<?php
declare(strict_types=1);

require_once __DIR__ . '/../includes/bootstrap.php';
require_once __DIR__ . '/../includes/KorrespondAgent.php';

dbnToolsRequireMethod('POST');
dbnToolsRequireAuth();

@ini_set('output_buffering', '0');
@ini_set('zlib.output_compression', '0');
@ini_set('implicit_flush', '1');
while (ob_get_level() > 0) { @ob_end_clean(); }
ob_implicit_flush(true);

header('Content-Type: application/x-ndjson; charset=utf-8');
header('Cache-Control: no-store');
header('X-Accel-Buffering: no');

$startTime = microtime(true);
$language  = 'en';
$creditDeducted = false;
$ftUid = 0;

$emit = function (string $event, array $payload = []) use ($startTime): void {
    $payload['event'] = $event;
    $payload['t_ms']  = (int)round((microtime(true) - $startTime) * 1000);
    echo json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) . "\n";
    @flush();
};

try {
    // ── Parse input (JSON or multipart) ─────────────────────────────────────────
    $isMultipart = stripos((string)($_SERVER['CONTENT_TYPE'] ?? ''), 'multipart/form-data') !== false;
    if ($isMultipart) {
        $payloadRaw = (string)($_POST['payload'] ?? '');
        if ($payloadRaw === '') {
            throw new DbnToolsHttpException('Multipart request missing payload.', 422, 'missing_payload');
        }
        $input = json_decode($payloadRaw, true);
        if (!is_array($input)) {
            throw new DbnToolsHttpException('Invalid payload JSON.', 422, 'invalid_payload_json');
        }
    } else {
        $raw = file_get_contents('php://input');
        if ($raw === false || strlen($raw) > 200000) {
            throw new DbnToolsHttpException('Request body unreadable or too large.', 413, 'body_too_large');
        }
        $input = json_decode((string)$raw, true);
        if (!is_array($input)) {
            throw new DbnToolsHttpException('Request body must be valid JSON.', 400, 'invalid_json');
        }
    }

    // ── Normalise + validate ────────────────────────────────────────────────────
    $language = dbnToolsNormalizeLanguage($input['language'] ?? 'en');

    $allowedBodies = ['barnehage','school_1_10','sfo','nav','bufdir','barnevernet',
        'kommune_other','statsforvalter','trygderetten','tingrett','other'];
    $allowedOutput = ['email','formal','filing','call_prep'];
    $allowedTone   = ['cooperative','neutral','firm','adversarial','warm'];
    $allowedMode   = ['reply','initiate'];

    $intake = [
        'mode'           => in_array($input['mode'] ?? '', $allowedMode, true) ? $input['mode'] : 'initiate',
        'recipient_body' => in_array($input['recipient_body'] ?? '', $allowedBodies, true) ? $input['recipient_body'] : 'other',
        'output_type'    => in_array($input['output_type'] ?? '', $allowedOutput, true) ? $input['output_type'] : 'email',
        'tone'           => in_array($input['tone'] ?? '', $allowedTone, true) ? $input['tone'] : 'neutral',
        'language'       => $language,
        'case_ref'       => mb_substr(trim((string)($input['case_ref'] ?? '')), 0, 120, 'UTF-8'),
        'where'          => mb_substr(trim((string)($input['where'] ?? '')), 0, 200, 'UTF-8'),
        'parties_text'   => mb_substr(trim((string)($input['parties_text'] ?? '')), 0, 2000, 'UTF-8'),
        'narrative'      => mb_substr(trim((string)($input['narrative'] ?? '')), 0, 8000, 'UTF-8'),
        'goal'           => mb_substr(trim((string)($input['goal'] ?? '')), 0, 600, 'UTF-8'),
        'deadlines'      => is_array($input['deadlines'] ?? null)
            ? array_slice(array_values(array_filter(array_map(
                fn($d) => mb_substr(trim((string)$d), 0, 60, 'UTF-8'),
                $input['deadlines']
            ))), 0, 6) : [],
        'clarifications' => is_array($input['clarifications'] ?? null) ? $input['clarifications'] : [],
    ];

    $forceDraft = !empty($input['force_draft']);
    $hasClarif  = !empty($intake['clarifications']);

    // ── Extract uploaded files (Reply mode) ─────────────────────────────────────
    $receivedText = '';
    $attachmentsText = '';
    $attachmentNames = [];
    if (!empty($_FILES['files']) && is_array($_FILES['files']['tmp_name'] ?? null)) {
        $count = count($_FILES['files']['tmp_name']);
        if ($count > 4) {
            throw new DbnToolsHttpException('At most 4 files can be uploaded per request.', 413, 'too_many_files');
        }
        for ($i = 0; $i < $count; $i++) {
            $file = [
                'name'     => $_FILES['files']['name'][$i]     ?? '',
                'type'     => $_FILES['files']['type'][$i]     ?? '',
                'tmp_name' => $_FILES['files']['tmp_name'][$i] ?? '',
                'error'    => $_FILES['files']['error'][$i]    ?? UPLOAD_ERR_NO_FILE,
                'size'     => $_FILES['files']['size'][$i]     ?? 0,
            ];
            $extracted = dbnToolsExtractUploadedFile($file);
            $attachmentNames[] = $extracted['filename'];
            if ($i === 0) {
                $receivedText = $extracted['text'];
            } else {
                $attachmentsText .= "\n\n--- " . $extracted['filename'] . " ---\n\n" . $extracted['text'];
            }
            $emit('progress', [
                'detail' => DbnKorrespondAgent::L('file_read', $language, [
                    'name'  => $extracted['filename'],
                    'chars' => $extracted['chars'],
                ]),
            ]);
        }
    }
    $intake['received_text']    = $receivedText;
    $intake['attachments_text'] = $attachmentsText;

    if ($intake['mode'] === 'reply' && $receivedText === '' && $intake['narrative'] === '') {
        throw new DbnToolsHttpException(
            'For reply mode, upload the received letter or paste its text.',
            422, 'reply_no_input'
        );
    }
    if ($intake['mode'] === 'initiate' && $intake['narrative'] === '') {
        throw new DbnToolsHttpException(
            'Describe the situation in "What happened" before drafting.',
            422, 'initiate_no_narrative'
        );
    }

    $emit('start', [
        'mode'         => $intake['mode'],
        'body'         => $intake['recipient_body'],
        'output_type'  => $intake['output_type'],
        'language'     => $language,
        'attachments'  => $attachmentNames,
    ]);

    // ── Pass 1: classify + gap-check ────────────────────────────────────────────
    $emit('progress', ['detail' => DbnKorrespondAgent::L('analyzing', $language)]);
    $agent    = new DbnKorrespondAgent();
    $classify = $agent->classify($intake);
    $emit('classify', ['result' => [
        'summary'            => $classify['summary'],
        'parties'            => $classify['parties'],
        'decision_or_action' => $classify['decision_or_action'],
        'deadlines'          => $classify['deadlines'],
        'applicable_acts'    => $classify['applicable_acts'],
        'jurisdiction'       => $classify['jurisdiction'],
        'suggested_goal'     => $classify['suggested_goal'],
    ]]);

    $missing = $classify['missing_facts'] ?? [];
    if (!empty($missing) && !$forceDraft && !$hasClarif) {
        // Gate: emit clarify and stop — NO credit deduct
        $emit('clarify', ['questions' => $missing]);
        $emit('end', ['stopped_at' => 'clarify']);
        exit;
    }

    // ── Deduct credit now (Pass 2 starts) ───────────────────────────────────────
    $ftUid = dbnToolsFreeTierCheck('korrespond');
    $ftRemaining = dbnToolsFreeTierDeduct($ftUid, 'korrespond');
    $creditDeducted = true;
    if ($ftRemaining >= 0) {
        header('X-Credits-Remaining: ' . $ftRemaining);
    }

    // ── Pass 2: retrieve law → draft → self-check → translate ──────────────────
    $result = $agent->generate($intake, $classify, $emit);
    $result['ok']         = true;
    $result['latency_ms'] = (int)round((microtime(true) - $startTime) * 1000);

    dbnToolsLogMetadata([
        'tool'         => 'korrespond',
        'language'     => $language,
        'ok'           => true,
        'latency_ms'   => $result['latency_ms'],
        'source_count' => is_array($result['cited_law'] ?? null) ? count($result['cited_law']) : 0,
        'deployment'   => 'gpt-4o',
    ]);

    $emit('final', ['result' => $result]);

} catch (DbnToolsHttpException $e) {
    $latency = (int)round((microtime(true) - $startTime) * 1000);
    dbnToolsLogMetadata([
        'tool'       => 'korrespond',
        'language'   => $language,
        'ok'         => false,
        'latency_ms' => $latency,
        'error_code' => $e->errorCode,
    ]);
    $emit('error', ['code' => $e->errorCode, 'message' => $e->getMessage(), 'status' => $e->status]);
} catch (Throwable $e) {
    error_log('Korrespond fatal: ' . $e->getMessage());
    $latency = (int)round((microtime(true) - $startTime) * 1000);
    dbnToolsLogMetadata([
        'tool'       => 'korrespond',
        'language'   => $language,
        'ok'         => false,
        'latency_ms' => $latency,
        'error_code' => 'internal_error',
    ]);
    $emit('error', ['code' => 'internal_error', 'message' => 'Korrespond could not complete this request.']);
}