#!/bin/sh
# regenerate runtime client config from env before caddy starts.
#
# the SPA fetches /config.json at startup, so this lets one prebuilt image be
# deployed with different relays per environment without a rebuild. set
# NOSTERM_DEFAULT_RELAYS to a comma-separated list of relay websocket urls.
set -eu

CONFIG_PATH=/srv/config.json
RELAYS="${NOSTERM_DEFAULT_RELAYS:-}"

# build a json array from the comma-separated list, trimming blanks.
relays_json=""
IFS=','
for relay in $RELAYS; do
	# trim surrounding whitespace.
	trimmed="$(printf '%s' "$relay" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')"
	[ -z "$trimmed" ] && continue
	if [ -z "$relays_json" ]; then
		relays_json="\"$trimmed\""
	else
		relays_json="$relays_json,\"$trimmed\""
	fi
done
unset IFS

printf '{\n  "relays": [%s]\n}\n' "$relays_json" > "$CONFIG_PATH"

if [ -n "$relays_json" ]; then
	echo "[entrypoint] wrote $CONFIG_PATH with relays: $RELAYS"
else
	echo "[entrypoint] no NOSTERM_DEFAULT_RELAYS set; wrote empty relay list"
fi

# hand off to the container command (caddy).
exec "$@"