#!/bin/bash

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

# Initialize basic variables
. /etc/konata.conf

# Parse incoming messages
input=$(cat /dev/stdin)
msg=$(jq -r '.message.text' <<< $input)
msg=$(sed "s/_/\ /g" <<< $msg)
cmd=$(cut -d" " -f1 <<< $msg)
args=($(cut -d" " -f2- <<< $msg))
chat=$(jq -r '.message.chat.id' <<< $input)
user=$(jq -r '.message.from.username' <<< $input)

# Append bot's tag to any command without one
if ! grep -q "/.*@" <<< $cmd
then
	cmd=${cmd}@$bot
fi
# Convert k.command to /command
if grep -q "k\." <<< $cmd
then
	cmd=$(sed "s/k\./\//g" <<< $cmd)
fi

# 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"
}
escape(){
	sed "s/[$1]/\\\&/g" <<< $2
}
sendraw(){
	curl -sX POST "https://api.telegram.org/bot$token/sendMessage" \
		-d "chat_id=$chat" -d "parse_mode=markdownv2" \
		-d "disable_web_page_preview=true" -d "text=$1"
}
sendlog(){
	chat=$logchat
	sendmsg "$1"
}
sendfile(){
	curl -sF document=@"$1" "https://api.telegram.org/bot$token/sendDocument?chat_id=$chat"
}
sendpic(){
	curl -sX POST "https://api.telegram.org/bot$token/sendPhoto" \
		-d "chat_id=$chat" -d "parse_mode=markdownv2" \
		-d "photo=$1" -d "caption=$2"
}

# Debugging commands
debug(){
	[ ! -z $debug ] && echo "[DEBUG] $1" >&2
}

# Public commands
help(){
	sendmsg "Hiya! I'm [ghnou](https://t.me/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.
	- /ud \[term\] - Get a definition from Urban Dictionary.
	- /konata - Get one of my selfies :3
	- /4c \[board\] - Get a random image from 4chan.
	- /repo - Get my source code.
	Admin only commands:
	- /mp3 \[link\] - Download an mp3 file from YouTube.
	- /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=$(curl -s "https://corona.lmao.ninja/v2/countries/${args[*]}")
	country=$(jq -r '.country' <<< $stats)
	cases=$(jq -r '.todayCases' <<< $stats)
	pm=$(jq -r '.testsPerOneMillion' <<< $stats)
	pct=$(echo "scale = 2; $pm / 10000" | bc)
	if jq -re '.country' <<< $stats
	then
		sendmsg "Today's COVID-19 cases for $country: $cases \($pct% of the population tested\). Stay safe!"
	else
		sendmsg "This country doesn't have any stats!"
	fi
}

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

ud(){
	enc=$(echo "${args[*]}" | sed "s/\ /%20/g")
	res=$(curl -s "https://api.urbandictionary.com/v0/define?term=$enc")
	if jq -re '.list[0].definition' <<< $res
	then
		def=$(jq -r '.list[0].definition' <<< $res | sed "s/[][]//g")
		sam=$(jq -r '.list[0].example' <<< $res | sed "s/[][]//g")
		sendmsg "*Definition for __${args[*]}__:*
		$(escape "()" "$def")
		*Example:*
		$(escape "()" "$sam")"
	else
		sendmsg "No definition found for ${args[*]}."
	fi
}

konata(){
	data=$(curl -s "https://konachan.net/post.json?limit=1&page=1&tags=order:random%20izumi_konata")
	jpeg=$(jq -r '.[0].jpeg_url' <<< $data)
	file=$(jq -r '.[0].file_url' <<< $data)
	sfw=$(jq -r '.[0].rating' <<< $data)
	if [ $sfw == "s" ]
	then
		sendpic "$jpeg" "[sauce]($file)"
	else
		sendmsg "This picture appears to be NSFW! Here's the [sauce]($file)."
	fi
}

4c(){
	tmp="/tmp/4chan"
	json="$tmp/${args[0]}.json"
	[ ! -d $tmp ] && mkdir $tmp
	[ $(find $json -mmin +60) ] && rm $json
	[ ! -f $json ] && wget -O $json https://a.4cdn.org/${args[0]}/threads.json
	thread=$(jq -r '.[].threads[].no' < $json | shuf | head -n1)
	img=$(curl https://a.4cdn.org/${args[0]}/thread/$thread.json | jq -r '.posts[].tim' | shuf | head -n1)
	url="https://i.4cdn.org/${args[0]}/$img"
	# TODO: Try to determine from JSON output whether image is PNG or JPG.
	sendpic "$url.jpg"
	sendpic "$url.png"
}

repo(){
	sendmsg "You can find my source code [here](https://git.ghnou.su/ghnou/konata)."
}

# Administrative
mp3(){
	admin
	tmp="/tmp/mp3"
	[ ! -d $tmp ] && mkdir $tmp
	sendmsg "Downloading, this might take a while..."
	youtube-dl -f 140 --max-filesize 50M -o "$tmp/%(title)s.%(ext)s" "${args[*]}"
	rm $tmp/*.part
	if [ -f $tmp/* ]
	then
		sendfile "$tmp/$(ls $tmp)"
		rm $tmp/*
	else
		sendmsg "I couldn't download this file. Perhaps it's too large?"
	fi
}

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 "\`$(whoami)@${HOSTNAME}:${PWD}$\` \`${args[*]}\`
	\`$(echo ${args[*]} | bash - 2>&1)\`"
}

fail(){
	debug "User @$user tried to execute $cmd and was rejected."
	sendmsg "Sorry, you are not allowed to use this command!"
	exit 1
}

admin(){
	case $user in
		ghnou)	true ;;
		*)	fail ;;
	esac
	debug "Admin @$user tried to execute $cmd and was approved."
}

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

# Miscellaneous
tag(){
	sendmsg "Please stand by, he'll get to your message soon™️..."
	sendlog "You've been tagged: $msg"
}

# Match incoming messages
case "$cmd" in
	# Public commands
	/help@$bot)		help ;;
	/start@$bot)		help ;;
	/alive@$bot)		alive ;;
	/cv@$bot*)		cv ;;
	/id@$bot)		id ;;
	/ud@$bot*)		ud ;;
	/konata@$bot*)		konata ;;
	/4c@$bot*)		4c ;;
	/repo@$bot)		repo ;;
	# Administrative
	/mp3@$bot*)		mp3 ;;
	/stat@$bot)		stat ;;
	/term@$bot*)		term ;;
	# Notes and such
	!anyone*)		anyone ;;
esac

case "$msg" in
	# Miscellaneous
	*@ghnou*)		tag ;;
esac