// routes/products.js —— 产品管理 CRUD
const { pool } = require('../db')

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/products —— 列表
async function list(req, res) {
  try {
    const { page, pageSize, offset } = pagination(req.query)
    const { name, type, supplier } = req.query

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

    if (name) {
      where += ' AND name LIKE ?'
      params.push(`%${name}%`)
    }
    if (type) {
      where += ' AND type LIKE ?'
      params.push(`%${type}%`)
    }
    if (supplier) {
      where += ' AND supplier LIKE ?'
      params.push(`%${supplier}%`)
    }

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

    const [rows] = await pool.query(
      `SELECT * FROM products ${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('[products list] error:', e)
    res.status(500).json({ code: 500, message: e.message })
  }
}

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

// POST /api/products —— 新增
async function create(req, res) {
  const {
    name, type, quantity, price, unit, specification, supplier, remark,
  } = req.body || {}

  if (!name) {
    return res.status(400).json({ code: 400, message: '产品名称必填' })
  }

  try {
    const [result] = await pool.query(
      `INSERT INTO products (name, type, quantity, price, unit, specification, supplier, remark)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
      [name,
        type || null,
        quantity !== undefined ? quantity : 0,
        price !== undefined ? price : 0.00,
        unit || '件',
        specification || null,
        supplier || null,
        remark || null]
    )
    const [rows] = await pool.query('SELECT * FROM products WHERE id = ?', [result.insertId])
    res.json({ code: 0, message: 'ok', data: rows[0] })
  } catch (e) {
    console.error('[products create] error:', e)
    res.status(500).json({ code: 500, message: e.message })
  }
}

// PUT /api/products/:id —— 更新
async function update(req, res) {
  const { id } = req.params
  const fields = [
    'name', 'type', 'quantity', 'price', 'unit', 'specification', 'supplier', 'remark',
  ]

  try {
    const [existing] = await pool.query('SELECT id FROM products WHERE id = ?', [id])
    if (existing.length === 0) {
      return res.status(404).json({ code: 404, message: '产品不存在' })
    }

    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 products SET ${sets.join(', ')} WHERE id = ?`, params)

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

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

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