package mux

import (
	"github.com/bwmarrin/discordgo"
	"time"
sc	"strconv"
	"container/list"
)


// Channel for posting reminders -- inits in main
var RemChan chan Reminder

// Stores a reminder to be posted to a given user
type Reminder struct {
	NotifyAfter	time.Time
	Reason		string
	User			discordgo.User
	ChannelID	string
	Session		discordgo.Session
}

// Reminder daemon process that gets started in main and listens on RemChan
func Reminders() {
	// Should be a heap and persist across reboots
	rems := list.New()
	for {
		select {
		case r := <- RemChan:
			// Handle new reminder
			rems.PushBack(r)
			
		default:
			// Check for any due reminders
			for e := rems.Front(); ; e = e.Next() {
				if e == nil {
					break
				}
				
				r, _ := e.Value.(Reminder)
				if time.Now().After(r.NotifyAfter) {
					// If we have passed the time of desired notification
					r.Session.ChannelMessageSend(r.ChannelID, r.Reason)
					rems.Remove(e)
				}
			}
		
			time.Sleep(50 * time.Millisecond)
		}
	}
}

// Reminds a user about a given reason after a specified time interval has passed
func (m *Mux) RemindMe(ds *discordgo.Session, dm *discordgo.Message, ctx *Context) {
	resp := ""
	
	// remindme 20m dothing
	if len(ctx.Fields) >= 3 {
		var rem Reminder
		periodLong := ctx.Fields[len(ctx.Fields)-2]
		reasonLong := ctx.Fields[2 : len(ctx.Fields)]
		rem.User = *dm.Author
		rem.ChannelID = dm.ChannelID
		rem.Session = *ds
		
		reason := ""
		for _, v := range reasonLong {
			reason += v
			reason += " "
		}
		rem.Reason = reason
		
		interval := periodLong[len(periodLong)-1]
		period, err := sc.Atoi(periodLong[:len(periodLong)-2])
		if err != nil {
			resp += "Invalid period value."
			goto SEND
		}
		
		var dur time.Duration
		switch interval {
		case 's':
			dur = time.Second
		case 'm':
			dur = time.Minute
		case 'h':
			dur = time.Hour
		default:
			resp += "Invalid interval specifier."
			goto SEND
		}

		rem.NotifyAfter = time.Now().Add(time.Duration(period) * dur)
		
		RemChan <- rem
		
	} else {
		resp += "Please specify a time operator in the form [int][type] and a description (20h do thing)."
	}
	
	SEND:
	resp += "\n"

	ds.ChannelMessageSend(dm.ChannelID, resp)

	return
}