#!/bin/bash

printf "Content-Type: text/plain\n\n"

. /etc/konata.conf
input=$(cat /dev/stdin)

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)

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

help(){
	sendmsg "Hiya! I'm @ghnou's personal bot, Konata.
	Currently I have the following features:
	- /alive - Check whether I'm running.
	- /cv [country] - Check COVID-19 stats.
	- /id - Get the current chat's ID.
	- /help - Show this help message.
	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!"
}

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

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)\`"
}

cv(){
	stats=$(curl -sL corona.lmao.ninja/v2/countries/$args)
	country=$(jq -r '.country' <<< $stats)
	cases=$(jq -r '.todayCases' <<< $stats)
	sendmsg "Today's COVID-19 cases for $country: $cases. Stay safe!"
}

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

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

fail(){
	sendmsg "Sorry, you are not allowed to use this command!"
	exit 1
}

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

case "$cmd" in
	/start*|/help*)		help ;;
	/alive*)		alive ;;
	/stat*)			stat ;;
	/cv*|/corona*)		cv ;;
	/id*)			id ;;
	/term*)			term ;;
	*@ghnou*)		tag ;;
	*@konatasanbot*)	hiya ;;
esac