if (!Cache.prototype.add) {
  Cache.prototype.add = function add(request) {
    return this.addAll([request]);
  };
}

if (!Cache.prototype.addAll) {
  Cache.prototype.addAll = function addAll(requests) {
    var cache = this;

    // Since DOMExceptions are not constructable:
    function NetworkError(message) {
      this.name = 'NetworkError';
      this.code = 19;
      this.message = message;
    }
    NetworkError.prototype = Object.create(Error.prototype);

    return Promise.resolve()
      .then(function() {
        if (arguments.length < 1) throw new TypeError();

        // Simulate sequence<(Request or USVString)> binding:
        var sequence = [];

        requests = requests.map((request) => {
          if (request instanceof Request) {
            return request;
          } else {
            return String(request); // may throw TypeError
          }
        });

        return Promise.all(
          requests.map((request) => {
            if (typeof request === 'string') {
              request = new Request(request);
            }

            var scheme = new URL(request.url).protocol;

            if (scheme !== 'http:' && scheme !== 'https:') {
              throw new NetworkError('Invalid scheme');
            }

            return fetch(request.clone());
          }),
        );
      })
      .then((responses) => {
        // TODO: check that requests don't overwrite one another
        // (don't think this is possible to polyfill due to opaque responses)
        return Promise.all(
          responses.map((response, i) => {
            return cache.put(requests[i], response);
          }),
        );
      })
      .then(() => {
        return undefined;
      });
  };
}

if (!CacheStorage.prototype.match) {
  // This is probably vulnerable to race conditions (removing caches etc)
  CacheStorage.prototype.match = function match(request, opts) {
    var caches = this;

    return this.keys().then((cacheNames) => {
      var match;

      return cacheNames.reduce((chain, cacheName) => {
        return chain.then(() => {
          return (
            match ||
            caches
              .open(cacheName)
              .then((cache) => {
                return cache.match(request, opts);
              })
              .then((response) => {
                match = response;
                return match;
              })
          );
        });
      }, Promise.resolve());
    });
  };
}

module.exports = self.caches;