<?php

use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;

// Auth middleware
$authMiddleware = function (Request $request, $handler) {
    $authHeader = $request->getHeaderLine('Authorization');
    if (!$authHeader || !str_starts_with($authHeader, 'Bearer ')) {
        $response = new \Slim\Psr7\Response();
        $response->getBody()->write(json_encode(['error' => 'Unauthorized']));
        return $response->withStatus(401)->withHeader('Content-Type', 'application/json');
    }
    $token = substr($authHeader, 7);
    $decoded = jwtVerify($token);
    if (!$decoded) {
        $response = new \Slim\Psr7\Response();
        $response->getBody()->write(json_encode(['error' => 'Invalid token']));
        return $response->withStatus(401)->withHeader('Content-Type', 'application/json');
    }
    $request = $request->withAttribute('userId', $decoded['userId']);
    return $handler->handle($request);
};

// Health check
$app->get('/api/health', function (Request $request, Response $response) {
    $response->getBody()->write(json_encode(['status' => 'ok']));
    return $response->withHeader('Content-Type', 'application/json');
});

// Auth routes
$app->post('/api/auth/login', function (Request $request, Response $response) {
    $body = json_decode((string)$request->getBody(), true);
    $password = $body['password'] ?? '';
    $config = require __DIR__ . '/config.php';

    if (!$password) {
        $response->getBody()->write(json_encode(['error' => 'Password required']));
        return $response->withStatus(400)->withHeader('Content-Type', 'application/json');
    }
    if ($password !== $config['password']) {
        $response->getBody()->write(json_encode(['error' => 'Invalid password']));
        return $response->withStatus(401)->withHeader('Content-Type', 'application/json');
    }

    $userId = 'admin';
    $token = jwtGenerate($userId);
    $response->getBody()->write(json_encode([
        'token' => $token,
        'user' => ['id' => $userId, 'username' => 'admin']
    ]));
    return $response->withHeader('Content-Type', 'application/json');
});

$app->get('/api/auth/me', function (Request $request, Response $response) {
    $userId = $request->getAttribute('userId');
    $response->getBody()->write(json_encode([
        'id' => $userId,
        'username' => 'admin'
    ]));
    return $response->withHeader('Content-Type', 'application/json');
})->add($authMiddleware);

// Conversation routes
$app->get('/api/conversations', function (Request $request, Response $response) {
    $userId = $request->getAttribute('userId');
    $db = getDb();
    $stmt = $db->prepare("SELECT id, title, model_name, model_base_url, model_id, temperature, max_tokens, created_at, updated_at FROM conversations WHERE user_id = ? ORDER BY updated_at DESC");
    $stmt->execute([$userId]);
    $rows = $stmt->fetchAll();
    $response->getBody()->write(json_encode($rows));
    return $response->withHeader('Content-Type', 'application/json');
})->add($authMiddleware);

$app->get('/api/conversations/{id}', function (Request $request, Response $response, array $args) {
    $userId = $request->getAttribute('userId');
    $id = $args['id'];
    $db = getDb();

    $stmt = $db->prepare('SELECT * FROM conversations WHERE id = ? AND user_id = ?');
    $stmt->execute([$id, $userId]);
    $conv = $stmt->fetch();
    if (!$conv) {
        $response->getBody()->write(json_encode(['error' => 'Conversation not found']));
        return $response->withStatus(404)->withHeader('Content-Type', 'application/json');
    }

    $stmt = $db->prepare('SELECT id, role, content, timestamp FROM messages WHERE conversation_id = ? ORDER BY timestamp ASC');
    $stmt->execute([$id]);
    $messages = $stmt->fetchAll();

    $response->getBody()->write(json_encode(array_merge($conv, ['messages' => $messages])));
    return $response->withHeader('Content-Type', 'application/json');
})->add($authMiddleware);

$app->post('/api/conversations', function (Request $request, Response $response) {
    $userId = $request->getAttribute('userId');
    $body = json_decode((string)$request->getBody(), true);
    $title = $body['title'] ?? '新对话';
    $modelConfig = $body['modelConfig'] ?? null;

    $db = getDb();
    $id = bin2hex(random_bytes(16));
    $now = time() * 1000;

    $stmt = $db->prepare('INSERT INTO conversations (id, user_id, title, model_name, model_base_url, model_id, api_key, temperature, max_tokens, system_prompt, created_at, updated_at) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)');
    $stmt->execute([
        $id, $userId, $title,
        $modelConfig['name'] ?? null,
        $modelConfig['baseUrl'] ?? null,
        $modelConfig['model'] ?? null,
        $modelConfig['apiKey'] ?? null,
        $modelConfig['temperature'] ?? 0.7,
        $modelConfig['maxTokens'] ?? 4096,
        $modelConfig['systemPrompt'] ?? null,
        $now, $now
    ]);

    $stmt = $db->prepare('SELECT * FROM conversations WHERE id = ?');
    $stmt->execute([$id]);
    $conv = $stmt->fetch();

    $response->getBody()->write(json_encode(array_merge($conv, ['messages' => []])));
    return $response->withStatus(201)->withHeader('Content-Type', 'application/json');
})->add($authMiddleware);

$app->put('/api/conversations/{id}', function (Request $request, Response $response, array $args) {
    $userId = $request->getAttribute('userId');
    $id = $args['id'];
    $body = json_decode((string)$request->getBody(), true);
    $title = $body['title'] ?? null;
    $modelConfig = $body['modelConfig'] ?? null;

    $db = getDb();
    $stmt = $db->prepare('SELECT id FROM conversations WHERE id = ? AND user_id = ?');
    $stmt->execute([$id, $userId]);
    if (!$stmt->fetch()) {
        $response->getBody()->write(json_encode(['error' => 'Conversation not found']));
        return $response->withStatus(404)->withHeader('Content-Type', 'application/json');
    }

    $now = time() * 1000;
    $stmt = $db->prepare('UPDATE conversations SET title = COALESCE(?, title), model_name = COALESCE(?, model_name), model_base_url = COALESCE(?, model_base_url), model_id = COALESCE(?, model_id), api_key = COALESCE(?, api_key), temperature = COALESCE(?, temperature), max_tokens = COALESCE(?, max_tokens), system_prompt = COALESCE(?, system_prompt), updated_at = ? WHERE id = ?');
    $stmt->execute([
        $title,
        $modelConfig['name'] ?? null,
        $modelConfig['baseUrl'] ?? null,
        $modelConfig['model'] ?? null,
        $modelConfig['apiKey'] ?? null,
        $modelConfig['temperature'] ?? null,
        $modelConfig['maxTokens'] ?? null,
        $modelConfig['systemPrompt'] ?? null,
        $now, $id
    ]);

    $stmt = $db->prepare('SELECT * FROM conversations WHERE id = ?');
    $stmt->execute([$id]);
    $conv = $stmt->fetch();

    $stmt = $db->prepare('SELECT id, role, content, timestamp FROM messages WHERE conversation_id = ? ORDER BY timestamp ASC');
    $stmt->execute([$id]);
    $messages = $stmt->fetchAll();

    $response->getBody()->write(json_encode(array_merge($conv, ['messages' => $messages])));
    return $response->withHeader('Content-Type', 'application/json');
})->add($authMiddleware);

$app->delete('/api/conversations/{id}', function (Request $request, Response $response, array $args) {
    $userId = $request->getAttribute('userId');
    $id = $args['id'];
    $db = getDb();

    $stmt = $db->prepare('DELETE FROM conversations WHERE id = ? AND user_id = ?');
    $stmt->execute([$id, $userId]);
    if ($stmt->rowCount() === 0) {
        $response->getBody()->write(json_encode(['error' => 'Conversation not found']));
        return $response->withStatus(404)->withHeader('Content-Type', 'application/json');
    }
    $response->getBody()->write(json_encode(['success' => true]));
    return $response->withHeader('Content-Type', 'application/json');
})->add($authMiddleware);

$app->delete('/api/conversations/{id}/messages', function (Request $request, Response $response, array $args) {
    $userId = $request->getAttribute('userId');
    $id = $args['id'];
    $db = getDb();

    $stmt = $db->prepare('SELECT id FROM conversations WHERE id = ? AND user_id = ?');
    $stmt->execute([$id, $userId]);
    if (!$stmt->fetch()) {
        $response->getBody()->write(json_encode(['error' => 'Conversation not found']));
        return $response->withStatus(404)->withHeader('Content-Type', 'application/json');
    }

    $stmt = $db->prepare('DELETE FROM messages WHERE conversation_id = ?');
    $stmt->execute([$id]);

    $now = time() * 1000;
    $stmt = $db->prepare('UPDATE conversations SET updated_at = ? WHERE id = ?');
    $stmt->execute([$now, $id]);

    $response->getBody()->write(json_encode(['success' => true]));
    return $response->withHeader('Content-Type', 'application/json');
})->add($authMiddleware);

// Chat route (SSE)
$app->post('/api/chat', function (Request $request, Response $response) {
    $userId = $request->getAttribute('userId');
    $body = json_decode((string)$request->getBody(), true);
    $conversationId = $body['conversationId'] ?? '';
    $content = trim($body['content'] ?? '');

    if (!$conversationId || !$content) {
        $response->getBody()->write(json_encode(['error' => 'conversationId and content required']));
        return $response->withStatus(400)->withHeader('Content-Type', 'application/json');
    }

    $db = getDb();

    $stmt = $db->prepare('SELECT * FROM conversations WHERE id = ? AND user_id = ?');
    $stmt->execute([$conversationId, $userId]);
    $conv = $stmt->fetch();
    if (!$conv) {
        $response->getBody()->write(json_encode(['error' => 'Conversation not found']));
        return $response->withStatus(404)->withHeader('Content-Type', 'application/json');
    }

    // Load history
    $stmt = $db->prepare("SELECT role, content FROM messages WHERE conversation_id = ? ORDER BY timestamp ASC");
    $stmt->execute([$conversationId]);
    $history = $stmt->fetchAll();

    // Build messages
    $messages = [];
    if ($conv['system_prompt']) {
        $messages[] = ['role' => 'system', 'content' => $conv['system_prompt']];
    }
    foreach ($history as $msg) {
        if ($msg['role'] !== 'system') {
            $messages[] = ['role' => $msg['role'], 'content' => $msg['content']];
        }
    }
    $messages[] = ['role' => 'user', 'content' => $content];

    // Save user message
    $userMsgId = bin2hex(random_bytes(16));
    $now = time() * 1000;
    $stmt = $db->prepare('INSERT INTO messages (id, conversation_id, role, content, timestamp) VALUES (?, ?, ?, ?, ?)');
    $stmt->execute([$userMsgId, $conversationId, 'user', $content, $now]);

    // Update title if first message
    $stmt = $db->prepare('SELECT COUNT(*) as cnt FROM messages WHERE conversation_id = ?');
    $stmt->execute([$conversationId]);
    $msgCount = $stmt->fetch()['cnt'] ?? 0;
    if ($msgCount == 1) {
        $newTitle = mb_substr($content, 0, 20) . (mb_strlen($content) > 20 ? '...' : '');
        $stmt = $db->prepare('UPDATE conversations SET title = ?, updated_at = ? WHERE id = ?');
        $stmt->execute([$newTitle, $now, $conversationId]);
    }

    // Check model config
    if (!$conv['model_base_url'] || !$conv['api_key'] || !$conv['model_id']) {
        $errMsg = 'Error: 模型配置不完整，请先在「配置」中设置 API 地址、API Key 和模型 ID';
        $errMsgId = bin2hex(random_bytes(16));
        $stmt = $db->prepare('INSERT INTO messages (id, conversation_id, role, content, timestamp) VALUES (?, ?, ?, ?, ?)');
        $stmt->execute([$errMsgId, $conversationId, 'assistant', $errMsg, $now]);
        $response->getBody()->write(json_encode(['error' => 'Model config incomplete']));
        return $response->withStatus(400)->withHeader('Content-Type', 'application/json');
    }

    // SSE output
    header('Content-Type: text/event-stream');
    header('Cache-Control: no-cache');
    header('Connection: keep-alive');
    header('X-Accel-Buffering: no');

    while (ob_get_level() > 0) ob_end_flush();
    ob_implicit_flush(true);

    // Send user message confirmation
    echo "data: " . json_encode(['type' => 'user', 'id' => $userMsgId, 'content' => $content]) . "\n\n";
    flush();

    // Call LLM API via curl
    $assistantMsgId = bin2hex(random_bytes(16));
    $fullContent = '';

    $payload = json_encode([
        'model' => $conv['model_id'],
        'messages' => $messages,
        'temperature' => (float)$conv['temperature'],
        'max_tokens' => (int)$conv['max_tokens'],
        'stream' => true,
    ]);

    $ch = curl_init($conv['model_base_url'] . '/chat/completions');
    curl_setopt_array($ch, [
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => $payload,
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/json',
            'Authorization: Bearer ' . $conv['api_key'],
        ],
        CURLOPT_RETURNTRANSFER => false,
        CURLOPT_WRITEFUNCTION => function ($ch, $data) use (&$fullContent) {
            $lines = explode("\n", $data);
            foreach ($lines as $line) {
                $line = trim($line);
                if (!$line || !str_starts_with($line, 'data: ')) continue;
                $jsonStr = substr($line, 6);
                if ($jsonStr === '[DONE]') continue;
                $parsed = json_decode($jsonStr, true);
                if (!$parsed) continue;
                $delta = $parsed['choices'][0]['delta']['content'] ?? '';
                if ($delta) {
                    $fullContent .= $delta;
                    echo "data: " . json_encode(['type' => 'delta', 'content' => $delta]) . "\n\n";
                    flush();
                }
            }
            return strlen($data);
        },
        CURLOPT_TIMEOUT => 120,
        CURLOPT_CONNECTTIMEOUT => 30,
    ]);

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

    if ($error) {
        $errMsg = 'Error: ' . $error;
        echo "data: " . json_encode(['type' => 'error', 'content' => $errMsg]) . "\n\n";
    }

    // Save assistant message
    $stmt = $db->prepare('INSERT INTO messages (id, conversation_id, role, content, timestamp) VALUES (?, ?, ?, ?, ?)');
    $stmt->execute([$assistantMsgId, $conversationId, 'assistant', $fullContent, time() * 1000]);

    $stmt = $db->prepare('UPDATE conversations SET updated_at = ? WHERE id = ?');
    $stmt->execute([time() * 1000, $conversationId]);

    echo "data: " . json_encode(['type' => 'done', 'id' => $assistantMsgId, 'content' => $fullContent]) . "\n\n";
    echo "data: [DONE]\n\n";
    flush();

    exit(0);
})->add($authMiddleware);