<?php
// WEVIA Sovereign Gateway v2 — Routes through WEVIA Brain
header('Content-Type: application/json');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type, Authorization, x-api-key, anthropic-version');
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') { http_response_code(204); exit; }

$input = json_decode(file_get_contents('php://input'), true) ?: [];
$messages = $input['messages'] ?? [];
$max_tokens = $input['max_tokens'] ?? 2000;

// Extract last user message
$msg = '';
foreach (array_reverse($messages) as $m) {
    if (($m['role'] ?? '') === 'user') { $msg = $m['content'] ?? ''; break; }
}
if (!$msg && $messages) $msg = end($messages)['content'] ?? 'hello';

// Add system context
$system = '';
foreach ($messages as $m) {
    if (($m['role'] ?? '') === 'system') { $system = $m['content'] ?? ''; break; }
}
if ($system) $msg = "[System: " . substr($system, 0, 500) . "] " . $msg;

// Call WEVIA Brain (sovereign: Groq/Cerebras/Mistral)
$ch = curl_init('http://127.0.0.1/wevia-ia/weval-chatbot-api.php');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT => 60,
    CURLOPT_HTTPHEADER => ['Content-Type: application/json', 'Host: weval-consulting.com'],
    CURLOPT_POSTFIELDS => json_encode(['message' => $msg, 'mode' => 'fast']),
]);
$resp = curl_exec($ch);
curl_close($ch);

$data = json_decode($resp, true);
$text = $data['response'] ?? 'Sovereign AI processing...';
$provider = $data['provider'] ?? 'WEVIA Sovereign';

// Detect format: Anthropic or OpenAI
$uri = $_SERVER['REQUEST_URI'] ?? '';
$is_anthropic = strpos($uri, '/v1/messages') !== false || 
    !empty($_SERVER['HTTP_ANTHROPIC_VERSION']) ||
    isset($input['anthropic_version']);

if ($is_anthropic) {
    echo json_encode([
        'id' => 'msg_wevia_' . substr(md5(uniqid()), 0, 12),
        'type' => 'message',
        'role' => 'assistant',
        'content' => [['type' => 'text', 'text' => $text]],
        'model' => 'wevia-sovereign-' . preg_replace('/[^a-zA-Z0-9]/', '', $provider),
        'stop_reason' => 'end_turn',
        'usage' => ['input_tokens' => 100, 'output_tokens' => intval(strlen($text) / 4)],
    ]);
} else {
    echo json_encode([
        'id' => 'chatcmpl-wevia-' . substr(md5(uniqid()), 0, 8),
        'object' => 'chat.completion',
        'model' => 'wevia-sovereign-' . preg_replace('/[^a-zA-Z0-9]/', '', $provider),
        'choices' => [['index' => 0, 'message' => ['role' => 'assistant', 'content' => $text], 'finish_reason' => 'stop']],
        'usage' => ['prompt_tokens' => 100, 'completion_tokens' => intval(strlen($text) / 4)],
    ]);
}