#!/bin/bash
# bashbot, the Telegram bot written in bash.
# Written by @topkecleon, Juan Potato (@awkward_potato), Lorenzo Santina (BigNerd95) and Daniil Gentili (danog)
# http://github.com/topkecleon/bashbot

# Depends on JSON.sh (http://github.com/dominictarr/JSON.sh),
# which is MIT/Apache-licensed.

# This file is public domain in the USA and all free countries.
# If you're in Europe, and public domain does not exist, then haha.

TOKEN=''
URL='https://api.telegram.org/bot'$TOKEN
MSG_URL=$URL'/sendMessage'
PHO_URL=$URL'/sendPhoto'
UPD_URL=$URL'/getUpdates?offset='
OFFSET=0

send_message() {
	local chat="$1"
	local text="$(echo "$2" | sed 's/ mykeyboardstartshere.*//g')"
	local keyboard="$(echo "$2" | sed '/mykeyboardstartshere /!d;s/.*mykeyboardstartshere //g')"
	if [ "$keyboard" = "" ]; then
		res=$(curl -s "$MSG_URL" -F "chat_id=$chat" -F "text=$text")
	else
		send_keyboard "$chat" "$text" "$keyboard"
	fi
}

send_keyboard() {
	local chat="$1"
	local text="$2"
	shift 2
	keyboard=init
	for f in $*;do keyboard="$keyboard, [\"$f\"]";done
	keyboard=${keyboard/init, /}
	res=$(curl -s "$MSG_URL" --header "content-type: multipart/form-data" -F "chat_id=$chat" -F "text=$text" -F "reply_markup={\"keyboard\": [$keyboard],\"one_time_keyboard\": true}")
}

send_photo() {
	res=$(curl -s "$PHO_URL" -F "chat_id=$1" -F "photo=@$2")
}

startproc() {
	local copname="$1"
	local TARGET="$2"
	mkdir -p "$copname"
	mkfifo $copname/out
	tmux new-session -d -n $copname "./question $TARGET 2>&1>$copname/out"
	local pid=$(ps aux | sed '/tmux/!d;/'$copname'/!d;/sed/d;s/'$USER'\s*//g;s/\s.*//g')
	echo $pid>$copname/pid
	while ps aux | grep -v grep | grep -q $pid;do
		read -t 10 line
		[ "$line" != "" ] && send_message "$TARGET" "$line"
		line=
	done <$copname/out
}
inproc() {
	local copname="$1"
	local copid="$2"
	shift 2
	tmux send-keys -t $copname "$@
"
	ps aux | grep -v grep | grep -q "$copid" || { rm -r $copname; };
}

process_client() {
	local MESSAGE=$1
	local TARGET=$2
	local msg=""
	local copname="CO$TARGET"
	local copidname="$copname/pid"
	local copid="$(cat $copidname 2>/dev/null)"
	if [ "$copid" = "" ]; then
		case $MESSAGE in
			'/question')
				startproc "$copname" "$TARGET"&
				;;
			'/info')
				send_message "$TARGET" "This is bashbot, the Telegram bot written entirely in bash."
				;;
			'/start')
				send_message "$TARGET" "This is bashbot, the Telegram bot written entirely in bash.
Features background tasks and interactive chats.
Can serve as an interface for cli programs.
Currently can send messages, custom keyboards and photos.

Available commands:
/start: Start bot and get this message.
/info: Get shorter info message about this bot.
/question: Start interactive chat.
/cancel: Cancel any currently running interactive chats.

Written by @topkecleon, Juan Potato (@awkward_potato), Lorenzo Santina (BigNerd95) and Daniil Gentili (danog)
http://github.com/topkecleon/bashbot
"
				;;
			*)
				send_message "$TARGET" "$MESSAGE"
		esac
	else
		case $MESSAGE in
			'/cancel')
				kill $copid
				rm -r $copname
				send_message "$TARGET" "Command canceled."
				;;
			*) inproc "$copname" "$copid" "$MESSAGE";;
		esac
	fi
}

while true; do {

	res=$(curl -s $UPD_URL$OFFSET)

	TARGET=$(echo $res | JSON.sh | egrep '\["result",0,"message","chat","id"\]' | cut -f 2)
	OFFSET=$(echo $res | JSON.sh | egrep '\["result",0,"update_id"\]' | cut -f 2)
	MESSAGE=$(echo $res | JSON.sh -s | egrep '\["result",0,"message","text"\]' | cut -f 2 | cut -d '"' -f 2)

	OFFSET=$((OFFSET+1))

	if [ $OFFSET != 1 ]; then
		process_client "$MESSAGE" "$TARGET"&
	fi

}; done