package service

import (
	"log"

	"gorm.io/gorm"

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

// BackfillPricingColumns 2026-07 定价字段消歧的一次性数据迁移（幂等，可反复执行）：
//   - stock_in_items / stock_out_items：unit_price→cost_price、total_price→cost_amount
//   - stock_in_orders：total_amount→cost_total；stock_out_orders：total_amount→sale_total
//   - stock_out_items.sale_amount = sale_price×quantity（待定价行保持 0）
//   - stock_out_orders.profit_total = Σ(sale_price>0 ? (sale_price-cost_price)×qty : 0)
//
// 只在新列为 0 且旧列非 0 时拷贝，不修改旧列（旧列观察一版后手动 DROP）。
// profit_total 以「为 0 且存在已定价明细」为待回填判据——利润恰为 0 的单重算一次
// 结果不变，幂等。全新安装（schema.sql 已无旧列）时整体跳过。
func BackfillPricingColumns(db *gorm.DB) {
	// 旧列存在性守卫：四张表的旧列是同批产生的，抽查一张即可
	// （model 已无 UnitPrice 字段，HasColumn 会按原始列名探测）
	if !db.Migrator().HasColumn(&model.StockOutItem{}, "unit_price") {
		return
	}
	stmts := []string{
		`UPDATE stock_in_items SET cost_price = unit_price WHERE cost_price = 0 AND unit_price <> 0`,
		`UPDATE stock_in_items SET cost_amount = total_price WHERE cost_amount = 0 AND total_price <> 0`,
		`UPDATE stock_in_orders SET cost_total = total_amount WHERE cost_total = 0 AND total_amount <> 0`,
		`UPDATE stock_out_items SET cost_price = unit_price WHERE cost_price = 0 AND unit_price <> 0`,
		`UPDATE stock_out_items SET cost_amount = total_price WHERE cost_amount = 0 AND total_price <> 0`,
		`UPDATE stock_out_items SET sale_amount = sale_price * quantity WHERE sale_amount = 0 AND sale_price > 0`,
		`UPDATE stock_out_orders SET sale_total = total_amount WHERE sale_total = 0 AND total_amount <> 0`,
		`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 profit_total = 0 AND EXISTS (
			SELECT 1 FROM stock_out_items i2
			WHERE i2.order_id = stock_out_orders.id AND i2.sale_price > 0
		)`,
	}
	for _, q := range stmts {
		res := db.Exec(q)
		if res.Error != nil {
			log.Printf("backfill pricing columns failed (%.60s...): %v", q, res.Error)
		} else if res.RowsAffected > 0 {
			log.Printf("backfill pricing: %d rows (%.60s...)", res.RowsAffected, q)
		}
	}
}