#!/bin/bash

# Hard requirement for lighttpd
printf "Content-Type: text/plain\n\n"

# Initialize basic variables
. /etc/konata.conf
input=$(cat /dev/stdin)
bot="konatasanbot"

# Parse incoming messages
cmd=$(jq -r '.message.text' <<< $input)
args=$(cut -d" " -f2- <<< $cmd)
chat=$(jq -r '.message.chat.id' <<< $input)
user=$(jq -r '.message.from.username' <<< $input)

# Functions for outgoing messages
sendmsg(){
	# Escape any special characters first, see https://0x0.st/NO7J.
	fmt=$(sed 's/[][~!@#$%^&*()-_=+{}\|;:",<.>/?'"'"']/\\&/g' <<< $1 | sed 's/\t//g')
	sendraw "$fmt"
}
sendraw(){
	curl -X POST "https://api.telegram.org/bot$token/sendMessage" \
		-d "chat_id=$chat" -d "parse_mode=markdownv2" \
		-d "disable_web_page_preview=true" -d "text=$1"
}
sendfile(){
	curl -sF document=@"$1" "https://api.telegram.org/bot$token/sendDocument?chat_id=$chat"
}

# Public commands
help(){
	sendmsg "Hiya! I'm @ghnou's personal bot, Konata.
	Currently I have the following features:
	- /help - Show this help message.
	- /alive - Check whether I'm running.
	- /cv [country] - Check COVID-19 stats.
	- /id - Get the current chat's ID.
	- /mp3 [link] - Download an mp3 file from YouTube.
	Admin only commands:
	- /stat - Uptime, memory, storage stats.
	- /term - Execute a command on the system.

	And a lot more to come!"
}

alive(){
	sendmsg "Alive and well!"
}

cv(){
	stats=$(curl -sL "corona.lmao.ninja/v2/countries/$args")
	country=$(jq -r '.country' <<< $stats)
	cases=$(jq -r '.todayCases' <<< $stats)
	if [ "$(jq -r '.message' <<< $stats)" != "null" ]
	then
		sendmsg "This country doesn't have any stats!"
	else
		sendmsg "Today's COVID-19 cases for $country: $cases. Stay safe!"
	fi
}

id(){
	sendmsg "Chat ID: $chat"
}

mp3(){
	admin
	tmp="/tmp/mp3"
	[ -d $tmp ] && mkdir $tmp
	sendmsg "Downloading, this might take a while..."
	youtube-dl --add-metadata --metadata-from-title "%(artist)s - %(title)s" -x --audio-format mp3 -o "$tmp/%(title)s.%(ext)s" "$args"
	sendfile "$tmp/$(ls $tmp)"
	rm $tmp/*
}

# Administrative
stat(){
	admin
	total=$(grep MemTotal /proc/meminfo | awk '{print $2}')
	avail=$(grep MemAvailable /proc/meminfo | awk '{print $2}')
	used=$(bc <<< "$total-$avail")
	sendmsg "$(uptime | cut -c2-)
	I am using ${used}K of memory and \
	$(df -h / | tail -n1 | awk '{print $3}') of storage."
}

term(){
	admin
	sendmsg "\`$(echo $args | bash - 2>&1)\`"
}

fail(){
	sendmsg "Sorry, you are not allowed to use this command!"
}

admin(){
	case $user in
		ghnou)	continue ;;
		*)	fail ;;
	esac
}

# Notes and such
anyone(){
	sendraw "Quite possibly\. [Why do you ask?](https://dontasktoask.com)"
}

# Miscellaneous
tag(){
	sendmsg "Please stand by, he'll get to your message soon™️..."
}

hiya(){
	sendmsg "Hiya! :3"
}

# Match incoming messages
case "$cmd" in
	# Public commands
	/help | /help@$bot)	help ;;
	/start | /start@$bot)	help ;;
	/alive | /alive@$bot)	alive ;;
	/cv* | /cv@$bot*)	cv ;;
	/id | /id@$bot)		id ;;
	/mp3* | /mp3@$bot*)	mp3 ;;
	# Administrative
	/stat | /stat@$bot)	stat ;;
	/term* | /term@$bot*)	term ;;
	# Notes and such
	!anyone)		anyone ;;
	# Miscellaneous
	*@ghnou*)		tag ;;
	*@konatasanbot*)	hiya ;;
esac