/*
   Copyright 2014 CoreOS, Inc.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package client

import (
	"net/http"
	"net/url"

	"github.com/coreos/etcd/Godeps/_workspace/src/code.google.com/p/go.net/context"
)

type HTTPClient interface {
	Do(context.Context, HTTPAction) (*http.Response, []byte, error)
	Sync() error
}

type httpActionDo interface {
	Do(context.Context, HTTPAction) (*http.Response, []byte, error)
}

type HTTPAction interface {
	HTTPRequest(url.URL) *http.Request
}

// CancelableTransport mimics http.Transport to provide an interface which can be
// substituted for testing (since the RoundTripper interface alone does not
// require the CancelRequest method)
type CancelableTransport interface {
	http.RoundTripper
	CancelRequest(req *http.Request)
}

func NewHTTPClient(tr CancelableTransport, eps []string) (*httpClusterClient, error) {
	c := httpClusterClient{
		transport: tr,
		endpoints: make([]httpActionDo, len(eps)),
	}

	for i, ep := range eps {
		u, err := url.Parse(ep)
		if err != nil {
			return nil, err
		}

		c.endpoints[i] = &httpClient{
			transport: tr,
			endpoint:  *u,
		}
	}

	return &c, nil
}

type httpClusterClient struct {
	transport CancelableTransport
	endpoints []httpActionDo
}

func (c *httpClusterClient) Do(ctx context.Context, act HTTPAction) (*http.Response, []byte, error) {
	//TODO(bcwaldon): introduce retry logic so all endpoints are attempted
	return c.endpoints[0].Do(ctx, act)
}

func (c *httpClusterClient) Sync(ctx context.Context) error {
	mAPI := NewMembersAPI(c)
	ms, err := mAPI.List(ctx)
	if err != nil {
		return err
	}

	eps := make([]string, 0)
	for _, m := range ms {
		eps = append(eps, m.ClientURLs...)
	}
	nc, err := NewHTTPClient(c.transport, eps)
	if err != nil {
		return err
	}

	*c = *nc
	return nil
}