#!/usr/bin/env sh

USAGE="ssync-index [options] [CONFIG_FILE]
    OPTIONS
        -k [KEY_FILE] override conigured key file
        -o [OUTPUT_DIR] override configured index output dir
        -l local only
        -r remote only
        -v verbose logging
        -h print this message"

# HELPER METHODS
function verbose_log {
    if [ ! -z "$VERBOSE_FLAG" ]; then
	echo "$1"
    fi
}
function lines {
    wc -l $1 | cut -d' ' -f1
}
function get_default_index_dir {
    local cache_path=ssync/index/
    local cache_dir=
    if [ ! -z "$XDG_CACHE_DIR" ]; then
	cache_dir=$XDG_CACHE_DIR/$cache_path
    else
	cache_dir=/tmp/
    fi

    mkdir -p $cache_dir/$cache_path
    echo $cache_dir/$cache_path
}

# GLOBAL VALUES
DEFAULT_INDEX_WINDOW=86400
LOCAL_ONLY_FLAG=
REMOTE_ONLY_FLAG=
VERBOSE_FLAG=
KEY_FILE_FLAG=
KEY_FILE_ARG=
OUTPUT_DIR_FLAG=
OUTPUT_DIR_ARG=

# OPTIONS PARSING
while getopts "hvlro:k:" opt; do
    case "${opt}" in
	h) echo "$USAGE"
	   exit 1
	   ;;
	o) OUTPUT_DIR_FLAG=1
	   OUTPUT_DIR_ARG="$OPTARG"
	   ;;
	k) KEY_FILE_FLAG=1
	   KEY_FILE_ARG="$OPTARG"
	   ;;
	l) LOCAL_ONLY_FLAG=1
	   ;;
	r) REMOTE_ONLY_FLAG=1
	   ;;
	v) VERBOSE_FLAG=1
	   ;;
    esac
done

shift $(($OPTIND -1))

if [ $# -eq 0 ]; then
    echo "$USAGE"
    exit 1

fi

CONFIG_FILE=$1

# CONFIG PARSING
if [ -z "$CONFIG_FILE" ]; then
    echo "CONFIG_FILE is missing."
    exit 1
fi

if [ ! -f $CONFIG_FILE ]; then
    echo "$CONFIG_FILE does not exist."
    exit 1
fi

source $CONFIG_FILE

# CONFIG VALIDATION
if [ -z "$remote_host" ]; then
    echo "Config is missing remote_host"
    exit 1
fi

if [ -z "$remote_root_dir" ]; then
    echo "Config is missing remote_root_dir"
    exit 1
fi

if [ -z "$keyfile" ]; then
    echo "Config is missing keyfile"
    exit 1
elif [ ! -f "$keyfile" ]; then
    echo "Configured keyfile '$keyfile' does not exist"
    exit 1
fi

if [ -z "$local_root_dir" ]; then
    echo "Config is missing local_root_dir"
    exit 1
elif [ ! -d "$local_root_dir" ]; then
    echo "Configured local_root_dir '$local_root_dir' does not exist"
    exit 1
fi

# VALUE SETTING

if [ -z "$index_window_s" ]; then
    index_window_s=$DEFAULT_INDEX_WINDOW
fi

local_index_file=
remote_index_file=
if [ ! -z "$OUTPUT_DIR_FLAG" ]; then
    index_dir=$OUTPUT_DIR_ARG
fi

if [ ! -z "$index_dir" ]; then
    if [ ! -d "$index_dir" ]; then
	echo "Configured index_dir '$index_dir' does not exist"
	exit 1
    fi
else
  index_dir=$(get_default_index_dir)
fi

# RUN INDEXING

ts=$(date -u +%s)
local_index_file=${index_dir}/${ts}_local.idx
remote_index_file=${index_dir}/${ts}_remote.idx
newermt=$(date -d "$index_window_s seconds ago" -u -Is)
verbose_log "Targetting files from $index_window_s seconds ago: $newermt"

# index remote host relative to your fetch dir
if [ -z "$LOCAL_ONLY_FLAG" ]; then
    verbose_log "Generating remote index from ${remote_root_dir} to ${remote_index_file}"
    ssh -i $keyfile $remote_host \
	"find ${remote_root_dir} -type f -newermt $newermt -exec realpath {} \;" > $remote_index_file
    verbose_log "Indexed $(lines $remote_index_file) remote files"
fi

# index local filenames ONLY
if [ -z "$REMOTE_ONLY_FLAG" ]; then
    verbose_log "Generate local index from ${local_root_dir} to ${local_index_file}"
    find ${local_root_dir} -type f -exec basename {} \; > $local_index_file
    verbose_log "Indexed $(lines $local_index_file) local files"
fi