<?php
// Copyright (C) 2004-2026 The Cacti Group. GPL-2.0-or-later.

namespace Cacti\Tests\Helpers;

/** Source contracts ignore formatting, while retaining token kinds and literals. */
final class PhpSource {
	public static function normalizeWhitespace(string $source) : string {
		$output = '';

		foreach (token_get_all($source) as $token) {
			$id   = is_array($token) ? $token[0] : 0;
			$text = is_array($token) ? $token[1] : $token;

			if (in_array($id, [T_WHITESPACE, T_COMMENT, T_DOC_COMMENT], true)) {
				if (!str_ends_with($output, ' ')) {
					$output .= ' ';
				}
			} else {
				$output .= $text;
			}
		}

		return $output;
	}

	private static function encode(string $source, bool $fragment = false) : array {
		if ($fragment) {
			$source = '<?php ' . $source;
		}

		$encoded = [];
		$offsets = [];
		$offset  = 0;

		foreach (token_get_all($source) as $token) {
			$id   = is_array($token) ? $token[0] : 0;
			$text = is_array($token) ? $token[1] : $token;

			if (!in_array($id, [T_OPEN_TAG, T_WHITESPACE, T_COMMENT, T_DOC_COMMENT], true)) {
				$encoded[] = json_encode([$id, $text], JSON_THROW_ON_ERROR);
				$offsets[] = $offset;
			}

			$offset += strlen($text);
		}

		return [implode("\n", $encoded), $offsets];
	}

	public static function position(string $source, string $fragment) : int|false {
		[$encoded, $offsets] = self::encode($source);
		[$needle]            = self::encode($fragment, true);
		$match               = self::match($encoded, $needle);

		return $match === false ? false : $offsets[substr_count(substr($encoded, 0, $match), "\n")];
	}

	public static function count(string $source, string $fragment) : int {
		[$encoded] = self::encode($source);
		[$needle]  = self::encode($fragment, true);
		$count     = 0;
		$offset    = 0;

		while (($match = self::match($encoded, $needle, $offset)) !== false) {
			$count++;
			$offset = $match + strlen($needle);
		}

		return $count;
	}

	private static function match(string $source, string $needle, int $offset = 0) : int|false {
		if ($needle === '') {
			throw new \InvalidArgumentException('A PHP source contract needs at least one token.');
		}

		while (($match = strpos($source, $needle, $offset)) !== false) {
			$end = $match + strlen($needle);

			if (($match === 0 || $source[$match - 1] === "\n") &&
				($end === strlen($source) || $source[$end] === "\n")) {
				return $match;
			}

			$offset = $match + 1;
		}

		return false;
	}
}

expect()->extend('toContainPhp', function (string $fragment) {
	\PHPUnit\Framework\Assert::assertNotFalse(
		PhpSource::position($this->value, $fragment),
		'Expected PHP token sequence: ' . $fragment
	);

	return $this;
});