package utils

import (
	"fmt"
	"os"
	"path/filepath"
	"time"

	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"gorm.io/gorm"

	"filestoragesystem/internal/model"
)

var logger *zap.Logger

// Logger 获取全局日志对象
func Logger() *zap.Logger {
	if logger == nil {
		logger, _ = zap.NewProduction()
	}
	return logger
}

// InitLogger 初始化zap日志(控制台 + 可选文件)
func InitLogger(level, dir string) (*zap.Logger, error) {
	lvl := zapcore.InfoLevel
	_ = lvl.UnmarshalText([]byte(level))

	encoderCfg := zap.NewProductionEncoderConfig()
	encoderCfg.EncodeTime = zapcore.ISO8601TimeEncoder
	encoderCfg.EncodeLevel = zapcore.CapitalLevelEncoder

	cores := make([]zapcore.Core, 0, 3)

	// 控制台
	consoleSyncer := zapcore.AddSync(os.Stdout)
	consoleEncoder := zapcore.NewConsoleEncoder(encoderCfg)
	cores = append(cores, zapcore.NewCore(consoleEncoder, consoleSyncer, lvl))

	// 文件
	if dir != "" {
		if err := os.MkdirAll(dir, 0o755); err == nil {
			fileSyncer := zapcore.AddSync(&dateRollFile{dir: dir})
			fileEncoder := zapcore.NewJSONEncoder(encoderCfg)
			cores = append(cores, zapcore.NewCore(fileEncoder, fileSyncer, lvl))
		}
	}

	logger = zap.New(zapcore.NewTee(cores...), zap.AddCaller(), zap.AddCallerSkip(1))
	return logger, nil
}

// dateRollFile 按天滚动的日志文件
type dateRollFile struct {
	dir string
	f   *os.File
	day string
}

func (d *dateRollFile) Write(p []byte) (int, error) {
	today := time.Now().Format("2006-01-02")
	if d.f == nil || d.day != today {
		if d.f != nil {
			_ = d.f.Close()
		}
		path := filepath.Join(d.dir, "app-"+today+".log")
		f, err := os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o644)
		if err != nil {
			return 0, err
		}
		d.f, d.day = f, today
	}
	return d.f.Write(p)
}

func (d *dateRollFile) Sync() error {
	if d.f != nil {
		return d.f.Sync()
	}
	return nil
}

// ---- 系统日志异步落库 ----

var sysLogDB *gorm.DB
var sysLogCh chan model.SystemLog

// InitSystemLog 初始化系统日志异步写入器
func InitSystemLog(db *gorm.DB) {
	sysLogDB = db
	sysLogCh = make(chan model.SystemLog, 256)
	go func() {
		for entry := range sysLogCh {
			if err := sysLogDB.Create(&entry).Error; err != nil {
				Logger().Error("写入系统日志失败", zap.Error(err))
			}
		}
	}()
}

// SystemLog 异步记录一条系统日志
func SystemLog(level, module, message string) {
	if sysLogCh == nil {
		return
	}
	select {
	case sysLogCh <- model.SystemLog{Level: level, Module: module, Message: message, CreatedAt: time.Now()}:
	default:
		// 队列满则丢弃，避免阻塞业务
	}
}

// SystemLogDetail 异步记录带详情的系统日志
func SystemLogDetail(level, module, message, requestID, ip, extra string) {
	if sysLogCh == nil {
		return
	}
	select {
	case sysLogCh <- model.SystemLog{
		Level: level, Module: module, Message: message,
		RequestID: requestID, IP: ip, ExtraData: extra, CreatedAt: time.Now(),
	}:
	default:
	}
}

// Info 记录info级别系统日志
func Info(module, format string, args ...interface{}) {
	SystemLog("info", module, fmt.Sprintf(format, args...))
}

// Warn 记录warn级别系统日志
func Warn(module, format string, args ...interface{}) {
	SystemLog("warn", module, fmt.Sprintf(format, args...))
}

// Error 记录error级别系统日志
func Error(module, format string, args ...interface{}) {
	SystemLog("error", module, fmt.Sprintf(format, args...))
}