<?php
/**
 * WEVIA MCP Layer v1.0 — Model Context Protocol
 * Pattern #17 from Claude Code architecture
 * 
 * Dual mode:
 *   SERVER: Exposes WEVIA tools as MCP endpoints (JSON-RPC 2.0)
 *   CLIENT: Consumes external MCP servers (tool discovery + invocation)
 * 
 * Spec: https://modelcontextprotocol.io
 * 
 * SERVER endpoint: /api/mcp.php  (this file)
 * CLIENT: wevia_mcp_discover() + wevia_mcp_invoke()
 * 
 * Usage: require_once __DIR__ . '/wevia-mcp-layer.php';
 */

define('MCP_VERSION', '1.0.0');
define('MCP_PROTOCOL', '2024-11-05'); // MCP spec version

// ═══════════════════════════════════════════════════════════════
// MCP SERVER — Expose WEVIA tools as MCP endpoints
// ═══════════════════════════════════════════════════════════════

function mcp_server_handle($request) {
    $method = $request['method'] ?? '';
    $params = $request['params'] ?? [];
    $id = $request['id'] ?? null;

    switch ($method) {
        case 'initialize':
            return mcp_response($id, [
                'protocolVersion' => MCP_PROTOCOL,
                'capabilities' => [
                    'tools' => ['listChanged' => false],
                    'resources' => ['subscribe' => false, 'listChanged' => false],
                ],
                'serverInfo' => [
                    'name' => 'wevia-mcp-server',
                    'version' => MCP_VERSION,
                    'description' => 'WEVIA Sovereign AI — Tool Server'
                ]
            ]);

        case 'tools/list':
            return mcp_response($id, ['tools' => mcp_list_tools()]);

        case 'tools/call':
            $toolName = $params['name'] ?? '';
            $toolArgs = $params['arguments'] ?? [];
            return mcp_response($id, mcp_call_tool($toolName, $toolArgs));

        case 'resources/list':
            return mcp_response($id, ['resources' => mcp_list_resources()]);

        case 'resources/read':
            $uri = $params['uri'] ?? '';
            return mcp_response($id, mcp_read_resource($uri));

        case 'ping':
            return mcp_response($id, []);

        default:
            return mcp_error($id, -32601, "Method not found: $method");
    }
}

function mcp_list_tools() {
    return [
        [
            'name' => 'wevia_chat',
            'description' => 'Send a message to WEVIA sovereign AI chatbot',
            'inputSchema' => [
                'type' => 'object',
                'properties' => [
                    'message' => ['type' => 'string', 'description' => 'User message'],
                    'mode' => ['type' => 'string', 'enum' => ['fast', 'balanced', 'verified'], 'default' => 'balanced'],
                    'lang' => ['type' => 'string', 'default' => 'fr'],
                ],
                'required' => ['message']
            ]
        ],
        [
            'name' => 'wevia_kb_search',
            'description' => 'Search WEVIA knowledge base (32 tables, 2490+ entries)',
            'inputSchema' => [
                'type' => 'object',
                'properties' => [
                    'query' => ['type' => 'string', 'description' => 'Search query'],
                    'limit' => ['type' => 'integer', 'default' => 5],
                ],
                'required' => ['query']
            ]
        ],
        [
            'name' => 'wevia_pdf_generate',
            'description' => 'Generate a professional PDF document on any topic',
            'inputSchema' => [
                'type' => 'object',
                'properties' => [
                    'topic' => ['type' => 'string', 'description' => 'Document topic/title'],
                    'sections' => ['type' => 'integer', 'default' => 8],
                ],
                'required' => ['topic']
            ]
        ],
        [
            'name' => 'wevia_mermaid',
            'description' => 'Generate a Mermaid diagram (flowchart, sequence, class, etc.)',
            'inputSchema' => [
                'type' => 'object',
                'properties' => [
                    'description' => ['type' => 'string', 'description' => 'What to diagram'],
                    'type' => ['type' => 'string', 'enum' => ['flowchart', 'sequence', 'class', 'state', 'er', 'gantt'], 'default' => 'flowchart'],
                ],
                'required' => ['description']
            ]
        ],
        [
            'name' => 'wevia_web_search',
            'description' => 'Sovereign web search via SearXNG',
            'inputSchema' => [
                'type' => 'object',
                'properties' => [
                    'query' => ['type' => 'string'],
                    'max_results' => ['type' => 'integer', 'default' => 5],
                ],
                'required' => ['query']
            ]
        ],
        [
            'name' => 'wevia_benchmark',
            'description' => 'Get AI ecosystem benchmark data (66 AIs, 222 skills)',
            'inputSchema' => [
                'type' => 'object',
                'properties' => [
                    'ai_name' => ['type' => 'string', 'description' => 'Specific AI name or "all"'],
                ],
                'required' => []
            ]
        ],
    ];
}

function mcp_call_tool($name, $args) {
    switch ($name) {
        case 'wevia_chat':
            $ch = curl_init('http://127.0.0.1/wevia-ia/weval-chatbot-api.php');
            curl_setopt_array($ch, [
                CURLOPT_POST => true, CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 30,
                CURLOPT_HTTPHEADER => ['Content-Type: application/json'],
                CURLOPT_POSTFIELDS => json_encode([
                    'message' => $args['message'] ?? '',
                    'mode' => $args['mode'] ?? 'balanced',
                    'lang' => $args['lang'] ?? 'fr',
                ])
            ]);
            $r = curl_exec($ch); curl_close($ch);
            $d = json_decode($r, true);
            return ['content' => [['type' => 'text', 'text' => $d['response'] ?? 'No response']]];

        case 'wevia_kb_search':
            $query = $args['query'] ?? '';
            $limit = $args['limit'] ?? 5;
            // Direct KB query
            try {
                @require_once('/opt/wevads/vault/credentials.php');
                $pdo = new PDO("pgsql:host=10.1.0.3;dbname=adx_system", "admin", "admin123");
                $st = $pdo->prepare("SELECT title, content, category FROM admin.wevia_kb WHERE LOWER(content) LIKE LOWER(?) LIMIT ?");
                $st->execute(["%$query%", $limit]);
                $results = $st->fetchAll(PDO::FETCH_ASSOC);
                return ['content' => [['type' => 'text', 'text' => json_encode($results, JSON_UNESCAPED_UNICODE)]]];
            } catch (Exception $e) {
                return ['content' => [['type' => 'text', 'text' => 'KB search error: ' . $e->getMessage()]]];
            }

        case 'wevia_benchmark':
            $cache = @json_decode(@file_get_contents('/var/www/html/api/ai-benchmark-cache.json'), true);
            $aiName = $args['ai_name'] ?? 'all';
            if ($aiName === 'all') {
                $lb = $cache['leaderboard'] ?? [];
                arsort($lb);
                return ['content' => [['type' => 'text', 'text' => json_encode(array_slice($lb, 0, 20, true))]]];
            }
            $ai = $cache['all_ais'][$aiName] ?? null;
            return ['content' => [['type' => 'text', 'text' => $ai ? json_encode($ai) : "AI '$aiName' not found"]]];

        case 'wevia_web_search':
            $ch = curl_init('http://127.0.0.1:8888/search?q=' . urlencode($args['query'] ?? '') . '&format=json&categories=general');
            curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 10]);
            $r = curl_exec($ch); curl_close($ch);
            $d = json_decode($r, true);
            $results = array_slice($d['results'] ?? [], 0, $args['max_results'] ?? 5);
            $text = implode("\n\n", array_map(fn($r) => "**{$r['title']}**\n{$r['url']}\n{$r['content']}", $results));
            return ['content' => [['type' => 'text', 'text' => $text ?: 'No results']]];

        default:
            return ['content' => [['type' => 'text', 'text' => "Unknown tool: $name"]], 'isError' => true];
    }
}

function mcp_list_resources() {
    return [
        ['uri' => 'wevia://benchmark/leaderboard', 'name' => 'AI Benchmark Leaderboard', 'mimeType' => 'application/json'],
        ['uri' => 'wevia://config/providers', 'name' => 'Active Providers', 'mimeType' => 'application/json'],
        ['uri' => 'wevia://status/health', 'name' => 'System Health', 'mimeType' => 'application/json'],
    ];
}

function mcp_read_resource($uri) {
    switch ($uri) {
        case 'wevia://benchmark/leaderboard':
            $cache = @json_decode(@file_get_contents('/var/www/html/api/ai-benchmark-cache.json'), true);
            return ['contents' => [['uri' => $uri, 'mimeType' => 'application/json', 'text' => json_encode($cache['leaderboard'] ?? [])]]];
        case 'wevia://config/providers':
            return ['contents' => [['uri' => $uri, 'mimeType' => 'application/json', 'text' => json_encode(['chain' => 'Groq→Cerebras→SambaNova→Mistral→Alibaba', 'sovereign' => 'Local→EU→Free→Paid'])]]];
        case 'wevia://status/health':
            return ['contents' => [['uri' => $uri, 'mimeType' => 'application/json', 'text' => json_encode(['status' => 'ok', 'modules' => ['WCP' => 'v1.0', 'WSI' => 'v1.0', 'Dream' => 'active', 'MCP' => 'v1.0'], 'uptime' => exec('uptime -p 2>/dev/null')])]]];
        default:
            return ['contents' => []];
    }
}

// ═══════════════════════════════════════════════════════════════
// MCP CLIENT — Consume external MCP servers
// ═══════════════════════════════════════════════════════════════

function wevia_mcp_discover($serverUrl, $timeout = 10) {
    /**
     * Discover tools from an external MCP server.
     * Returns array of available tools with schemas.
     */
    // Initialize
    $init = wevia_mcp_call($serverUrl, 'initialize', [
        'protocolVersion' => MCP_PROTOCOL,
        'capabilities' => [],
        'clientInfo' => ['name' => 'wevia-mcp-client', 'version' => MCP_VERSION]
    ], $timeout);

    if (!$init) return ['error' => 'init_failed'];

    // List tools
    $tools = wevia_mcp_call($serverUrl, 'tools/list', [], $timeout);
    return $tools['tools'] ?? [];
}

function wevia_mcp_invoke($serverUrl, $toolName, $arguments = [], $timeout = 30) {
    /**
     * Invoke a tool on an external MCP server.
     */
    $result = wevia_mcp_call($serverUrl, 'tools/call', [
        'name' => $toolName,
        'arguments' => $arguments,
    ], $timeout);

    return $result;
}

function wevia_mcp_call($serverUrl, $method, $params = [], $timeout = 10) {
    $payload = json_encode([
        'jsonrpc' => '2.0',
        'id' => uniqid('mcp_'),
        'method' => $method,
        'params' => $params,
    ]);

    $ch = curl_init($serverUrl);
    curl_setopt_array($ch, [
        CURLOPT_POST => true,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => $timeout,
        CURLOPT_HTTPHEADER => ['Content-Type: application/json', 'Accept: application/json'],
        CURLOPT_POSTFIELDS => $payload,
    ]);
    $r = curl_exec($ch);
    $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($code !== 200 || !$r) return null;
    $d = json_decode($r, true);
    return $d['result'] ?? null;
}

// ═══════════════════════════════════════════════════════════════
// MCP REGISTRY — Track connected MCP servers
// ═══════════════════════════════════════════════════════════════

function wevia_mcp_registry() {
    /**
     * Registry of known MCP servers.
     * Auto-populated by OSS Discovery + manual config.
     */
    $registryFile = '/opt/wevads/vault/mcp-registry.json';
    if (!file_exists($registryFile)) {
        $default = [
            'servers' => [
                ['name' => 'wevia-local', 'url' => 'http://127.0.0.1/api/mcp.php', 'type' => 'local', 'active' => true],
            ],
            'last_scan' => null,
        ];
        @file_put_contents($registryFile, json_encode($default, JSON_PRETTY_PRINT));
        return $default;
    }
    return json_decode(file_get_contents($registryFile), true) ?: [];
}

function wevia_mcp_register_server($name, $url, $type = 'external') {
    $registry = wevia_mcp_registry();
    $registry['servers'][] = ['name' => $name, 'url' => $url, 'type' => $type, 'active' => true, 'added' => date('c')];
    @file_put_contents('/opt/wevads/vault/mcp-registry.json', json_encode($registry, JSON_PRETTY_PRINT));
    return true;
}

// ═══════════════════════════════════════════════════════════════
// JSON-RPC HELPERS
// ═══════════════════════════════════════════════════════════════

function mcp_response($id, $result) {
    return ['jsonrpc' => '2.0', 'id' => $id, 'result' => $result];
}

function mcp_error($id, $code, $message) {
    return ['jsonrpc' => '2.0', 'id' => $id, 'error' => ['code' => $code, 'message' => $message]];
}

// ═══════════════════════════════════════════════════════════════
// STANDALONE SERVER MODE — if called directly as /api/mcp.php
// ═══════════════════════════════════════════════════════════════

if (basename($_SERVER['SCRIPT_FILENAME'] ?? '') === 'wevia-mcp-layer.php' || 
    basename($_SERVER['SCRIPT_FILENAME'] ?? '') === 'mcp.php') {
    header('Content-Type: application/json');
    
    // Auth check
    $key = $_GET['k'] ?? $_SERVER['HTTP_X_MCP_KEY'] ?? '';
    if ($key !== 'WEVADS2026' && $key !== 'MCP2026') {
        http_response_code(403);
        die(json_encode(mcp_error(null, -32000, 'Unauthorized')));
    }
    
    $body = json_decode(file_get_contents('php://input'), true);
    if (!$body || !isset($body['method'])) {
        die(json_encode(mcp_error(null, -32700, 'Parse error')));
    }
    
    die(json_encode(mcp_server_handle($body)));
}

error_log("MCP: wevia-mcp-layer v" . MCP_VERSION . " loaded (server+client)");