msgPurge.go

package main

import (
	"fmt"
	"strconv"
	"strings"
	"time"

	"github.com/bwmarrin/discordgo"
)

func init() {
	newCommand("purge",
		discordgo.PermissionAdministrator|discordgo.PermissionManageMessages|discordgo.PermissionManageServer,
		true, msgPurge).setHelp("Args: [number] [@user]\n\nPurges 'number' amount of messages. Optionally, purge only the messages from a given user!\nAdmin only\n\nExample:\n`!owo purge 300`\n" +
		"Example 2:\n`!owo purge 300 @Strum355#1180`").add()
}

func msgPurge(s *discordgo.Session, m *discordgo.MessageCreate, msglist []string) {
	if len(msglist) < 2 {
		s.ChannelMessageSend(m.ChannelID, "Gotta specify a number of messages to delete~")
		return
	}

	purgeAmount, err := strconv.Atoi(msglist[1])
	if err != nil {
		if strings.HasPrefix(msglist[1], "@") {
			msglist[1] = "@" + zerowidth + strings.TrimPrefix(msglist[1], "@")
		}
		s.ChannelMessageSend(m.ChannelID, fmt.Sprintf("How do i delete %s messages? Please only give numbers!", msglist[1]))
		return
	}

	var userToPurge string
	if len(msglist) == 3 {
		submatch := userIDRegex.FindStringSubmatch(msglist[2])
		if len(submatch) == 0 {
			s.ChannelMessageSend(m.ChannelID, "Couldn't find that user :(")
			return
		}
		userToPurge = submatch[1]
	}

	deleteMessage(m.Message, s)

	if userToPurge == "" {
		err = standardPurge(purgeAmount, s, m)
	} else {
		err = userPurge(purgeAmount, s, m, userToPurge)
	}

	if err == nil {
		msg, _ := s.ChannelMessageSend(m.ChannelID, "Successfully deleted :ok_hand:")
		time.Sleep(time.Second * 5)
		deleteMessage(msg, s)
	}
}

func getMessages(amount int, id string, s *discordgo.Session) (list []*discordgo.Message, err error) {
	list, err = s.ChannelMessages(id, amount, "", "", "")
	if err != nil {
		log.Error("error getting messages to delete", err)
	}
	return
}

func standardPurge(purgeAmount int, s *discordgo.Session, m *discordgo.MessageCreate) error {
	var outOfDate bool
	for purgeAmount > 0 {
		list, err := getMessages(purgeAmount%100, m.ChannelID, s)
		if err != nil {
			s.ChannelMessageSend(m.ChannelID, "There was an issue deleting messages :(")
			return err
		}

		//if more was requested to be deleted than exists
		if len(list) == 0 {
			break
		}

		var purgeList []string
		for _, msg := range list {
			timeSince, err := getMessageAge(msg, s, m)
			if err != nil {
				//if the time is malformed for whatever reason, we'll try the next message
				continue
			}

			if timeSince.Hours()/24 >= 14 {
				outOfDate = true
				break
			}

			purgeList = append(purgeList, msg.ID)
		}

		if err := massDelete(purgeList, s, m); err != nil {
			return err
		}

		if outOfDate {
			break
		}

		purgeAmount -= len(purgeList)
	}

	return nil
}

func userPurge(purgeAmount int, s *discordgo.Session, m *discordgo.MessageCreate, userToPurge string) error {
	var outOfDate bool
	for purgeAmount > 0 {
		del := purgeAmount % 100
		var purgeList []string

		for len(purgeList) < del {
			list, err := getMessages(100, m.ChannelID, s)
			if err != nil {
				s.ChannelMessageSend(m.ChannelID, "There was an issue deleting messages :(")
				return err
			}

			//if more was requested to be deleted than exists
			if len(list) == 0 {
				break
			}

			for _, msg := range list {
				if len(purgeList) == del {
					break
				}

				if msg.Author.ID != userToPurge {
					continue
				}

				timeSince, err := getMessageAge(msg, s, m)
				if err != nil {
					//if the time is malformed for whatever reason, we'll try the next message
					continue
				}

				if timeSince.Hours()/24 >= 14 {
					outOfDate = true
					break
				}

				purgeList = append(purgeList, msg.ID)
			}

			if outOfDate {
				break
			}
		}

		if err := massDelete(purgeList, s, m); err != nil {
			return err
		}

		if outOfDate {
			break
		}

		purgeAmount -= len(purgeList)
	}

	return nil
}

func massDelete(list []string, s *discordgo.Session, m *discordgo.MessageCreate) (err error) {
	if err = s.ChannelMessagesBulkDelete(m.ChannelID, list); err != nil {
		s.ChannelMessageSend(m.ChannelID, "There was an issue deleting messages :(")
		log.Error("error purging", err)
	}
	return
}

func getMessageAge(msg *discordgo.Message, s *discordgo.Session, m *discordgo.MessageCreate) (time.Duration, error) {
	then, err := msg.Timestamp.Parse()
	if err != nil {
		log.Error("error parsing time", err)
		return time.Duration(0), err
	}
	return time.Since(then), nil
}