#!/usr/bin/env sh

USAGE="ssync-queue [options] -l LOCAL_INDEX_FILE -r REMOTE_INDEX_FILE -o QUEUE_OUTPUT_FILE
    OPTIONS
        -l LOCAL_INDEX_FILE
	   target local index file
	-r REMOTE_INDEX_FILE
	   target remote index file
	-o QUEUE_OUTPUT_FILE
	   queue output file
	-v verbose logging
        -h print this message"

# HELPER FUNCTIONS

verbose_log() {
    if [ ! -z "$VERBOSE_FLAG" ]; then
	echo "$@"
    fi
}
lines() {
    echo $(wc -l $1 | cut -d' ' -f1)
}

# OPTIONS

VERBOSE_FLAG=
LOCAL_FILE_FLAG=
REMOTE_FILE_FLAG=
QUEUE_FILE_FLAG=
CONFIG_FILE_FLAG=
LOCAL_FILE_ARG=
REMOTE_FILE_ARG=
QUEUE_FILE_ARG=

while getopts "hvl:r:o:" opt; do
    case "${opt}" in
	l) LOCAL_FILE_FLAG=1
	   LOCAL_FILE_ARG="${OPTARG}"
	   ;;
	r) REMOTE_FILE_FLAG=1
	   REMOTE_FILE_ARG="${OPTARG}"
	   ;;
	o) QUEUE_FILE_FLAG=1
	   QUEUE_FILE_ARG="${OPTARG}"
	   ;;
	v) VERBOSE_FLAG=1
	   ;;
	h) echo "$USAGE"
	   exit 1
	   ;;
    esac
done

shift $(($OPTIND -1))

if [ -z "$LOCAL_FILE_FLAG" ]; then
    echo "-l LOCAL_INDEX_FILE option is required"
    exit 1
elif [ ! -f "$LOCAL_FILE_ARG" ]; then
    echo "local index file '$LOCAL_FILE_ARG' does not exist"
    exit 1
fi

if [ -z "$REMOTE_FILE_FLAG" ]; then
    echo "-r REMOTE_INDEX_FILE option is required"
    exit 1
elif [ ! -f "$REMOTE_FILE_ARG" ]; then
    echo "remote index file '${REMOTE_FILE_ARG}' does not exist"
    exit 1
fi

if [ -z "$QUEUE_FILE_FLAG" ]; then
    echo "-q QUEUE_OUTPUT_FILE option is required"
    exit 1
fi

queue_tmp_dir=$(mktemp -d /tmp/ssync_queue_run.XXXXXX)
verbose_log "Writing temp files to $queue_tmp_dir"

# get remote filenames
remote_index_filenames_file=$queue_tmp_dir/remote_filenames.idx
verbose_log "Writing remote index filenames to $remote_index_filenames_file"
cat $REMOTE_FILE_ARG | xargs -I{} basename {} > $remote_index_filenames_file
original_line_count=$(lines $REMOTE_FILE_ARG)
unique_line_count=$(sort -u $remote_index_filenames_file | lines)
verbose_log "Remote index contains $unique_line_count unique filenames out of $original_line_count indexed files"

if [ $original_line_count != $unique_line_count ]; then
    echo "Remote index contains non-unique files. Check $REMOTE_INDEX_FILE to find which files aren't unique" >&2
fi

# find which filenames are unique to the remote
local_sorted=$queue_tmp_dir/local_sorted.idx
remote_sorted=$queue_tmp_dir/remote_sorted.idx
remote_only_filenames_file=$queue_tmp_dir/remote_only_filenames.idx
sort $LOCAL_FILE_ARG > $local_sorted
sort $remote_index_filenames_file > $remote_sorted
comm -23 $remote_sorted $local_sorted > $remote_only_filenames_file
verbose_log "Found $(lines $remote_only_filenames_file) remote only files"

# push matching files into queue
cat $remote_only_filenames_file | xargs -I{} grep "^.*{}$" $REMOTE_FILE_ARG >> $QUEUE_FILE_ARG
verbose_log "Added $(lines $QUEUE_FILE_ARG) to the queue"