package config

import (
	"bytes"
	"fmt"
	"log"
	"os"
	"path/filepath"

	"github.com/joho/godotenv"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

var DB *gorm.DB

// JWTSecret is the secret key used for signing JWT tokens
var JWTSecret = "your-secret-key" // Default value, should be set via JWT_SECRET environment variable in production

// utf8BOM 用于剥离 Windows 编辑器常写入的 UTF-8 BOM，否则 godotenv 会解析失败
var utf8BOM = []byte{0xEF, 0xBB, 0xBF}

// tryLoadEnv 尝试加载指定路径的 .env；成功则记录日志并返回 true。
// 会先去掉 UTF-8 BOM，再按 godotenv 默认语义：不覆盖已存在的 OS 环境变量。
func tryLoadEnv(path string) bool {
	if path == "" {
		return false
	}
	raw, err := os.ReadFile(path)
	if err != nil {
		return false
	}
	raw = bytes.TrimPrefix(raw, utf8BOM)
	envMap, err := godotenv.Parse(bytes.NewReader(raw))
	if err != nil {
		log.Printf("Warning: found .env at %s but failed to parse: %v", path, err)
		return false
	}
	applied := 0
	for k, v := range envMap {
		if os.Getenv(k) == "" {
			_ = os.Setenv(k, v)
			applied++
		}
	}
	log.Printf("Loaded .env file from %s (%d keys applied)", path, applied)
	return true
}

// collectEnvCandidates 收集候选 .env 路径：可执行文件旁、cwd、cwd/server、向上 3 级
func collectEnvCandidates() []string {
	seen := map[string]struct{}{}
	var list []string
	add := func(p string) {
		abs, err := filepath.Abs(p)
		if err != nil {
			abs = p
		}
		if _, ok := seen[abs]; ok {
			return
		}
		seen[abs] = struct{}{}
		list = append(list, abs)
	}

	if execPath, err := os.Executable(); err == nil {
		add(filepath.Join(filepath.Dir(execPath), ".env"))
	} else {
		log.Printf("Warning: Failed to get executable path: %v", err)
	}

	cwd, err := os.Getwd()
	if err != nil {
		log.Printf("Warning: Failed to get working directory: %v", err)
		cwd = "."
	}
	add(filepath.Join(cwd, ".env"))
	add(filepath.Join(cwd, "server", ".env")) // 从仓库根启动时

	// 向上最多 3 级父目录查找 .env 与 server/.env
	dir := cwd
	for i := 0; i < 3; i++ {
		parent := filepath.Dir(dir)
		if parent == dir {
			break
		}
		dir = parent
		add(filepath.Join(dir, ".env"))
		add(filepath.Join(dir, "server", ".env"))
	}
	return list
}

// LoadEnvFile 依次尝试多个路径加载 .env（后加载补缺，不覆盖已有 OS 环境变量）
func LoadEnvFile() {
	loadedPaths := []string{}
	for _, p := range collectEnvCandidates() {
		if tryLoadEnv(p) {
			loadedPaths = append(loadedPaths, p)
		}
	}

	if len(loadedPaths) == 0 {
		log.Println("Info: no .env loaded; relying on process environment variables")
	} else {
		log.Printf("Env load summary: %d file(s) loaded", len(loadedPaths))
	}

	appID := os.Getenv("WECHAT_APP_ID")
	secret := os.Getenv("WECHAT_APP_SECRET")
	log.Printf(
		"WeChat env: APP_ID_set=%v SECRET_set=%v",
		appID != "",
		secret != "",
	)
}

func InitDB() {
	var err error

	// Try to get DSN from environment variable, otherwise use default
	dsn := os.Getenv("DB_DSN")
	if dsn == "" {
		dsn = "root:root@tcp(127.0.0.1:3306)/nl_blog?charset=utf8mb4&parseTime=True&loc=Local"
		//dsn = "root:mysql_PKC65h@tcp(127.0.0.1:3306)/nl_blog?charset=utf8mb4&parseTime=True&loc=Local"
	}

	// Try to get JWT secret from environment variable
	if secret := os.Getenv("JWT_SECRET"); secret != "" {
		JWTSecret = secret
	}

	DB, err = gorm.Open(mysql.Open(dsn), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Silent), // 禁用 GORM 日志，使用自定义日志
		// 不使用 NowFunc，因为我们使用模型钩子手动处理 int64 时间戳
	})
	if err != nil {
		log.Fatal("Failed to connect to database:", err)
	}

	sqlDB, err := DB.DB()
	if err != nil {
		log.Fatal("Failed to get underlying sql.DB:", err)
	}

	if err = sqlDB.Ping(); err != nil {
		log.Fatal("Failed to ping database:", err)
	}

	fmt.Println("Database connected successfully")
}

func CloseDB() {
	if DB != nil {
		sqlDB, err := DB.DB()
		if err == nil {
			sqlDB.Close()
		}
	}
}