#!/usr/bin/php
<?php

function getOrderedWorkspaces()
{
    $json = shell_exec('i3-msg -t get_workspaces');
    $workspaces = json_decode($json);

    $ordered = [];

    foreach ($workspaces as $w) {
        $ordered[] = $w->name;
    }

    sort($ordered);

    foreach ($ordered as $k => $v) {
        foreach ($workspaces as $x => $w) {
            if ($w->name == $v) {
                $ordered[$k] = $w;
                unset($workspaces[$x]);
            }
        }
    }

    return $ordered;
}

function getMoveOption()
{
    global $argv;

    if (!isset($argv[1])) {
        $argv[1] = 'next';
    }

    return in_array($argv[1], ['next', 'previous']) ? $argv[1] : 'next';
}

function getNextWorkspace($workspaces)
{
    $key = 0;

    foreach ($workspaces as $k => $v) {
        if ($v->focused) {
            $key = $k;
        }
    }

    return $workspaces[($key + 1) % count($workspaces)];
}

function getPreviousWorkspace($workspaces)
{
    $count = count($workspaces);
    $key = 0;

    foreach ($workspaces as $k => $v) {
        if ($v->focused) {
            $key = $k;
        }
    }

    return $workspaces[--$key >= 0 ? $key : $count - 1];
}

function moveToWorkspace($workspace)
{
    shell_exec(sprintf("i3-msg 'workspace \"%s\"'", $workspace->name));
}

$workspaces = getOrderedWorkspaces();
moveToWorkspace('next' === getMoveOption() ? getNextWorkspace($workspaces) : getPreviousWorkspace($workspaces));