const express = require('express');
const path = require('path');
const fs = require('fs');
const os = require('os');
const { createRequire } = require('module');

const app = express();
app.use(express.json({ limit: '10mb' }));
app.use(express.static(path.join(__dirname, 'public')));

const MODELS = {
    sonnet: 'claude-sonnet-4-6',
    haiku: 'claude-haiku-4-5-20251001',
};

function getAccessToken() {
    const configDir = process.env.CLAUDE_CONFIG_DIR || path.join(os.homedir(), '.claude');
    const credsPath = path.join(configDir, '.credentials.json');
    try {
        const creds = JSON.parse(fs.readFileSync(credsPath, 'utf8'));
        return creds?.claudeAiOauth?.accessToken || null;
    } catch (e) {
        return null;
    }
}

function createClient(accessToken) {
    const Anthropic = require('@anthropic-ai/sdk');
    // OAuth token: use as apiKey — SDK sends x-api-key header
    // Some versions also support authToken for Bearer auth
    try {
        return new Anthropic({ authToken: accessToken });
    } catch (e) {
        return new Anthropic({ apiKey: accessToken });
    }
}

app.post('/api/chat', async (req, res) => {
    const { text, model = 'sonnet' } = req.body;
    if (!text?.trim()) return res.status(400).json({ error: 'text required' });

    const modelId = MODELS[model] || MODELS.sonnet;
    const accessToken = getAccessToken();

    if (!accessToken) {
        return res.status(500).json({ error: 'No credentials found in ' + (process.env.CLAUDE_CONFIG_DIR || '~/.claude') });
    }

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

    const heartbeat = setInterval(() => res.write(': ping\n\n'), 15000);

    try {
        const client = createClient(accessToken);
        const stream = await client.messages.stream({
            model: modelId,
            max_tokens: 8192,
            messages: [{ role: 'user', content: text }],
        });

        for await (const event of stream) {
            if (event.type === 'content_block_delta' && event.delta?.type === 'text_delta') {
                res.write(`data: ${JSON.stringify({ text: event.delta.text })}\n\n`);
            }
        }
    } catch (err) {
        console.error('[api error]', err.message);
        res.write(`data: ${JSON.stringify({ error: err.message })}\n\n`);
    } finally {
        clearInterval(heartbeat);
        res.write('data: [DONE]\n\n');
        res.end();
    }
});

app.listen(8108, () => console.log('sechenov :8108'));