#!/bin/sh

set -eu

# ElectrumX reads its own configuration from the environment, so this script
# only fills in defaults and checks the two mistakes that are expensive to
# diagnose later. Every variable below is ElectrumX's own name, not ours —
# anything documented upstream works here unchanged.

export COIN="${COIN:-Bitcoin}"
export NET="${NET:-mainnet}"
export DB_DIRECTORY="${DB_DIRECTORY:-/data}"
# Required by ElectrumX 2.0 (it refuses to start without it). rocksdb is what
# the image ships the libraries for.
export DB_ENGINE="${DB_ENGINE:-rocksdb}"
# Plaintext Electrum protocol plus the local RPC the health check talks to.
# Add ssl://:50002 to serve TLS (see the certificate section below).
export SERVICES="${SERVICES:-tcp://:50001,rpc://localhost:8000}"
# Off by default: this image is meant for private indexers behind a known
# daemon. A node that announces itself to the public server network is a
# deliberate act — set PEER_DISCOVERY=on and PEER_ANNOUNCE=true for it.
export PEER_DISCOVERY="${PEER_DISCOVERY:-off}"
export PEER_ANNOUNCE="${PEER_ANNOUNCE:-false}"

if [ -z "${DAEMON_URL:-}" ]
then
	echo "DAEMON_URL is required, e.g. http://user:password@bitcoind:8332" >&2
	exit 1
fi

# NET names the coin class ElectrumX looks up, and a wrong one is not a
# harmless mismatch: the class carries the genesis hash, so a testnet index
# pointed at a regtest daemon fails at the first block with a message about
# hashes rather than about configuration. The check exists mostly for one
# specific typo — bitcoind calls these networks `main` and `test`, ElectrumX
# calls them `mainnet` and `testnet`, and the pair is usually configured from
# the same .env.
case "$NET" in
	mainnet | testnet | testnet4 | signet | regtest | mutinynet) ;;
	*)
		echo "NET must be one of mainnet, testnet, testnet4, signet, regtest, mutinynet (got '$NET')" >&2
		exit 1
		;;
esac

# A named volume starts out owned by root. Non-recursive: only the empty case
# needs fixing, and a mainnet index is hundreds of gigabytes.
mkdir -p "$DB_DIRECTORY"
if [ "$(stat -c %u "$DB_DIRECTORY")" != "$USER_UID" ]
then
	chown "$USER_UID:$USER_GID" "$DB_DIRECTORY"
fi

# TLS on demand. ElectrumX requires both files as soon as SERVICES mentions
# ssl://, and refuses to start when they are missing — generating a self-signed
# pair is the difference between "works out of the box" and a startup error
# nobody expects from adding a port. Clients must trust it explicitly; a real
# certificate is supplied by pointing SSL_CERTFILE/SSL_KEYFILE elsewhere.
case "$SERVICES" in
	*ssl://*)
		export SSL_CERTFILE="${SSL_CERTFILE:-${DB_DIRECTORY}/electrumx.crt}"
		export SSL_KEYFILE="${SSL_KEYFILE:-${DB_DIRECTORY}/electrumx.key}"
		if [ ! -f "$SSL_CERTFILE" ] || [ ! -f "$SSL_KEYFILE" ]
		then
			echo "generating a self-signed certificate for $SSL_CERTFILE"
			openssl req -x509 -newkey rsa:2048 -nodes -days 3650 \
				-subj "/CN=electrumx" \
				-keyout "$SSL_KEYFILE" -out "$SSL_CERTFILE" 2>/dev/null
			chown "$USER_UID:$USER_GID" "$SSL_CERTFILE" "$SSL_KEYFILE"
			chmod 600 "$SSL_KEYFILE"
		fi
		;;
esac

exec gosu electrumx electrumx_server "$@"