import * as http from 'http';
import { Product } from './interfaces/ISettings';
import verifyProductName from './verifyProductName';

export default function getFileContents(product: Product, from: number, to: number): Promise<Buffer> {
  return new Promise((resolve, reject) => {
    if (!verifyProductName(product)) {
      return reject(`"${product}" is not a valid product.`);
    }
    //TODO: also verify from and to

    //Generate URL
    const path = `/patch/${product}/${product}_${from}to${to}.solidpkg`;

    const request = http.request({
      family: 4,
      host: 'cdn-patch.swtor.com',
      path,
    }, (response) => {
      if (response.statusCode !== 200) {
        return reject(`Expected status code 200 but received ${response.statusCode}`);
      }
      const headerLength = Number(response.headers['content-length']);

      const chunkList: Buffer[] = [];
      let totalLength = 0;
      response.on('data', (chunk: Buffer) => {
        chunkList.push(chunk);
        totalLength += chunk.length;
      });
      response.on('end', () => {
        if (totalLength !== headerLength) {
          return reject(`Expected length ${headerLength} but received ${totalLength}`);
        }
        const fileContents = Buffer.concat(chunkList, totalLength);
        resolve(fileContents);
      });
    });

    request.on('error', (e) => {
      reject(e);
    });
    request.end();
  });
}