<?php
/**
 * Migration: Alte Wiki-Artikel (main_collection) → Neue Wiki-Struktur (knowledgecenter_posts)
 *
 * CLI-only. Idempotent (über legacy_collection_id). Pro Artikel transaktional.
 *
 * Aufruf:
 *   php migrate_old_wiki.php --dry-run --collection-id=1491
 *   php migrate_old_wiki.php --apply --collection-id=1491 --api-key=KEY
 *   php migrate_old_wiki.php --apply --limit=5 --api-key=KEY
 *   php migrate_old_wiki.php --apply  (alle Artikel)
 *
 * Optionen:
 *   --dry-run              Standard. Nur analysieren, nichts schreiben.
 *   --apply                Wirklich migrieren (DB + Dateien).
 *   --collection-id=N      Nur diesen Artikel migrieren.
 *   --limit=N              Maximal N Artikel migrieren (für Tests).
 *   --api-key=KEY          Gemini API Key (oder via GEMINI_API_KEY env).
 *   --skip-summaries       Keine KI-Zusammenfassung generieren.
 *   --verbose              Mehr Details ausgeben.
 *   --help                 Diese Hilfe.
 */

if (PHP_SAPI !== 'cli') {
    fwrite(STDERR, "Dieses Skript ist CLI-only.\n");
    exit(2);
}

$currDir   = __DIR__;
$rootDir   = dirname(dirname(dirname($currDir)));
$mysydeDir = $rootDir . '/mysyde';

require_once($rootDir . '/vendor/autoload.php');

$envDir      = $rootDir . '/config';
$envFilePath = $envDir . '/.env';
if (is_dir($envDir) && file_exists($envFilePath) && is_readable($envFilePath)) {
    $dotenv = new \Dotenv\Dotenv($envDir);
    $dotenv->load();
}

require_once($mysydeDir . '/common/common_functions.inc.php');
$connEnv = (local_environment()) ? $mysydeDir . '/dc.config.php' : $mysydeDir . '/dc-server.config.php';
require_once($connEnv);
db_connect();

// ------- Args -------
$opts = [
    'dry-run'         => true,
    'apply'           => false,
    'collection-id'   => null,
    'limit'           => null,
    'api-key'         => getenv('GEMINI_API_KEY') ?: null,
    'skip-summaries'  => false,
    'summaries-only'  => false,
    'verbose'         => false,
];

foreach (array_slice($argv, 1) as $arg) {
    if ($arg === '--help' || $arg === '-h') {
        echo "Usage: php migrate_old_wiki.php [--dry-run|--apply] [--collection-id=N] [--limit=N] [--api-key=KEY] [--skip-summaries] [--verbose]\n";
        exit(0);
    }
    if ($arg === '--apply')           { $opts['apply'] = true;  $opts['dry-run'] = false; continue; }
    if ($arg === '--dry-run')         { $opts['dry-run'] = true; $opts['apply'] = false;  continue; }
    if ($arg === '--skip-summaries')  { $opts['skip-summaries'] = true;   continue; }
    if ($arg === '--summaries-only')  { $opts['summaries-only'] = true;  continue; }
    if ($arg === '--verbose')         { $opts['verbose'] = true; continue; }
    if (preg_match('/^--collection-id=(\d+)$/', $arg, $m)) { $opts['collection-id'] = (int)$m[1]; continue; }
    if (preg_match('/^--limit=(\d+)$/', $arg, $m))         { $opts['limit'] = (int)$m[1]; continue; }
    if (preg_match('/^--api-key=(.+)$/', $arg, $m))        { $opts['api-key'] = $m[1]; continue; }
    fwrite(STDERR, "Unbekannte Option: $arg\n");
    exit(2);
}

$dryRun      = !$opts['apply'];
$verbose     = $opts['verbose'];
$apiKey      = $opts['api-key'];
$skipSummary = $opts['skip-summaries'];
$userdataDir = $rootDir . '/userdata';

// ------- Log-Datei -------
$logDir  = $userdataDir . '/knowledgecenter_update/migrations';
if (!is_dir($logDir)) @mkdir($logDir, 0775, true);
$logFile = $logDir . '/wiki_migration_' . gmdate('Ymd_His') . '.log';
$logFp   = fopen($logFile, 'w');
if (!$logFp) { fwrite(STDERR, "Log-Datei nicht anlegbar: $logFile\n"); exit(3); }
fwrite(STDOUT, "Log: $logFile\n");

// ------- Logging -------
function logmsg(string $msg, string $level = 'INFO'): void {
    global $verbose, $logFp;
    $line = '[' . gmdate('Y-m-d H:i:s') . " UTC] [$level] $msg\n";
    fwrite($logFp, $line);
    if ($verbose || in_array($level, ['ERROR', 'FAIL', 'OK', 'WARN', 'HEAD', 'SKIP', 'PROMPT'], true)) {
        fwrite(STDOUT, $line);
    }
}

// ------- Phase 0: Schema-Vorbereitung -------
logmsg("Prüfe Schema ...", 'HEAD');

mysqli_query($GLOBALS['mysql_con'],
    "ALTER TABLE knowledgecenter_posts ADD COLUMN IF NOT EXISTS legacy_collection_id INT NULL");
mysqli_query($GLOBALS['mysql_con'],
    "CREATE UNIQUE INDEX IF NOT EXISTS idx_legacy_collection ON knowledgecenter_posts(legacy_collection_id)");

// ------- Hilfsfunktionen -------

/**
 * Returns ['teaser' => string, 'content' => string]
 * setup_content_id=55 (kc_teaser, data-field) → teaser
 * setup_content_id=58 (kc_article, textcontent_header) → content
 */
function assemble_content(int $cid): array {
    $sql = "SELECT mcl.main_collection_setup_content_id, mcl.main_sitepart_id,
                   mcl.main_sitepart_header_id, mcl.data
            FROM main_collection_link mcl
            WHERE mcl.main_collection_id = $cid
            ORDER BY mcl.id";
    $res     = mysqli_query($GLOBALS['mysql_con'], $sql);
    $teaser  = '';
    $content = '';
    while ($row = mysqli_fetch_assoc($res)) {
        $scid = (int)$row['main_collection_setup_content_id'];
        if ($scid === 55) {
            // Teaser: plain text im data-Feld, keine HTML-Tags
            $text = trim($row['data'] ?? '');
            if ($text !== '') {
                $teaser .= ($teaser !== '' ? ' ' : '') . $text;
            }
        } elseif ($row['main_sitepart_id'] == 1 && $row['main_sitepart_header_id'] > 0) {
            // Artikeltext: HTML aus textcontent_header (setup_content_id=58 oder ähnlich)
            $hid  = (int)$row['main_sitepart_header_id'];
            $hres = mysqli_query($GLOBALS['mysql_con'],
                "SELECT content FROM textcontent_header WHERE id = $hid LIMIT 1");
            if ($hrow = mysqli_fetch_assoc($hres)) {
                $content .= $hrow['content'];
            }
        }
    }
    return ['teaser' => $teaser, 'content' => $content];
}

function get_article_files(int $cid): array {
    // sitepart_id 5, 6, 10 sind filegallery-Typen; sitepart_id=1 ist textcontent_header (nicht joinen!)
    $sql = "SELECT DISTINCT fl.filename, fl.extension, fl.description
            FROM main_collection_link mcl
            JOIN filegallery_line fl ON fl.header_id = mcl.main_sitepart_header_id
            WHERE mcl.main_collection_id = $cid
              AND mcl.main_sitepart_id IN (5, 6, 10)
              AND mcl.main_sitepart_header_id > 0
              AND fl.filename != ''
            ORDER BY fl.sorting";
    $res   = mysqli_query($GLOBALS['mysql_con'], $sql);
    $files = [];
    while ($row = mysqli_fetch_assoc($res)) {
        $files[] = $row;
    }
    return $files;
}

function extract_pdf_text(string $filePath): string {
    if (!file_exists($filePath) || filesize($filePath) === 0) return '';
    try {
        $parser = new \Smalot\PdfParser\Parser();
        $pdf    = $parser->parseFile($filePath);
        $text   = trim($pdf->getText());
        return preg_replace('/\s+/', ' ', $text);
    } catch (\Throwable $e) {
        return '';
    }
}

function generate_summary(string $htmlContent, array $files, string $userdataDir, string $apiKey, string $title, string $teaser = ''): ?string {
    $parts = [];

    // Teaser bevorzugen: bereits plain text, sehr kurz → spart Input-Tokens
    if (strlen($teaser) > 30) {
        $parts[] = $teaser;
    }

    // Fließtext: HTML entfernen, auf 1500 Zeichen cappen
    $plainText = html_entity_decode(strip_tags($htmlContent), ENT_HTML5 | ENT_QUOTES, 'UTF-8');
    $plainText = trim(preg_replace('/\s+/', ' ', $plainText));
    if (strlen($plainText) > 30) {
        $parts[] = mb_substr($plainText, 0, 1500);
    }

    // PDFs nur wenn sonst kein Inhalt vorhanden, auf 800 Zeichen begrenzen
    if (empty($parts)) {
        foreach ($files as $file) {
            if (strtolower($file['extension']) !== 'pdf') continue;
            $pdfText = extract_pdf_text($userdataDir . '/' . $file['filename']);
            if (strlen($pdfText) > 50) {
                $label   = $file['description'] ?: basename($file['filename']);
                $parts[] = 'Anhang "' . $label . '": ' . mb_substr($pdfText, 0, 800);
                break; // ein PDF reicht
            }
        }
    }

    if (empty($parts)) {
        return null;
    }

    $prompt = "Fasse in 2-3 deutschen Sätzen zusammen. Nur Zusammenfassung.\nTitel: $title\n\n"
        . implode("\n\n", $parts);

    logmsg("  PROMPT (" . strlen($prompt) . " Zeichen)", 'PROMPT');

    $payload = json_encode([
        'contents'         => [['parts' => [['text' => $prompt]]]],
        'generationConfig' => [
            'maxOutputTokens' => 150,
            'temperature'     => 0.2,
            'thinkingConfig'  => ['thinkingBudget' => 0],
        ],
    ]);

    $url      = 'https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=' . urlencode($apiKey);
    $resp     = '';
    $httpCode = 0;
    $attempts = [[0, null], [5, 503], [15, 503], [30, 429], [60, 429]];
    foreach ($attempts as [$wait, $label]) {
        if ($wait > 0) {
            logmsg("  Gemini $httpCode – warte {$wait}s (retry) ...", 'WARN');
            sleep($wait);
        }
        $ch = curl_init($url);
        curl_setopt_array($ch, [
            CURLOPT_POST           => true,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT        => 30,
            CURLOPT_HTTPHEADER     => ['Content-Type: application/json'],
            CURLOPT_POSTFIELDS     => $payload,
        ]);
        $resp     = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        if ($httpCode !== 503 && $httpCode !== 429) break;
    }

    if ($httpCode !== 200) {
        logmsg("Gemini API Fehler HTTP $httpCode: " . substr($resp, 0, 200), 'WARN');
        return null;
    }

    $data    = json_decode($resp, true);
    $summary = trim($data['candidates'][0]['content']['parts'][0]['text'] ?? '');
    if (strlen($summary) < 30) {
        logmsg("  Gemini Roh-Antwort: " . substr($resp, 0, 500), 'WARN');
    }
    return $summary;
}

// ------- Permissions aus main_collection auf Post übertragen -------
function copy_permissions_to_post(int $postId, int $collectionId): void {
    $maps = [
        ['src' => 'main_collection_mandant_link',     'src_col' => 'main_mandant_id',     'dst' => 'knowledgecenter_post_mandant',     'dst_col' => 'mandant_id'],
        ['src' => 'main_collection_department_link',  'src_col' => 'main_department_id',  'dst' => 'knowledgecenter_post_department',  'dst_col' => 'department_id'],
        ['src' => 'main_collection_role_link',        'src_col' => 'main_role_id',        'dst' => 'knowledgecenter_post_role',        'dst_col' => 'role_id'],
        ['src' => 'main_collection_einricht_link',    'src_col' => 'main_einricht_id',    'dst' => 'knowledgecenter_post_einricht',    'dst_col' => 'einricht_id'],
        ['src' => 'main_collection_fachbereich_link', 'src_col' => 'main_fachbereich_id', 'dst' => 'knowledgecenter_post_fachbereich', 'dst_col' => 'fachbereich_id'],
    ];

    foreach ($maps as $m) {
        $sql = "INSERT IGNORE INTO {$m['dst']} (post_id, {$m['dst_col']})
                SELECT $postId, {$m['src_col']} FROM {$m['src']} WHERE main_collection_id = $collectionId";
        mysqli_query($GLOBALS['mysql_con'], $sql);
    }
}

// ------- Artikel laden -------
$whereClause = "mc.main_collection_setup_id = 3 AND mc.is_archived = 0 AND mc.active = 1 AND mc.description != ''";
if ($opts['collection-id'] !== null) {
    $whereClause .= " AND mc.id = " . (int)$opts['collection-id'];
}

// ------- Summaries-only Modus: fehlende Summaries für bereits migrierte Posts nachfüllen -------
if ($opts['summaries-only']) {
    if (!$apiKey) { fwrite(STDERR, "--summaries-only benötigt --api-key\n"); exit(2); }

    $sumSql = "SELECT p.id as post_id, p.legacy_collection_id, pv.id as version_id, pv.title,
                      pv.teaser, pv.content
               FROM knowledgecenter_posts p
               JOIN knowledgecenter_post_versions pv ON pv.post_id = p.id AND pv.version_number = 1
               WHERE (pv.summary IS NULL OR pv.summary = '')
                 AND p.legacy_collection_id IS NOT NULL";
    if ($opts['collection-id'] !== null) {
        $sumSql .= " AND p.legacy_collection_id = " . (int)$opts['collection-id'];
    }
    if ($opts['limit'] !== null) {
        $sumSql .= " LIMIT " . (int)$opts['limit'];
    }
    $sumResult = mysqli_query($GLOBALS['mysql_con'], $sumSql);
    $sumTotal  = mysqli_num_rows($sumResult);
    logmsg("Summaries-only: $sumTotal Posts ohne Summary", 'HEAD');
    $sumStats = ['ok' => 0, 'fail' => 0];

    while ($sumRow = mysqli_fetch_assoc($sumResult)) {
        $postId    = (int)$sumRow['post_id'];
        $collId    = (int)$sumRow['legacy_collection_id'];
        $versionId = (int)$sumRow['version_id'];
        $title     = $sumRow['title'];

        $files   = get_article_files($collId);
        $teaser  = $sumRow['teaser'] ?? '';
        $summary = generate_summary($sumRow['content'], $files, $userdataDir, $apiKey, $title, $teaser) ?? '';

        if ($summary === '') {
            logmsg("  [FAIL] Post $postId \"$title\": leere Summary", 'WARN');
            $sumStats['fail']++;
        } else {
            $sumEsc = mysqli_real_escape_string($GLOBALS['mysql_con'], $summary);
            mysqli_query($GLOBALS['mysql_con'],
                "UPDATE knowledgecenter_post_versions SET summary = '$sumEsc' WHERE id = $versionId");
            logmsg("[OK  ] Post $postId \"$title\": " . mb_substr($summary, 0, 80), 'OK');
            $sumStats['ok']++;
        }
        sleep(4); // 15 RPM Free-Tier: mind. 4 Sek. zwischen Requests
    }

    logmsg(sprintf("Summaries fertig. ok=%d  fail=%d", $sumStats['ok'], $sumStats['fail']), 'HEAD');
    logmsg("Log-Datei: $logFile", 'HEAD');
    fclose($logFp);
    exit(0);
}

$sql = "SELECT mc.id, mc.description, mc.creation_date, mc.modified_date,
               mc.validity_from, mc.validity_to
        FROM main_collection mc
        WHERE $whereClause
        ORDER BY mc.id";
if ($opts['limit'] !== null) {
    $sql .= " LIMIT " . (int)$opts['limit'];
}
$result = mysqli_query($GLOBALS['mysql_con'], $sql);
$total  = mysqli_num_rows($result);

logmsg("Modus=" . ($dryRun ? 'DRY-RUN' : 'APPLY') . "  Artikel=$total  Limit=" .
    ($opts['limit'] ?? 'alle') . "  API=" . ($apiKey && !$skipSummary ? 'ja' : 'nein'), 'HEAD');

$stats = ['ok' => 0, 'skipped' => 0, 'fail' => 0];

while ($row = mysqli_fetch_assoc($result)) {
    $cid   = (int)$row['id'];
    $title = $row['description'];

    // Idempotenz-Check
    $already = mysqli_query($GLOBALS['mysql_con'],
        "SELECT id FROM knowledgecenter_posts WHERE legacy_collection_id = $cid LIMIT 1");
    if ($already && mysqli_num_rows($already) > 0) {
        logmsg("Artikel $cid \"$title\" – bereits migriert, überspringe.", 'SKIP');
        $stats['skipped']++;
        continue;
    }

    $parts       = assemble_content($cid);
    $teaserHtml  = $parts['teaser'];
    $htmlContent = $parts['content'];
    $files       = get_article_files($cid);
    $htmlLen     = strlen($htmlContent);

    $catRes    = mysqli_query($GLOBALS['mysql_con'],
        "SELECT knowledgecenter_category_id FROM knowledgecenter_collection_link WHERE main_collection_id = $cid");
    $catIds    = [];
    while ($cr = mysqli_fetch_assoc($catRes)) {
        $catIds[] = (int)$cr['knowledgecenter_category_id'];
    }

    logmsg("Artikel $cid \"$title\" | Teaser=" . strlen($teaserHtml) . "B | HTML=" . $htmlLen . "B | Dateien=" . count($files) .
        " | Kategorien=[" . implode(',', $catIds) . "]");

    if ($dryRun) {
        $stats['ok']++;
        continue;
    }

    // Summary generieren (vor der Transaktion, API-Call außerhalb)
    $summary = '';
    if (!$skipSummary && $apiKey) {
        $fullContent = $teaserHtml . $htmlContent;
        $generated = generate_summary($fullContent, $files, $userdataDir, $apiKey, $title);
        $summary   = $generated ?? '';
        logmsg("  Summary: " . (strlen($summary) > 0 ? '"' . mb_substr($summary, 0, 100) . '"' : '(leer)'));
        sleep(4); // 15 RPM Free-Tier: mind. 4 Sek. zwischen Requests
    }

    // HTML-Entities dekodieren für saubere UTF-8 Speicherung
    $cleanHtml = html_entity_decode($htmlContent, ENT_HTML5 | ENT_QUOTES, 'UTF-8');

    mysqli_query($GLOBALS['mysql_con'], 'START TRANSACTION');
    try {
        $titleEsc   = mysqli_real_escape_string($GLOBALS['mysql_con'], $title);
        $summaryEsc = mysqli_real_escape_string($GLOBALS['mysql_con'], $summary);
        $teaserEsc  = mysqli_real_escape_string($GLOBALS['mysql_con'], $teaserHtml);
        $contentEsc = mysqli_real_escape_string($GLOBALS['mysql_con'], $cleanHtml);
        $createdAt  = date('Y-m-d H:i:s', (int)$row['creation_date']);
        $modifiedAt = date('Y-m-d H:i:s', (int)$row['modified_date']);
        $validFrom  = $row['validity_from']  ? "'" . $row['validity_from']  . "'" : 'NULL';
        $validUntil = $row['validity_to']    ? "'" . $row['validity_to']    . "'" : 'NULL';

        // knowledgecenter_posts
        $sqlPost = "INSERT INTO knowledgecenter_posts (legacy_collection_id, created_at, modified_at)
                    VALUES ($cid, '$createdAt', '$modifiedAt')";
        if (!mysqli_query($GLOBALS['mysql_con'], $sqlPost)) {
            throw new RuntimeException("Post-Insert: " . mysqli_error($GLOBALS['mysql_con']));
        }
        $postId = (int)mysqli_insert_id($GLOBALS['mysql_con']);

        // knowledgecenter_post_versions
        $sqlVer = "INSERT INTO knowledgecenter_post_versions
                       (post_id, version_number, language_id, title, teaser, content, summary, state, modified_at, valid_from, valid_until)
                   VALUES
                       ($postId, 1, 1, '$titleEsc', '$teaserEsc', '$contentEsc', '$summaryEsc', 1, '$modifiedAt', $validFrom, $validUntil)";
        if (!mysqli_query($GLOBALS['mysql_con'], $sqlVer)) {
            throw new RuntimeException("Version-Insert: " . mysqli_error($GLOBALS['mysql_con']));
        }

        // Kategorie-Links
        foreach ($catIds as $catId) {
            mysqli_query($GLOBALS['mysql_con'],
                "INSERT IGNORE INTO knowledgecenter_category_post (category_id, post_id) VALUES ($catId, $postId)");
        }

        // Permissions aus main_collection auf Post übertragen
        copy_permissions_to_post($postId, $cid);

        // Dateiverknüpfungen: Original-Pfad beibehalten, keine Kopie
        foreach ($files as $file) {
            $srcPath = $userdataDir . '/' . $file['filename'];
            if (!file_exists($srcPath)) {
                logmsg("  Quelldatei nicht gefunden: " . $file['filename'], 'WARN');
                continue;
            }
            $relPath = '/userdata/' . $file['filename'];
            $descEsc = mysqli_real_escape_string($GLOBALS['mysql_con'], $file['description'] ?: basename($file['filename']));
            $pathEsc = mysqli_real_escape_string($GLOBALS['mysql_con'], $relPath);
            mysqli_query($GLOBALS['mysql_con'],
                "INSERT INTO knowledgecenter_post_files (post_id, description, path)
                 VALUES ($postId, '$descEsc', '$pathEsc')");
            logmsg("  Datei verknüpft: " . $file['filename']);
        }

        mysqli_query($GLOBALS['mysql_con'], 'COMMIT');
        logmsg("[OK  ] Artikel $cid → Post $postId \"$title\"", 'OK');
        $stats['ok']++;

    } catch (\Throwable $e) {
        mysqli_query($GLOBALS['mysql_con'], 'ROLLBACK');
        logmsg("[FAIL] Artikel $cid \"$title\": " . $e->getMessage(), 'FAIL');
        $stats['fail']++;
    }
}

logmsg(sprintf("Fertig. ok=%d  skipped=%d  fail=%d  modus=%s",
    $stats['ok'], $stats['skipped'], $stats['fail'],
    $dryRun ? 'DRY-RUN' : 'APPLY'), 'HEAD');
logmsg("Log-Datei: $logFile", 'HEAD');
fclose($logFp);