#!/bin/sh

set -eu

export BITCOIND_CHAIN="${BITCOIND_CHAIN:-main}"
export BITCOIND_USER="${BITCOIND_USER:-user}"
export BITCOIND_PASSWORD="${BITCOIND_PASSWORD:-pass}"
export BITCOIND_FALLBACKFEE="${BITCOIND_FALLBACKFEE:-0}"
export BITCOIND_RPCBIND="${BITCOIND_RPCBIND:-0.0.0.0}"
export BITCOIND_RPCALLOWIP="${BITCOIND_RPCALLOWIP:-0.0.0.0/0}"
export BITCOIND_TXINDEX="${BITCOIND_TXINDEX:-0}"
export BITCOIND_TXOSPENDERINDEX="${BITCOIND_TXOSPENDERINDEX:-0}"
export BITCOIND_EXTRA_ARGS="${BITCOIND_EXTRA_ARGS:-}"

# The chain name decides the default RPC port, so an unknown value must stop the
# container rather than fall through to a default: "-chain=testnet" (the name
# Core does not use -- it wants "test") would otherwise be a mainnet node
# holding a wallet the caller believes is worthless.
case "$BITCOIND_CHAIN" in
	main)    default_port=8332 ;;
	test)    default_port=18332 ;;
	signet)  default_port=38332 ;;
	regtest) default_port=18443 ;;
	*)
		echo "BITCOIND_CHAIN must be one of main, test, signet, regtest (got '$BITCOIND_CHAIN')" >&2
		exit 1
		;;
esac

export BITCOIND_PORT="${BITCOIND_PORT:-$default_port}"
case "$BITCOIND_PORT" in
	'' | *[!0-9]*)
		echo "BITCOIND_PORT must be a positive integer" >&2
		exit 1
		;;
esac

# A named volume starts out owned by root. Non-recursive on purpose: the only
# case that needs fixing is the empty datadir, and a synced mainnet chain is
# hundreds of gigabytes -- walking it on every start would add minutes to each
# restart. A datadir moved here from an image with another uid must be chowned
# by hand, once (see README, "Notes").
mkdir -p "$BITCOIN_DATA"
if [ "$(stat -c %u "$BITCOIN_DATA")" != "$USER_UID" ]
then
	chown "$USER_UID:$USER_GID" "$BITCOIN_DATA"
fi

# Credentials for bitcoin-cli, so the health check does not have to repeat them
# on a command line. Written before the daemon starts and readable only by the
# daemon's user. rpcport is deliberately at the top level: bitcoin-cli is
# invoked without -chain and therefore reads the mainnet section, whatever chain
# the daemon runs -- what matters is that the number matches.
cli_conf="${BITCOIN_DATA}/cli.conf"
umask 077
cat > "$cli_conf" <<EOF
rpcconnect=127.0.0.1
rpcport=${BITCOIND_PORT}
rpcuser=${BITCOIND_USER}
rpcpassword=${BITCOIND_PASSWORD}
EOF
chown "$USER_UID:$USER_GID" "$cli_conf"
umask 022

# Everything goes on the command line rather than into bitcoin.conf. Core treats
# rpcport, port and bind as network-specific options: in a config file they only
# apply inside the matching [main]/[test]/[regtest] section, while on the
# command line they apply to the chain in force. One list that behaves the same
# on every network is worth more here than a config file nobody edits.
set -- \
	-chain="$BITCOIND_CHAIN" \
	-datadir="$BITCOIN_DATA" \
	-server=1 \
	-printtoconsole=1 \
	-rpcport="$BITCOIND_PORT" \
	-rpcuser="$BITCOIND_USER" \
	-rpcpassword="$BITCOIND_PASSWORD" \
	-rpcbind="$BITCOIND_RPCBIND" \
	-rpcallowip="$BITCOIND_RPCALLOWIP" \
	-txindex="$BITCOIND_TXINDEX" \
	-txospenderindex="$BITCOIND_TXOSPENDERINDEX" \
	-fallbackfee="$BITCOIND_FALLBACKFEE" \
	"$@"

# Unquoted on purpose: this is the one variable whose whole point is to be split
# into separate arguments.
# shellcheck disable=SC2086
set -- "$@" $BITCOIND_EXTRA_ARGS

exec gosu bitcoin bitcoind "$@"