const express = require('express');
const path = require('path');
const fs = require('fs');
const os = require('os');

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;
    }
}

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 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 apiResp = await fetch('https://api.anthropic.com/v1/messages', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'Authorization': `Bearer ${accessToken}`,
                'anthropic-version': '2023-06-01',
                'anthropic-beta': 'claude-code-20250219,oauth-2025-04-20,interleaved-thinking-2025-05-14,fine-grained-tool-streaming-2025-05-14',
                'x-app': 'cli',
                'User-Agent': 'claude-cli/2.1.114',
            },
            body: JSON.stringify({
                model: modelId,
                max_tokens: 8192,
                stream: true,
                system: "You are Claude Code, Anthropic's official CLI for Claude.",
                messages: [{ role: 'user', content: text }],
            }),
        });

        if (!apiResp.ok) {
            const errText = await apiResp.text();
            res.write(`data: ${JSON.stringify({ error: `${apiResp.status}: ${errText.substring(0, 500)}` })}\n\n`);
            return;
        }

        const reader = apiResp.body.getReader();
        const decoder = new TextDecoder();
        let buf = '';

        while (true) {
            const { done, value } = await reader.read();
            if (done) break;
            buf += decoder.decode(value, { stream: true });
            const events = buf.split('\n\n');
            buf = events.pop();
            for (const ev of events) {
                const dataLine = ev.split('\n').find(l => l.startsWith('data: '));
                if (!dataLine) continue;
                const payload = dataLine.slice(6);
                if (payload === '[DONE]') continue;
                try {
                    const obj = JSON.parse(payload);
                    if (obj.type === 'content_block_delta' && obj.delta?.type === 'text_delta') {
                        res.write(`data: ${JSON.stringify({ text: obj.delta.text })}\n\n`);
                    }
                } catch (e) {}
            }
        }
    } 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'));