#!/usr/bin/env bash
# dependencies:
# tar, xz, stat, par2create (from par2cmdline package), md5sum, du, awk, jq
set -e

check_command() {
	CMD="$1"

	if ! command -v "$CMD" 2>&1 /dev/null
	then
		gum log -l "fatal" "Executable: $CMD was not found."
		exit 1
	fi
}

gum log -t kitchen -l info "Checking for dependencies:"
check_command awk
check_command du
check_command find
check_command jq
check_command md5sum
check_command par2create
check_command stat
check_command tar
check_command xz
gum log -t kitchen -l info "All dependencies found!"

ARCHIVE_DB="$HOME"/.local/state/archives.json

create_archive() {
	ARCHIVE_NAME="$1"
	ARCHIVE_DESTINATION="$2"
	TARGET="$3"

	gum log -t kitchen -l info "Creating tar for $TARGET."
	tar cfP "$ARCHIVE_NAME".tar "$TARGET"
	mv "$ARCHIVE_NAME".tar "$ARCHIVE_DESTINATION"
	gum log -t kitchen -l info "Finished creating tar for $TARGET."

	gum log -l info "Proceeding to archive."
	cd "$ARCHIVE_DESTINATION" || exit 0
	[ -f "$ARCHIVE_NAME".tar.xz ] && rm "$ARCHIVE_NAME".tar.xz && gum log -t kitchen -l info "Removed old $ARCHIVE_NAME.tar.xz."

	gum log -l info -t kitchen "Compressing: $ARCHIVE_NAME.tar"
	xz -v -e -9 "$ARCHIVE_NAME".tar

	DIR_SIZE="$(du -sh "$TARGET" | awk '{print $1}')"
	ARCHIVE_SIZE="$(du -sh "$ARCHIVE_NAME".tar.xz | awk '{print $1}')"
	gum log -l info -t kitchen "Finished archiving $TARGET."
	gum style --bold "Compressed $TARGET ($DIR_SIZE) to $ARCHIVE_NAME ($ARCHIVE_SIZE)."
}

create_parchive() {
	gum log -l info -t kitchen "Creating parity archive."
	ARCHIVE="$1"
	find . -name '*par2' -exec rm {} \;
	par2create -r30 -n1 "$ARCHIVE"
}

update_json() {
	INDEX="$1"
	ARCHIVE_TIME="$2"
	UPLOAD_TIME="$3"
	MD5SUM="$4"

	FOO="$(jq ".[$INDEX].timestamps.last_archive = $ARCHIVE_TIME" < "$ARCHIVE_DB" \
		| jq ".[$INDEX].timestamps.last_upload = $UPLOAD_TIME" \
		| jq ".[$INDEX].md5sum = \"$MD5SUM"\")"
	echo "$FOO" > "$ARCHIVE_DB"
}

ARCHIVE_COUNT="$(jq '.[].name' < "$ARCHIVE_DB" | wc -l)"
ARCHIVE_COUNT="$((ARCHIVE_COUNT - 1))"
for i in $(seq 0 "$ARCHIVE_COUNT")
do
	JSON="$(jq ".[$i]" < "$ARCHIVE_DB")"
	TARGET="$(echo "$JSON" | jq -r '.target')"
	TARGET="${TARGET/#\~/$HOME}"
	ARCHIVE="$(echo "$JSON" | jq '.archive')"
	ARCHIVE_NAME="$(echo "$ARCHIVE" | jq -r '.name')"
	ARCHIVE_PATH="$(echo "$ARCHIVE" | jq -r '.destination')"
	ARCHIVE_PATH="${ARCHIVE_PATH/#\~/$HOME}"
	SYNC_COMMAND="$(echo "$JSON" | jq -r '.sync_command')"
	mkdir -p "$ARCHIVE_PATH"

	create_archive "$ARCHIVE_NAME" "$ARCHIVE_PATH" "$TARGET"

	create_parchive "$ARCHIVE_NAME".tar.xz

	ARCHIVE_TIME="$(stat -c %W "$ARCHIVE_NAME".tar.xz)"
	MD5SUM="$(md5sum "$ARCHIVE_NAME".tar.xz | awk '{print $1}')"

	bash -c "$SYNC_COMMAND"; UPLOAD_TIME="$(date +%s)"

	update_json "$i" "$ARCHIVE_TIME" "$UPLOAD_TIME" "$MD5SUM"
done