package monitor

import (
	"encoding/json"
	"errors"
	"time"

	"github.com/golang-collections/go-datastructures/queue"
)

type Duration struct {
	time.Duration
}

func (d *Duration) MarshalJSON() ([]byte, error) {
	return json.Marshal(d.Duration)
}

func (d *Duration) UnmarshalJSON(b []byte) error {
	var v interface{}
	if err := json.Unmarshal(b, &v); err != nil {
		return err
	}
	switch value := v.(type) {
	case float64:
		d.Duration = time.Duration(value)
		return nil
	case string:
		var err error
		d.Duration, err = time.ParseDuration(value)
		if err != nil {
			return err
		}
		return nil
	default:
		return errors.New("invalid duration")
	}
}

type Item struct {
	URL      string
	Interval Duration
	next     time.Time
}

func NewItem(URL string, Interval time.Duration) *Item {
	return &Item{
		URL:      URL,
		Interval: Duration{Interval},
		next:     time.Now(),
	}
}

func (item *Item) Compare(other queue.Item) int {
	j, ok := other.(*Item)
	if !ok {
		return 0
	}
	if item.next.Before(j.next) {
		return -1
	} else if item.next.After(j.next) {
		return 1
	}
	if item.Interval.Duration < j.Interval.Duration {
		return -1
	} else if item.Interval.Duration > j.Interval.Duration {
		return 1
	}
	return 0
}

func (item *Item) increment() *Item {
	item.next = time.Now().Add(item.Interval.Duration)
	return item
}