const WebSocket = require('ws');
const axios = require('axios');
const https = require('https');
const { version: AGENT_VERSION } = require('./package.json');
require('dotenv').config();

const WS_URL = process.env.WS_URL;
const WS_TOKEN = process.env.WS_TOKEN;

if (!WS_URL) {
    console.error('WS_URL is not set in .env');
    process.exit(1);
}

const INITIAL_BACKOFF_MS = 2000;
const MAX_BACKOFF_MS = 60000;
const PROXY_TIMEOUT_MS = 30000;

// Capabilities advertised in the hello handshake so the bot can log what
// this agent understands. Keep additive; older bots ignore unknown caps.
const AGENT_CAPABILITIES = ['insecure', 'hello'];

// Shared https.Agent used only when the bot flags a proxied request with
// `insecure: true` (e.g. reaching Store Info Web, which is served with an
// internal-CA cert Node doesn't know about). All other requests use axios's
// default (validated) TLS. Kept as a module-level singleton so we don't
// leak sockets per request.
const insecureHttpsAgent = new https.Agent({ rejectUnauthorized: false });

let ws = null;
let reconnectAttempts = 0;
let shuttingDown = false;

/**
 * If WS_TOKEN is provided, send it as an Authorization: Bearer header so the
 * secret stays out of access logs. (The server still accepts the legacy
 * ?token=... query parameter for backward compatibility.)
 */
function buildClientOptions() {
    if (!WS_TOKEN) return undefined;
    return { headers: { Authorization: `Bearer ${WS_TOKEN}` } };
}

function connect() {
    console.log(`Connecting to ${WS_URL}...`);

    ws = new WebSocket(WS_URL, buildClientOptions());

    ws.on('open', () => {
        console.log(`Remote Agent v${AGENT_VERSION} connected to wbxStoreProvision`);
        reconnectAttempts = 0;
        // One-shot hello so the bot can log which agent version + capabilities
        // are on the other end of the socket. Fire-and-forget — the bot
        // tolerates its absence for backward compatibility with v1.1 agents.
        try {
            ws.send(
                JSON.stringify({
                    type: 'hello',
                    version: AGENT_VERSION,
                    capabilities: AGENT_CAPABILITIES,
                }),
            );
        } catch (err) {
            console.error('Failed to send hello:', err.message);
        }
    });

    ws.on('message', async (data) => {
        let request;
        try {
            request = JSON.parse(data);
            if (request.action !== 'proxyRequest') return;

            const insecure = request.insecure === true;
            console.log(
                `Proxying ${request.method || 'GET'} ${request.url}${insecure ? ' (insecure TLS)' : ''}`,
            );

            const response = await axios({
                method: request.method || 'GET',
                url: request.url,
                headers: request.headers || {},
                auth: request.auth || undefined,
                data: request.body || undefined,
                timeout: PROXY_TIMEOUT_MS,
                ...(insecure ? { httpsAgent: insecureHttpsAgent } : {}),
            });

            ws.send(
                JSON.stringify({
                    requestId: request.requestId,
                    status: response.status,
                    data: response.data,
                    headers: response.headers,
                }),
            );
        } catch (err) {
            console.error('Proxy error:', err.message);
            ws.send(
                JSON.stringify({
                    requestId: request ? request.requestId : null,
                    error: err.message,
                    status: err.response?.status || 500,
                    data: err.response?.data || null,
                }),
            );
        }
    });

    ws.on('close', (code) => {
        console.log(`Disconnected (code: ${code}).`);
        if (!shuttingDown) scheduleReconnect();
    });

    ws.on('error', (err) => {
        console.error('WebSocket error:', err.message);
    });
}

function scheduleReconnect() {
    reconnectAttempts++;
    const backoff = Math.min(
        INITIAL_BACKOFF_MS * Math.pow(1.5, reconnectAttempts - 1),
        MAX_BACKOFF_MS,
    );
    console.log(
        `Reconnecting in ${Math.round(backoff / 1000)}s... (attempt ${reconnectAttempts})`,
    );
    setTimeout(connect, backoff);
}

connect();

function shutdownRemote(signal) {
    console.log(`${signal} received. Shutting down remote agent...`);
    shuttingDown = true;
    if (ws) {
        try {
            ws.close();
        } catch {
            // ignore close errors during shutdown
        }
    }
    process.exit(0);
}

process.on('SIGINT', () => shutdownRemote('SIGINT'));
process.on('SIGTERM', () => shutdownRemote('SIGTERM'));