const { query, transaction } = require('../config/database')

async function getSpecs(ctx) {
  const goodsId = ctx.query.goods_id
  if (!goodsId) {
    ctx.body = { code: 400, message: '缺少 goods_id 参数' }
    return
  }

  const rows = await query('SELECT * FROM goods_specs WHERE goods_id = ? ORDER BY price ASC', [goodsId])
  ctx.body = { code: 200, data: rows }
}

async function createSpec(ctx) {
  const { goods_id, spec_name, price, stock = 0 } = ctx.request.body

  if (!goods_id || !spec_name || price === undefined) {
    ctx.body = { code: 400, message: '缺少必填参数' }
    return
  }

  const result = await query(
    'INSERT INTO goods_specs (goods_id, spec_name, price, stock) VALUES (?, ?, ?, ?)',
    [goods_id, spec_name, price, stock]
  )

  ctx.body = { code: 200, data: { id: result.insertId } }
}

async function updateSpec(ctx) {
  const id = ctx.params.id
  const { spec_name, price, stock } = ctx.request.body

  const fields = []
  const params = []
  if (spec_name !== undefined) { fields.push('spec_name = ?'); params.push(spec_name) }
  if (price !== undefined) { fields.push('price = ?'); params.push(price) }
  if (stock !== undefined) { fields.push('stock = ?'); params.push(stock) }

  if (fields.length > 0) {
    params.push(id)
    await query(`UPDATE goods_specs SET ${fields.join(', ')} WHERE id = ?`, params)
  }

  ctx.body = { code: 200, message: '更新成功' }
}

async function deleteSpec(ctx) {
  const id = ctx.params.id
  await query('DELETE FROM goods_specs WHERE id = ?', [id])
  ctx.body = { code: 200, message: '删除成功' }
}

async function batchSave(ctx) {
  const { goods_id, specs } = ctx.request.body

  if (!goods_id || !Array.isArray(specs)) {
    ctx.body = { code: 400, message: '参数错误' }
    return
  }

  await transaction(async (conn) => {
    await conn.execute('DELETE FROM goods_specs WHERE goods_id = ?', [goods_id])
    for (const spec of specs) {
      if (spec.spec_name && spec.price !== undefined) {
        await conn.execute(
          'INSERT INTO goods_specs (goods_id, spec_name, price, stock) VALUES (?, ?, ?, ?)',
          [goods_id, spec.spec_name, spec.price, spec.stock || 0]
        )
      }
    }
  })

  ctx.body = { code: 200, message: '保存成功' }
}

module.exports = {
  getSpecs,
  createSpec,
  updateSpec,
  deleteSpec,
  batchSave
}