<?php
header('Content-Type: application/json');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: POST');
header('Access-Control-Allow-Headers: Content-Type');

// Load environment variables
$envFile = __DIR__ . '/../../config/.env';

// Fallback for server environment
if (!file_exists($envFile)) {
    $envFile = '/var/www/stefanzweig/dev/config/.env';
}

// Additional fallback for different server configurations
if (!file_exists($envFile)) {
    $envFile = $_SERVER['DOCUMENT_ROOT'] . '/../config/.env';
}

// Debug: Log the path being used
error_log("TTS API: Looking for .env file at: " . $envFile);
error_log("TTS API: File exists: " . (file_exists($envFile) ? 'YES' : 'NO'));
if (file_exists($envFile)) {
    $lines = file($envFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
    foreach ($lines as $line) {
        if (strpos($line, '=') !== false && strpos($line, '#') !== 0) {
            list($key, $value) = explode('=', $line, 2);
            $_ENV[trim($key)] = trim($value);
        }
    }
}

// Get OpenAI API key
$openaiKey = $_ENV['OPENAI_API_KEY'] ?? null;

if (!$openaiKey) {
    http_response_code(500);
    echo json_encode([
        'error' => 'OpenAI API key not configured',
        'debug' => [
            'env_file_exists' => file_exists($envFile),
            'env_file_path' => $envFile,
            'env_vars' => array_keys($_ENV),
            'current_dir' => __DIR__,
            'server_root' => $_SERVER['DOCUMENT_ROOT'] ?? 'unknown',
            'tried_paths' => [
                __DIR__ . '/../../config/.env',
                '/var/www/stefanzweig/dev/config/.env',
                $_SERVER['DOCUMENT_ROOT'] . '/../config/.env'
            ]
        ]
    ]);
    exit;
}

if (($_SERVER['REQUEST_METHOD'] ?? 'GET') !== 'POST') {
    http_response_code(405);
    echo json_encode(['error' => 'Method not allowed']);
    exit;
}

$input = json_decode(file_get_contents('php://input'), true);

if (!isset($input['text']) || !isset($input['voice'])) {
    http_response_code(400);
    echo json_encode(['error' => 'Missing required parameters: text, voice']);
    exit;
}

$text = $input['text'];
$voice = $input['voice'];
$speed = $input['speed'] ?? 1.0;

// Validate voice
$validVoices = ['alloy', 'echo', 'fable', 'onyx', 'nova', 'shimmer'];
if (!in_array($voice, $validVoices)) {
    http_response_code(400);
    echo json_encode(['error' => 'Invalid voice']);
    exit;
}

// Check cache first
$cacheDir = __DIR__ . '/../../tmp/audio_cache/';
if (!is_dir($cacheDir)) {
    mkdir($cacheDir, 0755, true);
}

$cacheKey = md5($text . $voice . $speed);
$cacheFile = $cacheDir . $cacheKey . '.mp3';

if (file_exists($cacheFile)) {
    // Return cached audio
    $audioData = base64_encode(file_get_contents($cacheFile));
    echo json_encode([
        'success' => true,
        'audio' => $audioData,
        'cached' => true
    ]);
    exit;
}

// Call OpenAI TTS API
$url = 'https://api.openai.com/v1/audio/speech';
$data = [
    'model' => 'tts-1',
    'input' => $text,
    'voice' => $voice,
    'speed' => $speed
];

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Authorization: Bearer ' . $openaiKey,
    'Content-Type: application/json'
]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);

$response = curl_exec($ch);
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
$error = curl_error($ch);
curl_close($ch);

if ($error) {
    http_response_code(500);
    echo json_encode(['error' => 'CURL error: ' . $error]);
    exit;
}

if ($httpCode !== 200) {
    http_response_code($httpCode);
    echo json_encode(['error' => 'OpenAI API error', 'response' => $response]);
    exit;
}

// Save to cache
file_put_contents($cacheFile, $response);

// Return audio data
$audioData = base64_encode($response);
echo json_encode([
    'success' => true,
    'audio' => $audioData,
    'cached' => false
]);
?>