package logger

import (
	"fmt"
	"io"
	"os"
	"strings"
	"sync"
	"sync/atomic"
	"time"

	"Moonshark/color"
)

// Log levels
const (
	LevelDebug = iota
	LevelInfo
	LevelWarn
	LevelError
	LevelFatal
)

// Level config
var levels = map[int]struct {
	tag   string
	color func(string) string
}{
	LevelDebug: {"D", color.Cyan},
	LevelInfo:  {"I", color.Blue},
	LevelWarn:  {"W", color.Yellow},
	LevelError: {"E", color.Red},
	LevelFatal: {"F", color.Purple},
}

var (
	global     *Logger
	globalOnce sync.Once
)

type Logger struct {
	out       io.Writer
	enabled   atomic.Bool
	timestamp atomic.Bool
	debug     atomic.Bool
	colors    atomic.Bool
	mu        sync.Mutex
}

func init() {
	globalOnce.Do(func() {
		global = &Logger{out: os.Stdout}
		global.enabled.Store(true)
		global.timestamp.Store(true)
		global.colors.Store(true)
	})
}

func applyColor(text string, colorFunc func(string) string) string {
	if global.colors.Load() {
		return colorFunc(text)
	}
	return text
}

func write(level int, msg string) {
	if !global.enabled.Load() {
		return
	}

	if level == LevelDebug && !global.debug.Load() {
		return
	}

	var parts []string

	if global.timestamp.Load() {
		ts := applyColor(time.Now().Format("3:04PM"), color.Gray)
		parts = append(parts, ts)
	}

	if cfg, ok := levels[level]; ok {
		tag := applyColor("["+cfg.tag+"]", cfg.color)
		parts = append(parts, tag)
	}

	parts = append(parts, msg)
	line := strings.Join(parts, " ") + "\n"

	global.mu.Lock()
	fmt.Fprint(global.out, line)
	if level == LevelFatal {
		if f, ok := global.out.(*os.File); ok {
			f.Sync()
		}
	}
	global.mu.Unlock()

	if level == LevelFatal {
		os.Exit(1)
	}
}

func log(level int, format string, args ...any) {
	var msg string
	if len(args) > 0 {
		msg = fmt.Sprintf(format, args...)
	} else {
		msg = format
	}
	write(level, msg)
}

func Debugf(format string, args ...any) { log(LevelDebug, format, args...) }
func Infof(format string, args ...any)  { log(LevelInfo, format, args...) }
func Warnf(format string, args ...any)  { log(LevelWarn, format, args...) }
func Errorf(format string, args ...any) { log(LevelError, format, args...) }
func Fatalf(format string, args ...any) { log(LevelFatal, format, args...) }

func Raw(format string, args ...any) {
	if !global.enabled.Load() {
		return
	}

	var msg string
	if len(args) > 0 {
		msg = fmt.Sprintf(format, args...)
	} else {
		msg = format
	}

	global.mu.Lock()
	fmt.Fprint(global.out, msg+"\n")
	global.mu.Unlock()
}

func Request(status int, method, path string, duration time.Duration) {
	if !global.enabled.Load() {
		return
	}

	var statusColor func(string) string
	switch {
	case status < 300:
		statusColor = color.Green
	case status < 400:
		statusColor = color.Cyan
	case status < 500:
		statusColor = color.Yellow
	default:
		statusColor = color.Red
	}

	var dur string
	us := duration.Microseconds()
	switch {
	case us < 1000:
		dur = fmt.Sprintf("%.0fµs", float64(us))
	case us < 1000000:
		dur = fmt.Sprintf("%.1fms", float64(us)/1000)
	default:
		dur = fmt.Sprintf("%.2fs", duration.Seconds())
	}

	var parts []string

	if global.timestamp.Load() {
		ts := applyColor(time.Now().Format("3:04PM"), color.Gray)
		parts = append(parts, ts)
	}

	parts = append(parts,
		applyColor("["+method+"]", color.Gray),
		applyColor(fmt.Sprintf("%d", status), statusColor),
		applyColor(path, color.Gray),
		applyColor(dur, color.Gray),
	)

	msg := strings.Join(parts, " ")

	global.mu.Lock()
	fmt.Fprint(global.out, msg+"\n")
	global.mu.Unlock()
}

func SetOutput(w io.Writer) {
	global.mu.Lock()
	global.out = w
	global.mu.Unlock()
}

func Enable()                { global.enabled.Store(true) }
func Disable()               { global.enabled.Store(false) }
func IsEnabled() bool        { return global.enabled.Load() }
func EnableColors()          { global.colors.Store(true) }
func DisableColors()         { global.colors.Store(false) }
func ColorsEnabled() bool    { return global.colors.Load() }
func Timestamp(enabled bool) { global.timestamp.Store(enabled) }
func Debug(enabled bool)     { global.debug.Store(enabled) }
func IsDebug() bool          { return global.debug.Load() }