// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';

import 'base_client.dart';
import 'base_request.dart';
import 'byte_stream.dart';
import 'request.dart';
import 'response.dart';
import 'streamed_response.dart';

// TODO(nweiz): once Dart has some sort of Rack- or WSGI-like standard for
// server APIs, MockClient should conform to it.

/// A mock HTTP client designed for use when testing code that uses
/// [BaseClient]. This client allows you to define a handler callback for all
/// requests that are made through it so that you can mock a server without
/// having to send real HTTP requests.
class MockClient extends BaseClient {
  /// The handler for receiving [StreamedRequest]s and sending
  /// [StreamedResponse]s.
  final MockClientStreamHandler _handler;

  MockClient._(this._handler);

  /// Creates a [MockClient] with a handler that receives [Request]s and sends
  /// [Response]s.
  MockClient(MockClientHandler fn)
    : this._((baseRequest, bodyStream) {
      return bodyStream.toBytes().then((bodyBytes) {
        var request = new Request(baseRequest.method, baseRequest.url)
            ..persistentConnection = baseRequest.persistentConnection
            ..followRedirects = baseRequest.followRedirects
            ..maxRedirects = baseRequest.maxRedirects
            ..headers.addAll(baseRequest.headers)
            ..bodyBytes = bodyBytes
            ..finalize();

        return fn(request);
      }).then((response) {
        return new StreamedResponse(
            new ByteStream.fromBytes(response.bodyBytes),
            response.statusCode,
            contentLength: response.contentLength,
            request: baseRequest,
            headers: response.headers,
            isRedirect: response.isRedirect,
            persistentConnection: response.persistentConnection,
            reasonPhrase: response.reasonPhrase);
      });
    });

  /// Creates a [MockClient] with a handler that receives [StreamedRequest]s and
  /// sends [StreamedResponse]s.
  MockClient.streaming(MockClientStreamHandler fn)
    : this._((request, bodyStream) {
      return fn(request, bodyStream).then((response) {
        return new StreamedResponse(
            response.stream,
            response.statusCode,
            contentLength: response.contentLength,
            request: request,
            headers: response.headers,
            isRedirect: response.isRedirect,
            persistentConnection: response.persistentConnection,
            reasonPhrase: response.reasonPhrase);
      });
    });

  /// Sends a request.
  Future<StreamedResponse> send(BaseRequest request) async {
    var bodyStream = request.finalize();
    return await _handler(request, bodyStream);
  }
}

/// A handler function that receives [StreamedRequest]s and sends
/// [StreamedResponse]s. Note that [request] will be finalized.
typedef Future<StreamedResponse> MockClientStreamHandler(
    BaseRequest request, ByteStream bodyStream);

/// A handler function that receives [Request]s and sends [Response]s. Note that
/// [request] will be finalized.
typedef Future<Response> MockClientHandler(Request request);