const { query } = require('../config/database')
const { toRelativeUrl, processGoodsImages } = require('../utils/image-url')
const { paginate } = require('../utils/pagination')
const path = require('path')
const fs = require('fs')

function parseImages(images) {
  if (!images) return []
  try {
    const parsed = typeof images === 'string' ? JSON.parse(images) : images
    return Array.isArray(parsed) ? parsed : []
  } catch { return [] }
}

function deleteImageFiles(urls) {
  for (const url of urls) {
    const filePath = path.join(__dirname, '..', 'public', url.replace(/^\//, ''))
    fs.unlink(filePath, () => {})
  }
}

async function getGoods(ctx) {
  let sql = 'SELECT * FROM goods WHERE 1=1'
  const params = []

  if (ctx.query.hot === '1') {
    sql += ' AND is_hot = 1'
  }

  if (ctx.query.isNew === '1') {
    sql += ' AND is_new = 1'
  }

  if (ctx.query.category_id) {
    sql += ' AND category_id = ?'
    params.push(parseInt(ctx.query.category_id))
  }

  if (ctx.query.keyword) {
    const kw = String(ctx.query.keyword).trim().slice(0, 50)
    if (kw) {
      const escaped = kw.replace(/[\\%_]/g, c => '\\' + c)
      sql += ' AND name LIKE ?'
      params.push(`%${escaped}%`)
    }
  }

  if (ctx.query.inStock === '1') {
    sql += ' AND stock > 0'
  }

  const sortField = ctx.query.sortBy || 'id'
  const sortOrder = ctx.query.sortOrder === 'asc' ? 'ASC' : 'DESC'
  const validSortFields = ['id', 'price', 'sales', 'stock', 'created_at']

  if (validSortFields.includes(sortField)) {
    sql += ` ORDER BY ${sortField} ${sortOrder}`
  } else {
    sql += ' ORDER BY id DESC'
  }

  if (ctx.query.limit && !ctx.query.page) {
    sql += ' LIMIT ?'
    params.push(parseInt(ctx.query.limit))
    const goods = await query(sql, params)
    ctx.body = { code: 200, data: processGoodsImages(goods) }
    return
  }

  const result = await paginate(query, sql, params, ctx.query.page, ctx.query.pageSize)
  if (result.data) result.data = processGoodsImages(result.data)

  ctx.body = {
    code: 200,
    ...result
  }
}

async function getGoodsById(ctx) {
  const goodsId = parseInt(ctx.params.id)
  const goods = await query('SELECT * FROM goods WHERE id = ?', [goodsId])

  if (goods.length > 0) {
    ctx.body = {
      code: 200,
      data: processGoodsImages(goods)[0]
    }
  } else {
    ctx.body = {
      code: 404,
      message: '商品不存在'
    }
  }
}

async function createGoods(ctx) {
  const { name, price, unit, categoryId, images, stock, pricingType, isHot, isNew, remark, goodsNo, barcode } = ctx.request.body

  if (!name || !price || !unit) {
    ctx.body = {
      code: 400,
      message: '缺少必填字段'
    }
    return
  }

  if (stock !== undefined && stock !== 0) {
    ctx.body = {
      code: 400,
      message: '新建商品请保持库存为 0，通过「入库/采购」或「库存调整」接口补充'
    }
    return
  }
  
  // 将图片URL转换为相对路径存储
  const relativeImages = (images || []).map(img => toRelativeUrl(img))
  
  const sql = `INSERT INTO goods 
    (name, price, cost_price, unit, category_id, images, stock, pricing_type, is_hot, is_new, remark, goods_no, barcode)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
  
  const params = [
    name,
    parseFloat(price),
    parseFloat(ctx.request.body.costPrice || 0),
    unit,
    categoryId || null,
    JSON.stringify(relativeImages),
    parseInt(stock) || 0,
    parseInt(pricingType) || 1,
    parseInt(isHot) || 0,
    parseInt(isNew) || 0,
    remark || '',
    goodsNo || '',
    barcode || ''
  ]
  
  try {
    const result = await query(sql, params)
    ctx.body = {
      code: 200,
      message: '添加成功',
      data: { id: result.insertId }
    }
  } catch (error) {
    console.error('添加商品失败:', error)
    ctx.body = {
      code: 500,
      message: '添加失败'
    }
  }
}

const GOODS_UPDATEABLE_FIELDS = [
  'name', 'price', 'originalPrice', 'unit', 'categoryId',
  'images', 'pricingType', 'isHot', 'isNew', 'description', 'goodsNo', 'barcode', 'remark'
]

async function updateGoods(ctx) {
  const goodsId = parseInt(ctx.params.id)
  const body = ctx.request.body

  if ('stock' in body) {
    ctx.body = { code: 400, message: '请通过「库存调整」接口修改库存，不能直接编辑' }
    return
  }

  const filtered = {}
  for (const key of GOODS_UPDATEABLE_FIELDS) {
    if (key in body) {
      filtered[key] = body[key]
    }
  }

  const { name, price, unit, pricingType, isHot, isNew, description } = filtered

  if (!name || !price || !unit) {
    ctx.body = {
      code: 400,
      message: '缺少必填字段'
    }
    return
  }

  const setFields = []
  const params = []

  setFields.push('name = ?', 'price = ?', 'original_price = ?', 'unit = ?')
  params.push(name, parseFloat(price), parseFloat(filtered.originalPrice || 0), unit)

  setFields.push('category_id = ?')
  params.push(filtered.categoryId || null)

  if (filtered.images !== undefined) {
    const relativeImages = (filtered.images || []).map(img => toRelativeUrl(img))
    setFields.push('images = ?')
    params.push(JSON.stringify(relativeImages))

    const existing = await query('SELECT images FROM goods WHERE id = ?', [goodsId])
    if (existing.length > 0) {
      const oldImages = parseImages(existing[0].images)
      const oldFiles = oldImages.filter(u => u.startsWith('/uploads/') && !relativeImages.includes(u))
      deleteImageFiles(oldFiles)
    }
  }

  if (filtered.goodsNo !== undefined) {
    setFields.push('goods_no = ?')
    params.push(filtered.goodsNo || '')
  }
  if (filtered.barcode !== undefined) {
    setFields.push('barcode = ?')
    params.push(filtered.barcode || '')
  }
  if (filtered.remark !== undefined) {
    setFields.push('remark = ?')
    params.push(filtered.remark || '')
  }

  setFields.push('pricing_type = ?', 'is_hot = ?', 'is_new = ?', 'description = ?')
  params.push(parseInt(pricingType) || 1, parseInt(isHot) || 0, parseInt(isNew) || 0, description || '')

  params.push(goodsId)

  try {
    const result = await query(`UPDATE goods SET ${setFields.join(', ')} WHERE id = ?`, params)
    if (result.affectedRows > 0) {
      ctx.body = { code: 200, message: '更新成功' }
    } else {
      ctx.body = { code: 404, message: '商品不存在' }
    }
  } catch (error) {
    console.error('更新商品失败:', error)
    ctx.body = { code: 500, message: '更新失败' }
  }
}

async function deleteGoods(ctx) {
  const goodsId = parseInt(ctx.params.id)
  
  try {
    const existing = await query('SELECT images FROM goods WHERE id = ?', [goodsId])
    const result = await query('DELETE FROM goods WHERE id = ?', [goodsId])
    if (result.affectedRows > 0) {
      if (existing.length > 0) {
        const oldImages = parseImages(existing[0].images)
        deleteImageFiles(oldImages.filter(u => u.startsWith('/uploads/')))
      }
      ctx.body = {
        code: 200,
        message: '删除成功'
      }
    } else {
      ctx.body = {
        code: 404,
        message: '商品不存在'
      }
    }
  } catch (error) {
    console.error('删除商品失败:', error)
    ctx.body = {
      code: 500,
      message: '删除失败'
    }
  }
}

// 批量更新商品
async function batchUpdate(ctx) {
  const { ids, isOnSale } = ctx.request.body

  if (!Array.isArray(ids) || ids.length === 0) {
    ctx.body = { code: 400, message: '请选择要操作的商品' }
    return
  }

  // 允许批量更新的字段
  const setFields = []
  const params = []

  if (isOnSale !== undefined) {
    setFields.push('is_on_sale = ?')
    params.push(parseInt(isOnSale))
  }

  if (setFields.length === 0) {
    ctx.body = { code: 400, message: '缺少更新字段' }
    return
  }

  // 构建 IN 占位符
  const placeholders = ids.map(() => '?').join(', ')
  params.push(...ids)

  try {
    const sql = `UPDATE goods SET ${setFields.join(', ')} WHERE id IN (${placeholders})`
    const result = await query(sql, params)
    ctx.body = {
      code: 200,
      message: `成功更新${result.affectedRows}个商品`,
      data: { affectedRows: result.affectedRows }
    }
  } catch (error) {
    console.error('批量更新商品失败:', error)
    ctx.body = { code: 500, message: '批量更新失败' }
  }
}

module.exports = {
  getGoods,
  getGoodsById,
  createGoods,
  updateGoods,
  deleteGoods,
  batchUpdate
}