#!/bin/bash

###########################
####### LOAD CONFIG #######
###########################

while [ $# -gt 0 ]; do
        case $1 in
                -c)
                        if [ -r "$2" ]; then
                                source "$2"
                                shift 2
                        else
                                ${ECHO} "Unreadable config file \"$2\"" 1>&2
                                exit 1
                        fi
                        ;;
                *)
                        ${ECHO} "Unknown Option \"$1\"" 1>&2
                        exit 2
                        ;;
        esac
done

if [ $# = 0 ]; then
        SCRIPTPATH=$(cd ${0%/*} && pwd -P)
        source $SCRIPTPATH/pg_backup.config
fi;

###########################
#### PRE-BACKUP CHECKS ####
###########################

# Make sure we're running as the required backup user
if [ "$BACKUP_USER" != "" -a "$(id -un)" != "$BACKUP_USER" ]; then
	echo "This script must be run as $BACKUP_USER. Exiting." 1>&2
	exit 1;
fi;


###########################
### INITIALISE DEFAULTS ###
###########################

if [ ! $HOSTNAME ]; then
	HOSTNAME="localhost"
fi;

if [ ! $USERNAME ]; then
	USERNAME="postgres"
fi;


###########################
#### START THE BACKUPS ####
###########################


FINAL_BACKUP_DIR=$BACKUP_DIR"`date +\%Y-\%m-\%d`/"

echo "Making backup directory in $FINAL_BACKUP_DIR"

if ! mkdir -p $FINAL_BACKUP_DIR; then
	echo "Cannot create backup directory in $FINAL_BACKUP_DIR. Go and fix it!" 1>&2
	exit 1;
fi;

#######################
### GLOBALS BACKUPS ###
#######################

echo -e "\n\nPerforming globals backup"
echo -e "--------------------------------------------\n"

if [ $ENABLE_GLOBALS_BACKUPS = "yes" ]
then
        echo "Globals backup"

        set -o pipefail
        if ! docker exec $DOCKER_CONTAINER /bin/bash -c "pg_dumpall -g -h \"$HOSTNAME\" -U \"$USERNAME\" " | gzip -9 > $FINAL_BACKUP_DIR"globals".sql.gz.in_progress; then
                echo "[!!ERROR!!] Failed to produce globals backup" 1>&2
        else
                mv $FINAL_BACKUP_DIR"globals".sql.gz.in_progress $FINAL_BACKUP_DIR"globals".sql.gz
        fi
        set +o pipefail
else
	echo "None"
fi


###########################
### SCHEMA-ONLY BACKUPS ###
###########################

for SCHEMA_ONLY_DB in ${SCHEMA_ONLY_LIST//,/ }
do
	SCHEMA_ONLY_CLAUSE="$SCHEMA_ONLY_CLAUSE or datname ~ '$SCHEMA_ONLY_DB'"
done

SCHEMA_ONLY_QUERY="select datname from pg_database where false $SCHEMA_ONLY_CLAUSE order by datname;"

echo -e "\n\nPerforming schema-only backups"
echo -e "--------------------------------------------\n"

SCHEMA_ONLY_DB_LIST=`docker exec $DOCKER_CONTAINER /bin/bash -c "psql -h \"$HOSTNAME\" -U \"$USERNAME\" -At -c \"$SCHEMA_ONLY_QUERY\" postgres"`

echo -e "The following databases were matched for schema-only backup:\n${SCHEMA_ONLY_DB_LIST}\n"

for DATABASE in $SCHEMA_ONLY_DB_LIST
do
	echo "Schema-only backup of $DATABASE"

	set -o pipefail
	if ! docker exec $DOCKER_CONTAINER /bin/bash -c "pg_dump -Fp -s -h \"$HOSTNAME\" -U \"$USERNAME\" \"$DATABASE\"" | gzip -9 > $FINAL_BACKUP_DIR"$DATABASE"_SCHEMA.sql.gz.in_progress; then
		echo "[!!ERROR!!] Failed to backup database schema of $DATABASE" 1>&2
	else
		mv $FINAL_BACKUP_DIR"$DATABASE"_SCHEMA.sql.gz.in_progress $FINAL_BACKUP_DIR"$DATABASE"_SCHEMA.sql.gz
	fi
	set +o pipefail
done


###########################
###### FULL BACKUPS #######
###########################

for SCHEMA_ONLY_DB in ${SCHEMA_ONLY_LIST//,/ }
do
	EXCLUDE_SCHEMA_ONLY_CLAUSE="$EXCLUDE_SCHEMA_ONLY_CLAUSE and datname !~ '$SCHEMA_ONLY_DB'"
done

FULL_BACKUP_QUERY="select datname from pg_database where not datistemplate and datallowconn $EXCLUDE_SCHEMA_ONLY_CLAUSE order by datname;"

echo -e "\n\nPerforming full backups"
echo -e "--------------------------------------------\n"

for DATABASE in `docker exec $DOCKER_CONTAINER /bin/bash -c "psql -h \"$HOSTNAME\" -U \"$USERNAME\" -At -c \"$FULL_BACKUP_QUERY\" postgres"`
do
	if [ $ENABLE_PLAIN_BACKUPS = "yes" ]
	then
		echo "Plain backup of $DATABASE"

		set -o pipefail
		if ! docker exec ${DOCKER_CONTAINER} /bin/bash -c "pg_dump -Fp -h \"$HOSTNAME\" -U \"$USERNAME\" \"$DATABASE\"" | gzip -9 > $FINAL_BACKUP_DIR"$DATABASE".sql.gz.in_progress; then
			echo "[!!ERROR!!] Failed to produce plain backup database $DATABASE" 1>&2
		else
			mv $FINAL_BACKUP_DIR"$DATABASE".sql.gz.in_progress $FINAL_BACKUP_DIR"$DATABASE".sql.gz
		fi
		set +o pipefail
	fi

	if [ $ENABLE_CUSTOM_BACKUPS = "yes" ]
	then
		echo "Custom backup of $DATABASE"

		if ! docker exec ${DOCKER_CONTAINER} /bin/bash -c "pg_dump -Fc -h \"$HOSTNAME\" -U \"$USERNAME\" \"$DATABASE\"" > $FINAL_BACKUP_DIR"$DATABASE".custom.in_progress; then
			echo "[!!ERROR!!] Failed to produce custom backup database $DATABASE" 1>&2
		else
			mv $FINAL_BACKUP_DIR"$DATABASE".custom.in_progress $FINAL_BACKUP_DIR"$DATABASE".custom
		fi
	fi

done

echo -e "\nAll database backups complete!"