<?php
declare(strict_types=1);

require_once __DIR__ . '/../includes/LegalTools.php';
require_once __DIR__ . '/../includes/ToolModels.php';

dbnToolsRequireMethod('POST');
dbnToolsRequireAuth();
$ftUid = dbnToolsFreeTierCheck('summarize');

$input    = dbnToolsJsonInput(400000);
$language = dbnToolsNormalizeLanguage($input['language'] ?? 'en');
$engine   = ToolModels::engineForUser($ftUid, (string)($input['engine'] ?? 'azure_mini'));
$slices   = is_array($input['slices'] ?? null) ? array_values(array_filter($input['slices'])) : [];

// Streaming headers — flush each NDJSON line as it's written
header('Content-Type: application/x-ndjson; charset=utf-8');
header('X-Accel-Buffering: no');
header('Cache-Control: no-cache, no-store');
while (ob_get_level()) {
    ob_end_clean();
}

$emit = static function (string $event, array $payload): void {
    echo json_encode(['event' => $event] + $payload, JSON_UNESCAPED_UNICODE) . "\n";
    flush();
};

try {
    $text = dbnToolsInjectDocContent($input, dbnToolsString($input, 'text', 128000, false));

    if (mb_strlen(trim($text), 'UTF-8') < 50) {
        $emit('error', [
            'error' => 'Paste text, upload a file, or select a document before running.',
            'code'  => 'empty_text',
        ]);
        exit;
    }

    $emit('progress', [
        'step'   => 'text_ready',
        'detail' => mb_strlen($text, 'UTF-8') . ' chars ready.',
    ]);

    $corpusContext = '';
    if (!empty($slices)) {
        $sliceCount = count($slices);
        $emit('progress', [
            'step'   => 'corpus_search',
            'detail' => 'Searching legal corpus (' . $sliceCount . ' slice' . ($sliceCount === 1 ? '' : 's') . ')…',
        ]);
        $svc           = new DbnLegalToolsService();
        $query         = mb_substr(trim($text), 0, 600, 'UTF-8');
        $corpusContext = $svc->corpusContextForSummarize($query, 8);
        $emit('progress', [
            'step'   => 'corpus_done',
            'detail' => $corpusContext !== ''
                ? 'Legal context retrieved.'
                : 'No matching passages found; summarising without corpus.',
        ]);
    }

    $emit('progress', [
        'step'   => 'generating',
        'detail' => 'Generating summary…',
    ]);

    $result = (new DbnLegalToolsService())->summarizeWithContext($text, $language, $engine, $corpusContext);

    if ($ftUid > 0) {
        $balance          = dbnToolsFreeTierDeduct($ftUid, 'summarize');
        $result['balance'] = $balance;
    }

    $emit('final', $result);

} catch (DbnToolsHttpException $e) {
    $emit('error', ['error' => $e->getMessage(), 'code' => (string)$e->getCode()]);
} catch (Throwable $e) {
    error_log('summarize error: ' . $e->getMessage());
    $emit('error', ['error' => 'An unexpected error occurred. Please try again.', 'code' => 'server_error']);
}