#!/bin/bash

# Variables
DATADIR="/var/lib/postgresql/data"
DUMP_DIR="/mnt/data"
DUMP_FILE="$DUMP_DIR/database-dump.sql"
export PGPASSWORD="$POSTGRES_PASSWORD"

# Don't start database as long as backup is running
while [ -f "$DUMP_DIR/backup-is-running" ]; do
    echo "Waiting for backup container to finish..."
    echo "If this is incorrect because the backup container is not running anymore (because it was forcefully killed), you might delete the lock file which is by default stored here:"
    echo "/var/lib/docker/volumes/nextcloud_aio_database_dump/_data/backup-is-running"
    sleep 10
done

# Check if dump dir is writeable
if ! [ -w "$DUMP_DIR" ]; then
    echo "DUMP dir is not writeable by postgres user."
    exit 1
fi

# Delete the datadir once (needed for setting the correct credentials on old instances once)
if ! [ -f "$DUMP_DIR/export.failed" ] && ! [ -f "$DUMP_DIR/initial-cleanup-done" ]; then
    set -ex
    rm -rf "${DATADIR:?}/"*
    touch "$DUMP_DIR/initial-cleanup-done"
    set +ex
fi

# Test if some things match
# shellcheck disable=SC2235
if ( [ -f "$DATADIR/PG_VERSION" ] && [ "$PG_MAJOR" != "$(cat "$DATADIR/PG_VERSION")" ] ) \
|| ( ! [ -f "$DATADIR/PG_VERSION" ] && ( [ -f "$DUMP_FILE" ] || [ -f "$DUMP_DIR/export.failed" ] ) ); then
    # The DUMP_file must be provided
    if ! [ -f "$DUMP_FILE" ]; then
        echo "Unable to restore the database because the database dump is missing."
        exit 1
    fi

    # If database export was unsuccessful, skip update 
    if [ -f "$DUMP_DIR/export.failed" ]; then
        echo "Database export failed the last time. Most likely was the export time not high enough."
        echo "Please report this to https://github.com/nextcloud/all-in-one/issues. Thanks!"
        exit 1
    fi

    # Inform
    echo "Restoring from database dump."

    # Exit if any command fails
    set -ex

    # Remove old database files
    rm -rf "${DATADIR:?}/"*

    # Change database port to a random port temporarily
    export PGPORT=11000

    # Create new database
    exec docker-entrypoint.sh postgres &

    # Wait for creation
    while ! nc -z localhost 11000; do
        echo "Waiting for the database to start."
        sleep 5
    done

    # Check if the line we grep for later on is there
    GREP_STRING='Name: oc_appconfig; Type: TABLE; Schema: public; Owner:'
    if ! grep -q "$GREP_STRING" "$DUMP_FILE"; then
        echo "The needed oc_appconfig line is not there which is unexpected."
        echo "Please report this to https://github.com/nextcloud/all-in-one/issues. Thanks!"
        exit 1
    fi

    # Get the Owner
    DB_OWNER="$(grep "$GREP_STRING" "$DUMP_FILE" | grep -oP 'Owner:.*$' | sed 's|Owner:||;s| ||g')"
    if [ "$DB_OWNER" != "oc_$POSTGRES_USER" ]; then
        DIFFERENT_DB_OWNER=1
        psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --dbname "$POSTGRES_DB" <<-EOSQL
            CREATE USER "$DB_OWNER" WITH PASSWORD '$POSTGRES_PASSWORD' CREATEDB;
            ALTER DATABASE "$POSTGRES_DB" OWNER TO "$DB_OWNER";
EOSQL
    fi

    # Restore database
    echo "Restoring the database from database dump"
    psql "$POSTGRES_DB" -U "$POSTGRES_USER" < "$DUMP_FILE"

    # Correct permissions
    if [ -n "$DIFFERENT_DB_OWNER" ]; then
        psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --dbname "$POSTGRES_DB" <<-EOSQL
            ALTER DATABASE "$POSTGRES_DB" OWNER TO "oc_$POSTGRES_USER";
            REASSIGN OWNED BY "$DB_OWNER" TO "oc_$POSTGRES_USER";
EOSQL
    fi

    # Shut down the database to be able to start it again
    pg_ctl stop -m fast

    # Change database port back to default
    export PGPORT=5432

    # Don't exit if command fails anymore
    set +ex
fi

# Cover the last case
if ! [ -f "$DATADIR/PG_VERSION" ] && ! [ -f "$DUMP_FILE" ]; then
    # Remove old database files if somehow there should be some
    rm -rf "${DATADIR:?}/"*
fi

echo "Setting max connections..."
MEMORY=$(mawk '/MemTotal/ {printf "%d", $2/1024}' /proc/meminfo)
MAX_CONNECTIONS=$((MEMORY/50+3))
if [ -n "$MAX_CONNECTIONS" ]; then
    sed -i "s|^max_connections =.*|max_connections = $MAX_CONNECTIONS|" "/var/lib/postgresql/data/postgresql.conf"
fi

# Catch docker stop attempts
trap 'true' SIGINT SIGTERM

# Start the database
exec docker-entrypoint.sh postgres &
wait $!

# Continue with shutdown procedure: do database dump, etc.
rm -f "$DUMP_FILE.temp"
touch "$DUMP_DIR/export.failed"
if pg_dump --username "$POSTGRES_USER" "$POSTGRES_DB" > "$DUMP_FILE.temp"; then
    rm -f "$DUMP_FILE"
    mv "$DUMP_FILE.temp" "$DUMP_FILE"
    pg_ctl stop -m fast
    rm "$DUMP_DIR/export.failed"
    echo 'Database dump successful!'
    exit 0
else
    pg_ctl stop -m fast
    echo "Database dump unsuccessful!"
    exit 1
fi