const express = require('express');
const cors = require('cors');
const { createProxyMiddleware } = require('http-proxy-middleware');
const { spawn } = require('child_process');
const fs = require('fs');
const path = require('path');
const dns = require('dns');
const https = require('https');
const GeminiWebAPI = require('./GeminiWebAPI.cjs');

// === IN-MEMORY LOG CAPTURE ===
const appLogs = [];
const maxLogs = 500;
function addLog(source, msg) {
    appLogs.push(`[${new Date().toISOString()}] [${source}] ${msg}`);
    if (appLogs.length > maxLogs) appLogs.shift();
}
// =============================

// Force Node to use reliable public DNS instead of Hugging Face's broken K8s DNS
dns.setServers(['8.8.8.8', '1.1.1.1', '8.8.4.4']);

// Custom HTTPS Agent that intercepts DNS and bypasses the OS 
const proxyAgent = new https.Agent({
    keepAlive: true,
    lookup: (hostname, options, callback) => {
        // Force manual DNS resolution for Telegram
        if (hostname.includes('telegram.org')) {
            dns.resolve4(hostname, (err, addresses) => {
                if (err) return dns.lookup(hostname, options, callback); // Fallback
                if (options && options.all) {
                    callback(null, addresses.map(a => ({ address: a, family: 4 })));
                } else {
                    callback(null, addresses[0], 4);
                }
            });
        } else {
            // Native lookup for others
            dns.lookup(hostname, options, callback);
        }
    }
});

const app = express();
app.use(cors());

// Safe JSON parser that won't crash on 'null' or weird payloads from the Expo app
app.use(express.json({ strict: false, limit: '50mb' }));
app.use((err, req, res, next) => {
    if (err instanceof SyntaxError && err.status === 400 && 'body' in err) {
        console.error('[JSON Parse Error]', err.message);
        return res.status(400).json({ error: "Invalid JSON payload" }); // Send JSON instead of HTML
    }
    next();
});

const PORT = process.env.PORT || 7860;

// Automatic Cookie Injection for Headless Hugging Face
if (process.env.GEMINI_SESSION_B64) {
    console.log("Found GEMINI_SESSION_B64 environment variable. Injecting session cookies...");
    try {
        const decoded = Buffer.from(process.env.GEMINI_SESSION_B64, 'base64').toString('utf8');
        fs.writeFileSync('./user_session.json', decoded);
        console.log("✅ Successfully injected user_session.json");
    } catch (e) {
        console.error("❌ Failed to decode GEMINI_SESSION_B64:", e.message);
    }
}

// Initialize GeminiWebAPI
console.log("Starting Web API Proxy layer...");
const gemini = new GeminiWebAPI({
    headless: true,
    userDataDir: './user_data_hybrid'
});

gemini.auth().then(() => {
    console.log("✅ GeminiWebAPI Authenticated and Ready.");
}).catch(err => {
    console.error("❌ Failed to authenticate GeminiWebAPI:", err);
    // On Hugging face we might not have a session json initially.
    // It will freeze waiting for manual login.
    console.log("❗ WARNING: No session found. Browser automation requires manual login on first run.");
});

// ==========================================
// OPENAI COMPATIBLE API (/v1/chat/completions)
// ==========================================
app.post('/v1/chat/completions', async (req, res) => {
    try {
        const { messages, stream } = req.body;

        if (!messages || messages.length === 0) {
            return res.status(400).json({ error: "Missing messages array" });
        }

        const lastUserMessage = messages.filter(m => m.role === 'user').pop();
        if (!lastUserMessage) {
            return res.status(400).json({ error: "No user message found" });
        }

        // Just take the raw content string
        let promptText = "";
        if (typeof lastUserMessage.content === 'string') {
            promptText = lastUserMessage.content;
        } else if (Array.isArray(lastUserMessage.content)) {
            promptText = lastUserMessage.content.map(c => c.text || JSON.stringify(c)).join("\n");
        }

        if (!gemini.isAuthenticated) {
            return res.status(503).json({ error: "GeminiWebAPI is not authenticated yet. Please check logs." });
        }

        console.log(`[Proxy] Forwarding prompt to Gemini Web (Stream: ${!!stream}): ${promptText.substring(0, 50)}...`);

        if (stream) {
            // Setup SSE
            res.setHeader('Content-Type', 'text/event-stream');
            res.setHeader('Cache-Control', 'no-cache');
            res.setHeader('Connection', 'keep-alive');

            let lastLength = 0;
            await gemini.askStream(promptText, (currentText, thinking) => {
                if (currentText && currentText.length > lastLength) {
                    const delta = currentText.slice(lastLength);
                    lastLength = currentText.length;

                    const chunkObj = {
                        id: `chatcmpl-${Date.now()}`,
                        object: "chat.completion.chunk",
                        created: Math.floor(Date.now() / 1000),
                        model: "gemini-web",
                        choices: [{
                            index: 0,
                            delta: { content: delta }
                        }]
                    };
                    res.write(`data: ${JSON.stringify(chunkObj)}\n\n`);
                }
            });

            res.write('data: [DONE]\n\n');
            res.end();
            return;
        }

        // Non-streaming fallback
        const responseText = await gemini.ask(promptText);

        const responseObj = {
            id: `chatcmpl-${Date.now()}`,
            object: "chat.completion",
            created: Math.floor(Date.now() / 1000),
            model: "gemini-web",
            choices: [{
                index: 0,
                message: {
                    role: "assistant",
                    content: responseText,
                },
                finish_reason: "stop"
            }],
            usage: { prompt_tokens: 0, completion_tokens: 0, total_tokens: 0 }
        };

        res.json(responseObj);

    } catch (e) {
        console.error("[Proxy] Error processing request:", e);
        if (!res.headersSent) {
            res.status(500).json({ error: e.message });
        } else {
            res.end();
        }
    }
});

// ==========================================
// GRAVITYCLAW EXPO APP COMPATIBILITY (/api/chat)
// ==========================================
app.post('/api/chat', async (req, res) => {
    try {
        const { message } = req.body;

        if (!message) {
            return res.status(400).json({ error: "Message is required" });
        }

        res.setHeader('Content-Type', 'text/event-stream');
        res.setHeader('Cache-Control', 'no-cache');
        res.setHeader('Connection', 'keep-alive');
        // Necessary to flush headers immediately in some environments
        res.flushHeaders && res.flushHeaders();

        const sendEvent = (type, data) => {
            res.write(`data: ${JSON.stringify({ type, ...data })}\n\n`);
        };

        if (!gemini.isAuthenticated) {
            sendEvent('error', { message: "GeminiWebAPI is not authenticated yet." });
            return res.end();
        }

        // The Expo App hardcodes "start" to show the typing indicator
        sendEvent('start', { status: 'Processing...' });

        const startTime = Date.now();
        const responseText = await gemini.ask(message);

        // The Expo App waits for "done" to show the final message
        sendEvent('done', {
            response: responseText,
            metadata: {
                executionTimeMs: Date.now() - startTime,
                tokens: Math.floor(responseText.length / 4),
                cost: "$0.00"
            }
        });

        res.end();

    } catch (e) {
        console.error("[Proxy Expo App] Error:", e);
        if (!res.headersSent) {
            res.status(500).json({ error: e.message });
        } else {
            res.write(`data: ${JSON.stringify({ type: 'error', message: e.message })}\n\n`);
            res.end();
        }
    }
});

// ==========================================
// TELEGRAM API PROXY (manual fetch-based, bypasses HF's HTTPS block)
// ==========================================
app.use('/tg', async (req, res) => {
    // Strip /tg prefix → forward to api.telegram.org
    const targetPath = req.originalUrl.replace(/^\/tg/, '');
    const targetUrl = `https://api.telegram.org${targetPath}`;

    try {
        // Collect request body — Express may have already parsed it
        let body = undefined;
        if (req.method === 'POST') {
            if (req.body !== undefined && req.body !== null) {
                // Express already parsed the JSON body
                body = Buffer.from(JSON.stringify(req.body));
            } else {
                // Fallback: read raw stream
                body = await new Promise((resolve, reject) => {
                    const chunks = [];
                    req.on('data', c => chunks.push(c));
                    req.on('end', () => resolve(Buffer.concat(chunks)));
                    req.on('error', reject);
                });
            }
        }

        // Use native https module with our custom DNS-resolving agent
        const result = await new Promise((resolve, reject) => {
            const urlObj = new URL(targetUrl);
            const options = {
                hostname: urlObj.hostname,
                port: 443,
                path: urlObj.pathname + urlObj.search,
                method: req.method,
                agent: proxyAgent,
                headers: {
                    'Content-Type': req.headers['content-type'] || 'application/json',
                    'Accept': 'application/json',
                    ...(body ? { 'Content-Length': body.length } : {})
                },
                timeout: 120000 // 2 min for long polling
            };

            const proxyReq = https.request(options, (proxyRes) => {
                const chunks = [];
                proxyRes.on('data', c => chunks.push(c));
                proxyRes.on('end', () => {
                    resolve({
                        status: proxyRes.statusCode,
                        headers: proxyRes.headers,
                        body: Buffer.concat(chunks)
                    });
                });
            });

            proxyReq.on('error', reject);
            proxyReq.on('timeout', () => {
                proxyReq.destroy();
                reject(new Error('Telegram API request timed out'));
            });

            if (body) proxyReq.write(body);
            proxyReq.end();
        });

        // Forward response back to Go client
        res.writeHead(result.status, {
            'Content-Type': result.headers['content-type'] || 'application/json',
            'Connection': 'close' // Critical for fasthttp compatibility
        });
        res.end(result.body);

    } catch (err) {
        console.error('[TG Proxy Error]', err.message);
        addLog('TG-Proxy', `ERROR: ${err.message}`);
        res.writeHead(502, { 'Content-Type': 'application/json', 'Connection': 'close' });
        res.end(JSON.stringify({ ok: false, error_code: 502, description: `Proxy error: ${err.message}` }));
    }
});

// ==========================================
// WEBHOOK PROXY TO PICOCLAW
// ==========================================
app.use('/webhook', (req, res) => {
    // We forward webhook requests (e.g. from Telegram to line)
    // from this front proxy port 7860 down to picoclaw's raw port 18790
    console.log(`[Proxy] Webhook intercepted: ${req.method} ${req.url}`);

    const fetch = require('node-fetch'); // Let's use fetch if available or native http

    const targetUrl = `http://127.0.0.1:18790/webhook${req.url}`;

    // Simplistic forwarder just for telegram JSON bodies
    const options = {
        method: req.method,
        headers: {
            'Content-Type': req.headers['content-type'] || 'application/json'
        },
        body: ['GET', 'HEAD'].includes(req.method) ? undefined : JSON.stringify(req.body)
    };

    fetch(targetUrl, options)
        .then(response => response.json())
        .then(data => res.status(response.status).json(data))
        .catch(err => {
            console.error(`[Proxy] Webhook forwarding error:`, err);
            res.status(502).json({ error: "Bad Gateway" });
        });
});

// Health check needed by huggingface
app.get('/', (req, res) => {
    res.json({ status: "alive", component: "Picoclaw-Hybrid-Proxy" });
});

// Expose logs for remote debugging
app.get('/logs', (req, res) => {
    res.json(appLogs);
});

// Debug endpoint to inspect container filesystem and env vars
app.get('/debug', (req, res) => {
    const configPath = path.resolve(__dirname, 'data/config.json');
    const binaryPath = path.resolve(__dirname, 'picoclaw-bin');
    const dataDir = path.resolve(__dirname, 'data');
    const appDir = __dirname;

    const info = {
        __dirname: appDir,
        configPath,
        configExists: fs.existsSync(configPath),
        configContent: null,
        binaryExists: fs.existsSync(binaryPath),
        dataDirExists: fs.existsSync(dataDir),
        dataDirContents: null,
        appDirContents: null,
        env: {
            PICOCLAW_CONFIG: process.env.PICOCLAW_CONFIG || '(not set)',
            PICOCLAW_HOME: process.env.PICOCLAW_HOME || '(not set)',
            HOME: process.env.HOME || '(not set)',
            PORT: process.env.PORT || '(not set)',
        }
    };

    try { info.appDirContents = fs.readdirSync(appDir); } catch (e) { info.appDirContents = e.message; }
    try { info.dataDirContents = fs.readdirSync(dataDir); } catch (e) { info.dataDirContents = e.message; }
    try { info.configContent = fs.readFileSync(configPath, 'utf8'); } catch (e) { info.configContent = e.message; }

    // Also check ~/.picoclaw/config.json (the default fallback path)
    const homeConfigPath = path.join(process.env.HOME || '/root', '.picoclaw', 'config.json');
    info.homeConfigPath = homeConfigPath;
    info.homeConfigExists = fs.existsSync(homeConfigPath);
    try { info.homeConfigContent = fs.readFileSync(homeConfigPath, 'utf8'); } catch (e) { info.homeConfigContent = e.message; }

    res.json(info);
});


// Start Express
app.listen(PORT, '0.0.0.0', () => {
    console.log(`\n🚀 Proxy Server Listening on port ${PORT}`);
    startPicoclaw();
});


// ==========================================
// SPAWN PICOCLAW
// ==========================================
let picoclawProcess;

function startPicoclaw() {
    const binaryPath = path.resolve(__dirname, 'picoclaw-bin');

    if (!fs.existsSync(binaryPath)) {
        console.error(`❌ ERROR: Picoclaw binary not found at ${binaryPath}. Make sure it compiled during the Docker build stage!`);
        return;
    }

    console.log(`🌀 Spawning Picoclaw agent...`);

    // Override /etc/resolv.conf at RUNTIME so Go binary can resolve api.telegram.org
    // (K8s may overwrite the Docker-build-time version)
    try {
        fs.writeFileSync('/etc/resolv.conf', 'nameserver 8.8.8.8\nnameserver 1.1.1.1\nnameserver 8.8.4.4\n');
        console.log('✅ /etc/resolv.conf overridden with Google DNS');
    } catch (e) {
        console.warn('⚠️ Could not override /etc/resolv.conf:', e.message);
    }

    // Provide the config file explicitly
    picoclawProcess = spawn(binaryPath, ['gateway'], {
        env: {
            ...process.env,
            PICOCLAW_CONFIG: path.resolve(__dirname, 'data/config.json'),
            PICOCLAW_CHANNELS_TELEGRAM_BASE_URL: "http://127.0.0.1:7860/tg",
            // Force telego to use net/http instead of the buggy fasthttp by providing a dummy proxy env var.
            // telego switches to net/http when HTTPS_PROXY is found.
            // NO_PROXY="*" ensures the standard library immediately ignores the dummy proxy for all requests.
            HTTPS_PROXY: "http://127.0.0.1:1",
            NO_PROXY: "*"
        }
    });

    picoclawProcess.stdout.on('data', (data) => {
        const str = data.toString();
        console.log(`[Pico] ${str}`);
        addLog('Pico', str.trim());
    });
    picoclawProcess.stderr.on('data', (data) => {
        const str = data.toString();
        console.error(`[Pico] ${str}`);
        addLog('Pico ERR', str.trim());
    });

    picoclawProcess.on('close', (code) => {
        console.log(`[Pico] Process exited with code ${code}`);
        addLog('Pico EXIT', `Code ${code}`);
    });
}

// Ensure the Expo app doesn't get HTML 404s for other API endpoints
app.all('/api/*', (req, res) => {
    // Send safe empty mocks for GravityClaw endpoints like history, list sessions etc.
    res.json({ success: true, history: [], sessions: [], notifications: [], content: "Mocked by HF Proxy" });
});

// Cleanup
process.on('SIGTERM', () => {
    if (picoclawProcess) picoclawProcess.kill();
    gemini.close();
    process.exit(0);
});
process.on('SIGINT', () => {
    if (picoclawProcess) picoclawProcess.kill();
    gemini.close();
    process.exit(0);
});