#!/usr/bin/env bash

# SPDX-FileCopyrightText: 2022 Patrick Spek <p.spek@tyil.nl>
#
# SPDX-License-Identifier: AGPL-3.0-or-later

subcommand() {
	# Retrieve the passphrase used by Borg
	BORG_PASSPHRASE="$(config "bashtard.backup.passphrase")"

	if [[ -z "$BORG_PASSPHRASE" ]]
	then
		emerg "$BASHTARD_NAME/backup" "No passphrase set in bashtard.backup.passphrase"
		return 3
	fi

	export BORG_PASSPHRASE

	# Run backups for all configured elements, if none were explicitly
	# specified
	if (( $# < 1 ))
	then
		debug "$BASHTARD_NAME/backup" "Retrieving elements from config"

		while read -r element
		do
			set -- "$@" "$(config "$element")"
		done < <(config_subkeys "bashtard.backup.elements")
	fi

	# If there are still no configured elements, this is a good time to
	# return an error instead
	if (( $# < 1 ))
	then
		emerg "$BASHTARD_NAME/backup" "No elements to back up"
		return 3
	fi

	# Loop over all repositories, and run backup functions for each of them
	while read -r key
	do
		index="$(awk -F. '{ print $NF }' <<< "$key")"

		for element in "$@"
		do
			"backup_$element" "$index"
		done

		info "$BASHTARD_NAME/backup/$index" "Backups completed"
	done < <(config_subkeys "bashtard.backup.repositories")
}

backup_filesystem() {
	local index=$1 ; shift
	local borg
	local cmd_create
	local cmd_prune
	local indexes

	borg="$(config "bashtard.backup.borg.command" "borg")"
	remote="$(config "bashtard.backup.borg.remote_paths.$index" "borg")"
	repo="$(config "bashtard.backup.repositories.$index")"

	if ! command -v "$borg" > /dev/null 2>&1
	then
		emerg "$BASHTARD_NAME/backup/$index" "The backup command depends on '$borg' being installed and available in your \$PATH"
		return 4
	fi

	# Prune old backups
	info "$BASHTARD_NAME/backup/$index" "Pruning filesystem backups in $repo"
	cmd_prune=(
		"$borg" "prune"
		"--keep-daily" "$(config "bashtard.backup.keep.daily")"
		"--keep-weekly" "$(config "bashtard.backup.keep.weekly")"
		"--keep-monthly" "$(config "bashtard.backup.keep.monthly")"
		"--keep-yearly" "$(config "bashtard.backup.keep.yearly")"
		"--prefix" "{fqdn}-"
		"--remote-path" "$remote"
		"$repo/hostfs"
	)

	notice "$BASHTARD_NAME/backup/$index" "> ${cmd_prune[*]}"
	${cmd_prune[@]}

	# Create new backups
	info "$BASHTARD_NAME/backup/$index" "Writing new filesystem backup to $repo"
	cmd_create=(
		"$borg" "create"
		"--one-file-system"
		"--remote-path" "$remote"
		"$repo/hostfs::{fqdn}-$(datetime)"
	)

	# Add all paths to the command
	while read -r path
	do
		cmd_create+=("$(config "$path")")
	done < <(config_subkeys "bashtard.backup.fs.paths")

	notice "$BASHTARD_NAME/backup/$index" "> ${cmd_create[*]}"
	${cmd_create[@]}
}

backup_database_postgresql() {
	local index=$1 ; shift
	local borg
	local remote
	local repo

	if ! command -v "psql" > /dev/null 2>&1
	then
		emerg "$BASHTARD_NAME/backup/$index" "The backup command depends on 'psql' being installed and available in your \$PATH"
		return 4
	fi

	if ! command -v "pg_dump" > /dev/null 2>&1
	then
		emerg "$BASHTARD_NAME/backup/$index" "The backup command depends on 'pg_dump' being installed and available in your \$PATH"
		return 4
	fi

	PGPASSWORD="$(config "bashtard.backup.db.postgresql.password" "")"
	PGUSER="$(config "bashtard.backup.db.postgresql.user" "postgres")"
	borg="$(config "bashtard.backup.borg.command" "borg")"
	remote="$(config "bashtard.backup.borg.remote_paths.$index" "borg")"
	repo="$(config "bashtard.backup.repositories.$index")"

	[[ -n $PGPASSWORD ]] && export PGPASSWORD
	export PGUSER

	while read -r database
	do
		[[ $database == "postgres" ]] && continue
		[[ $database =~ template* ]] && continue

		local cmd_create
		local cmd_prune

		# Prune old backups
		info "$BASHTARD_NAME/backup/$index" "Pruning PostgreSQL backups of $database in $repo"
		cmd_prune=(
			"$borg" "prune"
			"--keep-daily" "$(config "bashtard.backup.keep.daily")"
			"--keep-weekly" "$(config "bashtard.backup.keep.weekly")"
			"--keep-monthly" "$(config "bashtard.backup.keep.monthly")"
			"--keep-yearly" "$(config "bashtard.backup.keep.yearly")"
			"--prefix" "$database-"
			"--remote-path" "$remote"
			"$repo/postgresql-$database"
		)

		notice "$BASHTARD_NAME/backup/$index" "> ${cmd_prune[*]}"
		${cmd_prune[@]}

		# Create new backups
		info "$BASHTARD_NAME/backup/$index" "Writing new PostgreSQL backup of $database to $repo"
		cmd_create=(
			"borg" "create"
			"--remote-path" "$remote"
			"$repo/postgresql-$database::$database-$(datetime)"
			"-"
		)

		notice "$BASHTARD_NAME/backup/$index" "> pg_dump "$database" | ${cmd_create[*]}"
		pg_dump "$database" | ${cmd_create[@]}
	done < <(psql -AXt -d template1 -c "SELECT datname FROM pg_database")
}