package utils

import (
	"database/sql/driver"
	"fmt"
	"strings"
	"time"

	"gorm.io/gorm"
	"gorm.io/gorm/schema"
)

var AsiaShanghai *time.Location

func init() {
	var err error
	AsiaShanghai, err = time.LoadLocation("Asia/Shanghai")
	if err != nil {
		AsiaShanghai = time.FixedZone("CST", 8*3600)
	}
}

// CustomTime 自定义时间类型
type CustomTime struct {
	time.Time
}

// Now 获取当前时间
func Now() CustomTime {
	return CustomTime{time.Now().In(AsiaShanghai)}
}

// Format 返回 yyyy-mm-dd H:i:s 格式字符串

func (ct CustomTime) Format(layouts ...string) string {
	if ct.IsZero() {
		return ""
	}

	layout := time.DateTime // 默认格式：2006-01-02 15:04:05

	if len(layouts) > 0 && layouts[0] != "" {
		layout = layouts[0]
	}

	return ct.Time.Format(layout)
}

// String 实现 Stringer 接口
// func (ct CustomTime) String() string {
// 	return ct.Format()
// }

func (ct CustomTime) String() string {
	if ct.Time.IsZero() {
		return ""
	}
	return ct.Time.Format(time.DateTime)
}

// MarshalJSON 实现 JSON 序列化
func (ct CustomTime) MarshalJSON() ([]byte, error) {
	if ct.IsZero() {
		return []byte("null"), nil
	}
	return []byte(`"` + ct.Format() + `"`), nil
}

// UnmarshalJSON 实现 JSON 反序列化
func (ct *CustomTime) UnmarshalJSON(data []byte) error {
	str := string(data)
	if str == "null" || str == `""` {
		ct.Time = time.Time{}
		return nil
	}

	// 去除引号
	str = strings.Trim(str, `"`)

	// 尝试解析多种格式
	formats := []string{
		"2006-01-02",
		"2006-01-02 15:04:05",
		"2006-01-02T15:04:05Z07:00",
		time.RFC3339,
		time.RFC3339Nano,
	}

	var err error
	for _, layout := range formats {
		ct.Time, err = time.Parse(layout, str)
		if err == nil {
			return nil
		}
	}

	return fmt.Errorf("invalid time format: %s", str)
}

// Value 实现 driver.Valuer 接口 (数据库写入)
func (ct CustomTime) Value() (driver.Value, error) {
	if ct.IsZero() {
		return nil, nil
	}
	return ct.Time, nil
}

// Scan 实现 sql.Scanner 接口 (数据库读取)
func (ct *CustomTime) Scan(value interface{}) error {
	if value == nil {
		ct.Time = time.Time{}
		return nil
	}

	switch v := value.(type) {
	case time.Time:
		ct.Time = v
		return nil
	case []byte:
		return ct.UnmarshalJSON(v)
	case string:
		return ct.UnmarshalJSON([]byte(v))
	default:
		return fmt.Errorf("unsupported type: %T", value)
	}
}

// GormDataType 定义 GORM 数据库类型
func (CustomTime) GormDataType() string {
	return "datetime"
}

// GormDBDataType 定义 GORM 数据库类型 (v2 版本)
func (CustomTime) GormDBDataType(db *gorm.DB, field *schema.Field) string {
	switch db.Dialector.Name() {
	case "mysql", "sqlite":
		return "datetime"
	case "postgres":
		return "timestamp"
	default:
		return "datetime"
	}
}

func ParseTime(s string) (time.Time, error) {
	formats := []string{
		"2006-01-02",
		"2006-01-02 15:04:05",
	}

	var t time.Time
	var err error

	for _, layout := range formats {
		t, err = time.ParseInLocation(layout, s, time.Local)
		if err == nil {
			return t, nil
		}
	}

	return time.Time{}, fmt.Errorf("invalid time format: %s", s)
}

func dayBoundary(s string, h, m, sec int) (CustomTime, error) {
	t, err := ParseTime(s)
	if err != nil {
		return CustomTime{}, err
	}

	return CustomTime{
		Time: time.Date(t.Year(), t.Month(), t.Day(), h, m, sec, 0, t.Location()),
	}, nil
}

func TimeStart(day int, timeStr string) string {
	// 2. 格式化开始时间：前一天 23:59:59
	startTime, err := time.Parse(time.DateOnly, timeStr)
	if err == nil {
		startTime = startTime.Add(time.Duration(-24*day) * time.Hour) // 减N天
		startResult := startTime.Format(time.DateOnly)
		return startResult + " 23:59:59"
	}
	return ""
}

func TimeEnd(day int, timeStr string) string {
	endTime, err := time.Parse(time.DateOnly, timeStr)
	if err == nil {
		endTime = endTime.Add(time.Duration(+24*day) * time.Hour) // 加一天
		endResult := endTime.Format(time.DateTime)
		return endResult
	}
	return ""
}

func TimeToUnix(timeStr string, layout string) (int64, error) {
	t, err := time.ParseInLocation(layout, timeStr, time.FixedZone("CST", 8*3600))
	if err != nil {
		Logger.Error(err)
		return 0, err
	}

	// 转 11 位时间戳（秒）
	return t.Unix(), nil
}
func ParseCustomTime(s string) (CustomTime, error) {
	ct := CustomTime{}
	// UnmarshalJSON 需要带双引号的json字符串，所以包装成json字符串格式
	err := ct.UnmarshalJSON([]byte(`"` + s + `"`))
	if err != nil {
		return CustomTime{}, err
	}
	return ct, nil
}