"${key}" is required`); continue; }
    if (val === undefined && rule.default !== undefined) { patched[key] = rule.default; continue; }
    if (val !== undefined && rule.type) {
      const actual = Array.isArray(val) ? 'array' : typeof val;
      if (actual !== rule.type) errors.push(`"${key}" expected ${rule.type}, got ${actual}`);
    }
    if (val !== undefined && rule.enum && !rule.enum.includes(val)) errors.push(`"${key}" must be one of [${rule.enum.join(', ')}]`);
    if (val !== undefined && typeof rule.validator === 'function') {
      try { const r = rule.validator(val); if (r !== true) errors.push(`"${key}": ${r}`); } catch (e: any) { errors.push(`"${key}": ${e.message}`); }
    }
  }
  return { valid: errors.length === 0, errors, patched };
};

// ============ Preset plugins ============

const escapeAttr = (s: any): string => String(s == null ? '' : s).replace(/&/g, '&amp;').replace(/"/g, '&quot;').replace(/</g, '&lt;').replace(/>/g, '&gt;');

const autoSavePlugin: Plugin = {
  name: 'autoSave', version: '0.1.1', description: 'Auto-save to localStorage', priority: 100,
  install(editor, options?: Record<string, any>) {
    if (!editor || typeof editor.getValue !== 'function') return;
    const opts = options || (this as any);
    const key: string = opts.key || ('me-draft-' + (editor.id || ''));
    const delay: number = opts.delay || 1000;
    const state = { _timer: null as ReturnType<typeof setTimeout> | null };
    const save = () => {
      if (state._timer) { clearTimeout(state._timer); state._timer = null; }
      try { localStorage.setItem(key, editor.getValue!()); if (typeof editor._emit === 'function') editor._emit('autosave', { key, value: editor.getValue!() }); }
      catch (e) { console.warn('MeEditor autoSave:', e); }
    };
    const _onInput = () => { if (state._timer) clearTimeout(state._timer); state._timer = setTimeout(save, delay); };
    const _onBlur = save;
    const _onSave = save;
    if (typeof editor.on === 'function') {
      editor.on('change', _onInput);
      editor.on('blur', _onBlur);
      editor.on('save', _onSave);
    }
    (editor as any).restoreDraft = () => { try { const v = localStorage.getItem(key); if (v != null && typeof editor.setValue === 'function') editor.setValue(v); return v; } catch (_) { return null; } };
    (editor as any).clearDraft = () => { try { localStorage.removeItem(key); } catch (_) {} return editor; };
    (editor as any).getDraftKey = () => key;
    setPluginState(editor, K_AUTOSAVE, { state, _onInput, _onBlur, _onSave, save });
  },
  destroy(editor) {
    const cleanup = pluginState<any>(editor, K_AUTOSAVE);
    if (cleanup) {
      if (cleanup.state._timer) { clearTimeout(cleanup.state._timer); cleanup.state._timer = null; }
      if (editor && typeof editor.off === 'function') {
        if (cleanup._onInput) editor.off('change', cleanup._onInput);
        if (cleanup._onBlur) editor.off('blur', cleanup._onBlur);
        if (cleanup._onSave) editor.off('save', cleanup._onSave);
      }
      deletePluginState(editor, K_AUTOSAVE);
    }
  },
};

const exportToolPlugin: Plugin = {
  name: 'exportTool', version: '0.1.0', description: 'Export Markdown/HTML', priority: 50,
  install(editor) {
    if (!editor || typeof editor.getValue !== 'function') return;
    const download = (filename: string, content: string, mime: string) => {
      if (typeof document === 'undefined') return;
      const blob = new Blob([content], { type: mime + ';charset=utf-8' });
      const url = URL.createObjectURL(blob);
      const a = document.createElement('a'); a.href = url; a.download = filename;
      document.body.appendChild(a); a.click(); document.body.removeChild(a);
      setTimeout(() => URL.revokeObjectURL(url), 0);
    };
    const stamp = () => { const d = new Date(); const pad = (n: number) => String(n).padStart(2, '0'); return `${d.getFullYear()}${pad(d.getMonth()+1)}${pad(d.getDate())}-${pad(d.getHours())}${pad(d.getMinutes())}`; };
    const e = editor as any;
    const buildHTML = (opts: any = {}): string => {
      const title = opts.title || 'Document';
      const css = opts.css || '';
      const body = typeof editor.getHTML === 'function' ? editor.getHTML() : '';
      // Build minimal embedded CSS for the exported HTML
      const embedCSS = opts.embedCSS !== false ? `<style>
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC",sans-serif;font-size:14px;line-height:1.6;color:#1f2937;max-width:860px;margin:0 auto;padding:20px}
h1,h2,h3,h4,h5,h6{margin:1.4em 0 .6em;font-weight:650;line-height:1.3}
h1{font-size:1.9em;padding-bottom:.3em;border-bottom:1px solid #e5e7eb}
h2{font-size:1.55em;padding-bottom:.3em;border-bottom:1px solid #e5e7eb}
h3{font-size:1.3em}h4{font-size:1.12em}h5{font-size:1em}h6{font-size:.9em;color:#6b7280}
p{margin:.7em 0}a{color:#3b82f6;text-decoration:none}a:hover{text-decoration:underline}
strong{font-weight:650}em{font-style:italic}del{text-decoration:line-through;opacity:.75}
ul,ol{margin:.6em 0;padding-left:1.6em}li{margin:.25em 0}
li.me-task-item{list-style:none;margin-left:-1.4em}
li.me-task-item input{margin-right:.5em;vertical-align:middle}
blockquote{margin:.8em 0;padding:.4em 1em;border-left:3px solid #3b82f6;background:#f3f4f6;border-radius:0 6px 6px 0}
hr{border:0;height:1px;background:#e5e7eb;margin:1.6em 0}
code{font-family:"SF Mono",Consolas,monospace;font-size:.88em;padding:.15em .4em;background:#f3f4f6;border-radius:4px}
pre{margin:.9em 0;padding:14px 16px;background:#f3f4f6;border-radius:8px;overflow-x:auto;border:1px solid #e5e7eb}
pre code{padding:0;background:transparent;font-size:.9em;line-height:1.6;border-radius:0}
img{max-width:100%;height:auto;border-radius:6px}
table{border-collapse:collapse;width:100%;font-size:.93em;display:block;overflow-x:auto}
th,td{border:1px solid #e5e7eb;padding:7px 12px;text-align:left}
th{background:#f3f4f6;font-weight:600}
tr:nth-child(even) td{background:#f9fafb}
mark{background:rgba(250,204,21,.3);color:inherit;padding:.1em .2em;border-radius:3px}
sup{font-size:.75em}sub{font-size:.75em}
.me-math-block{display:block;margin:1.2em 0;padding:12px 16px;background:#f3f4f6;border-radius:8px;overflow-x:auto;font-family:monospace;text-align:center}
.me-math-inline{font-family:monospace}
dl{margin:.8em 0}dt{font-weight:650;margin:.6em 0 .2em}dd{margin:0 0 .3em 1.6em;color:#4b5563}
.me-footnote-ref a{font-size:.75em;vertical-align:super;text-decoration:none;color:#3b82f6}
.me-footnotes{margin-top:2em;border-top:1px solid #e5e7eb;padding-top:.8em;font-size:.9em;color:#6b7280}
.me-footnotes hr{display:none}
.me-footnotes ol{padding-left:1.2em}
.me-footnote-item{margin:.3em 0}
.me-footnote-backref{text-decoration:none;color:#3b82f6;margin-right:.4em}
.me-table-wrap{overflow-x:auto;margin:.9em 0}
</style>` : '';
      return `<!DOCTYPE html>\n<html lang="${opts.lang||'zh-CN'}">\n<head>\n<meta charset="utf-8"/>\n<meta name="viewport" content="width=device-width, initial-scale=1"/>\n<title>${title}</title>\n${css?`<style>${css}</style>`:''}${embedCSS}\n</head>\n<body>\n${body}\n</body>\n</html>`;
    };
    e.exportMarkdown = (filename?: string) => { download(filename || `metona-${stamp()}.md`, editor.getValue!(), 'text/markdown'); return editor; };
    e.exportHTML = (filename?: string, opts: any = {}) => {
      download(filename || `metona-${stamp()}.html`, buildHTML(opts), 'text/html');
      return editor;
    };
    e.exportPDF = (opts: any = {}) => {
      if (typeof document === 'undefined' || !editor.el) return editor;
      const iframe = document.createElement('iframe');
      iframe.style.position = 'fixed'; iframe.style.right = '0'; iframe.style.bottom = '0';
      iframe.style.width = '0'; iframe.style.height = '0'; iframe.style.border = '0';
      document.body.appendChild(iframe);
      const doc = iframe.contentDocument;
      if (!doc) { iframe.remove(); return editor; }
      doc.open(); doc.write(buildHTML(opts)); doc.close();
      setTimeout(() => {
        try { iframe.contentWindow?.print(); } catch (_) {}
        setTimeout(() => { if (iframe.parentNode) iframe.parentNode.removeChild(iframe); }, 1000);
      }, 50);
      return editor;
    };
  },
  destroy() {},
};

const searchReplacePlugin: Plugin = {
  name: 'searchReplace', version: '0.2.1', description: 'Search & Replace (Ctrl+F/H)', priority: 80,
  install(editor) {
    if (!editor || !editor.textarea || typeof document === 'undefined') return;
    // Inject style once globally
    if (!document.getElementById('me-search-style')) {
      const style = document.createElement('style'); style.id = 'me-search-style';
      style.textContent = `.me-search{position:absolute;top:10px;right:16px;z-index:20;display:flex;flex-direction:column;gap:8px;padding:12px;background:var(--md-bg,#1c2029);border:1px solid var(--md-border,rgba(255,255,255,0.12));border-radius:10px;box-shadow:0 12px 40px -8px rgba(0,0,0,0.4),0 0 0 1px rgba(255,255,255,0.05);font-size:13px;min-width:300px;backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);animation:meSearchIn .18s ease-out}@keyframes meSearchIn{from{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:translateY(0)}}.me-search-row{display:flex;gap:6px;align-items:center}.me-search-row+.me-search-row{margin-top:2px}.me-search input{flex:1;min-width:0;padding:7px 10px;border:1px solid var(--md-border,rgba(255,255,255,0.12));border-radius:6px;background:var(--md-textarea-bg,rgba(255,255,255,0.04));color:var(--md-text,#e6e8eb);font-size:13px;outline:none;transition:border-color .15s,box-shadow .15s}.me-search input::placeholder{color:var(--md-muted,#6b7280)}.me-search input:focus{border-color:var(--md-accent,#3b82f6);box-shadow:0 0 0 3px rgba(59,130,246,0.15)}.me-search .me-search-btn{display:inline-flex;align-items:center;justify-content:center;width:28px;height:28px;padding:0;border:1px solid rgba(255,255,255,0.08);border-radius:5px;background:rgba(255,255,255,0.04);color:var(--md-muted,#9ca3af);cursor:pointer;transition:all .12s;flex-shrink:0}.me-search .me-search-btn:hover{background:var(--md-accent,#3b82f6);color:#fff;border-color:var(--md-accent,#3b82f6)}.me-search .me-search-btn:active{transform:scale(.92)}.me-search .me-search-btn.me-active{background:var(--md-accent,#3b82f6);color:#fff;border-color:var(--md-accent,#3b82f6)}.me-search .me-search-btn svg{width:14px;height:14px}.me-search .me-search-count{color:var(--md-muted,#9ca3af);font-size:11.5px;min-width:28px;text-align:center;font-variant-numeric:tabular-nums}.me-search .me-search-close{margin-left:2px;font-size:16px;line-height:1}.me-search .me-search-close:hover{background:#ef4444;border-color:#ef4444}.me-search .me-search-replace-one,.me-search .me-search-replace-all{width:auto;padding:5px 10px;font-size:12px;font-weight:500;letter-spacing:.01em}.me-search .me-search-replace-all{background:rgba(59,130,246,0.12);border-color:rgba(59,130,246,0.3);color:var(--md-accent,#60a5fa)}.me-search .me-search-replace-all:hover{background:var(--md-accent,#3b82f6);color:#fff}`;
      document.head.appendChild(style);
    }

    const state = {
      _panel: null as HTMLElement | null,
      _regexMode: false,
      _matchCase: true,
      _wholeWord: false,
      _cleanup: null as (() => void) | null,
    };

    const WORD_CLASS = '[\\w\\u4e00-\\u9fff]';
    const escapeRegExpText = (s: string): string => s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');

    const buildPattern = (q: string): RegExp | null => {
      if (!q) return null;
      let src = state._regexMode ? q : escapeRegExpText(q);
      if (state._wholeWord) src = `(?<!${WORD_CLASS})(?:${src})(?!${WORD_CLASS})`;
      const flags = 'g' + (state._matchCase ? '' : 'i');
      try { return new RegExp(src, flags); } catch (_) { return null; }
    };

    const hasWordBoundary = (text: string, idx: number, len: number): boolean => {
      const isWord = (c: string | undefined) => !!c && /[\w\u4e00-\u9fff]/.test(c);
      return !isWord(text[idx - 1]) && !isWord(text[idx + len]);
    };

    const _updateReplaceVisible = () => {
      if (!state._panel) return;
      const show = state._panel.dataset.replace === '1';
      const row = state._panel.querySelector('.me-search-replace-row') as HTMLElement;
      if (row) row.style.display = show ? 'flex' : 'none';
    };

    const _close = () => {
      if (state._cleanup) { state._cleanup(); state._cleanup = null; }
      state._panel = null;
      if (editor && editor.textarea) editor.textarea.focus();
    };

    const _open = (showReplace?: boolean) => {
      if (state._panel) {
        state._panel.dataset.replace = showReplace ? '1' : '0';
        _updateReplaceVisible();
        const inp = state._panel.querySelector('.me-search-find') as HTMLInputElement;
        if (inp) { inp.focus(); inp.select(); }
        return;
      }
      const selected = editor.textarea.value.substring(editor.textarea.selectionStart, editor.textarea.selectionEnd);
      const panel = document.createElement('div'); panel.className = 'me-search';
      panel.dataset.replace = showReplace ? '1' : '0';
      panel.innerHTML = `<div class="me-search-row"><input type="text" class="me-search-find" placeholder="${t('searchPlaceholder')||'Find'}" value="${escapeAttr(selected)}"/><button class="me-search-btn me-search-prev" title="${t('findPrev')||'Previous'}"><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><polyline points="18 15 12 9 6 15"/></svg></button><button class="me-search-btn me-search-next" title="${t('findNext')||'Next'}"><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><polyline points="6 9 12 15 18 9"/></svg></button><span class="me-search-count"></span><button class="me-search-btn me-search-case me-active" title="${t('matchCase')||'Match Case'}">Aa</button><button class="me-search-btn me-search-word" title="${t('wholeWord')||'Whole Word'}">ab</button><button class="me-search-btn me-search-regex" title="${t('regex')||'Regex'}">.*</button><button class="me-search-btn me-search-close" title="${t('close')||'Close'}"><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/></svg></button></div><div class="me-search-row me-search-replace-row"><input type="text" class="me-search-replace" placeholder="${t('replacePlaceholder')||'Replace'}"/><button class="me-search-btn me-search-replace-one">${t('replace')||'Replace'}</button><button class="me-search-btn me-search-replace-all">${t('replaceAll')||'All'}</button></div>`;
      editor.el.appendChild(panel); state._panel = panel;
      _updateReplaceVisible();
      state._regexMode = false; state._matchCase = true; state._wholeWord = false;
      const fi = panel.querySelector('.me-search-find') as HTMLInputElement;
      const ri = panel.querySelector('.me-search-replace') as HTMLInputElement;
      const ce = panel.querySelector('.me-search-count') as HTMLElement;
      const regexBtn = panel.querySelector('.me-search-regex') as HTMLButtonElement;
      const caseBtn = panel.querySelector('.me-search-case') as HTMLButtonElement;
      const wordBtn = panel.querySelector('.me-search-word') as HTMLButtonElement;
      regexBtn.addEventListener('click', () => {
        state._regexMode = !state._regexMode;
        regexBtn.classList.toggle('me-active', state._regexMode);
        lastIdxs = findAll();
      });
      caseBtn.addEventListener('click', () => {
        state._matchCase = !state._matchCase;
        caseBtn.classList.toggle('me-active', state._matchCase);
        lastIdxs = findAll();
      });
      wordBtn.addEventListener('click', () => {
        state._wholeWord = !state._wholeWord;
        wordBtn.classList.toggle('me-active', state._wholeWord);
        lastIdxs = findAll();
      });
      const findAll = () => {
        const q = fi.value; if (!q) { ce.textContent = ''; return []; }
        const idxs: number[] = [];
        const re = buildPattern(q);
        if (!re) { ce.textContent = 'err'; return []; }
        let m: RegExpExecArray | null;
        while ((m = re.exec(editor.textarea.value)) !== null) {
          idxs.push(m.index);
          if (m[0].length === 0) re.lastIndex++;
        }
        ce.textContent = idxs.length ? `${idxs.length}` : '0';
        return idxs;
      };
      let lastIdxs: number[] = [];
      const selectAt = (idx: number, len?: number) => {
        editor.textarea.focus();
        editor.textarea.setSelectionRange(idx, idx + (len || fi.value.length));
      };
      const matchLenAt = (idx: number): number => {
        const text = editor.textarea.value;
        const q = fi.value; if (!q) return 0;
        if (!state._regexMode) {
          if (state._matchCase && text.slice(idx, idx + q.length) !== q) return 0;
          if (!state._matchCase && text.slice(idx, idx + q.length).toLowerCase() !== q.toLowerCase()) return 0;
          if (state._wholeWord && !hasWordBoundary(text, idx, q.length)) return 0;
          return q.length;
        }
        const re = buildPattern(q); if (!re) return 0;
        re.lastIndex = idx;
        const m = re.exec(text);
        return m && m.index === idx ? m[0].length : 0;
      };
      const findNext = () => {
        lastIdxs = findAll(); if (!lastIdxs.length) return;
        const cur = editor.textarea.selectionEnd;
        let next = lastIdxs.find((i: number) => i >= cur);
        if (next == null) next = lastIdxs[0];
        selectAt(next, matchLenAt(next) || fi.value.length);
      };
      const findPrev = () => {
        lastIdxs = findAll(); if (!lastIdxs.length) return;
        const cur = editor.textarea.selectionStart;
        let prev = -1;
        for (let i = lastIdxs.length-1; i>=0; i--) { if (lastIdxs[i] < cur) { prev = lastIdxs[i]; break; } }
        if (prev === -1) prev = lastIdxs[lastIdxs.length-1];
        selectAt(prev, matchLenAt(prev) || fi.value.length);
      };
      const replaceOne = () => {
        const q = fi.value, r = ri.value; if (!q) return;
        const ta = editor.textarea; const s = ta.selectionStart, e = ta.selectionEnd;
        const matchText = ta.value.substring(s, e);
        let matched = false;
        if (state._regexMode) {
          const re = buildPattern(q);
          if (re) { re.lastIndex = s; const m = re.exec(ta.value); matched = !!(m && m.index === s); }
        } else {
          const sameCase = state._matchCase ? matchText === q : matchText.toLowerCase() === q.toLowerCase();
          matched = sameCase && (!state._wholeWord || hasWordBoundary(ta.value, s, q.length));
        }
        if (matched) {
          ta.value = ta.value.substring(0, s) + r + ta.value.substring(e);
          ta.setSelectionRange(s, s + r.length);
        }
        editor._value = ta.value; if (typeof editor._pushHistory === 'function') editor._pushHistory();
        if (typeof editor._render === 'function') editor._render();
        if (typeof editor._emit === 'function') editor._emit('change', editor._value);
        findNext();
      };
      const replaceAll = () => {
        const q = fi.value, r = ri.value; if (!q) return;
        const ta = editor.textarea;
        const re = buildPattern(q);
        if (!re) return;
        ta.value = ta.value.replace(re, () => r);
        ta.setSelectionRange(0,0); editor._value = ta.value;
        if (typeof editor._pushHistory === 'function') editor._pushHistory();
        if (typeof editor._render === 'function') editor._render();
        if (typeof editor._emit === 'function') editor._emit('change', editor._value);
        findAll();
      };
      fi.addEventListener('input', () => { lastIdxs = findAll(); });
      fi.addEventListener('keydown', (e: KeyboardEvent) => { if (e.key === 'Enter') { e.preventDefault(); e.shiftKey ? findPrev() : findNext(); } if (e.key === 'Escape') { e.preventDefault(); _close(); } });
      ri.addEventListener('keydown', (e: KeyboardEvent) => { if (e.key === 'Enter') { e.preventDefault(); replaceOne(); } if (e.key === 'Escape') { e.preventDefault(); _close(); } });
      panel.querySelector('.me-search-next')!.addEventListener('click', findNext);
      panel.querySelector('.me-search-prev')!.addEventListener('click', findPrev);
      panel.querySelector('.me-search-close')!.addEventListener('click', () => _close());
      panel.querySelector('.me-search-replace-one')!.addEventListener('click', replaceOne);
      panel.querySelector('.me-search-replace-all')!.addEventListener('click', replaceAll);
      fi.focus(); fi.select();
      state._cleanup = () => { if (panel.parentNode) panel.parentNode.removeChild(panel); };
    };

    const _onKeydown = (e: KeyboardEvent) => {
      const mod = e.ctrlKey || e.metaKey;
      if (!mod) return;
      const k = e.key.toLowerCase();
      if (k === 'f') { e.preventDefault(); _open(false); }
      else if (k === 'h') { e.preventDefault(); _open(true); }
      else if (k === 'escape' && state._panel) { _close(); }
    };
    editor.textarea.addEventListener('keydown', _onKeydown);

    // Expose for tests via Symbol-keyed state (no public-property pollution)
    setPluginState(editor, K_SEARCH, { state, _open, _close, _onKeydown });
  },
  destroy(editor: EditorLike) {
    const exposed = pluginState<{ state: any; _onKeydown: ((e: KeyboardEvent) => void) | null }>(editor, K_SEARCH);
    if (exposed) {
      const state = exposed.state;
      if (state) {
        if (state._cleanup) { state._cleanup(); state._cleanup = null; }
        state._panel = null;
      }
      if (exposed._onKeydown && editor && editor.textarea) {
        editor.textarea.removeEventListener('keydown', exposed._onKeydown);
      }
      deletePluginState(editor, K_SEARCH);
    }
  },
};

const imagePastePlugin: Plugin = {
  name: 'imagePaste', version: '0.2.1', description: 'Paste image as base64', priority: 60,
  install(editor, options: any = {}) {
    if (!editor || !editor.textarea || typeof document === 'undefined') return;
    const maxSizeKB: number = options.maxSizeKB || 500;
    const _onPaste = (e: ClipboardEvent) => {
      const items = e.clipboardData?.items; if (!items) return;
      for (const item of items) {
        if (item.type?.startsWith('image/')) {
          const file = item.getAsFile();
          if (!file) continue;
          const sizeKB = file.size / 1024;
          if (maxSizeKB > 0 && sizeKB > maxSizeKB) {
            e.preventDefault();
            if (typeof editor.toast === 'function') editor.toast(t('imageTooLarge', { size: sizeKB.toFixed(0), max: maxSizeKB }) || `Image too large (${sizeKB.toFixed(0)}KB > ${maxSizeKB}KB)`, { type: 'warning' });
            break;
          }
          e.preventDefault();
          const reader = new FileReader(); reader.onload = () => { if (typeof editor.insert === 'function') editor.insert(`![image-${Date.now().toString(36)}.png](${reader.result})\n`); };
          reader.readAsDataURL(file); break;
        }
      }
    };
    editor.textarea.addEventListener('paste', _onPaste);
    setPluginState(editor, K_IMAGE_PASTE, _onPaste);
  },
  destroy(editor: EditorLike) {
    const _onPaste = pluginState<(e: ClipboardEvent) => void>(editor, K_IMAGE_PASTE);
    if (_onPaste && editor?.textarea) editor.textarea.removeEventListener('paste', _onPaste);
    deletePluginState(editor, K_IMAGE_PASTE);
  },
};

const shortcutHelpPlugin: Plugin = {
  name: 'shortcutHelp', version: '0.2.0', description: 'Press ? to show shortcuts', priority: 200,
  install(editor) {
    if (!editor || !editor.textarea || typeof document === 'undefined') return;
    if (!document.getElementById('me-shortcut-style')) {
      const s = document.createElement('style'); s.id = 'me-shortcut-style';
      s.textContent = `.me-shortcut-overlay{position:fixed;top:0;left:0;right:0;bottom:0;z-index:50;background:rgba(0,0,0,0.5);display:flex;align-items:center;justify-content:center}.me-shortcut-panel{background:var(--md-bg,#fff);border-radius:12px;padding:24px;max-width:560px;width:90%;max-height:80vh;overflow-y:auto;box-shadow:0 12px 40px rgba(0,0,0,0.3)}.me-shortcut-panel h3{font-size:16px;margin:0 0 16px;color:var(--md-text)}.me-shortcut-panel table{width:100%;border-collapse:collapse;font-size:13px}.me-shortcut-panel td{padding:6px 10px;border-bottom:1px solid var(--md-border)}.me-shortcut-panel td:first-child{font-family:var(--md-mono);font-size:12px;color:var(--md-accent);white-space:nowrap;width:40%}.me-shortcut-panel .me-shortcut-close{position:absolute;top:16px;right:20px;background:none;border:none;font-size:20px;cursor:pointer;color:var(--md-muted)}`;
      document.head.appendChild(s);
    }

    let _panel: HTMLElement | null = null;

    const _close = () => { if (_panel) { _panel.remove(); _panel = null; } };

    const _open = () => {
      if (_panel) { _close(); return; }
      // i18n-aware shortcut labels
      const builtin: [string, string][] = [
        ['Ctrl+B', t('bold') || 'Bold'], ['Ctrl+I', t('italic') || 'Italic'],
        ['Ctrl+U', t('underline') || 'Underline'], ['Ctrl+K', t('link') || 'Link'],
        ['Ctrl+E', t('code') || 'Code'], ['Ctrl+1/2/3', t('h1') || 'Heading'],
        ['Ctrl+Q', t('quote') || 'Quote'], ['Ctrl+Z', t('undo') || 'Undo'],
        ['Ctrl+Y', t('redo') || 'Redo'], ['Ctrl+S', t('save') || 'Save'],
        ['Ctrl+F', t('search') || 'Search'], ['Ctrl+H', t('replace') || 'Replace'],
        ['Tab', t('indent') || 'Indent'], ['Shift+Tab', t('outdent') || 'Outdent'],
        ['?', t('shortcuts') || 'Shortcuts'],
      ];
      let rows = ''; builtin.forEach(([c, d]) => { rows += `<tr><td>${c}</td><td>${d}</td></tr>`; });
      const overlay = document.createElement('div'); overlay.className = 'me-shortcut-overlay';
      overlay.innerHTML = `<div class="me-shortcut-panel"><h3>⌨️ ${t('shortcuts') || 'Shortcuts'}</h3><button class="me-shortcut-close">×</button><table>${rows}</table></div>`;
      overlay.addEventListener('click', (e) => { if (e.target === overlay || (e.target as HTMLElement).classList.contains('me-shortcut-close')) _close(); });
      document.body.appendChild(overlay); _panel = overlay;
    };

    const _onKeydown = (e: KeyboardEvent) => {
      if (e.key === '?' && !e.ctrlKey && !e.metaKey && !e.altKey) { e.preventDefault(); _open(); }
      if (e.key === 'Escape' && _panel) _close();
    };
    editor.textarea.addEventListener('keydown', _onKeydown);

    setPluginState(editor, K_SHORTCUT, { _panel, _open, _close, _onKeydown });
  },
  destroy(editor: EditorLike) {
    const state = pluginState<{ _panel: HTMLElement | null; _onKeydown: ((e: KeyboardEvent) => void) | null }>(editor, K_SHORTCUT);
    if (state) { if (state._panel) { state._panel.remove(); } }
    const _onKeydown = state?._onKeydown;
    if (_onKeydown && editor?.textarea) editor.textarea.removeEventListener('keydown', _onKeydown);
    deletePluginState(editor, K_SHORTCUT);
  },
};

const fileSystemPlugin: Plugin = {
  name: 'fileSystem', version: '0.2.0', description: 'File System Access API', priority: 90,
  install(editor) {
    if (!editor || typeof editor.getValue !== 'function') return;
    const hasAPI = typeof window !== 'undefined' && typeof (window as any).showOpenFilePicker === 'function';
    let _fileHandle: any = null;

    (editor as any).openFile = async (opts: any = {}) => {
      if (!hasAPI) { if (typeof editor.toast === 'function') editor.toast?.('File System Access API not supported', { type: 'warning' }); return null; }
      try {
        const [handle] = await (window as any).showOpenFilePicker({ types: [{ accept: { 'text/markdown': ['.md','.txt','.markdown'] } }], ...opts });
        _fileHandle = handle; const file = await handle.getFile(); const content = await file.text();
        if (typeof editor.setValue === 'function') editor.setValue(content);
        editor._emit?.('fileOpened', { name: file.name, handle }); return { name: file.name, content, handle };
      } catch (e: any) { if (e.name !== 'AbortError') console.error('Open file error:', e); return null; }
    };
    (editor as any).saveFile = async (opts: any = {}) => {
      let handle = _fileHandle;
      if (!handle || opts.saveAs) {
        if (!hasAPI) { if (typeof editor.toast === 'function') editor.toast?.('File System Access API not supported', { type: 'warning' }); return false; }
        try { handle = await (window as any).showSaveFilePicker({ types: [{ accept: { 'text/markdown': ['.md'] } }], suggestedName: opts.name || 'document.md' }); _fileHandle = handle; }
        catch (e: any) { if (e.name !== 'AbortError') console.error('Save error:', e); return false; }
      }
      try { const w = await handle.createWritable(); await w.write(editor.getValue!()); await w.close(); editor._emit?.('fileSaved', { handle }); return true; }
      catch (e) { _fileHandle = null; if (!opts.saveAs) return (editor as any).saveFile({ ...opts, saveAs: true }); console.error('Write error:', e); return false; }
    };
    (editor as any).saveFileAs = (name?: string) => (editor as any).saveFile({ saveAs: true, name });
    (editor as any).getFileHandle = () => _fileHandle;
    setPluginState(editor, K_FILESYSTEM, { getHandle: () => _fileHandle });
  },
  destroy(editor: EditorLike) {
    if (editor) { delete (editor as any).openFile; delete (editor as any).saveFile; delete (editor as any).saveFileAs; delete (editor as any).getFileHandle; }
    deletePluginState(editor, K_FILESYSTEM);
  },
};

// ============ Preset plugins table ============

export const presetPlugins: Record<string, Plugin> = {
  autoSave: autoSavePlugin, exportTool: exportToolPlugin, searchReplace: searchReplacePlugin,
  imagePaste: imagePastePlugin, shortcutHelp: shortcutHelpPlugin, fileSystem: fileSystemPlugin,
};

// ============ Plugin utils ============

export const pluginUtils = {
  createManager: () => new PluginManager(),
  manager: defaultPluginManager,
  register: (name: string, plugin: Plugin) => defaultPluginManager.register(name, plugin),
  unregister: (name: string) => defaultPluginManager.unregister(name),
  get: (name: string) => defaultPluginManager.get(name),
  has: (name: string) => defaultPluginManager.has(name),
  getAll: () => defaultPluginManager.getAll(),
  getNames: () => defaultPluginManager.getNames(),
  enable: (name: string) => defaultPluginManager.enable(name),
  disable: (name: string) => defaultPluginManager.disable(name),
  isEnabled: (name: string) => defaultPluginManager.isEnabled(name),
  getPreset: (name: string): Plugin | null => presetPlugins[name] ? { ...presetPlugins[name] } : null,
  getAllPresets: (): Record<string, Plugin> => Object.keys(presetPlugins).reduce((acc, k) => { acc[k] = { ...presetPlugins[k] }; return acc; }, {} as Record<string, Plugin>),
  createPlugin: (config: Partial<Plugin> = {}): Plugin => {
    const result: Plugin = { name: config.name || 'custom', version: config.version || '0.0.0', description: config.description || '', depends: config.depends || [], priority: config.priority || 0, install: () => {}, destroy: () => {}, ...config };
    if (typeof result.install !== 'function') result.install = () => {};
    if (typeof result.destroy !== 'function') result.destroy = () => {};
    return result;
  },
  validatePlugin: (plugin: any): { valid: boolean; errors: string[] } => {
    const errors: string[] = [];
    if (!plugin || typeof plugin !== 'object') errors.push('plugin must be an object');
    if (plugin && !plugin.name) errors.push('plugin must have a name');
    if (plugin && plugin.install && typeof plugin.install !== 'function') errors.push('install must be a function');
    return { valid: errors.length === 0, errors };
  },
  topologicalSort, validateConfig,
};

export default presetPlugins;