package tools

import (
	"context"
	"os"
	"path/filepath"
	"runtime/debug"
	"sync"

	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"gopkg.in/natefinch/lumberjack.v2"
)

var (
	panicLogger *zap.Logger
	panicOnce   sync.Once
	panicMu     sync.RWMutex
)

// initPanicLogger 初始化 panic logger
func initPanicLogger() {
	panicMu.Lock()
	defer panicMu.Unlock()

	if panicLogger != nil {
		return
	}

	panicLogPath := "logs/panic.log"
	logDir := filepath.Dir(panicLogPath)
	if logDir != "." && logDir != "" {
		_ = os.MkdirAll(logDir, 0755)
	}

	hook := lumberjack.Logger{
		Filename:   panicLogPath,
		MaxSize:    100,  // 100MB
		MaxBackups: 10,   // 保留10个备份
		MaxAge:     30,   // 保留30天
		Compress:   true, // 压缩旧日志
	}

	fileSyncer := zapcore.AddSync(&hook)

	encoderConfig := zapcore.EncoderConfig{
		TimeKey:        "time",
		LevelKey:       "level",
		NameKey:        "logger",
		CallerKey:      "linenum",
		MessageKey:     "msg",
		StacktraceKey:  "stacktrace",
		LineEnding:     zapcore.DefaultLineEnding,
		EncodeLevel:    zapcore.LowercaseLevelEncoder,
		EncodeTime:     zapcore.ISO8601TimeEncoder,
		EncodeDuration: zapcore.SecondsDurationEncoder,
		EncodeCaller:   zapcore.FullCallerEncoder,
		EncodeName:     zapcore.FullNameEncoder,
	}

	core := zapcore.NewCore(zapcore.NewJSONEncoder(encoderConfig), fileSyncer, zapcore.ErrorLevel)
	panicLogger = zap.New(core, zap.AddCaller(), zap.AddStacktrace(zapcore.ErrorLevel))
}

// getPanicLogger 获取 panic logger
func getPanicLogger() *zap.Logger {
	panicOnce.Do(initPanicLogger)
	panicMu.RLock()
	defer panicMu.RUnlock()
	return panicLogger
}

// RecoverPanic 捕获 panic 并记录日志
func RecoverPanic(ctx context.Context) {
	if err := recover(); err != nil {
		// 写入 panic.log 文件
		panicLogger := getPanicLogger()
		if panicLogger != nil {
			var traceID string
			if traceIDValue := ctx.Value(TraceIDKey{}); traceIDValue != nil {
				if tid, ok := traceIDValue.(string); ok {
					traceID = tid
				}
			}
			fields := []zap.Field{
				zap.Any("error", err),
				zap.String("stack", string(debug.Stack())),
			}
			if traceID != "" {
				fields = append(fields, zap.String("trace_id", traceID))
			}
			panicLogger.Error("RecoverPanic", fields...)
		}

		// 同时写入普通日志（保持原有行为）
		logger := WithTraceID(ctx.Value(TraceIDKey{}).(string))
		if logger != nil {
			logger.Error("RecoverPanic", zap.Any("error", err), zap.String("stack", string(debug.Stack())))
		}
	}
}