package logger

import (
	"context"
	"os"
	"path/filepath"
	"strings"

	"github.com/gofiber/fiber/v3"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"gopkg.in/natefinch/lumberjack.v2"
)

var Log *zap.Logger

const TraceIDKey = "request_id"

// ======================
// 配置结构
// ======================

type Config struct {
	Dir        string // 日志目录
	Level      string // debug info warn error
	MaxSize    int    // MB
	MaxBackups int
	MaxAge     int  // 天
	Compress   bool // 是否压缩
}

// ======================
// 初始化
// ======================

func Init(cfg Config) {
	if cfg.Dir == "" {
		cfg.Dir = "logs"
	}

	if cfg.Level == "" {
		cfg.Level = "info"
	}

	level := parseLevel(cfg.Level)

	encoderConfig := zapcore.EncoderConfig{
		TimeKey:      "time",
		LevelKey:     "level",
		MessageKey:   "msg",
		CallerKey:    "caller",
		EncodeLevel:  zapcore.CapitalLevelEncoder,
		EncodeTime:   zapcore.ISO8601TimeEncoder,
		EncodeCaller: zapcore.ShortCallerEncoder,
	}

	encoder := zapcore.NewJSONEncoder(encoderConfig)

	// 控制台
	consoleWriter := zapcore.AddSync(os.Stdout)

	// 文件 writer（info）
	infoWriter := getWriter(cfg, "info")

	// 文件 writer（error）
	errorWriter := getWriter(cfg, "error")

	// info core
	infoCore := zapcore.NewCore(
		encoder,
		zapcore.NewMultiWriteSyncer(consoleWriter, infoWriter),
		zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
			return lvl < zapcore.ErrorLevel && lvl >= level
		}),
	)

	// error core
	errorCore := zapcore.NewCore(
		encoder,
		zapcore.NewMultiWriteSyncer(consoleWriter, errorWriter),
		zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
			return lvl >= zapcore.ErrorLevel
		}),
	)

	core := zapcore.NewTee(infoCore, errorCore)

	Log = zap.New(core, zap.AddCaller(), zap.AddCallerSkip(1))
}

// ======================
// lumberjack writer
// ======================

func getWriter(cfg Config, level string) zapcore.WriteSyncer {
	dir := filepath.Join(cfg.Dir, level)
	_ = os.MkdirAll(dir, os.ModePerm)

	return zapcore.AddSync(&lumberjack.Logger{
		Filename:   filepath.Join(dir, level+".log"),
		MaxSize:    cfg.MaxSize,
		MaxBackups: cfg.MaxBackups,
		MaxAge:     cfg.MaxAge,
		Compress:   cfg.Compress,
	})
}

// ======================
// level 解析
// ======================

func parseLevel(lvl string) zapcore.Level {
	switch strings.ToLower(lvl) {
	case "debug":
		return zap.DebugLevel
	case "warn":
		return zap.WarnLevel
	case "error":
		return zap.ErrorLevel
	default:
		return zap.InfoLevel
	}
}

// ======================
// trace 支持（核心）
// ======================

// Fiber 中使用
func Ctx(c fiber.Ctx) *zap.Logger {
	if c == nil {
		return Log
	}

	traceID, _ := c.Locals(TraceIDKey).(string)
	if traceID == "" {
		return Log
	}

	return Log.With(zap.String("trace_id", traceID))
}

// Service / Repo 使用
func FromCtx(ctx context.Context) *zap.Logger {
	if ctx == nil {
		return Log
	}

	traceID, _ := ctx.Value(TraceIDKey).(string)
	if traceID == "" {
		return Log
	}

	return Log.With(zap.String("trace_id", traceID))
}

// 注入 trace
func WithTrace(ctx context.Context, traceID string) context.Context {
	return context.WithValue(ctx, TraceIDKey, traceID)
}

// ======================
// 优雅退出
// ======================

func Sync() {
	if Log != nil {
		_ = Log.Sync()
	}
}