#!/bin/bash

# Variables
DATADIR="/var/lib/postgresql/data"
export 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:"
    echo "sudo docker exec --user root nextcloud-aio-database rm /mnt/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

# Don't start if import failed
if [ -f "$DUMP_DIR/import.failed" ]; then
    echo "The database import failed. Please restore a backup and try again."
    echo "For further clues on what went wrong, look at the logs above."
    exit 1
fi

# Don't start if initialization failed
if [ -f "$DUMP_DIR/initialization.failed" ]; then
    echo "The database initialization failed. Most likely was a wrong timezone selected."
    echo "The selected timezone is '$TZ'." 
    echo "Please check if it is in the 'TZ identifier' column of the timezone list: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List"
    echo "For further clues on what went wrong, look at the logs above."
    echo "You might start again from scratch by following https://github.com/nextcloud/all-in-one#how-to-properly-reset-the-instance and selecting a proper timezone."
    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

    # Write output to logfile.
    exec > >(tee -i "$DUMP_DIR/database-import.log")
    exec 2>&1

    # Inform
    echo "Restoring from database dump."

    # Add import.failed file
    touch "$DUMP_DIR/import.failed"

    # 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 ! psql -d "postgresql://oc_$POSTGRES_USER:$POSTGRES_PASSWORD@localhost:11000/$POSTGRES_DB" -c "select now()"; 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 -qa "$GREP_STRING" "$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="$(grep -a "$GREP_STRING" "$DUMP_FILE" | grep -oP 'Owner:.*$' | sed 's|Owner:||;s| ||g')"
    if [ "$DB_OWNER" = "$POSTGRES_USER" ]; then
        echo "Unfortunately was the found database owner of the dump file the same as the POSTGRES_USER $POSTGRES_USER"
        echo "It is not possible to import a database dump from this database owner."
        echo "However you might rename the owner in the dumpfile to something else."
        exit 1
    elif [ "$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 "$DB_OWNER";
            GRANT ALL PRIVILEGES ON DATABASE "$POSTGRES_DB" TO "$DB_OWNER";
            GRANT ALL PRIVILEGES ON SCHEMA public TO "$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

    # Remove import failed file if everything went correctly
    rm "$DUMP_DIR/import.failed"
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

# Modify postgresql.conf
if [ -f "/var/lib/postgresql/data/postgresql.conf" ]; then
    echo "Setting max connections..."
    MEMORY=$(awk '/MemTotal/ {printf "%d", $2/1024}' /proc/meminfo)
    MAX_CONNECTIONS=$((MEMORY/50+3))
    if [ -n "$MAX_CONNECTIONS" ]; then
        # 100 is the default, we do not want to go lower than this
        if [ "$MAX_CONNECTIONS" -lt 100 ]; then
            MAX_CONNECTIONS=100
        fi
        sed -i "s|^max_connections =.*|max_connections = $MAX_CONNECTIONS|" "/var/lib/postgresql/data/postgresql.conf"
    fi

    # Do not log checkpoints
    if grep -q "#log_checkpoints" /var/lib/postgresql/data/postgresql.conf; then
        sed -i 's|#log_checkpoints.*|log_checkpoints = off|' /var/lib/postgresql/data/postgresql.conf
    fi
    # Close idling connections automatically after 3s which does not seem to happen automatically so that we run into max_connections limits
    if grep -q "#idle_session_timeout" /var/lib/postgresql/data/postgresql.conf; then
        sed -i 's|#idle_session_timeout.*|idle_session_timeout = 3000|' /var/lib/postgresql/data/postgresql.conf
    fi
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