/**
 * IPC Task Handlers — 任务管理域（P2-9 从 handlers.ts 拆分）
 *
 * 注意：此处为 UI 直连的 CRUD 通道；Agent 运行时走 task_manager 工具
 * （electron/harness/tools/built-in/task-manager.ts），两侧共享 tasks 表。
 */

import { ipcMain } from 'electron';
import { nanoid } from 'nanoid';
import type { IPCContext } from './context';

const VALID_TASK_PRIORITIES: readonly string[] = ['low', 'medium', 'high', 'critical'];
const VALID_TASK_STATUSES: readonly string[] = ['pending', 'in_progress', 'completed', 'blocked', 'cancelled'];

export function registerTaskHandlers(ctx: IPCContext): void {
  const { sessionService } = ctx;

  ipcMain.handle('tasks:list', async (_event, sessionId?: unknown) => {
    // M-46 修复: 校验 sessionId 类型（可选参数）
    if (sessionId !== undefined && (typeof sessionId !== 'string' || !sessionId)) {
      return { success: false, error: 'Invalid sessionId' };
    }
    const db = sessionService.getDB();
    let sql = 'SELECT * FROM tasks';
    const params: unknown[] = [];
    if (sessionId) {
      sql += ' WHERE session_id = ?';
      params.push(sessionId);
    }
    sql += ' ORDER BY order_idx ASC, created_at ASC';
    return { success: true, data: db.prepare(sql).all(...params) };
  });

  ipcMain.handle('tasks:create', async (_event, data: unknown) => {
    // M-46 修复: 校验 data 结构和字段类型/枚举
    if (!data || typeof data !== 'object') {
      return { success: false, error: 'Invalid task data' };
    }
    const req = data as Record<string, unknown>;
    if (typeof req.sessionId !== 'string' || !req.sessionId.trim()) {
      return { success: false, error: 'Invalid sessionId' };
    }
    if (typeof req.title !== 'string' || !req.title.trim()) {
      return { success: false, error: 'Invalid title' };
    }
    if (req.priority !== undefined && !VALID_TASK_PRIORITIES.includes(req.priority as string)) {
      return { success: false, error: `Invalid priority (must be one of: ${VALID_TASK_PRIORITIES.join(', ')})` };
    }
    if (req.parentId !== undefined && req.parentId !== null && typeof req.parentId !== 'string') {
      return { success: false, error: 'Invalid parentId' };
    }
    const db = sessionService.getDB();
    // P4 统一（v0.3.13）: ID 生成方式与 task_manager 工具一致（nanoid）
    const id = `task_${nanoid(12)}`;
    try {
      // P4 统一: 计算 order_idx = MAX(同 session+parent 的 order_idx) + 1（与 task_manager 工具一致）
      const parentId = (req.parentId as string | null) ?? null;
      let orderIdx = 0;
      if (parentId === null) {
        const orderRow = db.prepare(
          'SELECT COALESCE(MAX(order_idx), -1) AS maxOrder FROM tasks WHERE session_id = ? AND parent_id IS NULL'
        ).get(req.sessionId) as { maxOrder: number } | undefined;
        orderIdx = (orderRow?.maxOrder ?? -1) + 1;
      } else {
        const orderRow = db.prepare(
          'SELECT COALESCE(MAX(order_idx), -1) AS maxOrder FROM tasks WHERE session_id = ? AND parent_id = ?'
        ).get(req.sessionId, parentId) as { maxOrder: number } | undefined;
        orderIdx = (orderRow?.maxOrder ?? -1) + 1;
      }
      db.prepare(`
        INSERT INTO tasks (id, session_id, title, description, status, priority, parent_id, order_idx, created_at, updated_at)
        VALUES (?, ?, ?, ?, 'pending', ?, ?, ?, ?, ?)
      `).run(
        id,
        req.sessionId,
        req.title,
        typeof req.description === 'string' ? req.description : '',
        (req.priority as string) ?? 'medium',
        parentId,
        orderIdx,
        Date.now(),
        Date.now(),
      );
      return { success: true, id };
    } catch (error) {
      return { success: false, error: (error as Error).message };
    }
  });

  ipcMain.handle('tasks:update', async (_event, id: unknown, updates: unknown, sessionId: unknown) => {
    // M-47 修复: 校验 id 和 updates 结构/枚举
    if (typeof id !== 'string' || !id) {
      return { success: false, error: 'Invalid task id' };
    }
    // P1 修复（v0.3.13）: 补 session_id 越权保护（与 task_manager 工具一致）
    if (typeof sessionId !== 'string' || !sessionId) {
      return { success: false, error: 'Invalid sessionId' };
    }
    if (!updates || typeof updates !== 'object') {
      return { success: false, error: 'Invalid updates' };
    }
    const u = updates as Record<string, unknown>;
    if (u.status !== undefined && !VALID_TASK_STATUSES.includes(u.status as string)) {
      return { success: false, error: `Invalid status (must be one of: ${VALID_TASK_STATUSES.join(', ')})` };
    }
    if (u.priority !== undefined && !VALID_TASK_PRIORITIES.includes(u.priority as string)) {
      return { success: false, error: `Invalid priority (must be one of: ${VALID_TASK_PRIORITIES.join(', ')})` };
    }
    if (u.assignedTo !== undefined && u.assignedTo !== null && typeof u.assignedTo !== 'string') {
      return { success: false, error: 'Invalid assignedTo' };
    }
    // 审计补充修复: 补全 title/description 类型校验
    if (u.title !== undefined && typeof u.title !== 'string') {
      return { success: false, error: 'Invalid title (must be string)' };
    }
    if (u.description !== undefined && typeof u.description !== 'string') {
      return { success: false, error: 'Invalid description (must be string)' };
    }
    const db = sessionService.getDB();
    try {
      const fields: string[] = [];
      const values: unknown[] = [];
      if (u.title !== undefined) { fields.push('title = ?'); values.push(u.title); }
      if (u.description !== undefined) { fields.push('description = ?'); values.push(u.description); }
      if (u.status !== undefined) { fields.push('status = ?'); values.push(u.status); }
      if (u.priority !== undefined) { fields.push('priority = ?'); values.push(u.priority); }
      if (u.assignedTo !== undefined) { fields.push('assigned_to = ?'); values.push(u.assignedTo); }
      if (fields.length === 0) return { success: true };
      fields.push('updated_at = ?'); values.push(Date.now());
      if (u.status === 'completed') { fields.push('completed_at = ?'); values.push(Date.now()); }
      values.push(id, sessionId);
      // P1 修复（v0.3.13）: WHERE 补 session_id 校验，防越权修改其他会话任务
      db.prepare(`UPDATE tasks SET ${fields.join(', ')} WHERE id = ? AND session_id = ?`).run(...values);
      return { success: true };
    } catch (error) {
      return { success: false, error: (error as Error).message };
    }
  });

  ipcMain.handle('tasks:delete', async (_event, id: unknown, sessionId: unknown) => {
    // M-48 修复: 校验 id 类型
    if (typeof id !== 'string' || !id) {
      return { success: false, error: 'Invalid task id' };
    }
    // P1 修复（v0.3.13）: 补 session_id 越权保护
    if (typeof sessionId !== 'string' || !sessionId) {
      return { success: false, error: 'Invalid sessionId' };
    }
    const db = sessionService.getDB();
    try {
      db.prepare('DELETE FROM tasks WHERE id = ? AND session_id = ?').run(id, sessionId);
      return { success: true };
    } catch (error) {
      return { success: false, error: (error as Error).message };
    }
  });
}