// routes/customers.js —— 客户管理 CRUD
const { pool } = require('../db')

// 提取分页参数
function pagination(query) {
  const page = Math.max(Number(query.page) || 1, 1)
  const pageSize = Math.min(Math.max(Number(query.pageSize) || 10, 1), 100)
  const offset = (page - 1) * pageSize
  return { page, pageSize, offset }
}

// GET /api/customers —— 列表（支持搜索、分页）
async function list(req, res) {
  try {
    const { page, pageSize, offset } = pagination(req.query)
    const { name, phone, province, city, customer_type } = req.query

    let where = 'WHERE 1=1'
    const params = []

    if (name) {
      where += ' AND name LIKE ?'
      params.push(`%${name}%`)
    }
    if (phone) {
      where += ' AND phone LIKE ?'
      params.push(`%${phone}%`)
    }
    if (province) {
      where += ' AND province = ?'
      params.push(province)
    }
    if (city) {
      where += ' AND city = ?'
      params.push(city)
    }
    if (customer_type) {
      where += ' AND customer_type = ?'
      params.push(customer_type)
    }

    // 查总数
    const [[{ total }]] = await pool.query(
      `SELECT COUNT(*) AS total FROM customers ${where}`,
      params
    )

    // 查分页数据
    const [rows] = await pool.query(
      `SELECT * FROM customers ${where} ORDER BY id DESC LIMIT ? OFFSET ?`,
      [...params, pageSize, offset]
    )

    res.json({
      code: 0,
      message: 'ok',
      data: {
        list: rows,
        total,
        page,
        pageSize,
        totalPages: Math.ceil(total / pageSize),
      },
    })
  } catch (e) {
    console.error('[customers list] error:', e)
    res.status(500).json({ code: 500, message: e.message })
  }
}

// GET /api/customers/:id —— 详情
async function detail(req, res) {
  try {
    const [rows] = await pool.query('SELECT * FROM customers WHERE id = ?', [req.params.id])
    if (rows.length === 0) {
      return res.status(404).json({ code: 404, message: '客户不存在' })
    }
    res.json({ code: 0, message: 'ok', data: rows[0] })
  } catch (e) {
    console.error('[customers detail] error:', e)
    res.status(500).json({ code: 500, message: e.message })
  }
}

// POST /api/customers —— 新增
async function create(req, res) {
  const {
    name, phone, province, city, district,
    address, customer_type, email, remark,
  } = req.body || {}

  if (!name) {
    return res.status(400).json({ code: 400, message: '客户姓名必填' })
  }

  try {
    const [result] = await pool.query(
      `INSERT INTO customers (name, phone, province, city, district, address, customer_type, email, remark)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      [name, phone || null, province || null, city || null, district || null,
        address || null, customer_type || 'Normal', email || null, remark || null]
    )
    const [rows] = await pool.query('SELECT * FROM customers WHERE id = ?', [result.insertId])
    res.json({ code: 0, message: 'ok', data: rows[0] })
  } catch (e) {
    console.error('[customers create] error:', e)
    res.status(500).json({ code: 500, message: e.message })
  }
}

// PUT /api/customers/:id —— 更新
async function update(req, res) {
  const { id } = req.params
  const fields = [
    'name', 'phone', 'province', 'city', 'district',
    'address', 'customer_type', 'email', 'remark',
  ]

  try {
    // 先确认记录存在
    const [existing] = await pool.query('SELECT id FROM customers WHERE id = ?', [id])
    if (existing.length === 0) {
      return res.status(404).json({ code: 404, message: '客户不存在' })
    }

    // 动态构建 SET 子句（只更新传入的字段）
    const sets = []
    const params = []
    for (const f of fields) {
      if (req.body[f] !== undefined) {
        sets.push(`${f} = ?`)
        params.push(req.body[f])
      }
    }
    if (sets.length === 0) {
      return res.status(400).json({ code: 400, message: '没有需要更新的字段' })
    }

    params.push(id)
    await pool.query(`UPDATE customers SET ${sets.join(', ')} WHERE id = ?`, params)

    const [rows] = await pool.query('SELECT * FROM customers WHERE id = ?', [id])
    res.json({ code: 0, message: 'ok', data: rows[0] })
  } catch (e) {
    console.error('[customers update] error:', e)
    res.status(500).json({ code: 500, message: e.message })
  }
}

// DELETE /api/customers/:id —— 删除
async function remove(req, res) {
  const { id } = req.params
  try {
    const [existing] = await pool.query('SELECT id FROM customers WHERE id = ?', [id])
    if (existing.length === 0) {
      return res.status(404).json({ code: 404, message: '客户不存在' })
    }
    await pool.query('DELETE FROM customers WHERE id = ?', [id])
    res.json({ code: 0, message: 'ok' })
  } catch (e) {
    console.error('[customers delete] error:', e)
    res.status(500).json({ code: 500, message: e.message })
  }
}

module.exports = { list, detail, create, update, remove }