<?php
declare(strict_types=1);

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

dbnToolsRequireMethod('POST');
dbnToolsRequireAuth();

// ── Common params ─────────────────────────────────────────────────────────────

$validLangs  = ['auto', 'no', 'nn', 'en', 'sv', 'da', 'de', 'fr', 'es', 'pl', 'fi', 'nl', 'it', 'pt', 'ru', 'ar', 'tr', 'zh', 'ja', 'ko'];
$language    = strtolower(trim((string)($_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;
$engine      = in_array($_POST['engine'] ?? '', ['gpu', 'openai', 'azure'], true) ? $_POST['engine'] : 'gpu';
$validModels = ['tiny', 'base', 'small', 'medium', 'large-v2', 'large-v3'];
$model       = in_array($_POST['model'] ?? '', $validModels, true) ? $_POST['model'] : 'small';
$beamSize    = max(1, min(5, (int)($_POST['beam_size'] ?? 5)));
$task        = ($_POST['task'] ?? 'transcribe') === 'translate' ? 'translate' : 'transcribe';
$vadFilter   = !empty($_POST['vad_filter']) && $_POST['vad_filter'] !== '0';
$initPrompt  = substr(trim((string)($_POST['initial_prompt'] ?? '')), 0, 500);

// ── 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');
}

// OpenAI has a 25 MB file limit
if ($engine === 'openai' && $file['size'] > 25 * 1024 * 1024) {
    dbnToolsError('OpenAI Whisper API has a 25 MB file limit. Use the GPU engine for larger files.', 413, 'openai_file_too_large');
}

$t0 = microtime(true);

// ── Route to engine ───────────────────────────────────────────────────────────

if ($engine === 'openai') {
    $apiKey = trim((string)($_POST['openai_key'] ?? ''));
    if (!$apiKey || !str_starts_with($apiKey, 'sk-')) {
        dbnToolsError('A valid OpenAI API key (sk-…) is required for the OpenAI engine.', 400, 'missing_openai_key');
    }
    $result = transcribeViaOpenAI($file, $language, $task, $apiKey);

} elseif ($engine === 'azure') {
    $apiKey = trim((string)($_POST['azure_key'] ?? ''));
    $region = preg_replace('/[^a-z0-9]/', '', strtolower(trim((string)($_POST['azure_region'] ?? 'norwayeast'))));
    if (!$apiKey) {
        dbnToolsError('An Azure Speech API key is required for the Azure engine.', 400, 'missing_azure_key');
    }
    $result = transcribeViaAzure($file, $language, $apiKey, $region, $diarize);

} else {
    // GPU (default)
    $result = transcribeViaWhisperGpu($file, $language, $diarize, $numSpeakers, $model, $beamSize, $task, $vadFilter, $initPrompt);
}

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

// ── Speaker role labelling (GPU + diarize only) ───────────────────────────────

$segments    = $result['segments']    ?? [];
$numDetected = (int)($result['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);
}

// ── Log + respond ─────────────────────────────────────────────────────────────

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

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


// ── Engine implementations ────────────────────────────────────────────────────

function transcribeViaWhisperGpu(array $file, string $language, bool $diarize, int $numSpeakers,
                                  string $model, int $beamSize, string $task,
                                  bool $vadFilter, string $initPrompt): array
{
    $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";

    $fields = [
        'model'          => $model,
        'beam_size'      => (string)$beamSize,
        'task'           => $task,
        'vad_filter'     => $vadFilter ? '1' : '0',
        'initial_prompt' => $initPrompt,
    ];
    if ($language !== 'auto') $fields['language'] = $language;
    if ($diarize && $numSpeakers > 1) $fields['num_speakers'] = (string)$numSpeakers;

    foreach ($fields as $name => $value) {
        if ($value === '') continue;
        $body .= "--{$boundary}\r\n";
        $body .= "Content-Disposition: form-data; name=\"{$name}\"\r\n\r\n";
        $body .= $value . "\r\n";
    }
    $body .= "--{$boundary}--\r\n";

    $ch = curl_init($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,
    ]);
    $responseBody = curl_exec($ch);
    $httpCode     = (int)curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
    $curlErr      = curl_error($ch);
    curl_close($ch);

    if ($responseBody === false || $httpCode !== 200) {
        $detail = $curlErr ?: (is_string($responseBody) ? substr(strip_tags($responseBody), 0, 300) : '');
        dbnToolsError('Whisper service error (HTTP ' . $httpCode . '): ' . $detail, 502, 'whisper_error');
    }

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


function transcribeViaOpenAI(array $file, string $language, string $task, string $apiKey): array
{
    $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";
    $body    .= file_get_contents($file['tmp_name']) . "\r\n";
    $body    .= "--{$boundary}\r\nContent-Disposition: form-data; name=\"model\"\r\n\r\nwhisper-1\r\n";
    $body    .= "--{$boundary}\r\nContent-Disposition: form-data; name=\"response_format\"\r\n\r\nverbose_json\r\n";
    if ($language !== 'auto') {
        $body .= "--{$boundary}\r\nContent-Disposition: form-data; name=\"language\"\r\n\r\n{$language}\r\n";
    }
    if ($task === 'translate') {
        $body .= "--{$boundary}\r\nContent-Disposition: form-data; name=\"task\"\r\n\r\ntranslation\r\n";
    }
    $body .= "--{$boundary}--\r\n";

    $ch = curl_init('https://api.openai.com/v1/audio/transcriptions');
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => $body,
        CURLOPT_HTTPHEADER     => [
            "Authorization: Bearer {$apiKey}",
            "Content-Type: multipart/form-data; boundary={$boundary}",
            'Accept: application/json',
        ],
        CURLOPT_TIMEOUT => 300,
    ]);
    $responseBody = curl_exec($ch);
    $httpCode     = (int)curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
    $curlErr      = curl_error($ch);
    curl_close($ch);

    if ($responseBody === false || $httpCode !== 200) {
        $detail = $curlErr ?: (is_string($responseBody) ? substr(strip_tags($responseBody), 0, 300) : '');
        dbnToolsError('OpenAI API error (HTTP ' . $httpCode . '): ' . $detail, 502, 'openai_error');
    }

    $data = json_decode($responseBody, true);
    if (!is_array($data)) {
        dbnToolsError('Invalid response from OpenAI.', 502, 'openai_empty');
    }

    // Normalise to internal shape
    return [
        'text'               => (string)($data['text'] ?? ''),
        'language'           => (string)($data['language'] ?? $language),
        'duration_seconds'   => (float)($data['duration'] ?? 0),
        'processing_seconds' => 0,
        'segments'           => array_map(fn($s) => [
            'id'      => $s['id']    ?? 0,
            'start'   => $s['start'] ?? 0,
            'end'     => $s['end']   ?? 0,
            'text'    => $s['text']  ?? '',
            'speaker' => 'SPEAKER_00',
        ], $data['segments'] ?? []),
        'model' => 'openai/whisper-1',
    ];
}


function transcribeViaAzure(array $file, string $language, string $apiKey,
                             string $region, bool $diarize): array
{
    // Azure Batch Transcription — POST audio directly for short-form (<60 min)
    // Uses the simple REST endpoint for synchronous short audio transcription.
    $langCode = match($language) {
        'no', 'nb' => 'nb-NO',
        'nn'       => 'nn-NO',
        'en'       => 'en-US',
        'sv'       => 'sv-SE',
        'da'       => 'da-DK',
        'de'       => 'de-DE',
        'fr'       => 'fr-FR',
        'es'       => 'es-ES',
        'pl'       => 'pl-PL',
        'fi'       => 'fi-FI',
        'nl'       => 'nl-NL',
        'it'       => 'it-IT',
        'pt'       => 'pt-PT',
        default    => 'nb-NO',
    };

    // Mime type map
    $mimeMap = [
        'wav'  => 'audio/wav',  'mp3'  => 'audio/mpeg', 'ogg'  => 'audio/ogg',
        'oga'  => 'audio/ogg',  'm4a'  => 'audio/mp4',  'mp4'  => 'audio/mp4',
        'flac' => 'audio/flac', 'webm' => 'audio/webm', 'aac'  => 'audio/aac',
    ];
    $fileExt  = strtolower(pathinfo($file['name'], PATHINFO_EXTENSION));
    $mimeType = $mimeMap[$fileExt] ?? 'audio/wav';

    $endpoint = "https://{$region}.stt.speech.microsoft.com/speech/recognition/conversation/cognitiveservices/v1"
              . "?language={$langCode}&format=detailed";

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

    $ch = curl_init($endpoint);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => $fileContents,
        CURLOPT_HTTPHEADER     => [
            "Ocp-Apim-Subscription-Key: {$apiKey}",
            "Content-Type: {$mimeType}",
            'Accept: application/json',
        ],
        CURLOPT_TIMEOUT => 300,
    ]);
    $responseBody = curl_exec($ch);
    $httpCode     = (int)curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
    $curlErr      = curl_error($ch);
    curl_close($ch);

    if ($responseBody === false || $httpCode !== 200) {
        $detail = $curlErr ?: (is_string($responseBody) ? substr(strip_tags($responseBody), 0, 300) : '');
        dbnToolsError('Azure Speech error (HTTP ' . $httpCode . '): ' . $detail, 502, 'azure_error');
    }

    $data = json_decode($responseBody, true);
    if (!is_array($data) || empty($data['DisplayText'])) {
        dbnToolsError('Empty or invalid response from Azure Speech.', 502, 'azure_empty');
    }

    // Normalise to internal shape
    $text = (string)($data['DisplayText'] ?? '');
    $segs = [];
    foreach (($data['NBest'][0]['Words'] ?? []) as $i => $word) {
        $segs[] = [
            'id'      => $i,
            'start'   => round((float)($word['Offset'] ?? 0) / 10_000_000, 3),
            'end'     => round(((float)($word['Offset'] ?? 0) + (float)($word['Duration'] ?? 0)) / 10_000_000, 3),
            'text'    => (string)($word['Word'] ?? ''),
            'speaker' => 'SPEAKER_00',
        ];
    }

    return [
        'text'               => $text,
        'language'           => $langCode,
        'duration_seconds'   => 0,
        'processing_seconds' => 0,
        'segments'           => $segs,
        'model'              => "azure/{$langCode}",
    ];
}


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 [];
    }
}