package main

import (
	"io"
	"os"
	"path/filepath"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/sirupsen/logrus"
)

// Logger is the global logger instance
var Logger *logrus.Logger

// InitLogger initializes the structured logger with file output
func InitLogger(config *Config) error {
	Logger = logrus.New()

	// Set log level based on configuration
	level, err := logrus.ParseLevel(config.LogLevel)
	if err != nil {
		level = logrus.InfoLevel
	}
	Logger.SetLevel(level)

	// Set JSON formatter for structured logging
	Logger.SetFormatter(&logrus.JSONFormatter{
		TimestampFormat: time.RFC3339,
		FieldMap: logrus.FieldMap{
			logrus.FieldKeyTime:  "timestamp",
			logrus.FieldKeyLevel: "level",
			logrus.FieldKeyMsg:   "message",
		},
	})

	// Create log directory if it doesn't exist
	if err := os.MkdirAll(config.LogDir, 0755); err != nil {
		return err
	}

	// Create log file with timestamp
	logFile := filepath.Join(config.LogDir, "app.log")
	file, err := os.OpenFile(logFile, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
	if err != nil {
		return err
	}

	// Set output to both file and stdout
	multiWriter := io.MultiWriter(os.Stdout, file)
	Logger.SetOutput(multiWriter)

	// Log initialization with default fields
	Logger.WithFields(logrus.Fields{
		"service":     "counter-app",
		"environment": string(config.Environment),
		"version":     "1.0.0",
	}).Info("Logger initialized successfully")

	return nil
}

// GetLogger returns the global logger instance
func GetLogger() *logrus.Logger {
	if Logger == nil {
		// Fallback to standard logger if not initialized
		logrus.SetFormatter(&logrus.JSONFormatter{
			TimestampFormat: time.RFC3339,
		})
		return logrus.StandardLogger()
	}
	return Logger
}

// GetLoggerWithDefaults returns a logger entry with default fields
func GetLoggerWithDefaults(env Environment) *logrus.Entry {
	return Logger.WithFields(logrus.Fields{
		"service":     "counter-app",
		"environment": string(env),
		"version":     "1.0.0",
	})
}

// LoggingMiddleware creates a Gin middleware for HTTP request logging
func LoggingMiddleware(config *Config) gin.HandlerFunc {
	return gin.LoggerWithFormatter(func(param gin.LogFormatterParams) string {
		// Create structured log entry with default fields
		entry := Logger.WithFields(logrus.Fields{
			"service":     "counter-app",
			"environment": string(config.Environment),
			"version":     "1.0.0",
			"method":      param.Method,
			"path":        param.Path,
			"status":      param.StatusCode,
			"latency":     param.Latency.String(),
			"client_ip":   param.ClientIP,
			"user_agent":  param.Request.UserAgent(),
			"timestamp":   param.TimeStamp.Format(time.RFC3339),
		})

		// Set log level based on status code
		switch {
		case param.StatusCode >= 500:
			entry.Error("HTTP Request")
		case param.StatusCode >= 400:
			entry.Warn("HTTP Request")
		default:
			entry.Info("HTTP Request")
		}

		// Return empty string since we're handling logging ourselves
		return ""
	})
}