#!/usr/bin/env php
<?php

set_error_handler(function($_, $msg) {
 throw new Exception($msg);
});

if ($argc > 1) {
 $dir = $argv[1];
} else {
 $dir = __DIR__ . '/../..';
}
if (!is_dir($dir)) {
 echo "Directory $dir does not exist.\n";
 exit(1);
}

$it = new RecursiveIteratorIterator(
 new RecursiveDirectoryIterator($dir),
 RecursiveIteratorIterator::LEAVES_ONLY
);

$excludes = [
 // Bundled libraries / files.
 'ext/date/lib/',
 'ext/dom/lexbor/',
 'ext/fileinfo/data_file.c',
 'ext/fileinfo/libmagic/',
 'ext/gd/libgd/',
 'ext/hash/sha3/',
 'ext/hash/hash_whirlpool.c',
 'ext/hash/php_hash_whirlpool_tables.h',
 'ext/mbstring/libmbfl/',
 'ext/mbstring/unicode_data.h',
 'ext/opcache/jit/ir',
 'ext/pcre/pcre2lib/',
 'ext/standard/html_tables/html_table_gen.php',
 'sapi/cli/php_http_parser.c',
 'sapi/cli/php_http_parser.h',
 'sapi/litespeed/',
 // Not a PHP file.
 'ext/zlib/tests/data.inc',
 // Flexible HEREDOC/NOWDOC tests are likely whitespace sensitive.
 // TODO: Properly classify them.
 'Zend/tests/flexible-',
];

foreach ($it as $file) {
 if (!$file->isFile()) {
 continue;
 }

 $path = $file->getPathName();
 foreach ($excludes as $exclude) {
 if (strpos($path, $exclude) !== false) {
 continue 2;
 }
 }

 $lang = getLanguageFromExtension($file->getExtension());
 if ($lang === null) {
 continue;
 }

 $origCode = $code = file_get_contents($path);

 if ($lang === 'c') {
 $code = stripTrailingWhitespace($code);
 // TODO: Avoid this for now.
 // $code = reindentToTabs($code);
 } else if ($lang === 'php') {
 $code = stripTrailingWhitespace($code);
 $code = reindentToSpaces($code);
 } else if ($lang === 'phpt') {
 $code = transformTestCode($code, function(string $code) {
 $code = stripTrailingWhitespace($code);
 $code = reindentToSpaces($code);
 return $code;
 });
 }

 if ($origCode !== $code) {
 file_put_contents($path, $code);
 }
}

function stripTrailingWhitespace(string $code): string {
 return preg_replace('/\h+$/m', '', $code);
}

function reindentToTabs(string $code): string {
 return preg_replace_callback('/^ +/m', function(array $matches) {
 $tabSize = 4;
 $spaces = strlen($matches[0]);
 $tabs = intdiv($spaces, $tabSize);
 $spaces -= $tabs * $tabSize;
 return str_repeat("\t", $tabs) . str_repeat(" ", $spaces);
 }, $code);
}

function reindentToSpaces(string $code): string {
 return preg_replace_callback('/^[ \t]+/m', function(array $matches) {
 $tabSize = 4;
 $indent = 0;
 foreach (str_split($matches[0]) as $char) {
 if ($char === ' ') {
 $indent++;
 } else {
 $partialIndent = $indent % $tabSize;
 if ($partialIndent === 0) {
 $indent += $tabSize;
 } else {
 $indent += $tabSize - $partialIndent;
 }
 }
 }
 return str_repeat(" ", $indent);
 }, $code);
}

function transformTestCode(string $code, callable $transformer): string {
 // Don't transform whitespace-sensitive tests.
 if (strpos($code, '--WHITESPACE_SENSITIVE--') !== false) {
 return $code;
 }

 return preg_replace_callback(
 '/(--(?:FILE|SKIPIF|CLEAN)--)(.+?)(?=--[A-Z_]+--)/s',
 function(array $matches) use($transformer) {
 return $matches[1] . $transformer($matches[2]);
 },
 $code
 );
}

function getLanguageFromExtension(string $ext): ?string {
 switch ($ext) {
 case 'c':
 case 'h':
 case 'cpp':
 case 'y':
 case 'l':
 case 're':
 return 'c';
 case 'php':
 case 'inc':
 return 'php';
 case 'phpt':
 return 'phpt';
 default:
 return null;
 }
}