From 9a5e486430ab432008d3777731cc4c782cbfe7c8 Mon Sep 17 00:00:00 2001
From: Shigbeard <4262327+Shigbeard@users.noreply.github.com>
Date: Thu, 18 May 2023 22:40:06 +1000
Subject: [PATCH] Add Features - Mention and Channel Link conversion for
 Discord Relay (#4)

* Added functionality to convert mentions
---
 src/relayDiscord.go |  3 +++
 src/utils.go        | 56 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/src/relayDiscord.go b/src/relayDiscord.go
index 0d43733..825a268 100644
--- a/src/relayDiscord.go
+++ b/src/relayDiscord.go
@@ -44,6 +44,9 @@ func messageCreate(s *discordgo.Session, m *discordgo.MessageCreate) {
 		message = m.Content
 	}
 
+	// Convert all <@ >, <# >, and similarly formatted items in Discord messages to something we can actually read.
+	message = convertDiscordFormattedItems(message, m.GuildID)
+
 	// Convert <:example:868167672758693909> to :example:
 	message = filterDiscordEmotes(message)
 
diff --git a/src/utils.go b/src/utils.go
index 274194c..32ea2bd 100755
--- a/src/utils.go
+++ b/src/utils.go
@@ -81,6 +81,62 @@ func bToMb(b uint64) uint64 {
 	return b / 1024 / 1024
 }
 
+// convertDiscordFormattedItems : Formats Discord Formatted Items to Text Only
+func convertDiscordFormattedItems(str string, gid string) string {
+	// match all discord formatted items
+	reChannel := regexp.MustCompile(`<#(\d+)>`)
+	reMentionUser := regexp.MustCompile(`<@(?:\!)?(\d+)>`)
+	reMentionRole := regexp.MustCompile(`<@&(\d+)>`)
+
+	str = reChannel.ReplaceAllStringFunc(str, func(s string) string {
+		// get the channels for this guild
+		id := reChannel.FindStringSubmatch(s)[1]
+		channels, err := DiscordSession.GuildChannels(gid)
+		if err != nil {
+			log.Errorln("[utils:convertDiscordFormattedItems]", "Error getting guild channels: ", err)
+			return s
+		}
+		for _, c := range channels {
+			if c.ID == id {
+				return "<%" + c.Name + ">"
+			}
+		}
+
+		return s
+	})
+	reMentionUser.FindAllStringSubmatchIndex(str, -1)
+	str = reMentionUser.ReplaceAllStringFunc(str, func(s string) string {
+		// get the user for this guild
+		id := reMentionUser.FindStringSubmatch(s)[1]
+		member, err := DiscordSession.GuildMember(gid, id)
+		if err != nil {
+			log.Errorln("[utils:convertDiscordFormattedItems]", "Error getting guild member: ", err)
+			return s
+		}
+		if member.Nick != "" {
+			return "<@" + member.Nick + ">"
+		} else {
+			return "<@" + member.User.Username + ">"
+		}
+	})
+	str = reMentionRole.ReplaceAllStringFunc(str, func(s string) string {
+		// get the role for this guild
+		id := reMentionRole.FindStringSubmatch(s)[1]
+		roles, err := DiscordSession.GuildRoles(gid)
+		if err != nil {
+			log.Errorln("[utils:convertDiscordFormattedItems]", "Error getting guild roles: ", err)
+			return s
+		}
+		for _, r := range roles {
+			if r.ID == id {
+				return "<%@" + r.Name + ">"
+			}
+		}
+		return s
+	})
+	return str
+}
+
 // filterDiscordEmotes : Formats Discord Emotes Correctly
 func filterDiscordEmotes(str string) string {
 	re := regexp.MustCompile(`<:(\S+):\d+>`)