package reveil

import (
	"fmt"
	"sort"
	"time"

	"git.nemunai.re/nemunaire/reveil/config"
)

type Date time.Time

func (d *Date) MarshalJSON() (dst []byte, err error) {
	return []byte(fmt.Sprintf("\"%04d-%02d-%02d\"", time.Time(*d).Year(), time.Time(*d).Month(), time.Time(*d).Day())), nil
}

func (d *Date) UnmarshalJSON(src []byte) error {
	tmp, err := time.Parse("\"2006-01-02\"", string(src))
	if err != nil {
		return err
	}
	*d = Date(tmp)

	return nil
}

type Hour time.Time

func (h *Hour) MarshalJSON() (dst []byte, err error) {
	return []byte(fmt.Sprintf("\"%02d:%02d\"", time.Time(*h).Hour(), time.Time(*h).Minute())), nil
}

func (h *Hour) UnmarshalJSON(src []byte) error {
	tmp, err := time.Parse("\"15:04\"", string(src))
	if err != nil {
		return err
	}
	*h = Hour(tmp)

	return nil
}

func GetNextAlarm(cfg *config.Config, db *LevelDBStorage) (*time.Time, []Identifier, error) {
	alarmsRepeated, err := GetAlarmsRepeated(db)
	if err != nil {
		return nil, nil, err
	}

	var closestAlarm *time.Time
	var closestAlarmRoutines []Identifier
	for _, alarm := range alarmsRepeated {
		next := alarm.GetNextOccurence(cfg, db)
		if next != nil && (closestAlarm == nil || closestAlarm.After(*next)) {
			closestAlarm = next
			closestAlarmRoutines = alarm.FollowingRoutines
		}
	}

	alarmsSingle, err := GetAlarmsSingle(db)
	if err != nil {
		return nil, nil, err
	}

	now := time.Now()
	for _, alarm := range alarmsSingle {
		if closestAlarm == nil || (closestAlarm.After(alarm.Time) && alarm.Time.After(now)) {
			closestAlarm = &alarm.Time
			closestAlarmRoutines = alarm.FollowingRoutines
		}
	}

	return closestAlarm, closestAlarmRoutines, nil
}

func GetNextException(cfg *config.Config, db *LevelDBStorage) (*time.Time, error) {
	alarmsExceptions, err := GetAlarmExceptions(db)
	if err != nil {
		return nil, err
	}

	var closestException *time.Time
	for _, except := range alarmsExceptions {
		if except != nil && time.Time(*except.End).After(time.Now()) && (closestException == nil || closestException.After(time.Time(*except.Start))) {
			tmp := time.Time(*except.Start)
			closestException = &tmp
		}
	}

	return closestException, nil
}

func DropNextAlarm(cfg *config.Config, db *LevelDBStorage) error {
	timenext, _, err := GetNextAlarm(cfg, db)
	if err != nil {
		return err
	}

	alarmsRepeated, err := GetAlarmsRepeated(db)
	if err != nil {
		return err
	}

	for _, alarm := range alarmsRepeated {
		next := alarm.GetNextOccurence(cfg, db)
		if next != nil && *next == *timenext {
			start := Date(*next)
			stop := Date((*next).Add(time.Second))

			return PutAlarmException(db, &AlarmException{
				Start:   &start,
				End:     &stop,
				Comment: fmt.Sprintf("Automatic exception to cancel recurrent alarm %s", next.Format("Mon at 15:04")),
			})
		}
	}

	alarmsSingle, err := GetAlarmsSingle(db)
	if err != nil {
		return err
	}

	for _, alarm := range alarmsSingle {
		if alarm.Time == *timenext {
			return DeleteAlarmSingle(db, alarm)
		}
	}

	return fmt.Errorf("Unable to find the next alarm")
}

type Exceptions []time.Time

func (e Exceptions) Len() int {
	return len(e)
}

func (e Exceptions) Less(i, j int) bool {
	return e[i].Before(e[j])
}

func (e Exceptions) Swap(i, j int) {
	e[i], e[j] = e[j], e[i]
}

type AlarmRepeated struct {
	Id                Identifier   `json:"id"`
	Weekday           time.Weekday `json:"weekday"`
	StartTime         *Hour        `json:"time"`
	FollowingRoutines []Identifier `json:"routines"`
	IgnoreExceptions  bool         `json:"ignore_exceptions"`
	Comment           string       `json:"comment,omitempty"`
	Disabled          bool         `json:"disabled,omitempty"`
	Excepts           Exceptions   `json:"excepts,omitempty"`
	NextTime          *time.Time   `json:"next_time,omitempty"`
}

func (a *AlarmRepeated) FillExcepts(cfg *config.Config, db *LevelDBStorage) error {
	if a.IgnoreExceptions {
		return nil
	}

	exceptions, err := GetAlarmExceptions(db)
	if err != nil {
		return err
	}

	now := time.Now()

	for _, exception := range exceptions {
		end := time.Time(*exception.End).AddDate(0, 0, 1)
		if now.After(end) {
			continue
		}

		for t := time.Time(*exception.Start); end.After(t); t = t.AddDate(0, 0, 1) {
			if t.Weekday() == a.Weekday {
				a.Excepts = append(a.Excepts, time.Date(t.Year(), t.Month(), t.Day(), time.Time(*a.StartTime).Hour(), time.Time(*a.StartTime).Minute(), time.Time(*a.StartTime).Second(), 0, time.Local))
				t = t.AddDate(0, 0, 6)
			}
		}
	}

	sort.Sort(a.Excepts)

	return nil
}

func (a *AlarmRepeated) GetNextOccurence(cfg *config.Config, db *LevelDBStorage) *time.Time {
	if a.Disabled {
		return nil
	}

	if len(a.Excepts) == 0 {
		a.FillExcepts(cfg, db)
	}

	now := time.Now()

	today := time.Date(now.Year(), now.Month(), now.Day(), time.Time(*a.StartTime).Hour(), time.Time(*a.StartTime).Minute(), time.Time(*a.StartTime).Second(), 0, time.Local)
	if now.After(today) {
		today = today.AddDate(0, 0, 1)
	}

	end := today.AddDate(0, 0, 7)
	var nextOccurence time.Time
	for nextOccurence = today; end.After(nextOccurence); nextOccurence = nextOccurence.AddDate(0, 0, 1) {
		if nextOccurence.Weekday() == a.Weekday {
			break
		}
	}

	for _, except := range a.Excepts {
		if except.Equal(nextOccurence) {
			nextOccurence = nextOccurence.AddDate(0, 0, 7)
		}
	}

	return &nextOccurence
}

func GetAlarmRepeated(db *LevelDBStorage, id Identifier) (alarm *AlarmRepeated, err error) {
	alarm = &AlarmRepeated{}
	err = db.get(fmt.Sprintf("alarm-repeated-%s", id.ToString()), alarm)
	return
}

func GetAlarmsRepeated(db *LevelDBStorage) (alarms []*AlarmRepeated, err error) {
	iter := db.search("alarm-repeated-")
	defer iter.Release()

	for iter.Next() {
		var a AlarmRepeated

		err = decodeData(iter.Value(), &a)
		if err != nil {
			return
		}

		alarms = append(alarms, &a)
	}

	return
}

func PutAlarmRepeated(db *LevelDBStorage, alarm *AlarmRepeated) (err error) {
	var key string

	if alarm.Id.IsEmpty() {
		var id Identifier

		key, id, err = db.findBytesKey("alarm-repeated-", IDENTIFIER_LEN)
		if err != nil {
			return err
		}
		alarm.Id = id
	} else {
		key = fmt.Sprintf("alarm-repeated-%s", alarm.Id.ToString())
	}

	// Don't store this, this is autocalculated
	alarm.Excepts = nil
	alarm.NextTime = nil

	return db.put(key, alarm)
}

func DeleteAlarmRepeated(db *LevelDBStorage, alarm *AlarmRepeated) (err error) {
	return db.delete(fmt.Sprintf("alarm-repeated-%s", alarm.Id.ToString()))
}

type AlarmSingle struct {
	Id                Identifier   `json:"id"`
	Time              time.Time    `json:"time"`
	FollowingRoutines []Identifier `json:"routines"`
	Comment           string       `json:"comment,omitempty"`
}

func GetAlarmSingle(db *LevelDBStorage, id Identifier) (alarm *AlarmSingle, err error) {
	alarm = &AlarmSingle{}
	err = db.get(fmt.Sprintf("alarm-single-%s", id.ToString()), alarm)
	return
}

func GetAlarmsSingle(db *LevelDBStorage) (alarms []*AlarmSingle, err error) {
	iter := db.search("alarm-single-")
	defer iter.Release()

	for iter.Next() {
		var a AlarmSingle

		err = decodeData(iter.Value(), &a)
		if err != nil {
			return
		}

		alarms = append(alarms, &a)
	}

	return
}

func PutAlarmSingle(db *LevelDBStorage, alarm *AlarmSingle) (err error) {
	var key string

	if alarm.Id.IsEmpty() {
		var id Identifier

		key, id, err = db.findBytesKey("alarm-single-", IDENTIFIER_LEN)
		if err != nil {
			return err
		}
		alarm.Id = id
	} else {
		key = fmt.Sprintf("alarm-single-%s", alarm.Id.ToString())
	}

	return db.put(key, alarm)
}

func DeleteAlarmSingle(db *LevelDBStorage, alarm *AlarmSingle) (err error) {
	return db.delete(fmt.Sprintf("alarm-single-%s", alarm.Id.ToString()))
}

func RemoveOldAlarmsSingle(db *LevelDBStorage) error {
	alarms, err := GetAlarmsSingle(db)
	if err != nil {
		return err
	}

	now := time.Now()
	for _, alarm := range alarms {
		if now.After(time.Time(alarm.Time)) {
			err = DeleteAlarmSingle(db, alarm)
			if err != nil {
				return err
			}
		}
	}

	return nil
}

type AlarmException struct {
	Id      Identifier `json:"id"`
	Start   *Date      `json:"start"`
	End     *Date      `json:"end"`
	Comment string     `json:"comment,omitempty"`
}

func GetAlarmException(db *LevelDBStorage, id Identifier) (alarm *AlarmException, err error) {
	alarm = &AlarmException{}
	err = db.get(fmt.Sprintf("alarm-exception-%s", id.ToString()), alarm)
	return
}

func GetAlarmExceptions(db *LevelDBStorage) (alarms []*AlarmException, err error) {
	iter := db.search("alarm-exception-")
	defer iter.Release()

	for iter.Next() {
		var a AlarmException

		err = decodeData(iter.Value(), &a)
		if err != nil {
			return
		}

		alarms = append(alarms, &a)
	}

	return
}

func PutAlarmException(db *LevelDBStorage, alarm *AlarmException) (err error) {
	var key string

	if alarm.Id.IsEmpty() {
		var id Identifier

		key, id, err = db.findBytesKey("alarm-exception-", IDENTIFIER_LEN)
		if err != nil {
			return err
		}
		alarm.Id = id
	} else {
		key = fmt.Sprintf("alarm-exception-%s", alarm.Id.ToString())
	}

	return db.put(key, alarm)
}

func DeleteAlarmException(db *LevelDBStorage, alarm *AlarmException) (err error) {
	return db.delete(fmt.Sprintf("alarm-exception-%s", alarm.Id.ToString()))
}