dobetternorge-tools/api/transcribe.php

<?php
declare(strict_types=1);

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

dbnToolsRequireMethod('POST');
dbnToolsRequireAuth();

$validLangs  = ['auto', 'no', 'en', 'sv', 'da', 'de', 'fr', 'es', 'pl'];
$language    = strtolower(trim((string)($_POST['language'] ?? 'auto')));
if (!in_array($language, $validLangs, true)) $language = 'auto';

$diarize     = !empty($_POST['diarize']) && $_POST['diarize'] !== '0';
$numSpeakers = isset($_POST['num_speakers']) ? max(0, min(20, (int)$_POST['num_speakers'])) : 0;

// ── Validate upload ───────────────────────────────────────────────────────────

if (empty($_FILES['audio']) || $_FILES['audio']['error'] !== UPLOAD_ERR_OK) {
    $code = $_FILES['audio']['error'] ?? -1;
    $map  = [
        UPLOAD_ERR_INI_SIZE  => 'File exceeds server upload limit.',
        UPLOAD_ERR_FORM_SIZE => 'File exceeds form size limit.',
        UPLOAD_ERR_PARTIAL   => 'File was only partially uploaded.',
        UPLOAD_ERR_NO_FILE   => 'No audio file received.',
    ];
    dbnToolsError($map[$code] ?? "Upload error (code {$code}).", 400, 'upload_error');
}

$file     = $_FILES['audio'];
$maxBytes = 200 * 1024 * 1024;

if ($file['size'] > $maxBytes) {
    dbnToolsError('File too large. Maximum 200 MB.', 413, 'file_too_large');
}

$allowedExts = ['mp3', 'wav', 'ogg', 'oga', 'm4a', 'mp4', 'flac', 'webm', 'aac'];
$ext = strtolower(pathinfo($file['name'], PATHINFO_EXTENSION));
if (!in_array($ext, $allowedExts, true)) {
    dbnToolsError("Unsupported format: .{$ext}. Use MP3, WAV, OGG, M4A, FLAC, or WebM.", 415, 'unsupported_format');
}

// ── Build Whisper request ─────────────────────────────────────────────────────

$whisperBase = 'http://194.93.49.14:20019';
$endpoint    = $diarize ? $whisperBase . '/transcribe/diarize' : $whisperBase . '/transcribe';

$boundary = '----DBN' . bin2hex(random_bytes(8));
$body     = "--{$boundary}\r\n";
$body    .= 'Content-Disposition: form-data; name="file"; filename="' . addslashes(basename($file['name'])) . '"' . "\r\n";
$body    .= "Content-Type: application/octet-stream\r\n\r\n";

$fileContents = file_get_contents($file['tmp_name']);
if ($fileContents === false) {
    dbnToolsError('Could not read uploaded file.', 500, 'file_read_error');
}
$body .= $fileContents . "\r\n";

if ($language !== 'auto') {
    $body .= "--{$boundary}\r\n";
    $body .= "Content-Disposition: form-data; name=\"language\"\r\n\r\n";
    $body .= $language . "\r\n";
}

if ($diarize && $numSpeakers > 1) {
    $body .= "--{$boundary}\r\n";
    $body .= "Content-Disposition: form-data; name=\"num_speakers\"\r\n\r\n";
    $body .= $numSpeakers . "\r\n";
}

$body .= "--{$boundary}--\r\n";

// ── Call Whisper ──────────────────────────────────────────────────────────────

$t0 = microtime(true);

if (function_exists('curl_init')) {
    $ch = curl_init($endpoint);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => $body,
        CURLOPT_HTTPHEADER     => [
            "Content-Type: multipart/form-data; boundary={$boundary}",
            'Accept: application/json',
        ],
        CURLOPT_TIMEOUT        => 600,
    ]);
    $whisperBody = curl_exec($ch);
    $httpCode    = (int)curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
    $curlErr     = curl_error($ch);
    curl_close($ch);

    if ($whisperBody === false || $httpCode !== 200) {
        dbnToolsError('Whisper service error (HTTP ' . $httpCode . '): ' . $curlErr, 502, 'whisper_error');
    }
} else {
    $ctx = stream_context_create([
        'http' => [
            'method'        => 'POST',
            'timeout'       => 600,
            'header'        => "Content-Type: multipart/form-data; boundary={$boundary}\r\nAccept: application/json\r\n",
            'content'       => $body,
            'ignore_errors' => true,
        ],
    ]);
    $whisperBody = @file_get_contents($endpoint, false, $ctx);

    if ($whisperBody === false) {
        dbnToolsError('Whisper service unreachable. The GPU may be offline.', 502, 'whisper_unreachable');
    }
}

$latencyMs = (int)round((microtime(true) - $t0) * 1000);

$whisper = json_decode($whisperBody, true);
if (!is_array($whisper) || empty($whisper['text'])) {
    dbnToolsError('Empty or invalid response from Whisper.', 502, 'whisper_empty');
}

// ── Speaker role labelling ────────────────────────────────────────────────────

$segments    = is_array($whisper['segments'] ?? null) ? $whisper['segments'] : [];
$numDetected = (int)($whisper['num_speakers'] ?? 1);

if ($numDetected < 2 && $segments) {
    $uniqueSpeakers = array_filter(array_unique(array_column($segments, 'speaker')));
    if (count($uniqueSpeakers) > 1) $numDetected = count($uniqueSpeakers);
}

$speakerRoles = null;
if ($diarize && $numDetected > 1 && $segments) {
    $speakerRoles = dbnLabelSpeakerRoles($segments);
}

// ── Respond ───────────────────────────────────────────────────────────────────

dbnToolsLogMetadata([
    'tool'       => 'transcribe',
    'language'   => $language,
    'ok'         => true,
    'latency_ms' => $latencyMs,
]);

dbnToolsRespond([
    'ok'            => true,
    'tool'          => 'transcribe',
    'transcript'    => (string)$whisper['text'],
    'segments'      => $segments,
    'speaker_roles' => $speakerRoles,
    'num_speakers'  => $numDetected,
    'language'      => (string)($whisper['language'] ?? $language),
    'duration_sec'  => round((float)($whisper['duration_seconds'] ?? 0), 2),
    'model'         => (string)($whisper['model'] ?? 'whisper'),
    'latency_ms'    => $latencyMs,
]);

// ── Speaker role labelling helper ─────────────────────────────────────────────

function dbnLabelSpeakerRoles(array $segments): array
{
    $sample = array_slice(
        array_values(array_filter($segments, fn($s) => isset($s['speaker']))),
        0, 20
    );
    if (!$sample) return [];

    $lines  = array_map(fn($s) => "[{$s['speaker']}] " . trim((string)($s['text'] ?? '')), $sample);
    $azure  = new DbnAzureOpenAiGateway();
    $system = 'You are analyzing a legal proceeding transcript. '
        . 'Based on the first segments, identify the role of each speaker. '
        . 'Common roles in Norwegian legal proceedings: dommer (judge), advokat (lawyer), '
        . 'forelder (parent), barn (child), sakkyndig (expert witness), '
        . 'saksbehandler (caseworker), tolk (interpreter), vitne (witness), '
        . 'prosessfullmektig (counsel). '
        . 'Return ONLY valid JSON: {"SPEAKER_00":"dommer","SPEAKER_01":"forelder"}. '
        . 'Use Norwegian role names. Use "ukjent" if role cannot be determined. '
        . 'Only include speakers present in the input.';

    try {
        $text    = $azure->chatText([
            ['role' => 'system', 'content' => $system],
            ['role' => 'user',   'content' => implode("\n", $lines)],
        ], ['temperature' => 0.1, 'max_tokens' => 200]);
        $cleaned = preg_replace('/^```(?:json)?\s*|\s*```$/m', '', trim($text));
        $json    = json_decode($cleaned, true);
        return is_array($json) ? $json : [];
    } catch (Throwable) {
        return [];
    }
}