#!/usr/bin/env bash

set -Eeo pipefail

file_env() {
	local var="$1"
	local fileVar="${var}_FILE"
	local def="${2:-}"
	if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then
		printf >&2 'error: both %s and %s are set (but are exclusive)\n' "$var" "$fileVar"
		exit 1
	fi
	local val="$def"
	if [ "${!var:-}" ]; then
		val="${!var}"
	elif [ "${!fileVar:-}" ]; then
		val="$(< "${!fileVar}")"
	fi
	export "$var"="$val"
	unset "$fileVar"
}

docker_setup_env() {
	file_env 'POSTGRES_PASSWORD'
}

docker_create_db_directories() {
	local user; user="$(id -u)"
	mkdir -p "$PGDATA"
	chmod 00700 "$PGDATA" || :
	mkdir -p /var/run/postgresql || :
	chmod 03775 /var/run/postgresql || :
	if [ "$user" = '0' ]; then
		find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
		find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
	fi
}

docker_init_database_dir() {
	local uid; uid="$(id -u)"
	if ! getent passwd "$uid" &> /dev/null; then
		local wrapper
		for wrapper in {/usr,}/lib{/*,}/libnss_wrapper.so; do
			if [ -s "$wrapper" ]; then
				NSS_WRAPPER_PASSWD="$(mktemp)"
				NSS_WRAPPER_GROUP="$(mktemp)"
				export LD_PRELOAD="$wrapper" NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
				local gid; gid="$(id -g)"
				printf 'postgres:x:%s:%s:PostgreSQL:%s:/bin/false\n' "$uid" "$gid" "$PGDATA" > "$NSS_WRAPPER_PASSWD"
				printf 'postgres:x:%s:\n' "$gid" > "$NSS_WRAPPER_GROUP"
				break
			fi
		done
	fi
	eval 'initdb --username=postgres --pwfile=<(printf "%s\n" "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'

	if [[ "${LD_PRELOAD:-}" == */libnss_wrapper.so ]]; then
		rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
		unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
	fi
}

docker_temp_server_start() {
  NOTIFY_SOCKET= \
  PGUSER="${PGUSER:-postgres}" \
  pg_ctl -D "$PGDATA" \
  	-o "-c listen_addresses='*' -p 5432" \
   	-w start
}

docker_temp_server_stop() {
	PGUSER="${PGUSER:-postgres}" \
	pg_ctl -D "$PGDATA" -m fast -w stop
}

pg_setup_conf() {
	{
		printf "\n"
    printf "archive_command          = '/bin/true'\n"
    printf "archive_mode             = on\n"
    printf "hot_standby              = on\n"
    printf "max_wal_senders          = 10\n"
    printf "max_replication_slots    = 10\n"
    printf "shared_preload_libraries = 'repmgr'\n"
    if [[ -n $POSTGRES_MAX_CONNECTIONS ]]; then
      printf "\nmax_connections = '%s'\n" "$POSTGRES_MAX_CONNECTIONS"
    fi
	} >> "$PGDATA/postgresql.conf"
}

pg_setup_hba_conf() {
	{
		printf '\n'
    printf 'local all          all     trust\n'
    printf 'local replication  repmgr  trust\n'
    printf 'local repmgr       repmgr  trust\n'
		printf '\n'
    printf 'host  replication  repmgr  127.0.0.1/32  trust\n'
    printf 'host  repmgr       repmgr  127.0.0.1/32  trust\n'
		printf '\n'
    printf 'host  replication  repmgr  %s  trust\n' "${POSTGRES_NETWORK:-100.64.0.0/10}"
    printf 'host  repmgr       repmgr  %s  trust\n' "${POSTGRES_NETWORK:-100.64.0.0/10}"
    printf '\n'
    printf 'host  all all all scram-sha-256'
	} >> "$PGDATA/pg_hba.conf"
}

repmgr_setup_conf() {
  {
    printf "node_id   = %s\n" "$REPMGR_NODE_ID"
    printf "node_name = %s\n" "$REPMGR_NODE_NAME"
    printf "conninfo  = 'host=%s dbname=repmgr user=repmgr connect_timeout=2'\n" "$REPMGR_NODE_NAME"
    printf "\n"
    printf "data_directory        = '/var/lib/postgresql/data'\n"
    printf "use_replication_slots = on\n"
    printf "pg_bindir             = '/usr/lib/postgresql/15/bin/'\n"
    printf "\n"
    printf "failover            = automatic\n"
    printf "promote_command     = '/usr/bin/repmgr standby promote -f /etc/repmgr.conf --log-to-file'\n"
    printf "follow_command      = '/usr/bin/repmgr standby follow  -f /etc/repmgr.conf --log-to-file --upstream-node-id=%n'\n"
    printf "reconnect_attempts  = 3\n"
    printf "reconnect_interval  = 5\n"
  } > /etc/repmgr/repmgr.conf
}

sudo service ssh start

docker_setup_env
docker_create_db_directories
if [ "$(id -u)" = '0' ]; then
	exec gosu postgres "$BASH_SOURCE"
fi

if [[ ! -s "$PGDATA/PG_VERSION" ]]; then
  repmgr_setup_conf

  if [[ -z $REPMGR_UPSTREAM ]]; then
    docker_init_database_dir
    pg_setup_conf
    pg_setup_hba_conf

  	export PGPASSWORD="$POSTGRES_PASSWORD"
	  docker_temp_server_start

    psql -c "CREATE USER repmgr WITH SUPERUSER ENCRYPTED PASSWORD '${REPMGR_PASSWORD}';"
    psql -c "CREATE DATABASE repmgr WITH OWNER repmgr;"
    psql -c 'ALTER USER repmgr SET search_path TO repmgr, "$user", public;'

    if [[ -n $PGPOOL_PASSWORD ]]; then
      psql -c "CREATE USER pgpool WITH ENCRYPTED PASSWORD '${PGPOOL_PASSWORD}';"
    fi

		unset PGPASSWORD

    /usr/lib/postgresql/15/bin/repmgr -f /etc/repmgr.conf primary register


  else
    until /usr/lib/postgresql/15/bin/repmgr -h $REPMGR_UPSTREAM -U repmgr -f /etc/repmgr.conf standby clone --dry-run &> /dev/null
    do
      echo "Upstream host not ready. Waiting for 5 minutes..."
      sleep 300
    done
    echo "Upstream host found..."
    /usr/lib/postgresql/15/bin/repmgr -h $REPMGR_UPSTREAM -U repmgr -f /etc/repmgr.conf standby clone
	  docker_temp_server_start
    /usr/lib/postgresql/15/bin/repmgr -f /etc/repmgr.conf standby register --force

  fi

  docker_temp_server_stop
fi

set -m

postgres &

sleep 10
repmgrd -f /etc/repmgr.conf --pid-file /tmp/repmgrd.pid

while true
do
  echo "$(date)"
  sleep 3600
done