package rfctime

import (
	"encoding/json"
	"errors"
	"fmt"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/bsoncodec"
	"go.mongodb.org/mongo-driver/bson/bsonrw"
	"go.mongodb.org/mongo-driver/bson/bsontype"
	"reflect"
	"strconv"
	"strings"
	"time"
)

type Date struct {
	Year  int
	Month int
	Day   int
}

func (t Date) Time(loc *time.Location) time.Time {
	return time.Date(t.Year, time.Month(t.Month), t.Day, 0, 0, 0, 0, loc)
}

func (t Date) TimeUTC() time.Time {
	return time.Date(t.Year, time.Month(t.Month), t.Day, 0, 0, 0, 0, time.UTC)
}

func (t Date) TimeLocal() time.Time {
	return time.Date(t.Year, time.Month(t.Month), t.Day, 0, 0, 0, 0, time.Local)
}

func (t Date) MarshalBinary() ([]byte, error) {
	return t.TimeUTC().MarshalBinary()
}

func (t *Date) UnmarshalBinary(data []byte) error {
	nt := time.Time{}
	if err := nt.UnmarshalBinary(data); err != nil {
		return err
	}
	t.Year = nt.Year()
	t.Month = int(nt.Month())
	t.Day = nt.Day()
	return nil
}

func (t Date) GobEncode() ([]byte, error) {
	return t.TimeUTC().GobEncode()
}

func (t *Date) GobDecode(data []byte) error {
	nt := time.Time{}
	if err := nt.GobDecode(data); err != nil {
		return err
	}
	t.Year = nt.Year()
	t.Month = int(nt.Month())
	t.Day = nt.Day()
	return nil
}

func (t *Date) UnmarshalJSON(data []byte) error {
	str := ""
	if err := json.Unmarshal(data, &str); err != nil {
		return err
	}
	return t.ParseString(str)
}

func (t Date) MarshalJSON() ([]byte, error) {
	str := t.String()
	return json.Marshal(str)
}

func (t Date) MarshalText() ([]byte, error) {
	return []byte(t.String()), nil
}

func (t *Date) UnmarshalText(data []byte) error {
	return t.ParseString(string(data))
}

func (t *Date) UnmarshalBSONValue(bt bsontype.Type, data []byte) error {
	if bt == bsontype.Null {
		// we can't set nil in UnmarshalBSONValue (so we use default(struct))
		// Use mongoext.CreateGoExtBsonRegistry if you need to unmarsh pointer values
		// https://stackoverflow.com/questions/75167597
		// https://jira.mongodb.org/browse/GODRIVER-2252
		*t = Date{}
		return nil
	}
	if bt != bsontype.String {
		return errors.New(fmt.Sprintf("cannot unmarshal %v into Date", bt))
	}

	var tt string
	err := bson.RawValue{Type: bt, Value: data}.Unmarshal(&tt)
	if err != nil {
		return err
	}

	v, err := time.Parse(t.FormatStr(), tt)
	if err != nil {
		return err
	}
	t.Year = v.Year()
	t.Month = int(v.Month())
	t.Day = v.Day()

	return nil
}

func (t Date) MarshalBSONValue() (bsontype.Type, []byte, error) {
	return bson.MarshalValue(t.TimeUTC().Format(t.FormatStr()))
}

func (t Date) DecodeValue(dc bsoncodec.DecodeContext, vr bsonrw.ValueReader, val reflect.Value) error {
	if val.Kind() == reflect.Ptr && val.IsNil() {
		if !val.CanSet() {
			return errors.New("ValueUnmarshalerDecodeValue")
		}
		val.Set(reflect.New(val.Type().Elem()))
	}

	tp, src, err := bsonrw.Copier{}.CopyValueToBytes(vr)
	if err != nil {
		return err
	}

	if val.Kind() == reflect.Ptr && len(src) == 0 {
		val.Set(reflect.Zero(val.Type()))
		return nil
	}

	err = t.UnmarshalBSONValue(tp, src)
	if err != nil {
		return err
	}

	if val.Kind() == reflect.Ptr {
		val.Set(reflect.ValueOf(&t))
	} else {
		val.Set(reflect.ValueOf(t))
	}

	return nil
}

func (t Date) Serialize() string {
	return t.String()
}

func (t Date) FormatStr() string {
	return "2006-01-02"
}

func (t Date) Date() (year int, month time.Month, day int) {
	return t.TimeUTC().Date()
}

func (t Date) Weekday() time.Weekday {
	return t.TimeUTC().Weekday()
}

func (t Date) ISOWeek() (year, week int) {
	return t.TimeUTC().ISOWeek()
}

func (t Date) YearDay() int {
	return t.TimeUTC().YearDay()
}

func (t Date) AddDate(years int, months int, days int) Date {
	return NewDate(t.TimeUTC().AddDate(years, months, days))
}

func (t Date) Unix() int64 {
	return t.TimeUTC().Unix()
}

func (t Date) UnixMilli() int64 {
	return t.TimeUTC().UnixMilli()
}

func (t Date) UnixMicro() int64 {
	return t.TimeUTC().UnixMicro()
}

func (t Date) UnixNano() int64 {
	return t.TimeUTC().UnixNano()
}

func (t Date) Format(layout string) string {
	return t.TimeUTC().Format(layout)
}

func (t Date) GoString() string {
	return fmt.Sprintf("rfctime.Date{Year: %d, Month: %d, Day: %d}", t.Year, t.Month, t.Day)
}

func (t Date) String() string {
	return fmt.Sprintf("%04d-%02d-%02d", t.Year, t.Month, t.Day)
}

func (t *Date) ParseString(v string) error {
	split := strings.Split(v, "-")
	if len(split) != 3 {
		return errors.New("invalid date format: " + v)
	}
	year, err := strconv.ParseInt(split[0], 10, 32)
	if err != nil {
		return errors.New("invalid date format: " + v + ": " + err.Error())
	}
	month, err := strconv.ParseInt(split[1], 10, 32)
	if err != nil {
		return errors.New("invalid date format: " + v + ": " + err.Error())
	}
	day, err := strconv.ParseInt(split[2], 10, 32)
	if err != nil {
		return errors.New("invalid date format: " + v + ": " + err.Error())
	}

	if year < 0 {
		return errors.New("invalid date format: " + v + ": year is negative")
	}

	if month < 1 || month > 12 {
		return errors.New("invalid date format: " + v + ": month is out of range")
	}

	if day < 1 || day > 31 {
		return errors.New("invalid date format: " + v + ": day is out of range")
	}

	t.Year = int(year)
	t.Month = int(month)
	t.Day = int(day)

	return nil
}

func NewDate(t time.Time) Date {
	return Date{
		Year:  t.Year(),
		Month: int(t.Month()),
		Day:   t.Day(),
	}
}

func NowDate(loc *time.Location) Date {
	return NewDate(time.Now().In(loc))
}

func NowDateLoc() Date {
	return NewDate(time.Now().In(time.UTC))
}

func NowDateUTC() Date {
	return NewDate(time.Now().In(time.Local))
}