import fs from 'node:fs';
import path from 'node:path';

export const name = 'dsh-plugin-model-enhancer';
export const inject = ['webServer'];

let cachedData = null;
let lastFetchedAt = 0;
const CACHE_TTL_MS = 3600 * 1000; // 1 hour

async function getModelsDevData() {
  const now = Date.now();
  if (cachedData && now - lastFetchedAt < CACHE_TTL_MS) {
    return cachedData;
  }
  try {
    const res = await fetch('https://models.dev/api.json', {
      headers: {
        'User-Agent': 'DSH-Model-Enhancer/1.0.0'
      }
    });
    if (!res.ok) {
      throw new Error(`Failed to fetch models.dev: HTTP ${res.status}`);
    }
    const json = await res.json();
    cachedData = json;
    lastFetchedAt = now;
    return json;
  } catch (err) {
    if (cachedData) {
      // Fallback to stale cache if network fails
      return cachedData;
    }
    throw err;
  }
}

export function apply(ctx) {
  // 1. Models.dev Cache Proxy
  ctx.effect(() => {
    return ctx.webServer.register({
      kind: 'exact',
      path: '/api/models-dev/models',
      handler: async (req, res) => {
        res.setHeader('Access-Control-Allow-Origin', '*');
        res.setHeader('Access-Control-Allow-Methods', 'GET, OPTIONS');
        res.setHeader('Access-Control-Allow-Headers', 'Content-Type');

        if (req.method === 'OPTIONS') {
          res.writeHead(204);
          res.end();
          return;
        }

        if (req.method !== 'GET') {
          res.writeHead(405, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ error: 'Method Not Allowed' }));
          return;
        }

        try {
          const data = await getModelsDevData();
          res.writeHead(200, {
            'Content-Type': 'application/json',
            'Cache-Control': 'public, max-age=3600'
          });
          res.end(JSON.stringify(data));
        } catch (err) {
          ctx.logger?.error?.('[model-enhancer] Error fetching models.dev:', err);
          res.writeHead(500, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ error: err.message || 'Internal Server Error' }));
        }
      }
    });
  }, 'dsh-plugin-model-enhancer: webServer proxy route');

  // 2. Binary / Large Document File Upload to Workspace Endpoint
  ctx.effect(() => {
    return ctx.webServer.register({
      kind: 'exact',
      path: '/api/model-enhancer/upload',
      handler: async (req, res) => {
        res.setHeader('Access-Control-Allow-Origin', '*');
        res.setHeader('Access-Control-Allow-Methods', 'POST, OPTIONS');
        res.setHeader('Access-Control-Allow-Headers', 'Content-Type, X-Filename');

        if (req.method === 'OPTIONS') {
          res.writeHead(204);
          res.end();
          return;
        }

        if (req.method !== 'POST') {
          res.writeHead(405, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ error: 'Method Not Allowed' }));
          return;
        }

        try {
          const urlObj = new URL(req.url, 'http://127.0.0.1');
          const rawName = req.headers['x-filename'] || urlObj.searchParams.get('filename') || `upload_${Date.now()}.bin`;
          const decodedName = decodeURIComponent(rawName);
          const safeName = path.basename(decodedName);

          const uploadDir = path.join(process.cwd(), 'uploads');
          fs.mkdirSync(uploadDir, { recursive: true });

          const targetPath = path.join(uploadDir, safeName);
          const writeStream = fs.createWriteStream(targetPath);

          let totalBytes = 0;
          req.on('data', (chunk) => {
            totalBytes += chunk.length;
          });

          req.pipe(writeStream);

          writeStream.on('finish', () => {
            res.writeHead(200, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({
              ok: true,
              filename: safeName,
              path: path.join('uploads', safeName),
              size: totalBytes
            }));
          });

          writeStream.on('error', (err) => {
            ctx.logger?.error?.('[model-enhancer] Upload stream error:', err);
            res.writeHead(500, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: err.message || 'File write error' }));
          });
        } catch (err) {
          ctx.logger?.error?.('[model-enhancer] Upload handler error:', err);
          res.writeHead(500, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ error: err.message || 'Upload processing error' }));
        }
      }
    });
  }, 'dsh-plugin-model-enhancer: workspace file upload endpoint');
}