/*
Copyright 2015 The Kubernetes Authors 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 (
	"github.com/google/go-github/github"
	"github.com/kubernetes/deployment-manager/common"
	"github.com/kubernetes/deployment-manager/util"

	"fmt"
	"strings"
)

// githubRegistry implements the Registry interface and talks to github.
// The registry short URL and format determine how types are laid out in the
// registry.
type githubRegistry struct {
	name       string
	shortURL   string
	owner      string
	repository string
	path       string
	format     common.RegistryFormat
	service    RepositoryService
}

type RepositoryService interface {
	GetContents(
		owner, repo, path string,
		opt *github.RepositoryContentGetOptions,
	) (
		fileContent *github.RepositoryContent,
		directoryContent []*github.RepositoryContent,
		resp *github.Response,
		err error,
	)
}

// newGithubRegistry creates a githubRegistry.
func newGithubRegistry(name, shortURL string, format common.RegistryFormat, service RepositoryService) (*githubRegistry, error) {
	trimmed := util.TrimURLScheme(shortURL)
	owner, repository, path, err := parseGithubShortURL(trimmed)
	if err != nil {
		return nil, fmt.Errorf("cannot create Github template registry %s: %s", name, err)
	}

	return &githubRegistry{
		name:       name,
		shortURL:   trimmed,
		owner:      owner,
		repository: repository,
		path:       path,
		format:     format,
		service:    service,
	}, nil
}

func parseGithubShortURL(shortURL string) (string, string, string, error) {
	if !strings.HasPrefix(shortURL, "github.com/") {
		return "", "", "", fmt.Errorf("invalid Github short URL: %s", shortURL)
	}

	tPath := strings.TrimPrefix(shortURL, "github.com/")
	parts := strings.Split(tPath, "/")

	// Handle the case where there's no path after owner and repository.
	if len(parts) == 2 {
		return parts[0], parts[1], "", nil
	}

	// Handle the case where there's a path after owner and repository.
	if len(parts) == 3 {
		return parts[0], parts[1], parts[2], nil
	}

	return "", "", "", fmt.Errorf("invalid Github short URL: %s", shortURL)
}

// GetRegistryName returns the name of this registry
func (g githubRegistry) GetRegistryName() string {
	return g.name
}

// GetRegistryType returns the type of this registry.
func (g githubRegistry) GetRegistryType() common.RegistryType {
	return common.GithubRegistryType
}

// GetRegistryShortURL returns the short URL for this registry.
func (g githubRegistry) GetRegistryShortURL() string {
	return g.shortURL
}

// GetRegistryFormat returns the format of this registry.
func (g githubRegistry) GetRegistryFormat() common.RegistryFormat {
	return g.format
}

// GetRegistryOwner returns the owner name for this registry
func (g githubRegistry) GetRegistryOwner() string {
	return g.owner
}

// GetRegistryRepository returns the repository name for this registry.
func (g githubRegistry) GetRegistryRepository() string {
	return g.repository
}

// GetRegistryName returns the name of this registry
func (g githubRegistry) GetRegistryPath() string {
	return g.path
}