<?php
/**
 * SearchController
 *
 * Handles all data-fetching logic for the public search / répertoire page.
 * The entry point (public/search.php) delegates to this class and receives
 * a plain array of view variables ready for template inclusion.
 *
 * Responsibilities:
 *  - Rate-limit enforcement (returns early HTTP 429 response when needed)
 *  - GET parameter sanitisation and validation
 *  - Database queries (search + index listings)
 *  - OG / meta tag assembly
 *
 * The class has NO output side-effects; all template rendering stays in
 * public/search.php so the view layer remains easy to inspect and modify.
 */
class SearchController
{
    private const RATE_LIMIT_MAX      = 30;
    private const RATE_LIMIT_WINDOW   = 60; // seconds
    private const ITEMS_PER_PAGE      = 30;

    private Database  $db;
    private RateLimit $rateLimit;

    public function __construct(Database $db, RateLimit $rateLimit)
    {
        $this->db        = $db;
        $this->rateLimit = $rateLimit;
    }

    // ── Factory ───────────────────────────────────────────────────────────────

    /**
     * Convenience factory: builds dependencies, checks rate limit (sends 429
     * and exits if exceeded), then returns a ready-to-use controller instance.
     */
    public static function create(): self
    {
        require_once APP_ROOT . '/src/Database.php';
        require_once APP_ROOT . '/src/RateLimit.php';

        $rateLimit = new RateLimit(self::RATE_LIMIT_MAX, self::RATE_LIMIT_WINDOW);

        if (!$rateLimit->check()) {
            self::sendRateLimitResponse($rateLimit);
        }

        $rateLimit->sendHeaders();

        // Probabilistic cleanup (1-in-100 requests) to prune stale entries
        if (rand(1, 100) === 1) {
            $rateLimit->cleanup();
        }

        return new self(Database::getInstance(), $rateLimit);
    }

    // ── Main entry point ─────────────────────────────────────────────────────

    /**
     * Process the current request and return all variables needed by the view.
     *
     * @return array<string, mixed>
     */
    public function handle(): array
    {
        $searchParams = $this->collectSearchParams();
        $hasSearch    = !empty($searchParams);

        $page           = isset($_GET['page']) ? max(1, (int) $_GET['page']) : 1;
        $offset         = ($page - 1) * self::ITEMS_PER_PAGE;
        $validationError = null;

        $results    = [];
        $totalItems = 0;
        $totalPages = 0;
        $years        = [];
        $orientations = [];
        $apPrograms   = [];
        $keywords     = [];
        $students     = [];

        try {
            if ($hasSearch) {
                $results    = $this->db->searchTheses($searchParams, self::ITEMS_PER_PAGE, $offset);
                $totalItems = $this->db->countSearchResults($searchParams);
                $totalPages = (int) ceil($totalItems / self::ITEMS_PER_PAGE);
            }

            $years        = $this->db->getAvailableYears();
            $orientations = $this->db->getAllOrientations();
            $apPrograms   = $this->db->getAllAPPrograms();
            $keywords     = $this->db->getUsedTags();
            // Fetch id+authors only — lean query bypassing the fat v_theses_public view
            $students     = $this->db->getPublishedAuthors();

        } catch (InvalidArgumentException $e) {
            $validationError = $e->getMessage();
        } catch (Exception $e) {
            error_log('SearchController: ' . $e->getMessage());
            $validationError = 'Une erreur est survenue.';
        }

        // Build the author index map (répertoire index view)
        $authorMap = $this->buildAuthorMap($students);

        // Preserve all active search/filter params, strip 'page' (pagination partial adds it)
        $baseParams = array_diff_key($_GET, ['page' => '']);

        return [
            // Search state
            'searchParams'    => $searchParams,
            'hasSearch'       => $hasSearch,
            'page'            => $page,
            'totalItems'      => $totalItems,
            'totalPages'      => $totalPages,
            'results'         => $results,
            'validationError' => $validationError,
            'baseParams'      => $baseParams,

            // Filter / index data
            'years'           => $years,
            'orientations'    => $orientations,
            'apPrograms'      => $apPrograms,
            'keywords'        => $keywords,
            'authorMap'       => $authorMap,

            // Page meta
            'searchBarValue'  => $_GET['query'] ?? '',
            'pageTitle'       => 'Répertoire – Posterg',
            'metaDescription' => 'Parcourez le répertoire des mémoires de fin d\'études (TFE) de l\'erg – École de Recherches Graphiques de Bruxelles. Recherche par année, orientation, atelier et mots-clés.',
            'ogTags'          => [
                'type'        => 'website',
                'title'       => 'Répertoire – Posterg',
                'description' => 'Parcourez le répertoire des mémoires de fin d\'études (TFE) de l\'erg – École de Recherches Graphiques de Bruxelles. Recherche par année, orientation, atelier et mots-clés.',
                'url'         => 'https://posterg.erg.be/search.php',
                'site_name'   => 'Posterg – ERG',
            ],
            'currentNav'      => 'repertoire',
            'extraCss'        => ['/assets/css/search.css'],
            'bodyClass'       => 'search-body',
        ];
    }

    // ── Private helpers ───────────────────────────────────────────────────────

    /**
     * Sanitise and collect valid search parameters from $_GET.
     *
     * @return array<string, mixed>
     */
    private function collectSearchParams(): array
    {
        $params = [];

        if (!empty($_GET['query'])) {
            $params['query'] = trim((string) $_GET['query']);
        }
        if (!empty($_GET['year'])) {
            $params['year'] = (int) $_GET['year'];
        }
        if (!empty($_GET['orientation'])) {
            $params['orientation'] = (string) $_GET['orientation'];
        }
        if (!empty($_GET['ap_program'])) {
            $params['ap_program'] = (string) $_GET['ap_program'];
        }
        if (!empty($_GET['keyword'])) {
            $params['keyword'] = (string) $_GET['keyword'];
        }

        return $params;
    }

    /**
     * Build an alphabetically-sorted author → thesis-id map from the
     * published-authors list.  Each author name maps to their first thesis id.
     *
     * @param  array<int, array{id: int, authors: string}> $students
     * @return array<string, int>
     */
    private function buildAuthorMap(array $students): array
    {
        $map = [];

        foreach ($students as $s) {
            if (empty($s['authors'])) {
                continue;
            }
            foreach (explode(',', $s['authors']) as $name) {
                $name = trim($name);
                if ($name !== '' && !isset($map[$name])) {
                    $map[$name] = (int) $s['id'];
                }
            }
        }

        ksort($map);

        return $map;
    }

    // ── Rate-limit response ───────────────────────────────────────────────────

    /**
     * Send a 429 response and exit.  Never returns.
     */
    private static function sendRateLimitResponse(RateLimit $rateLimit): never
    {
        http_response_code(429);
        header('Retry-After: ' . $rateLimit->getResetTime());
        $retrySeconds = (int) $rateLimit->getResetTime();

        echo <<<HTML
<!DOCTYPE html>
<html lang="fr">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Trop de requêtes – Posterg</title>
    <style>
        *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
        body {
            background: #0d0d0d;
            color: #e0e0e0;
            font-family: 'Helvetica Neue', Arial, sans-serif;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 2rem;
        }
        .box { max-width: 520px; text-align: center; }
        .box__logo {
            font-size: 1.1rem; font-weight: 700;
            letter-spacing: .12em; text-transform: uppercase;
            color: #fff; margin-bottom: 2.5rem;
        }
        .box__title { font-size: 1.6rem; font-weight: 300; margin-bottom: 1rem; }
        .box__text  { font-size: .95rem; color: #999; line-height: 1.7; }
    </style>
</head>
<body>
    <div class="box">
        <div class="box__logo">POSTERG</div>
        <h1 class="box__title">Trop de requêtes</h1>
        <p class="box__text">Vous avez effectué trop de recherches en peu de temps.<br>
        Réessayez dans {$retrySeconds} secondes.</p>
    </div>
</body>
</html>
HTML;
        exit;
    }
}