import { Router } from 'express'
import pool from '../db/connection'
import { authMiddleware } from '../middleware/auth'

const router = Router()
router.use(authMiddleware)

/** 获取用户的周期模板列表 */
router.get('/', async (req, res) => {
  try {
    const userId = (req as any).userId
    const [rows] = await pool.execute(
      `SELECT rt.*, c.name as category_name, c.icon as category_icon, c.color as category_color
       FROM recurring_templates rt
       LEFT JOIN categories c ON rt.category_id = c.id
       WHERE rt.user_id = ?
       ORDER BY rt.is_active DESC, rt.next_date ASC`,
      [userId]
    )
    res.json({ code: 0, data: rows })
  } catch (error) {
    console.error('Get recurring templates error:', error)
    res.status(500).json({ code: 50000, message: '获取失败' })
  }
})

/** 创建周期模板 */
router.post('/', async (req, res) => {
  try {
    const userId = (req as any).userId
    const { amount, type, category_id, note, frequency, next_date, end_date, group_id } = req.body

    if (!amount || amount <= 0) {
      return res.status(400).json({ code: 40001, message: '请输入金额' })
    }
    if (!type || !['expense', 'income'].includes(type)) {
      return res.status(400).json({ code: 40001, message: '请选择类型' })
    }
    if (!category_id) {
      return res.status(400).json({ code: 40001, message: '请选择分类' })
    }
    if (!frequency || !['weekly', 'monthly', 'yearly'].includes(frequency)) {
      return res.status(400).json({ code: 40001, message: '请选择周期' })
    }
    if (!next_date) {
      return res.status(400).json({ code: 40001, message: '请选择开始日期' })
    }

    const [result] = await pool.execute(
      `INSERT INTO recurring_templates (user_id, amount, type, category_id, note, frequency, next_date, end_date, group_id)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      [userId, amount, type, category_id, note || '', frequency, next_date, end_date || null, group_id || null]
    )
    res.json({ code: 0, data: { id: (result as any).insertId } })
  } catch (error) {
    console.error('Create recurring template error:', error)
    res.status(500).json({ code: 50000, message: '创建失败' })
  }
})

/** 更新周期模板 */
router.put('/:id', async (req, res) => {
  try {
    const userId = (req as any).userId
    const { id } = req.params
    const { amount, type, category_id, note, frequency, next_date, end_date, is_active } = req.body

    // 校验所有权
    const [rows] = await pool.execute(
      'SELECT id FROM recurring_templates WHERE id = ? AND user_id = ?',
      [id, userId]
    )
    if ((rows as any[]).length === 0) {
      return res.status(404).json({ code: 40400, message: '模板不存在' })
    }

    const updates: string[] = []
    const params: any[] = []

    if (amount !== undefined) { updates.push('amount = ?'); params.push(amount) }
    if (type !== undefined) { updates.push('type = ?'); params.push(type) }
    if (category_id !== undefined) { updates.push('category_id = ?'); params.push(category_id) }
    if (note !== undefined) { updates.push('note = ?'); params.push(note) }
    if (frequency !== undefined) { updates.push('frequency = ?'); params.push(frequency) }
    if (next_date !== undefined) { updates.push('next_date = ?'); params.push(next_date) }
    if (end_date !== undefined) { updates.push('end_date = ?'); params.push(end_date) }
    if (is_active !== undefined) { updates.push('is_active = ?'); params.push(is_active) }

    if (updates.length === 0) {
      return res.status(400).json({ code: 40001, message: '无更新字段' })
    }

    params.push(id, userId)
    await pool.execute(
      `UPDATE recurring_templates SET ${updates.join(', ')} WHERE id = ? AND user_id = ?`,
      params
    )
    res.json({ code: 0 })
  } catch (error) {
    console.error('Update recurring template error:', error)
    res.status(500).json({ code: 50000, message: '更新失败' })
  }
})

/** 删除周期模板 */
router.delete('/:id', async (req, res) => {
  try {
    const userId = (req as any).userId
    const { id } = req.params

    const [rows] = await pool.execute(
      'SELECT id FROM recurring_templates WHERE id = ? AND user_id = ?',
      [id, userId]
    )
    if ((rows as any[]).length === 0) {
      return res.status(404).json({ code: 40400, message: '模板不存在' })
    }

    await pool.execute(
      'DELETE FROM recurring_templates WHERE id = ? AND user_id = ?',
      [id, userId]
    )
    res.json({ code: 0 })
  } catch (error) {
    console.error('Delete recurring template error:', error)
    res.status(500).json({ code: 50000, message: '删除失败' })
  }
})

/** 同步：检查所有活跃模板，生成到期交易 */
router.post('/sync', async (req, res) => {
  try {
    const userId = (req as any).userId
    // 获取该用户所有活跃且到期（next_date <= 今天）的模板
    const [templates] = await pool.execute(
      `SELECT * FROM recurring_templates
       WHERE user_id = ? AND is_active = 1 AND next_date <= CURDATE()
       ORDER BY next_date ASC`,
      [userId]
    )

    let generated = 0
    const today = new Date()
    const todayStr = today.toISOString().slice(0, 10)

    for (const t of templates as any[]) {
      let next = new Date(t.next_date)
      const end = t.end_date ? new Date(t.end_date) : null

      // 生成所有错过的交易
      while (next <= today) {
        if (end && next > end) break

        // 检查是否已生成过（避免重复）
        const [existing] = await pool.execute(
          `SELECT id FROM transactions
           WHERE user_id = ? AND recurring_id = ? AND date = ?`,
          [userId, t.id, next.toISOString().slice(0, 10)]
        )
        if ((existing as any[]).length === 0) {
          await pool.execute(
            `INSERT INTO transactions (user_id, amount, type, category_id, note, date, group_id, recurring_id)
             VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
            [userId, t.amount, t.type, t.category_id, t.note,
             next.toISOString().slice(0, 10), t.group_id, t.id]
          )
          generated++
        }

        // 推进到下一周期
        if (t.frequency === 'weekly') {
          next = new Date(next.getTime() + 7 * 86400000)
        } else if (t.frequency === 'monthly') {
          next = new Date(next.getFullYear(), next.getMonth() + 1, next.getDate())
        } else if (t.frequency === 'yearly') {
          next = new Date(next.getFullYear() + 1, next.getMonth(), next.getDate())
        }
      }

      // 更新 next_date 到下一周期
      let newNext: Date
      if (t.frequency === 'weekly') {
        newNext = new Date(new Date(t.next_date).getTime() + 7 * 86400000)
      } else if (t.frequency === 'monthly') {
        const d = new Date(t.next_date)
        newNext = new Date(d.getFullYear(), d.getMonth() + 1, d.getDate())
      } else {
        const d = new Date(t.next_date)
        newNext = new Date(d.getFullYear() + 1, d.getMonth(), d.getDate())
      }

      await pool.execute(
        'UPDATE recurring_templates SET next_date = ? WHERE id = ?',
        [newNext.toISOString().slice(0, 10), t.id]
      )
    }

    res.json({ code: 0, data: { generated } })
  } catch (error) {
    console.error('Sync recurring error:', error)
    res.status(500).json({ code: 50000, message: '同步失败' })
  }
})

export default router