From 70a7b1d0e5519a677a84baa242f4d4497c13131e Mon Sep 17 00:00:00 2001
From: Jannis R <mail@jannisr.de>
Date: Sun, 1 Apr 2018 22:52:07 +0200
Subject: [PATCH] in groups, react to replies as well

---
 commands/help.js                              |  7 +++--
 index.js                                      |  4 +--
 ...=> in-groups-only-mentions-and-replies.js} | 12 +++++---
 lib/text-without-mention.js                   | 30 ++++++++++---------
 4 files changed, 30 insertions(+), 23 deletions(-)
 rename lib/{in-groups-only-mentions.js => in-groups-only-mentions-and-replies.js} (55%)

diff --git a/commands/help.js b/commands/help.js
index 7625902..611a4a1 100644
--- a/commands/help.js
+++ b/commands/help.js
@@ -21,9 +21,10 @@ When specifying time, you can use the following formats:
 - \`tuesday at 6\`
 The data behind this bot is from VBB, so departures & routing will be just as (in)accurate as in the BVG & VBB apps.
 
-**When using this bot in a group**, telegram prevents it from listening to all messages. In this case you need to mention the bot in every message. For example:
-1. \`/a@${HANDLE} U Friedrichstr.\`
-2. \`@${HANDLE} in 10 min\``
+**When using this bot in a group**, telegram prevents it from listening to normal messages. In this case you need to have two choices:
+
+- Mention the bot in every message. For example: \`/a@${HANDLE} U Friedrichstr.\` and later \`@${HANDLE} in 10 min\`.
+- Always reply to the bot with the reply feature.`
 
 const help = async (ctx, next) => {
 	const group = ctx.chat.type === 'group'
diff --git a/index.js b/index.js
index 04b9db2..317bc43 100644
--- a/index.js
+++ b/index.js
@@ -4,7 +4,7 @@ const path = require('path')
 const Bot = require('telegraf')
 const url = require('url')
 
-const inGroupsOnlyMentions = require('./lib/in-groups-only-mentions')
+const inGroupsOnlyMentionsAndReplies = require('./lib/in-groups-only-mentions-and-replies')
 const textWithoutMention = require('./lib/text-without-mention')
 const logging = require('./lib/logging')
 const session = require('./lib/session')
@@ -33,7 +33,7 @@ const pathToDb = path.join(__dirname, 'vbb-telegram.ldb')
 
 const bot = new Bot(TOKEN)
 
-bot.use(inGroupsOnlyMentions)
+bot.use(inGroupsOnlyMentionsAndReplies)
 bot.use(textWithoutMention)
 bot.use(logging)
 bot.use(session(pathToDb))
diff --git a/lib/in-groups-only-mentions.js b/lib/in-groups-only-mentions-and-replies.js
similarity index 55%
rename from lib/in-groups-only-mentions.js
rename to lib/in-groups-only-mentions-and-replies.js
index 3da78d0..d77d5c7 100644
--- a/lib/in-groups-only-mentions.js
+++ b/lib/in-groups-only-mentions-and-replies.js
@@ -8,16 +8,20 @@ if (!HANDLE) {
 
 const mention = ('@' + HANDLE).toLowerCase()
 
-const inGroupsOnlyMentions = (ctx, next) => {
+const inGroupsOnlyMentionsAndReplies = (ctx, next) => {
 	if (!ctx.chat || !ctx.chat.type || !ctx.message) return null
 	if (ctx.chat.type === 'group') {
+		const replyMsg = ctx.message.reply_to_message
+		const isReply = replyMsg && replyMsg.from.username === HANDLE
 		const text = ctx.message.text
-		if (text) {
+		if (!isReply && text) {
 			const i = text.toLowerCase().indexOf(mention)
-			if (i < 0) return null // no mention
+			if (i < 0) {
+				return null // no mention
+			}
 		}
 	}
 	next()
 }
 
-module.exports = inGroupsOnlyMentions
+module.exports = inGroupsOnlyMentionsAndReplies
diff --git a/lib/text-without-mention.js b/lib/text-without-mention.js
index ad0f630..8271a0c 100644
--- a/lib/text-without-mention.js
+++ b/lib/text-without-mention.js
@@ -21,22 +21,24 @@ const textWithoutMention = (ctx, next) => {
 		next()
 		return
 	}
-	const text = ctx.message.text
+	const text = (ctx.message.text + '').toLowerCase()
 
 	const i = text.indexOf(mention)
-	if (i < 0) return null
-
-	const afterSpace = text[i - 1] === ' '
-	const atTheStart = i === 0
-	const beforeSpace = text[i + mention.length] === ' '
-	const atTheEnd = text.length === (i + mention.length)
-
-	let start = i, end = i + mention.length
-	if (afterSpace && atTheEnd) start--
-	else if (beforeSpace && atTheStart) end++
-	else if (beforeSpace && afterSpace) end++
-
-	ctx.message.textWithoutMention = text.slice(0, start) + text.slice(end)
+	if (i < 0) {
+		ctx.message.textWithoutMention = text
+	} else {
+		const afterSpace = text[i - 1] === ' '
+		const atTheStart = i === 0
+		const beforeSpace = text[i + mention.length] === ' '
+		const atTheEnd = text.length === (i + mention.length)
+
+		let start = i, end = i + mention.length
+		if (afterSpace && atTheEnd) start--
+		else if (beforeSpace && atTheStart) end++
+		else if (beforeSpace && afterSpace) end++
+
+		ctx.message.textWithoutMention = text.slice(0, start) + text.slice(end)
+	}
 	next()
 }