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

async function getPurchases(ctx) {
  let sql = `
    SELECT p.*, 
      (SELECT COUNT(*) FROM purchase_items WHERE purchase_id = p.id) as items_count
    FROM purchases p
    WHERE 1=1`
  const params = []

  if (ctx.query.keyword) {
    sql += ' AND (p.supplier_name LIKE ?)'
    params.push(`%${ctx.query.keyword}%`)
  }

  sql += ' ORDER BY p.created_at DESC'
  const purchases = await query(sql, params)

  ctx.body = {
    code: 200,
    data: purchases
  }
}

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

  if (purchases.length === 0) {
    ctx.body = { code: 404, message: '采购单不存在' }
    return
  }

  const purchase = purchases[0]
  const items = await query(
    `SELECT pi.*, g.name as goods_name 
     FROM purchase_items pi 
     LEFT JOIN goods g ON pi.goods_id = g.id 
     WHERE pi.purchase_id = ?`,
    [id]
  )

  purchase.items = items
  purchase.items_count = items.length

  ctx.body = {
    code: 200,
    data: purchase
  }
}

async function createPurchase(ctx) {
  const { supplier_id, items, remarks } = ctx.request.body

  if (!supplier_id || !items || items.length === 0) {
    ctx.body = { code: 400, message: '请选择供应商和采购商品' }
    return
  }

  const suppliers = await query('SELECT * FROM suppliers WHERE id = ?', [supplier_id])
  if (suppliers.length === 0) {
    ctx.body = { code: 404, message: '供应商不存在' }
    return
  }
  const supplier = suppliers[0]

  let total = 0
  for (const item of items) {
    total += (item.purchase_price || 0) * (item.quantity || 0)
  }

  const purchaseResult = await query(
    'INSERT INTO purchases (supplier_id, supplier_name, total, remarks) VALUES (?, ?, ?, ?)',
    [supplier_id, supplier.name, total, remarks || '']
  )

  const purchaseId = purchaseResult.insertId

  for (const item of items) {
    const goods = await query('SELECT name FROM goods WHERE id = ?', [item.goods_id])
    const goodsName = goods.length > 0 ? goods[0].name : ''
    await query(
      'INSERT INTO purchase_items (purchase_id, goods_id, goods_name, quantity, purchase_price) VALUES (?, ?, ?, ?, ?)',
      [purchaseId, item.goods_id, goodsName, item.quantity || 0, item.purchase_price || 0]
    )
  }

  ctx.body = {
    code: 200,
    message: '采购单创建成功',
    data: { id: purchaseId }
  }
}

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

  if (purchases.length === 0) {
    ctx.body = { code: 404, message: '采购单不存在' }
    return
  }

  const purchase = purchases[0]
  if (purchase.status === 1) {
    ctx.body = { code: 400, message: '该采购单已入库' }
    return
  }

  const items = await query('SELECT * FROM purchase_items WHERE purchase_id = ?', [id])

  for (const item of items) {
    const existing = await query('SELECT * FROM stock WHERE goods_id = ?', [item.goods_id])
    if (existing.length > 0) {
      await query(
        'UPDATE stock SET quantity = quantity + ? WHERE goods_id = ?',
        [item.quantity, item.goods_id]
      )
    } else {
      await query(
        'INSERT INTO stock (goods_id, quantity, warehouse) VALUES (?, ?, ?)',
        [item.goods_id, item.quantity, '默认仓库']
      )
    }
    await query(
      'UPDATE goods SET stock = stock + ? WHERE id = ?',
      [item.quantity, item.goods_id]
    )
  }

  await query('UPDATE purchases SET status = 1 WHERE id = ?', [id])

  ctx.body = {
    code: 200,
    message: '入库成功'
  }
}

module.exports = {
  getPurchases,
  getPurchaseById,
  createPurchase,
  inboundPurchase
}