/*
   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 (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	"github.com/docker/distribution/manifest/schema1"
	"github.com/docker/distribution/manifest/schema2"

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

// Repository holds information of a repository entity
type Repository struct {
	Name     string
	Endpoint *url.URL
	client   *http.Client
}

// NewRepository returns an instance of Repository
func NewRepository(name, endpoint string, client *http.Client) (*Repository, error) {
	name = strings.TrimSpace(name)

	u, err := utils.ParseEndpoint(endpoint)
	if err != nil {
		return nil, err
	}

	repository := &Repository{
		Name:     name,
		Endpoint: u,
		client:   client,
	}

	return repository, nil
}

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

	transport := NewTransport(GetHTTPTransport(insecure), modifiers...)
	return NewRepository(name, endpoint, &http.Client{
		Transport: transport,
		Timeout:   30 * time.Second,
	})
}

func parseError(err error) error {
	if urlErr, ok := err.(*url.Error); ok {
		if regErr, ok := urlErr.Err.(*registry_error.Error); ok {
			return regErr
		}
	}
	return err
}

// ListTag ...
func (r *Repository) ListTag() ([]string, error) {
	tags := []string{}
	req, err := http.NewRequest("GET", buildTagListURL(r.Endpoint.String(), r.Name), nil)
	if err != nil {
		return tags, err
	}

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

	defer resp.Body.Close()

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

	if resp.StatusCode == http.StatusOK {
		tagsResp := struct {
			Tags []string `json:"tags"`
		}{}

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

		tags = tagsResp.Tags

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

}

// ManifestExist ...
func (r *Repository) ManifestExist(reference string) (digest string, exist bool, err error) {
	req, err := http.NewRequest("HEAD", buildManifestURL(r.Endpoint.String(), r.Name, reference), nil)
	if err != nil {
		return
	}

	req.Header.Add(http.CanonicalHeaderKey("Accept"), schema1.MediaTypeManifest)
	req.Header.Add(http.CanonicalHeaderKey("Accept"), schema2.MediaTypeManifest)

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

	defer resp.Body.Close()

	if resp.StatusCode == http.StatusOK {
		exist = true
		digest = resp.Header.Get(http.CanonicalHeaderKey("Docker-Content-Digest"))
		return
	}

	if resp.StatusCode == http.StatusNotFound {
		return
	}

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

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

// PullManifest ...
func (r *Repository) PullManifest(reference string, acceptMediaTypes []string) (digest, mediaType string, payload []byte, err error) {
	req, err := http.NewRequest("GET", buildManifestURL(r.Endpoint.String(), r.Name, reference), nil)
	if err != nil {
		return
	}

	for _, mediaType := range acceptMediaTypes {
		req.Header.Add(http.CanonicalHeaderKey("Accept"), mediaType)
	}

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

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

	if resp.StatusCode == http.StatusOK {
		digest = resp.Header.Get(http.CanonicalHeaderKey("Docker-Content-Digest"))
		mediaType = resp.Header.Get(http.CanonicalHeaderKey("Content-Type"))
		payload = b
		return
	}

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

	return
}

// PushManifest ...
func (r *Repository) PushManifest(reference, mediaType string, payload []byte) (digest string, err error) {
	req, err := http.NewRequest("PUT", buildManifestURL(r.Endpoint.String(), r.Name, reference),
		bytes.NewReader(payload))
	if err != nil {
		return
	}
	req.Header.Set(http.CanonicalHeaderKey("Content-Type"), mediaType)

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

	defer resp.Body.Close()

	if resp.StatusCode == http.StatusCreated {
		digest = resp.Header.Get(http.CanonicalHeaderKey("Docker-Content-Digest"))
		return
	}

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

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

	return
}

// DeleteManifest ...
func (r *Repository) DeleteManifest(digest string) error {
	req, err := http.NewRequest("DELETE", buildManifestURL(r.Endpoint.String(), r.Name, digest), 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.StatusAccepted {
		return nil
	}

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

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

// DeleteTag ...
func (r *Repository) DeleteTag(tag string) error {
	digest, exist, err := r.ManifestExist(tag)
	if err != nil {
		return err
	}

	if !exist {
		return &registry_error.Error{
			StatusCode: http.StatusNotFound,
		}
	}

	return r.DeleteManifest(digest)
}

// BlobExist ...
func (r *Repository) BlobExist(digest string) (bool, error) {
	req, err := http.NewRequest("HEAD", buildBlobURL(r.Endpoint.String(), r.Name, digest), nil)
	if err != nil {
		return false, err
	}

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

	defer resp.Body.Close()

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

	if resp.StatusCode == http.StatusNotFound {
		return false, nil
	}

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

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

// PullBlob : client must close data if it is not nil
func (r *Repository) PullBlob(digest string) (size int64, data io.ReadCloser, err error) {
	req, err := http.NewRequest("GET", buildBlobURL(r.Endpoint.String(), r.Name, digest), nil)
	if err != nil {
		return
	}

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

	if resp.StatusCode == http.StatusOK {
		contengLength := resp.Header.Get(http.CanonicalHeaderKey("Content-Length"))
		size, err = strconv.ParseInt(contengLength, 10, 64)
		if err != nil {
			return
		}
		data = resp.Body
		return
	}
	// can not close the connect if the status code is 200
	defer resp.Body.Close()

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

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

	return
}

func (r *Repository) initiateBlobUpload(name string) (location, uploadUUID string, err error) {
	req, err := http.NewRequest("POST", buildInitiateBlobUploadURL(r.Endpoint.String(), r.Name), nil)
	req.Header.Set(http.CanonicalHeaderKey("Content-Length"), "0")

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

	defer resp.Body.Close()

	if resp.StatusCode == http.StatusAccepted {
		location = resp.Header.Get(http.CanonicalHeaderKey("Location"))
		uploadUUID = resp.Header.Get(http.CanonicalHeaderKey("Docker-Upload-UUID"))
		return
	}

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

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

	return
}

func (r *Repository) monolithicBlobUpload(location, digest string, size int64, data io.Reader) error {
	req, err := http.NewRequest("PUT", buildMonolithicBlobUploadURL(location, digest), data)
	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.StatusCreated {
		return nil
	}

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

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

// PushBlob ...
func (r *Repository) PushBlob(digest string, size int64, data io.Reader) error {
	location, _, err := r.initiateBlobUpload(r.Name)
	if err != nil {
		return err
	}
	return r.monolithicBlobUpload(location, digest, size, data)
}

// DeleteBlob ...
func (r *Repository) DeleteBlob(digest string) error {
	req, err := http.NewRequest("DELETE", buildBlobURL(r.Endpoint.String(), r.Name, digest), 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.StatusAccepted {
		return nil
	}

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

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

func buildPingURL(endpoint string) string {
	return fmt.Sprintf("%s/v2/", endpoint)
}

func buildTagListURL(endpoint, repoName string) string {
	return fmt.Sprintf("%s/v2/%s/tags/list", endpoint, repoName)
}

func buildManifestURL(endpoint, repoName, reference string) string {
	return fmt.Sprintf("%s/v2/%s/manifests/%s", endpoint, repoName, reference)
}

func buildBlobURL(endpoint, repoName, reference string) string {
	return fmt.Sprintf("%s/v2/%s/blobs/%s", endpoint, repoName, reference)
}

func buildInitiateBlobUploadURL(endpoint, repoName string) string {
	return fmt.Sprintf("%s/v2/%s/blobs/uploads/", endpoint, repoName)
}

func buildMonolithicBlobUploadURL(location, digest string) string {
	query := ""
	if strings.ContainsRune(location, '?') {
		query = "&"
	} else {
		query = "?"
	}
	query += fmt.Sprintf("digest=%s", digest)
	return fmt.Sprintf("%s%s", location, query)
}