#!/usr/bin/php
<?php

$argv[1] = $argv[1] ?? 'now';
$options = getopt('f:t:z:', ['from:', 'to:', 'timezone:'], $rest_index);
$args = array_slice($argv, $rest_index);
foreach ($options as $opt)
	if (is_array($opt)) {
		fwrite(STDERR, 'You can\'t set multiple time the same option' . PHP_EOL);
		exit(1);
	}

$tz = $options['timezone'] ?? $options['z'] ?? 'UTC';
if (date_default_timezone_set($tz) !== true) {
	fwrite(STDERR, 'Unknown timezone' . PHP_EOL);
	exit(1);
}

$from = NULL;
if (isset($options['from']) OR isset($options['f'])) {
	$from = $options['from'] ?? $options['f'];
	if (!in_array($from, ['local', 'unix', 'dit'])) {
		fwrite(STDERR, 'Unknown --from value' . PHP_EOL);
		exit(1);
	}
}

$to = NULL;
if (isset($options['to']) OR isset($options['t'])) {
	$to = $options['to'] ?? $options['t'];
	if (!in_array($to, ['local', 'unix', 'dit'])) {
		fwrite(STDERR, 'Unknown --to value' . PHP_EOL);
		exit(1);
	}
}

require 'libdit.php';

if (isset($args[0]) AND $args[0] === '-')
	foreach (stream_stdin() as $line)
		display($line, $from, $to, $tz);
else
	foreach ($args as $arg)
		display($arg, $from, $to, $tz);

function display($arg, $from, $to, $tz) {

	if (rtrim($arg) === 'exit' OR rtrim($arg) === 'quit')
		exit(0);

	if ($from === NULL) {
		if (($unix = stardit_to_unix($arg)) !== false)
			$from = 'dit';
		else {
			if (!($unix = strtotime($arg, time()))) {
				fwrite(STDERR, 'String argument "' . $arg . '" can\'t be translated to time' . PHP_EOL);
				exit(1);
			} else {
				$from = 'local';
			}
		}
	}
	$unix = match ($from) {
		'dit' => stardit_to_unix($arg),
		'unix' => $arg,
		'local' => strtotime($arg, time()),
	};

	if ($to === NULL) {
		$to = match ($from) {
			'dit' => 'local',
			'local','unix' => 'dit',
		};
	}
	echo match ($to) {
		'dit' => unix_to_stardit($unix),
		'unix' => $unix,
		'local' => date("Y/m/d H:i:s e", $unix),
	} . PHP_EOL;
}

function stream_stdin() {
	while ($line = fgets(STDIN))
		yield $line;
}