msync

#!/usr/bin/env bash

if [ -z "$LSYNCD_TEMPLATE" ]; then
    LSYNCD_TEMPLATE="$(dirname "$0")/template.lua"
fi

if [ -z "$XDG_RUNTIME_DIR" ]; then
    echo "Don't know where to store program state. Set XDG_RUNTIME_DIR."
    exit 1
fi

LSYNCD_DIR="$XDG_RUNTIME_DIR/machine-sync"
COUNT_FILE="$LSYNCD_DIR/count"

function create_dir {
    if [ ! -f "$COUNT_FILE" ]; then
        id=1
    else
        id=$(( $(cat "$COUNT_FILE") + 1 ))
    fi
    echo "$id" > "$COUNT_FILE"
    mkdir -p "$LSYNCD_DIR/$id"
    echo "$LSYNCD_DIR/$id"
}

function status {
    mkdir -p "$LSYNCD_DIR"
    # so that empty is reported correctly
    find "$LSYNCD_DIR" -maxdepth 1 -mindepth 1 -type d -printf '%P\n' | while read -r id; do
        pid=$(< "$LSYNCD_DIR/$id/pid")
        if ps -p "$pid" > /dev/null; then
            dir=$(basename "$(< "$LSYNCD_DIR/$id/dir")")
            machines=$(< "$LSYNCD_DIR/$id/machines")
            pid=$(< "$LSYNCD_DIR/$id/pid")
            echo "$id ($pid): $dir -> $machines"
        else
            rm -rf "${LSYNCD_DIR:--}/$id"
        fi
    done
}

function get_instance_from_dir {
    dir=$1
    mkdir -p "$LSYNCD_DIR"
    find "$LSYNCD_DIR" -maxdepth 1 -mindepth 1 -type d -printf '%P\n' | while read -r id; do
        if [ "$(< "$LSYNCD_DIR/$id/dir")" = "$dir" ]; then
            echo "$id"
            return 0
        fi
    done
}

function start {
    local -n _args=$1
    local -n _machines=$2

    # stop existing session of the same dir
    existing=$(get_instance_from_dir "$PWD")
    if [ -n "$existing" ]; then
        echo "Replacing with existing session $existing syncing to $(< "$LSYNCD_DIR/$existing/machines")"
        stop "$existing"
    fi

    dir=$(create_dir)

    prev_ifs="$IFS"
    IFS=:
    export MACHINES="${_machines[*]}"
    IFS="$prev_ifs"
    if [ -z "$debug" ]; then
        lsyncd -nodaemon "$LSYNCD_TEMPLATE" "${_args[@]}" &>"$dir/logs" & disown
    else
        lsyncd -nodaemon "$LSYNCD_TEMPLATE" "${_args[@]}"
    fi
    echo "$!" > "$dir/pid"
    echo "${_args[@]}" > "$dir/args"
    echo "$PWD" > "$dir/dir"
    echo "${_machines[@]}" > "$dir/machines"
}

function stop {
    for id in "$@"; do
        kill "$(< "$LSYNCD_DIR/$id/pid")" 2>/dev/null
        rm -rf "${LSYNCD_DIR:--}/$id"
    done
}

case "$1" in
    "")
        cmd="status"
        shift
        ;;
    start|status|stop)
        cmd="$1"
        shift
        ;;
    *)
        echo "first arg needs to be cmd (status|stop|start)"
        exit 1
        ;;
esac

case "$cmd" in
    status)
        status
        ;;
    start)
        machines=()
        args=()
        while [[ $# -gt 0 ]]; do
            case "$1" in
                --debug)
                    debug=1
                    shift
                    ;;
                -*)
                    args+=("$1")
                    shift
                    ;;
                *)
                    if [[ $1 == *:* ]]; then
                        echo "Do not pass targets with : as machines in there"
                        exit 1
                    fi
                    machines+=("$1")
                    shift
                    ;;
            esac
        done
        start args machines
        ;;
    stop)
        stop "$@"
        ;;
esac