package main

import (
	"fmt"
	"log"

	"github.com/gin-gonic/gin"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"

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

func main() {
	// 加载配置
	config.Load()

	// 生产环境启动前置检查
	if config.C.Server.Mode == "release" {
		if config.C.Server.CORSOrigin == "*" {
			log.Fatal("server.cors_origin must not be '*' in production — set it to the actual frontend origin")
		}
	}

	// 初始化数据库
	db := initDB()

	// ALTER 已有数据库的 enum，使 superadmin 在已运行实例上也生效（忽略错误）
	db.Exec("ALTER TABLE users MODIFY COLUMN role ENUM('admin','operator','readonly','superadmin') NOT NULL DEFAULT 'operator'")

	// 自动迁移（GORM AutoMigrate 只增不删，生产安全）
	autoMigrate(db)

	// 启动会话/失败登录保留期清理任务（后台 goroutine）
	service.StartSessionCleanup(db, config.C.Session.RetentionDays)

	// 启动 Gin
	gin.SetMode(config.C.Server.Mode)
	r := gin.New()
	r.Use(gin.Logger(), gin.Recovery())

	// 真实客户端 IP：只信任本机 nginx（127.0.0.1/::1）写的 X-Real-IP，丢弃客户端伪造的
	// X-Forwarded-For。这样 c.ClientIP() 返回不可伪造的真实 IP，是所有按 IP 限流/审计的基础。
	// 代理链：client → nginx(127.0.0.1:8445) → 后端(127.0.0.1:8080)；将来若在 nginx 前再加
	// 一层代理，需把其地址并入下列可信网段。
	_ = r.SetTrustedProxies([]string{"127.0.0.1", "::1"})
	r.RemoteIPHeaders = []string{"X-Real-IP"}

	// CORS
	corsOrigin := config.C.Server.CORSOrigin
	r.Use(func(c *gin.Context) {
		c.Header("Access-Control-Allow-Origin", corsOrigin)
		c.Header("Access-Control-Allow-Methods", "GET,POST,PUT,DELETE,OPTIONS")
		c.Header("Access-Control-Allow-Headers", "Authorization,Content-Type")
		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(204)
			return
		}
		c.Next()
	})

	// Serve uploaded images (in production, Nginx handles /images/)
	r.Static("/images", config.C.Storage.UploadDir)

	router.Setup(r, db)

	addr := fmt.Sprintf(":%s", config.C.Server.Port)
	log.Printf("Server starting on %s (mode: %s)", addr, config.C.Server.Mode)
	if err := r.Run(addr); err != nil {
		log.Fatalf("Server failed: %v", err)
	}
}

func initDB() *gorm.DB {
	dsn := config.C.Database.DSN
	if dsn == "" {
		log.Fatal("database.dsn is required in config")
	}

	logLevel := logger.Silent
	if config.C.Server.Mode == "debug" {
		logLevel = logger.Info
	}

	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{
		Logger:         logger.Default.LogMode(logLevel),
		TranslateError: true, // 把 MySQL 1062 翻译成 gorm.ErrDuplicatedKey，供编码撞唯一约束时重试
	})
	if err != nil {
		log.Fatalf("failed to connect database: %v", err)
	}

	sqlDB, _ := db.DB()
	sqlDB.SetMaxIdleConns(config.C.Database.MaxIdleConns)
	sqlDB.SetMaxOpenConns(config.C.Database.MaxOpenConns)
	return db
}

func autoMigrate(db *gorm.DB) {
	err := db.AutoMigrate(
		&model.Shop{},
		&model.User{},
		&model.License{},
		&model.LicenseDevice{},
		&model.LicenseCode{},
		&model.UserSession{},
		&model.LoginAttempt{},
		&model.ProductCategory{},
		&model.Product{},
		&model.Warehouse{},
		&model.Partner{},
		&model.StockInOrder{},
		&model.StockInItem{},
		&model.StockOutOrder{},
		&model.StockOutItem{},
		&model.Inventory{},
		&model.InventoryLog{},
		&model.InventoryCheck{},
		&model.InventoryCheckItem{},
		&model.FinanceRecord{},
		&model.NumberRule{},
		&model.ProductNameOption{},
		&model.ProductSeriesOption{},
		&model.ProductSpecOption{},
		&model.ProductOriginOption{},
		&model.ProductShelfLifeOption{},
		&model.ProductStorageOption{},
		&model.ProductDescriptionDoc{},
		&model.ProductImage{},
		&model.ErrorReport{},
		&model.Feedback{},
	)
	if err != nil {
		log.Fatalf("auto migrate failed: %v", err)
	}
	// products(shop_id, code) 联合唯一索引：ShopID 在共用 TenantBase 上无法用 struct tag 表达，
	// 故在此幂等显式建（保证同店内商品编码唯一，DB 层兜底防止重复编码静默落库）。
	if !db.Migrator().HasIndex(&model.Product{}, "uk_shop_code") {
		if err := db.Exec("CREATE UNIQUE INDEX uk_shop_code ON products (shop_id, code)").Error; err != nil {
			log.Fatalf("create unique index uk_shop_code failed: %v", err)
		}
	}
	// stock_out_items(shop_id, product_code) 复合索引：支撑出库列表「按商品编码反查单据」，
	// 避免在 2.6 万+ 明细行上全表扫。ShopID 在嵌入字段上无法用 struct tag 表达，故显式幂等建。
	if !db.Migrator().HasIndex(&model.StockOutItem{}, "idx_so_items_shop_code") {
		if err := db.Exec("CREATE INDEX idx_so_items_shop_code ON stock_out_items (shop_id, product_code)").Error; err != nil {
			log.Fatalf("create index idx_so_items_shop_code failed: %v", err)
		}
	}
	log.Println("AutoMigrate completed")
}