// Package log provides optional colored console logging, independent of decryption.
package log

import (
	"fmt"
	"os"
	"path"
	"runtime"
	"sync"
	"time"
)

// Logger writes timestamped, colorized log lines to stderr.
type Logger struct{}

// New returns a logger instance.
func New() *Logger { return &Logger{} }

func (l *Logger) Debug(a ...any) { output(1, "cyan", a...) }
func (l *Logger) Info(a ...any)  { output(1, "green", a...) }
func (l *Logger) Warn(a ...any)  { output(1, "yellow", a...) }
func (l *Logger) Error(a ...any) { output(1, "red", a...) }

// With returns the same logger (scope is ignored; kept for call-site compatibility).
func (l *Logger) With(_ any) *Logger { return l }

// PrintSuccess prints a green/cyan success line for CLI use.
func PrintSuccess(src, dst string) {
	mu.Lock()
	defer mu.Unlock()
	fmt.Fprintf(os.Stderr, "%s %s: ", time.Now().Format("15:04:05.000"), trace(3))
	fmt.Fprintf(os.Stderr, "操作成功: %s -> %s\n", green(src), cyan(dst))
}

var mu sync.Mutex

func output(skip int, color string, v ...any) {
	mu.Lock()
	defer mu.Unlock()
	fmt.Fprint(os.Stderr, time.Now().Format("15:04:05.000"), " ", trace(skip+2), " ")
	fmt.Fprintln(os.Stderr, colorize(color, fmt.Sprint(v...)))
}

func trace(skip int) string {
	_, file, line, ok := runtime.Caller(skip)
	if !ok {
		return "unknown:0"
	}
	return fmt.Sprintf("%s:%d", path.Base(file), line)
}

func colorize(color, s string) string {
	if !supportsColor() {
		return s
	}
	const reset = "\033[0m"
	switch color {
	case "red":
		return "\033[31m" + s + reset
	case "green":
		return "\033[32m" + s + reset
	case "yellow":
		return "\033[33m" + s + reset
	case "cyan":
		return "\033[36m" + s + reset
	default:
		return s
	}
}

func green(s string) string  { return colorize("green", s) }
func cyan(s string) string   { return colorize("cyan", s) }

func supportsColor() bool {
	if os.Getenv("NO_COLOR") != "" {
		return false
	}
	// Windows 10+ and most Unix terminals support ANSI.
	return true
}