#!/bin/bash

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

while [ $# -gt 0 ]; do
        case $1 in
                -c)
                        CONFIG_FILE_PATH="$2"
                        shift 2
                        ;;
                *)
                        ${ECHO} "Unknown Option \"$1\"" 1>&2
                        exit 2
                        ;;
        esac
done

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

if [ ! -r ${CONFIG_FILE_PATH} ] ; then
        echo "Could not load config file from ${CONFIG_FILE_PATH}" 1>&2
        exit 1
fi

source "${CONFIG_FILE_PATH}"

###########################
#### 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 ####
###########################

function perform_backups()
{
	SUFFIX=$1
	FINAL_BACKUP_DIR=$BACKUP_DIR"`date +\%Y-\%m-\%d`$SUFFIX/"

	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 > $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 > $FINAL_BACKUP_DIR"$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 > $FINAL_BACKUP_DIR"$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"
			else
				mv $FINAL_BACKUP_DIR"$DATABASE".custom.in_progress $FINAL_BACKUP_DIR"$DATABASE".custom
			fi
		fi

	done

	echo -e "\nAll database backups complete!"
}

# MONTHLY BACKUPS

DAY_OF_MONTH=`date +%d`

if [ $DAY_OF_MONTH -eq 1 ];
then
	# Delete all expired monthly directories
	find $BACKUP_DIR -maxdepth 1 -name "*-monthly" -exec rm -rf '{}' ';'

	perform_backups "-monthly"

	exit 0;
fi

# WEEKLY BACKUPS

DAY_OF_WEEK=`date +%u` #1-7 (Monday-Sunday)
EXPIRED_DAYS=`expr $((($WEEKS_TO_KEEP * 7) + 1))`

if [ $DAY_OF_WEEK = $DAY_OF_WEEK_TO_KEEP ];
then
	# Delete all expired weekly directories
	find $BACKUP_DIR -maxdepth 1 -mtime +$EXPIRED_DAYS -name "*-weekly" -exec rm -rf '{}' ';'

	perform_backups "-weekly"

	exit 0;
fi

# DAILY BACKUPS

# Delete daily backups 7 days old or more
find $BACKUP_DIR -maxdepth 1 -mtime +$DAYS_TO_KEEP -name "*-daily" -exec rm -rf '{}' ';'

perform_backups "-daily"