#!/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;


###########################
### 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=`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"

    if ! 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
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 `psql -h "$HOSTNAME" -U "$USERNAME" -At -c "$FULL_BACKUP_QUERY" postgres`
do
    if [ $ENABLE_PLAIN_BACKUPS = "yes" ]
    then
        echo "Plain backup of $DATABASE"

        if ! 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
    fi

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

        if ! pg_dump -Fc -h "$HOSTNAME" -U "$USERNAME" "$DATABASE" -f $FINAL_BACKUP_DIR"$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!"