package pkg

import (
	"context"
	"os"
	"strconv"

	"github.com/mattn/go-colorable"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"gopkg.in/natefinch/lumberjack.v2"
)

type LoggerConfig struct {
	Level           zapcore.Level
	Filename        string
	MaxSize         int
	MaxAge          int
	MaxBackups      int
	Compress        bool
	ConsoleEncoding bool // true for Console output, false for JSON
}

var loggerInstance *zap.Logger

// GetLogger returns a singleton logger instance
func GetLogger(ctx context.Context, config LoggerConfig) *zap.Logger {
	if loggerInstance == nil {
		createOrUpdateInstance(config)
	}
	return loggerInstance
}

func createOrUpdateInstance(config LoggerConfig) *zap.Logger {
	core := zapcore.NewTee(
		createFileCore(config),
		createStdoutCore(config),
	)
	loggerInstance = zap.New(core).WithOptions(
		zap.IncreaseLevel(config.Level),
	)
	return loggerInstance
}

// createFileCore creates the file logging core
func createFileCore(config LoggerConfig) zapcore.Core {
	fileEncoderConfig := zap.NewProductionEncoderConfig()
	fileEncoder := zapcore.NewJSONEncoder(fileEncoderConfig)

	fileWriteSyncer := zapcore.AddSync(&lumberjack.Logger{
		Filename:   config.Filename,
		MaxSize:    config.MaxSize,
		MaxAge:     config.MaxAge,
		MaxBackups: config.MaxBackups,
		Compress:   config.Compress,
	})

	return zapcore.NewCore(fileEncoder, fileWriteSyncer, zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
		return lvl >= zapcore.ErrorLevel
	}))
}

// createStdoutCore creates the stdout logging core based on config.ConsoleEncoding
func createStdoutCore(config LoggerConfig) zapcore.Core {
	var encoder zapcore.Encoder
	encoderConfig := zap.NewDevelopmentEncoderConfig()
	encoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
	encoderConfig.TimeKey = ""

	if config.ConsoleEncoding {
		encoder = zapcore.NewConsoleEncoder(encoderConfig)
	} else {
		encoder = zapcore.NewJSONEncoder(encoderConfig)
	}

	stdoutWriteSyncer := zapcore.AddSync(colorable.NewColorableStdout())

	return zapcore.NewCore(encoder, stdoutWriteSyncer, zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
		return true
	}))
}

func OverrideLoggerConfig(config LoggerConfig) {
	Logger = createOrUpdateInstance(config)
}

var level, err = strconv.Atoi(os.Getenv("LOG_LEVEL"))

var Logger = GetLogger(context.Background(), LoggerConfig{
	Level:           zapcore.Level(level),
	Filename:        "./tmp/error.log",
	MaxSize:         100,
	MaxAge:          90,
	MaxBackups:      30,
	Compress:        true,
	ConsoleEncoding: true,
})