<?php
/**
 * Flat-file JSON storage with locking, plus the site/gallery data accessors.
 */

declare(strict_types=1);

/** Read a JSON file; returns $default if missing or unreadable. */
function json_read(string $file, array $default = []): array
{
    if (!is_file($file)) {
        return $default;
    }
    $fh = fopen($file, 'r');
    if ($fh === false) {
        return $default;
    }
    flock($fh, LOCK_SH);
    $raw = stream_get_contents($fh);
    flock($fh, LOCK_UN);
    fclose($fh);
    $data = json_decode((string)$raw, true);
    return is_array($data) ? $data : $default;
}

/** Write a JSON file atomically (tmp file + rename) under an exclusive lock. */
function json_write(string $file, array $data): void
{
    $dir = dirname($file);
    if (!is_dir($dir)) {
        mkdir($dir, 0755, true);
    }
    $tmp = $file . '.' . bin2hex(random_bytes(6)) . '.tmp';
    $json = json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
    if (file_put_contents($tmp, $json, LOCK_EX) === false) {
        throw new RuntimeException("Cannot write $tmp");
    }
    if (!rename($tmp, $file)) {
        @unlink($tmp);
        throw new RuntimeException("Cannot replace $file");
    }
}

/** URL-safe random token. */
function random_token(int $chars = 8): string
{
    $alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    $out = '';
    for ($i = 0; $i < $chars; $i++) {
        $out .= $alphabet[random_int(0, strlen($alphabet) - 1)];
    }
    return $out;
}

/**
 * Transliterate German (and, best effort, other accented) characters to ASCII
 * so they survive in slugs, filenames and S3 keys instead of being dropped:
 * ä→ae, ö→oe, ü→ue, ß→ss, é→e, … Case is preserved.
 */
function ascii_transliterate(string $s): string
{
    $map = [
        'ä' => 'ae', 'ö' => 'oe', 'ü' => 'ue',
        'Ä' => 'Ae', 'Ö' => 'Oe', 'Ü' => 'Ue', 'ß' => 'ss',
    ];
    $s = strtr($s, $map);
    if (function_exists('iconv')) {
        $converted = @iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', $s);
        if ($converted !== false) {
            $s = $converted;
        }
    }
    return $s;
}

/** Turn a title into a URL slug fragment ("Wedding Müller" → "wedding-mueller"). */
function slugify(string $title): string
{
    $s = strtolower(ascii_transliterate($title));
    $s = preg_replace('/[^a-z0-9]+/', '-', $s) ?? '';
    $s = trim($s, '-');
    return $s !== '' ? $s : 'gallery';
}

/**
 * Sanitize an upload filename to a safe ASCII basename, keeping the extension.
 * German characters are transliterated rather than replaced by dashes, so
 * "Straße.jpg" becomes "Strasse.jpg" instead of "Stra-e.jpg".
 */
function safe_filename(string $name, string $fallback = 'file'): string
{
    $name = basename($name);
    $ext  = strtolower(pathinfo($name, PATHINFO_EXTENSION));
    $base = ascii_transliterate(pathinfo($name, PATHINFO_FILENAME));
    $base = preg_replace('/[^A-Za-z0-9._-]+/', '-', $base) ?? '';
    $base = trim($base, '-.');
    if ($base === '') {
        $base = $fallback;
    }
    $ext = preg_replace('/[^A-Za-z0-9]+/', '', $ext) ?? '';
    return $ext !== '' ? $base . '.' . $ext : $base;
}

// ---------------------------------------------------------------------------
// Local media (hero + showreel images in media/)
// ---------------------------------------------------------------------------

const MEDIA_EXTENSIONS = ['jpg', 'jpeg', 'png', 'gif', 'webp', 'avif'];

/**
 * Store one uploaded image in media/, full resolution, unmodified.
 * Returns the stored filename, or null if the upload is invalid.
 */
function media_store_upload(array $file): ?string
{
    if (($file['error'] ?? UPLOAD_ERR_NO_FILE) !== UPLOAD_ERR_OK) {
        return null;
    }
    $ext = strtolower(pathinfo($file['name'] ?? '', PATHINFO_EXTENSION));
    if (!in_array($ext, MEDIA_EXTENSIONS, true)) {
        return null;
    }
    // Cheap content sanity check without touching the image data.
    if (function_exists('getimagesize') && @getimagesize($file['tmp_name']) === false) {
        return null;
    }
    $base = ascii_transliterate(pathinfo($file['name'], PATHINFO_FILENAME));
    $base = trim(preg_replace('/[^A-Za-z0-9._-]+/', '-', $base) ?? '', '-.') ?: 'image';
    $name = substr($base, 0, 60) . '-' . random_token(6) . '.' . $ext;
    if (!move_uploaded_file($file['tmp_name'], MEDIA_DIR . '/' . $name)) {
        return null;
    }
    return $name;
}

/** Delete a local media file (filename only, no paths). */
function media_delete(string $name): void
{
    if ($name !== '' && basename($name) === $name) {
        @unlink(MEDIA_DIR . '/' . $name);
    }
}

// ---------------------------------------------------------------------------
// Site content (landing page + showreel)
// ---------------------------------------------------------------------------

function site_get(): array
{
    return json_read(DATA_DIR . '/site.json', [
        'intro_title' => 'Jane Doe',
        'intro_text'  => "Photographer based in Berlin.\nAvailable for portraits, weddings and events.",
        'hero_image'  => null,
        'showreel'    => [],
    ]);
}

function site_save(array $site): void
{
    json_write(DATA_DIR . '/site.json', $site);
}

// ---------------------------------------------------------------------------
// Galleries — one JSON file per gallery in data/galleries/
// ---------------------------------------------------------------------------

function gallery_file(string $slug): string
{
    // Slugs are generated by us, but never trust a request parameter in a path.
    if (!preg_match('/^[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9]$/', $slug) || strlen($slug) > 120) {
        throw new InvalidArgumentException('Invalid gallery slug');
    }
    return DATA_DIR . '/galleries/' . $slug . '.json';
}

function gallery_load(string $slug): ?array
{
    try {
        $file = gallery_file($slug);
    } catch (InvalidArgumentException) {
        return null;
    }
    $g = json_read($file);
    return $g === [] ? null : $g;
}

function gallery_save(array $gallery): void
{
    json_write(gallery_file($gallery['slug']), $gallery);
}

function gallery_delete(string $slug): void
{
    $file = gallery_file($slug);
    if (is_file($file)) {
        unlink($file);
    }
}

/** All galleries, newest first. */
function galleries_all(): array
{
    $out = [];
    foreach (glob(DATA_DIR . '/galleries/*.json') ?: [] as $file) {
        $g = json_read($file);
        if ($g !== []) {
            $out[] = $g;
        }
    }
    usort($out, fn($a, $b) => strcmp($b['created_at'] ?? '', $a['created_at'] ?? ''));
    return $out;
}

/** A gallery past its expiry date is treated as nonexistent for visitors. */
function gallery_is_expired(array $gallery): bool
{
    $expires = $gallery['expires_at'] ?? null;
    if ($expires === null || $expires === '') {
        return false;
    }
    // The gallery stays visible through the whole expiry day.
    return date('Y-m-d') > $expires;
}