/*
   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
   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 registry

import (
	"crypto/tls"
	"encoding/json"
	"io/ioutil"
	"net/http"
	"net/url"
	"strings"
	"time"

	"github.com/vmware/harbor/utils"
	registry_error "github.com/vmware/harbor/utils/registry/error"
)

// Registry holds information of a registry entity
type Registry struct {
	Endpoint *url.URL
	client   *http.Client
}

var secureHTTPTransport, insecureHTTPTransport *http.Transport

func init() {
	secureHTTPTransport = &http.Transport{
		TLSClientConfig: &tls.Config{
			InsecureSkipVerify: false,
		},
	}
	insecureHTTPTransport = &http.Transport{
		TLSClientConfig: &tls.Config{
			InsecureSkipVerify: true,
		},
	}
}

// GetHTTPTransport returns HttpTransport based on insecure configuration
func GetHTTPTransport(insecure bool) *http.Transport {
	if insecure {
		return insecureHTTPTransport
	}
	return secureHTTPTransport
}

// NewRegistry returns an instance of registry
func NewRegistry(endpoint string, client *http.Client) (*Registry, error) {
	u, err := utils.ParseEndpoint(endpoint)
	if err != nil {
		return nil, err
	}

	registry := &Registry{
		Endpoint: u,
		client:   client,
	}

	return registry, nil
}

// NewRegistryWithModifiers returns an instance of Registry according to the modifiers
func NewRegistryWithModifiers(endpoint string, insecure bool, modifiers ...Modifier) (*Registry, error) {

	transport := NewTransport(GetHTTPTransport(insecure), modifiers...)

	return NewRegistry(endpoint, &http.Client{
		Transport: transport,
		Timeout:   30 * time.Second,
	})
}

// Catalog ...
func (r *Registry) Catalog() ([]string, error) {
	repos := []string{}
	suffix := "/v2/_catalog?n=1000"
	var url string

	for len(suffix) > 0 {
		url = r.Endpoint.String() + suffix

		req, err := http.NewRequest("GET", url, nil)
		if err != nil {
			return repos, err
		}
		resp, err := r.client.Do(req)
		if err != nil {
			return nil, parseError(err)
		}

		defer resp.Body.Close()
		b, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return repos, err
		}

		if resp.StatusCode == http.StatusOK {
			catalogResp := struct {
				Repositories []string `json:"repositories"`
			}{}

			if err := json.Unmarshal(b, &catalogResp); err != nil {
				return repos, err
			}

			repos = append(repos, catalogResp.Repositories...)
			//Link: </v2/_catalog?last=library%2Fhello-world-25&n=100>; rel="next"
			link := resp.Header.Get("Link")
			if strings.HasSuffix(link, `rel="next"`) && strings.Index(link, "<") >= 0 && strings.Index(link, ">") >= 0 {
				suffix = link[strings.Index(link, "<")+1 : strings.Index(link, ">")]
			} else {
				suffix = ""
			}
		} else {
			return repos, &registry_error.Error{
				StatusCode: resp.StatusCode,
				Detail:     string(b),
			}
		}
	}
	return repos, nil
}

// Ping ...
func (r *Registry) Ping() error {
	req, err := http.NewRequest("GET", buildPingURL(r.Endpoint.String()), nil)
	if err != nil {
		return err
	}

	resp, err := r.client.Do(req)
	if err != nil {
		return parseError(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusOK {
		return nil
	}

	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return err
	}

	return &registry_error.Error{
		StatusCode: resp.StatusCode,
		Detail:     string(b),
	}
}