package logger

import (
	"context"
	"log/slog"
	"os"
	"strings"
)

type ctxKey struct{}

var (
	L      *slog.Logger = slog.Default()
	logKey              = ctxKey{}
)

// Init 初始化全局日志
func Init(level, format string) {
	var handler slog.Handler
	opts := &slog.HandlerOptions{
		Level: parseLevel(level),
	}

	if strings.ToLower(format) == "json" {
		handler = slog.NewJSONHandler(os.Stdout, opts)
	} else {
		handler = slog.NewTextHandler(os.Stdout, opts)
	}

	L = slog.New(handler)
	slog.SetDefault(L)
}

// FromContext 从 context 中获取 logger，如果不存在则返回全局 logger
func FromContext(ctx context.Context) *slog.Logger {
	if l, ok := ctx.Value(logKey).(*slog.Logger); ok {
		return l
	}
	return L
}

// WithContext 将 logger 注入 context
func WithContext(ctx context.Context, l *slog.Logger) context.Context {
	return context.WithValue(ctx, logKey, l)
}

func parseLevel(level string) slog.Level {
	switch strings.ToLower(level) {
	case "debug":
		return slog.LevelDebug
	case "info":
		return slog.LevelInfo
	case "warn":
		return slog.LevelWarn
	case "error":
		return slog.LevelError
	default:
		return slog.LevelInfo
	}
}

// 快捷方法，支持强类型 slog.Attr 或松散的 key-value 对
func Debug(msg string, args ...any) { L.Debug(msg, args...) }
func Info(msg string, args ...any)  { L.Info(msg, args...) }
func Warn(msg string, args ...any)  { L.Warn(msg, args...) }
func Error(msg string, args ...any) { L.Error(msg, args...) }