// fix-history-prices —— 一次性修复 import-history 出库明细的价格错列。
//
// 根因：旧系统出库单明细的「单价/金额」是售价口径（卖给客户的价，应收侧），
// import-history 却把它落到了 cost_price/cost_amount（成本列），sale_price/
// sale_amount 留 0（整单显示「待定价」）；而单头合计已按售价口径落 sale_total，
// 明细与单头自相矛盾。实证：ZXZ027628 出库明细"成本"14300 = 售价，
// 真实进价 13600 在库存/入库侧。
//
// 修复（仅动历史导入明细，即 product_id 指向 HIST-PLACEHOLDER 占位商品的行）：
//   - sale_price ← 原 cost_price、sale_amount ← 原 cost_amount（源售价归位）
//   - cost_price/cost_amount ← 按商品编号（序列号，一物一码）回查真实进价：
//     ① stock_in_items 同店同编号入库明细价 ② inventories.unit_price 库存快照价
//     ③ products.purchase_price 商品主数据进价；均查不到 → 0（成本待定）
//   - 涉及单据 profit_total 按 service.recalcStockOutProfit 同口径重算
//   - sale_total 不动（= 源单头合计，应收不变，财务无需冲账）
//
// 幂等：只处理 sale_price=0 且 cost_price>0 的占位明细，重跑自动跳过已修行。
// 默认 dry-run（事务内试算后回滚），--apply 才真正落库。
//
// 用法（在 backend/ 目录下执行）：
//
//	go run ./cmd/fix-history-prices --shop-code S001                # dry-run
//	go run ./cmd/fix-history-prices --shop-code S001 --apply        # 落库
package main

import (
	"errors"
	"flag"
	"fmt"
	"log"
	"math"
	"os"
	"strings"

	"gorm.io/driver/mysql"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"

	"github.com/wangjia/jiu/backend/config"
	"github.com/wangjia/jiu/backend/internal/model"
)

const placeholderProductCode = "HIST-PLACEHOLDER"

// errDryRun 哨兵错误：dry-run 模式下用它触发事务回滚（试算走完真实 SQL 但不落库）。
var errDryRun = errors.New("dry-run rollback")

type fixStats struct {
	Items             int      // 修复的出库明细行数
	CostFromStockIn   int      // 成本回填来源：入库明细
	CostFromInventory int      // 成本回填来源：库存快照
	CostFromProduct   int      // 成本回填来源：商品主数据进价
	CostUnmatched     int      // 查无进价（cost 置 0，成本待定）
	Orders            int      // 涉及并重算利润的出库单数
	TotalMismatches   []string // Σ明细售价小计 ≠ 单头 sale_total 的单号（只报不改）
}

type outItemRow struct {
	ID          uint64
	OrderID     uint64
	ProductCode string
	Quantity    float64
	CostPrice   float64
	CostAmount  float64
}

type costHit struct {
	price float64
	src   string // stock_in / inventory / product / ""(unmatched)
}

func round2(x float64) float64 { return math.Round(x*100) / 100 }

// lookupCost 按商品编号回查真实进价（商品编号=序列号，一物一码，匹配精确）。
func lookupCost(tx *gorm.DB, shopID uint64, code string) costHit {
	if strings.TrimSpace(code) == "" {
		return costHit{}
	}
	var p float64
	// ① 同店同编号的入库明细成本（历史导入入库价与正常入库价同源）
	row := tx.Raw(`SELECT cost_price FROM stock_in_items
		WHERE shop_id = ? AND product_code = ? AND cost_price > 0
		ORDER BY id DESC LIMIT 1`, shopID, code).Row()
	if row.Scan(&p) == nil && p > 0 {
		return costHit{p, "stock_in"}
	}
	// ② 库存快照价（快照列或经 product 关联均可命中）
	row = tx.Raw(`SELECT inv.unit_price FROM inventories inv
		LEFT JOIN products pr ON pr.id = inv.product_id AND pr.deleted_at IS NULL
		WHERE inv.shop_id = ? AND inv.deleted_at IS NULL AND inv.unit_price > 0
		  AND (inv.product_code = ? OR pr.code = ?)
		ORDER BY inv.id DESC LIMIT 1`, shopID, code, code).Row()
	if row.Scan(&p) == nil && p > 0 {
		return costHit{p, "inventory"}
	}
	// ③ 商品主数据进价
	row = tx.Raw(`SELECT purchase_price FROM products
		WHERE shop_id = ? AND code = ? AND deleted_at IS NULL AND purchase_price > 0
		ORDER BY id DESC LIMIT 1`, shopID, code).Row()
	if row.Scan(&p) == nil && p > 0 {
		return costHit{p, "product"}
	}
	return costHit{}
}

// fixShop 修复一家店的历史导入出库明细价格。apply=false 时事务回滚（dry-run）。
func fixShop(db *gorm.DB, shopID uint64, apply bool) (*fixStats, error) {
	// 占位商品可能已被用户在界面软删（线上即如此）——历史明细仍引用其 id，
	// 展示走快照列不受影响，这里按 id 定位范围即可，故不过滤 deleted_at。
	var ph model.Product
	if err := db.Where("shop_id = ? AND code = ?",
		shopID, placeholderProductCode).First(&ph).Error; err != nil {
		return nil, fmt.Errorf("未找到占位商品 %s（该店没有历史导入数据？）: %w", placeholderProductCode, err)
	}

	st := &fixStats{}
	err := db.Transaction(func(tx *gorm.DB) error {
		var items []outItemRow
		if err := tx.Raw(`SELECT id, order_id, product_code, quantity, cost_price, cost_amount
			FROM stock_out_items
			WHERE shop_id = ? AND product_id = ? AND sale_price = 0 AND cost_price > 0
			ORDER BY id`, shopID, ph.ID).Scan(&items).Error; err != nil {
			return err
		}
		st.Items = len(items)

		cache := map[string]costHit{}
		orderIDs := map[uint64]bool{}
		for _, it := range items {
			hit, ok := cache[it.ProductCode]
			if !ok {
				hit = lookupCost(tx, shopID, it.ProductCode)
				cache[it.ProductCode] = hit
			}
			switch hit.src {
			case "stock_in":
				st.CostFromStockIn++
			case "inventory":
				st.CostFromInventory++
			case "product":
				st.CostFromProduct++
			default:
				st.CostUnmatched++
			}
			if err := tx.Exec(`UPDATE stock_out_items
				SET sale_price = ?, sale_amount = ?, cost_price = ?, cost_amount = ?
				WHERE id = ?`,
				it.CostPrice, it.CostAmount, hit.price, round2(it.Quantity*hit.price), it.ID).Error; err != nil {
				return err
			}
			orderIDs[it.OrderID] = true
		}
		st.Orders = len(orderIDs)

		if len(orderIDs) > 0 {
			ids := make([]uint64, 0, len(orderIDs))
			for id := range orderIDs {
				ids = append(ids, id)
			}
			// 与 service.recalcStockOutProfit 同口径重算总利润
			if err := tx.Exec(`UPDATE stock_out_orders SET profit_total = (
				SELECT COALESCE(SUM(CASE WHEN i.sale_price > 0
					THEN (i.sale_price - i.cost_price) * i.quantity ELSE 0 END), 0)
				FROM stock_out_items i WHERE i.order_id = stock_out_orders.id
			) WHERE shop_id = ? AND id IN ?`, shopID, ids).Error; err != nil {
				return err
			}
			// 校验：修复后 Σ明细售价小计 应与源单头合计 sale_total 一致（只报不改）
			if err := tx.Raw(`SELECT o.order_no FROM stock_out_orders o
				WHERE o.shop_id = ? AND o.id IN ?
				  AND ABS(o.sale_total - (SELECT COALESCE(SUM(i.sale_amount),0)
					FROM stock_out_items i WHERE i.order_id = o.id)) > 0.01`,
				shopID, ids).Scan(&st.TotalMismatches).Error; err != nil {
				return err
			}
		}

		if !apply {
			return errDryRun
		}
		return nil
	})
	if err != nil && !errors.Is(err, errDryRun) {
		return nil, err
	}
	return st, nil
}

func main() {
	var (
		shopCode = flag.String("shop-code", "", "目标门店 code（与 shop-id 二选一）")
		shopID   = flag.Uint64("shop-id", 0, "目标门店 id（与 shop-code 二选一）")
		apply    = flag.Bool("apply", false, "真正落库（缺省 dry-run：试算后回滚）")
		envFile  = flag.String("env-file", "", "可选：systemd 风格 KEY=VALUE 环境文件（读取 DATABASE_DSN）")
	)
	flag.Parse()

	if *envFile != "" {
		loadEnvFile(*envFile)
	}
	config.Load()
	db, err := gorm.Open(mysql.Open(config.C.Database.DSN), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Silent),
	})
	if err != nil {
		log.Fatalf("连接数据库失败: %v", err)
	}

	var shop model.Shop
	switch {
	case *shopID > 0:
		if err := db.First(&shop, *shopID).Error; err != nil {
			log.Fatalf("门店 id=%d 不存在: %v", *shopID, err)
		}
	case *shopCode != "":
		if err := db.Where("code = ?", *shopCode).First(&shop).Error; err != nil {
			log.Fatalf("门店 code=%s 不存在: %v", *shopCode, err)
		}
	default:
		log.Fatal("必须指定 --shop-code 或 --shop-id")
	}

	st, err := fixShop(db, shop.ID, *apply)
	if err != nil {
		log.Fatalf("修复失败（已回滚，未改动任何数据）: %v", err)
	}

	mode := "*** DRY-RUN（已回滚，未写库）***"
	if *apply {
		mode = "已落库"
	}
	fmt.Println("═══════════════════════════════════════════")
	fmt.Println("  历史出库价格错列修复汇总 —— " + mode)
	fmt.Println("═══════════════════════════════════════════")
	fmt.Printf("  门店：%s (id=%d)\n", shop.Name, shop.ID)
	fmt.Printf("  修复明细行（售价←原成本列）：%d\n", st.Items)
	fmt.Printf("  成本回填：入库价 %d / 库存价 %d / 商品进价 %d / 查无(成本待定) %d\n",
		st.CostFromStockIn, st.CostFromInventory, st.CostFromProduct, st.CostUnmatched)
	fmt.Printf("  涉及出库单（已重算利润）：%d\n", st.Orders)
	if len(st.TotalMismatches) > 0 {
		fmt.Printf("  ⚠ 应收合计与明细不一致的单（未改动，需人工核）：%v\n", st.TotalMismatches)
	} else {
		fmt.Println("  应收合计校验：全部一致 ✓")
	}
}

func loadEnvFile(path string) {
	data, err := os.ReadFile(path)
	if err != nil {
		log.Fatalf("读取 env 文件 %s 失败: %v", path, err)
	}
	for _, line := range strings.Split(string(data), "\n") {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		eq := strings.IndexByte(line, '=')
		if eq <= 0 {
			continue
		}
		key := strings.TrimSpace(line[:eq])
		val := strings.TrimSpace(line[eq+1:])
		if len(val) >= 2 && (val[0] == '"' || val[0] == '\'') && val[len(val)-1] == val[0] {
			val = val[1 : len(val)-1]
		}
		_ = os.Setenv(key, val)
	}
}