// Filename: internal/logging/logging.go

package logging

import (
	"gemini-balancer/internal/config"
	"io"
	"os"
	"path/filepath"

	"github.com/sirupsen/logrus"
	"gopkg.in/natefinch/lumberjack.v2"
)

// 包级变量，用于存储日志轮转器
var logRotator *lumberjack.Logger

// NewLogger 返回标准的 *logrus.Logger（兼容 Fx 依赖注入）
func NewLogger(cfg *config.Config) *logrus.Logger {
	logger := logrus.New()

	// 设置日志级别
	level, err := logrus.ParseLevel(cfg.Log.Level)
	if err != nil {
		logger.WithField("configured_level", cfg.Log.Level).Warn("Invalid log level, defaulting to 'info'")
		level = logrus.InfoLevel
	}
	logger.SetLevel(level)

	// 设置日志格式
	if cfg.Log.Format == "json" {
		logger.SetFormatter(&logrus.JSONFormatter{
			TimestampFormat: "2006-01-02T15:04:05.000Z07:00",
			FieldMap: logrus.FieldMap{
				logrus.FieldKeyTime:  "timestamp",
				logrus.FieldKeyLevel: "level",
				logrus.FieldKeyMsg:   "message",
			},
		})
	} else {
		logger.SetFormatter(&logrus.TextFormatter{
			FullTimestamp:   true,
			TimestampFormat: "2006-01-02 15:04:05",
		})
	}

	// 添加全局字段
	hostname, _ := os.Hostname()
	logger = logger.WithFields(logrus.Fields{
		"service":  "gemini-balancer",
		"hostname": hostname,
	}).Logger

	// 设置日志输出
	if cfg.Log.EnableFile {
		if cfg.Log.FilePath == "" {
			logger.Warn("Log file enabled but no path specified. Logging to console only")
			logger.SetOutput(os.Stdout)
			return logger
		}

		logDir := filepath.Dir(cfg.Log.FilePath)
		if err := os.MkdirAll(logDir, 0750); err != nil {
			logger.WithError(err).Warn("Failed to create log directory. Logging to console only")
			logger.SetOutput(os.Stdout)
			return logger
		}

		// 配置日志轮转（保存到包级变量）
		logRotator = &lumberjack.Logger{
			Filename:   cfg.Log.FilePath,
			MaxSize:    getOrDefault(cfg.Log.MaxSize, 100),
			MaxBackups: getOrDefault(cfg.Log.MaxBackups, 7),
			MaxAge:     getOrDefault(cfg.Log.MaxAge, 30),
			Compress:   cfg.Log.Compress,
		}

		logger.SetOutput(io.MultiWriter(os.Stdout, logRotator))
		logger.WithField("log_file", cfg.Log.FilePath).Info("Logging to both console and file")
	} else {
		logger.SetOutput(os.Stdout)
	}

	logger.Info("Logger initialized successfully")
	return logger
}

// Close 关闭日志轮转器（在 main.go 中调用）
func Close() {
	if logRotator != nil {
		logRotator.Close()
	}
}

func getOrDefault(value, defaultValue int) int {
	if value <= 0 {
		return defaultValue
	}
	return value
}