package log

import (
	"context"
	"fmt"
	"io"
	"log/slog"
	"os"
	"path"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
	"time"

	"github.com/zeromicro/go-zero/core/logx"
	"go.opentelemetry.io/otel/trace"
	"gopkg.in/natefinch/lumberjack.v2"
)

var workdir, _ = filepath.Abs(filepath.Dir(os.Args[0]))

type Logger struct {
	*slog.Logger
}

func SetDefault(logger *Logger) {
	slog.SetDefault(logger.Logger)
}

func NewLogger(conf LogConf) *Logger {
	var log *slog.Logger

	logLevel := slog.LevelInfo
	switch strings.ToLower(conf.Level) {
	case "error":
		logLevel = slog.LevelError
	case "warn":
		logLevel = slog.LevelWarn
	case "info":
		logLevel = slog.LevelInfo
	case "debug":
		logLevel = slog.LevelDebug
	}

	if !path.IsAbs(conf.Filename) {
		conf.Filename = filepath.Join(workdir, conf.Filename)
	}

	// 按天切割日志：每天一个文件，命名格式 bj_power_mes-YYYY-MM-DD.log
	// 每天内仍�?lumberjack 按大小（MaxSize）滚动，保留 MaxBackups 个备�?
	dw := newDailyWriter(conf)

	var writer io.Writer = dw
	if conf.Console {
		writer = io.MultiWriter(writer, os.Stdout)
	}
	log = slog.New(NewContextHandler(writer, conf.Format, &slog.HandlerOptions{
		Level:     logLevel,
		AddSource: conf.AddSource,
		ReplaceAttr: func(_ []string, attr slog.Attr) slog.Attr {
			switch attr.Key {
			case "caller":
				return slog.Attr{}
			case slog.SourceKey:
				if source, ok := attr.Value.Any().(*slog.Source); ok {
					if source.File == "" {
						return slog.Attr{}
					}
					return slog.String(slog.SourceKey, " "+filepath.Base(source.File)+fmt.Sprintf(":%d", source.Line))
				}
			case slog.TimeKey:
				return slog.String(slog.TimeKey, attr.Value.Time().Format(conf.TimeFormat))
			}
			return attr
		},
	}))
	return &Logger{
		Logger: log,
	}
}

func (l *Logger) Alert(v any) {
	l.Logger.Info("%v", v)
}

func (l *Logger) Close() error {
	return nil
}

func (l *Logger) buildAttrs(fields []logx.LogField) []slog.Attr {
	attrs := make([]slog.Attr, 0, len(fields))
	for _, field := range fields {
		attrs = append(attrs, slog.Attr{
			Key:   field.Key,
			Value: slog.AnyValue(field.Value),
		})
	}
	return attrs
}

func (l *Logger) DebugCtx(ctx context.Context, v ...any) {
	if !l.Enabled(ctx, slog.LevelDebug) {
		return
	}
	var pcs [1]uintptr
	// skip [runtime.Callers, this function, this function's caller]
	runtime.Callers(2, pcs[:])
	pc := pcs[0]

	r := slog.NewRecord(time.Now(), slog.LevelDebug, fmt.Sprint(v...), pc)
	var attrs []slog.Attr
	spanCtx := trace.SpanContextFromContext(ctx)
	if spanCtx.HasTraceID() {
		attrs = append(attrs, slog.String("trace", spanCtx.TraceID().String()))
	}
	if spanCtx.HasSpanID() {
		attrs = append(attrs, slog.String("span", spanCtx.SpanID().String()))
	}
	r.AddAttrs(attrs...)
	if ctx == nil {
		ctx = context.Background()
	}
	_ = l.Handler().Handle(ctx, r)
}

func (l *Logger) log(ctx context.Context, level slog.Level, msg string, args ...any) {
	if !l.Enabled(ctx, level) {
		return
	}
	var pc uintptr
	var pcs [1]uintptr
	// skip [runtime.Callers, this function, this function's caller]
	runtime.Callers(5, pcs[:])
	pc = pcs[0]

	r := slog.NewRecord(time.Now(), level, msg, pc)
	r.Add(args...)
	if ctx == nil {
		ctx = context.Background()
	}
	_ = l.Handler().Handle(ctx, r)
}
func (l *Logger) logAttrs(ctx context.Context, level slog.Level, msg string, attrs ...slog.Attr) {
	if !l.Enabled(ctx, level) {
		return
	}
	var pcs [1]uintptr
	// skip [runtime.Callers, this function, this function's caller]
	runtime.Callers(5, pcs[:])
	pc := pcs[0]

	r := slog.NewRecord(time.Now(), level, msg, pc)
	r.AddAttrs(attrs...)
	if ctx == nil {
		ctx = context.Background()
	}
	_ = l.Handler().Handle(ctx, r)
}

func (l *Logger) Debug(v any, fields ...logx.LogField) {
	attrs := l.buildAttrs(fields)
	l.logAttrs(context.Background(), slog.LevelDebug, fmt.Sprintf("%v", v), attrs...)
}

func (l *Logger) Error(v any, fields ...logx.LogField) {
	attrs := l.buildAttrs(fields)
	l.logAttrs(context.Background(), slog.LevelError, fmt.Sprintf("%v", v), attrs...)
}

// skipHttpPollLog 过滤高频轮询日志：前端轮询接口（成功 GET）每秒数次刷屏，
// 无排障价值直接丢弃；写操作（POST/PUT/DELETE）与�?2xx 错误响应保留�?
func skipHttpPollLog(v any) bool {
	msg, ok := v.(string)
	if !ok || !strings.HasPrefix(msg, "[HTTP]") {
		return false
	}
	// 格式: [HTTP] 200 - GET /api/v1/jobs - 127.0.0.1:49864 - UA
	parts := strings.SplitN(msg, " - ", 3)
	if len(parts) < 3 {
		return false
	}
	code := strings.TrimSpace(strings.TrimPrefix(parts[0], "[HTTP]"))
	if len(code) < 1 || code[0] != '2' {
		return false
	}
	return strings.HasPrefix(parts[1], "GET ")
}

func (l *Logger) Info(v any, fields ...logx.LogField) {
	if skipHttpPollLog(v) {
		return
	}
	attrs := l.buildAttrs(fields)
	l.logAttrs(context.Background(), slog.LevelInfo, fmt.Sprintf("%v", v), attrs...)
}

func (l *Logger) Severe(v any) {
	l.log(context.Background(), slog.LevelError, fmt.Sprintf("%v", v))
}

func (l *Logger) Slow(v any, fields ...logx.LogField) {
	if skipHttpPollLog(v) {
		return
	}
	attrs := l.buildAttrs(fields)
	l.logAttrs(context.Background(), slog.LevelWarn, fmt.Sprintf("%v", v), attrs...)
}

func (l *Logger) Stack(v any) {
	l.log(context.Background(), slog.LevelError, fmt.Sprintf("%v", v))
}

func (l *Logger) Stat(v any, fields ...logx.LogField) {
	attrs := l.buildAttrs(fields)
	l.logAttrs(context.Background(), slog.LevelInfo, fmt.Sprintf("%v", v), attrs...)
}

// dailyWriter 按天切割日志写入器�?
// 每次 Write 时检查当前日期，跨天时自动切换文件�?
// 每天内由 lumberjack 按大小滚动，保留 MaxBackups 个备份�?
type dailyWriter struct {
	mu         sync.Mutex
	conf       LogConf
	baseDir    string
	baseName   string // 不含扩展名的基础文件名，�?"bj_power_mes"
	ext        string // 扩展名，�?".log"
	currentDay string
	lj         *lumberjack.Logger
}

func newDailyWriter(conf LogConf) *dailyWriter {
	dir := filepath.Dir(conf.Filename)
	ext := filepath.Ext(conf.Filename)
	base := strings.TrimSuffix(filepath.Base(conf.Filename), ext)
	// 确保日志目录存在
	if err := os.MkdirAll(dir, 0755); err != nil {
		// 创建目录失败时回退到可执行文件目录，避免程序启动失�?
		slog.Error("log: 创建日志目录失败，回退到工作目�?, "dir", dir, "error", err)
		dir = workdir
	}
	return &dailyWriter{
		conf:     conf,
		baseDir:  dir,
		baseName: base,
		ext:      ext,
	}
}

func (w *dailyWriter) Write(p []byte) (n int, err error) {
	w.mu.Lock()
	defer w.mu.Unlock()

	day := time.Now().Format("2006-01-02")
	if day != w.currentDay {
		// 跨天：关闭旧 writer，创建新文件
		if w.lj != nil {
			w.lj.Close()
		}
		filename := filepath.Join(w.baseDir, w.baseName+"-"+day+w.ext)
		w.lj = &lumberjack.Logger{
			Filename:   filename,
			MaxSize:    w.conf.MaxSize,
			MaxBackups: w.conf.MaxBackups,
			MaxAge:     w.conf.MaxAge,
			Compress:   w.conf.Compress,
		}
		w.currentDay = day
	}
	return w.lj.Write(p)
}