#!/bin/sh
# LaDOSE.DiscordBot reads its configuration from ./settings.json and from nothing else:
# Program.cs builds a ConfigurationBuilder with AddJsonFile("settings.json") and no
# AddEnvironmentVariables(), so a LADOSE_* variable would be invisible to it. This script
# renders that file at container start instead — the same indirection LaDOSE.WebApp's
# entrypoint uses to turn LADOSE_API_BASE_URL into /config.js. One image, any token.
#
# It writes only when LADOSE_DISCORD_TOKEN is set. Left unset, whatever settings.json is
# already at /app wins: the placeholder baked in by the build, or a file bind-mounted over
# it. Doing both — mounting settings.json read-only *and* setting the variable — fails
# here with EROFS rather than silently ignoring one of them.
set -eu

settings_file=/app/settings.json

# Drop control characters (newlines included) so a value cannot break out of its string
# literal, then escape backslashes before double quotes. A token containing " or \ stays
# inert data.
json_string() {
    printf '%s' "${1:-}" | tr -d '\001-\037' | sed -e 's/\\/\\\\/g' -e 's/"/\\"/g'
}

if [ -n "${LADOSE_DISCORD_TOKEN:-}" ]; then
    rest_url=${LADOSE_BOT_REST_URL:-http://api:5000}

    # All five keys, always. Program.cs calls .ToString() on each of them at startup, so a
    # missing one is a NullReferenceException before the bot ever reaches Discord.
    cat >"$settings_file" <<EOF
{
  "Discord": {
    "Token": "$(json_string "${LADOSE_DISCORD_TOKEN}")"
  },
  "Challonge": {
    "Token": "$(json_string "${LADOSE_CHALLONGE_API_KEY:-}")"
  },
  "REST": {
    "Url": "$(json_string "${rest_url}")",
    "User": "$(json_string "${LADOSE_BOT_REST_USER:-}")",
    "Password": "$(json_string "${LADOSE_BOT_REST_PASSWORD:-}")"
  }
}
EOF
    # The token is deliberately not echoed.
    echo "settings.json: rendered from the environment (REST:Url=$rest_url)" >&2
else
    echo "settings.json: LADOSE_DISCORD_TOKEN unset, using the file already at $settings_file" >&2
fi

exec "$@"