<?php

declare(strict_types=1);

$root = dirname(__DIR__);
$catalogDir = $root . '/catalog';
$allowedStatuses = [
    'draft',
    'unverified',
    'verified',
    'discontinued',
    'duplicate',
];

$allowedImageExtensions = ['webp', 'jpg', 'jpeg', 'png'];
$errors = [];
$checked = 0;

if (!is_dir($catalogDir)) {
    fwrite(STDERR, "Catalog directory not found: {$catalogDir}\n");
    exit(1);
}

$iterator = new RecursiveIteratorIterator(
    new RecursiveDirectoryIterator(
        $catalogDir,
        FilesystemIterator::SKIP_DOTS
    )
);

foreach ($iterator as $file) {
    if (!$file->isFile() || strtolower($file->getExtension()) !== 'json') {
        continue;
    }

    $checked++;
    $path = $file->getPathname();
    $relativePath = substr($path, strlen($root) + 1);

    $raw = file_get_contents($path);

    if ($raw === false) {
        $errors[] = "{$relativePath}: unable to read file";
        continue;
    }

    try {
        $record = json_decode($raw, true, 512, JSON_THROW_ON_ERROR);
    } catch (JsonException $exception) {
        $errors[] = "{$relativePath}: invalid JSON: {$exception->getMessage()}";
        continue;
    }

    if (!is_array($record)) {
        $errors[] = "{$relativePath}: root value must be an object";
        continue;
    }

    $required = [
        'catalog_version',
        'record_uuid',
        'manufacturer',
        'product_name',
        'caliber',
        'status',
        'last_updated',
    ];

    foreach ($required as $field) {
        if (!array_key_exists($field, $record)) {
            $errors[] = "{$relativePath}: missing required field '{$field}'";
        }
    }

    if (($record['catalog_version'] ?? null) !== 1) {
        $errors[] = "{$relativePath}: catalog_version must be 1";
    }

    if (
        isset($record['record_uuid']) &&
        !preg_match(
            '/^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i',
            (string) $record['record_uuid']
        )
    ) {
        $errors[] = "{$relativePath}: record_uuid is not a valid UUID";
    }

    foreach (['manufacturer', 'product_name', 'caliber'] as $field) {
        if (
            isset($record[$field]) &&
            (!is_string($record[$field]) || trim($record[$field]) === '')
        ) {
            $errors[] = "{$relativePath}: {$field} must be a non-empty string";
        }
    }

    if (
        isset($record['upc']) &&
        $record['upc'] !== null &&
        !preg_match('/^[0-9]{8,14}$/', (string) $record['upc'])
    ) {
        $errors[] = "{$relativePath}: upc must contain 8 to 14 digits";
    }

    if (
        isset($record['status']) &&
        !in_array($record['status'], $allowedStatuses, true)
    ) {
        $errors[] = "{$relativePath}: invalid status '{$record['status']}'";
    }

    if (
        isset($record['last_updated']) &&
        !preg_match('/^\d{4}-\d{2}-\d{2}$/', (string) $record['last_updated'])
    ) {
        $errors[] = "{$relativePath}: last_updated must use YYYY-MM-DD";
    }

    if (
        isset($record['sources']) &&
        !is_array($record['sources'])
    ) {
        $errors[] = "{$relativePath}: sources must be an array";
    }

    if (
        ($record['status'] ?? null) === 'verified' &&
        empty($record['sources'])
    ) {
        $errors[] = "{$relativePath}: verified records must include at least one source";
    }

    if (
        isset($record['image']) &&
        $record['image'] !== null
    ) {
        if (!is_array($record['image'])) {
            $errors[] = "{$relativePath}: image must be an object or null";
        } else {
            $imagePath = $record['image']['path'] ?? null;

            if (!is_string($imagePath) || $imagePath === '') {
                $errors[] = "{$relativePath}: image.path must be a non-empty string";
            } else {
                if (!str_starts_with($imagePath, 'images/')) {
                    $errors[] = "{$relativePath}: image.path must start with images/";
                }

                if (str_contains($imagePath, '..')) {
                    $errors[] = "{$relativePath}: image.path may not contain ..";
                }

                $extension = strtolower(pathinfo($imagePath, PATHINFO_EXTENSION));

                if (!in_array($extension, $allowedImageExtensions, true)) {
                    $errors[] = "{$relativePath}: unsupported image extension '{$extension}'";
                }

                $fullImagePath = $root . '/' . $imagePath;

                if (!is_file($fullImagePath)) {
                    $errors[] = "{$relativePath}: referenced image does not exist: {$imagePath}";
                }

                $checksum = $record['image']['sha256'] ?? null;

                if (
                    $checksum !== null &&
                    !preg_match('/^[a-f0-9]{64}$/i', (string) $checksum)
                ) {
                    $errors[] = "{$relativePath}: image.sha256 must be 64 hexadecimal characters";
                }

                if (
                    $checksum !== null &&
                    is_file($fullImagePath)
                ) {
                    $actualChecksum = hash_file('sha256', $fullImagePath);

                    if (!hash_equals(strtolower($checksum), strtolower($actualChecksum))) {
                        $errors[] = "{$relativePath}: image SHA-256 does not match";
                    }
                }
            }
        }
    }
}

if ($errors !== []) {
    fwrite(STDERR, "Catalog validation failed:\n\n");

    foreach ($errors as $error) {
        fwrite(STDERR, " - {$error}\n");
    }

    fwrite(STDERR, "\nChecked {$checked} product file(s).\n");
    exit(1);
}

echo "Catalog validation passed. Checked {$checked} product file(s).\n";