#!/bin/sh
set -euo pipefail

if [ -z "$MM_SERVER" ]; then
	echo "Set environment variable MM_SERVER to e.g. mattermost.example.com"
	exit 1
fi
mattermost_name="Zeus Mattermost"
team_name="zeus"

dir="$(dirname "$0")"

out="$dir/dist/channels/index.html"
mkdir -p "$(dirname "$out")"

cp go_to_channel.png dist/
cp main.css dist/

custom_emoji_file="$(mktemp --tmpdir custom_emoji.XXXXXXXXXX.json)"
mmcli listcustomemoji | jq -s > "$custom_emoji_file"

jqo() {
	json="$1"
	shift 1
	printf '%s' "$json" | jq -cr "$@" || { printf 'jq errored performing %s on this input: %s\n' "$*" "$json" >&2; }
}

htmlescape() {
	sed 's/&/\&amp;/g; s/</\&lt;/g; s/>/\&gt;/g; s/"/\&quot;/g; s/'"'"'/\&#39;/g'
}

emoji() {
	env --chdir "$dir" \
		python3 "$dir/emoji.py" "$custom_emoji_file"
}

markdown() {
	htmlescape | \
		{ pandoc --from=markdown+autolink_bare_uris+emoji --to=html || printf "Markdown conversion failed\n" >&2; } | \
		sed -E '
			s|<(h[0-6])[^>]*>|<div class="\1">|g
			s|</(h[0-6])>|</div>|g
			s/src="\(.*\)"/src=""/g
			' | \
		sed -f "$channels_sed_file" | \
		emoji
}

format_number() {
	awk '{printf "%'\''d\n", $1}'
}

format_timestamp() {
	format_str="$1"
	xargs -Ixxx date --date "@xxx" "+$format_str"
}

channels="$(mmcli ls "$team_name" | jq -cs 'sort_by(- .last_post_at) | .[]')"
channel_count="$(jqo "$channels" -s 'length')"
channels_sed_file="$(mktemp --tmpdir "mattermost_channels.XXXXXXXXX.sed")"
jqo "$channels" -s 'map(.name) | sort_by(length) | reverse | .[]' | sed 's|.*|s/~&/<a href=\"#channel_&\">CHANNEL[&]<\\/a>/g|' > "$channels_sed_file"
printf 's/CHANNEL\\[\\([^]]*\\)\\]/~\\1/g\n' >> "$channels_sed_file"

substitute_vars() {
	sed '
		s/$lastupdated/'"$(date '+%Y-%m-%d %H:%M')"'/g
		s/$mattermost_name/'"$mattermost_name"'/g
		s/$team_name/'"$team_name"'/g
		s/$channel_count/'"$channel_count"'/g
	'
}

substitute_vars <  "$dir"/header.html > "$out"

printf '%s\n' "$channels" | while IFS="" read -r chan || [ -n "$chan" ]; do
	if [ "$(jqo "$chan" '.type')" != O ]; then continue; fi

	name="$(jqo "$chan" '.name' | htmlescape)"
	display_name="$(jqo "$chan" '.display_name' | htmlescape)"
	purpose="$(jqo "$chan" '.purpose' | markdown)"
	header="$(jqo "$chan" '.header' | markdown)"
	create_at="$(jqo "$chan" '.create_at / 1000' | format_timestamp '%Y-%m-%d')"
	last_post_at="$(jqo "$chan" '.last_post_at / 1000' | format_timestamp '%Y-%m-%d %H:%M')"
	total_msg_count="$(jqo "$chan" '.total_msg_count' | format_number)"

	cat >> "$out" <<HERE
<div class="channel" id="channel_$name">
	<h2>$display_name <a href="https://mattermost.zeus.gent/zeus/$name" target="mattermost-webapp"><img src="../go_to_channel.png" alt="Go to channel" class="go_to_channel" /></a></h2>
	<dl>
HERE
	if [ -n "$purpose" ]; then
		cat >> "$out" <<HERE
		<div class="purpose">
			<dt>Purpose</dt>
			<dd>$purpose</dd>
		</div>

HERE
	fi
	if [ -n "$header" ]; then
		cat >> "$out" <<HERE
		<div class="header">
			<dt>Header</dt>
			<dd>$header</dd>
		</div>

HERE
	fi
	cat >> "$out" <<HERE
		<div class="stats">
			<div class="create_at">
				<dt>Created on</dt>
				<dd>$create_at</dd>
			</div>
			<div class="last_post_at">
				<dt>Last event</dt>
				<dd>$last_post_at</dd>
			</div>
			<div class="total_msg_count">
				<dt>Amount of messages</dt>
				<dd>$total_msg_count</dd>
			</div>
		</div>
	</dl>
</div>
HERE
	done

substitute_vars < "$dir"/footer.html >> "$out"