package logger

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	rotatelogs "github.com/lestrrat-go/file-rotatelogs"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

const (
	TRACKED = "trackID"
)

var (
	Logger     *zap.Logger
	loggerMux  sync.Once
	CallerSkip = 2
	initErr    error
)

// BuildLogger 初始化日志系统
func BuildLogger() error {
	loggerMux.Do(func() {
		initErr = initLogger()
	})
	return initErr
}

// initLogger 实际的日志初始化逻辑
func initLogger() error {
	logLevel := getLogLevel()
	logPath := os.Getenv("LOG_PATH")
	if logPath == "" {
		logPath = "./logs" // 默认日志路径
	}

	// 尝试创建日志目录
	if err := os.MkdirAll(logPath, 0755); err != nil {
		// 使用标准库的log记录错误，因为zap还没初始化
		log.Printf("无法创建日志目录 %s: %v", logPath, err)
		return fmt.Errorf("无法创建日志目录 %s: %w", logPath, err)
	}

	// 配置滚动日志（按天滚动，保留28天）
	logFileName := filepath.Join(logPath, "ego.%Y%m%d.log")
	logs, err := rotatelogs.New(
		logFileName,
		rotatelogs.WithMaxAge(28*24*time.Hour),
		rotatelogs.WithRotationTime(24*time.Hour),
	)
	if err != nil {
		log.Printf("创建滚动日志失败: %v", err)
		return fmt.Errorf("创建滚动日志失败: %w", err)
	}

	// 配置控制台输出
	consoleEncoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())
	consoleSyncer := zapcore.AddSync(os.Stdout)

	// 配置文件输出（生产环境JSON格式）
	prodEncoderConfig := zap.NewProductionEncoderConfig()
	prodEncoderConfig.EncodeTime = TimeEncoder
	prodEncoderConfig.CallerKey = "caller"
	prodEncoderConfig.EncodeCaller = zapcore.ShortCallerEncoder
	prodEncoder := zapcore.NewJSONEncoder(prodEncoderConfig)
	fileSyncer := zapcore.AddSync(logs)

	// 创建日志核心
	core := zapcore.NewTee(
		zapcore.NewCore(consoleEncoder, consoleSyncer, logLevel),
		zapcore.NewCore(prodEncoder, fileSyncer, logLevel),
	)

	// 初始化 Logger
	Logger = zap.New(core, zap.AddCaller(), zap.AddCallerSkip(CallerSkip))

	// 记录初始化成功
	Logger.Info("日志系统初始化成功",
		zap.String("log_path", logPath),
		zap.String("log_level", logLevel.String()),
	)

	return nil
}

// Debug 记录调试日志
func Debug(c *gin.Context, msg string, fields ...zap.Field) {
	if Logger != nil {
		logWithTrack(c, zap.DebugLevel, msg, fields...)
	}
}

// Info 记录信息日志
func Info(c *gin.Context, msg string, fields ...zap.Field) {
	if Logger != nil {
		logWithTrack(c, zap.InfoLevel, msg, fields...)
	}
}

// Warn 记录警告日志
func Warn(c *gin.Context, msg string, fields ...zap.Field) {
	if Logger != nil {
		logWithTrack(c, zap.WarnLevel, msg, fields...)
	}
}

// Error 记录错误日志
func Error(c *gin.Context, msg string, fields ...zap.Field) {
	if Logger != nil {
		logWithTrack(c, zap.ErrorLevel, msg, fields...)
	}
}

// logWithTrack 封装带 trackID 的日志记录
func logWithTrack(c *gin.Context, level zapcore.Level, msg string, fields ...zap.Field) {
	if Logger == nil {
		return
	}

	if c == nil {
		Logger.Check(level, msg).Write(fields...)
		return
	}
	trackID := GetTrackID(c)
	Logger.Check(level, msg).Write(append(fields, zap.String("trackID", trackID))...)
}

// GetTrackID 获取或生成 trackID
func GetTrackID(c *gin.Context) string {
	if trackID, exists := c.Get(TRACKED); exists {
		return trackID.(string)
	}
	if random, err := uuid.NewRandom(); err == nil {
		// 生成新的 trackID 并存入上下文
		newTrackID := strings.ToLower(random.String())
		c.Set(TRACKED, newTrackID)
		return newTrackID
	}
	return ""
}

// getLogLevel 根据环境变量获取日志级别
func getLogLevel() zapcore.Level {
	switch strings.ToLower(os.Getenv("LOG_LEVEL")) {
	case "debug":
		return zap.DebugLevel
	case "info":
		return zap.InfoLevel
	case "warn":
		return zap.WarnLevel
	case "error":
		return zap.ErrorLevel
	default:
		return zap.InfoLevel // 默认使用 Info 级别
	}
}

// TimeEncoder 自定义时间格式
func TimeEncoder(t time.Time, enc zapcore.PrimitiveArrayEncoder) {
	enc.AppendString(t.Format("2006-01-02 15:04:05.999"))
}