/*
Copyright 2016 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 repo

import (
	"io/ioutil"
	"net/http"
	"path/filepath"
	"strings"

	"gopkg.in/yaml.v2"

	"k8s.io/helm/pkg/chartutil"
	"k8s.io/helm/pkg/proto/hapi/chart"
	"k8s.io/helm/pkg/provenance"
)

var indexPath = "index.yaml"

// IndexFile represents the index file in a chart repository
type IndexFile struct {
	Entries map[string]*ChartRef
}

// NewIndexFile initializes an index.
func NewIndexFile() *IndexFile {
	return &IndexFile{Entries: map[string]*ChartRef{}}
}

// Add adds a file to the index
func (i IndexFile) Add(md *chart.Metadata, filename, baseURL, digest string) {
	name := strings.TrimSuffix(filename, ".tgz")
	cr := &ChartRef{
		Name:      name,
		URL:       baseURL + "/" + filename,
		Chartfile: md,
		Digest:    digest,
		Created:   nowString(),
	}
	i.Entries[name] = cr
}

// Need both JSON and YAML annotations until we get rid of gopkg.in/yaml.v2

// ChartRef represents a chart entry in the IndexFile
type ChartRef struct {
	Name      string          `yaml:"name" json:"name"`
	URL       string          `yaml:"url" json:"url"`
	Created   string          `yaml:"created,omitempty" json:"created,omitempty"`
	Removed   bool            `yaml:"removed,omitempty" json:"removed,omitempty"`
	Digest    string          `yaml:"digest,omitempty" json:"digest,omitempty"`
	Chartfile *chart.Metadata `yaml:"chartfile" json:"chartfile"`
}

// IndexDirectory reads a (flat) directory and generates an index.
//
// It indexes only charts that have been packaged (*.tgz).
//
// It writes the results to dir/index.yaml.
func IndexDirectory(dir, baseURL string) (*IndexFile, error) {
	archives, err := filepath.Glob(filepath.Join(dir, "*.tgz"))
	if err != nil {
		return nil, err
	}
	index := NewIndexFile()
	for _, arch := range archives {
		fname := filepath.Base(arch)
		c, err := chartutil.Load(arch)
		if err != nil {
			// Assume this is not a chart.
			continue
		}
		hash, err := provenance.DigestFile(arch)
		if err != nil {
			return index, err
		}
		index.Add(c.Metadata, fname, baseURL, hash)
	}
	return index, nil
}

// DownloadIndexFile fetches the index from a repository.
func DownloadIndexFile(repoName, url, indexFilePath string) error {
	var indexURL string

	indexURL = strings.TrimSuffix(url, "/") + "/index.yaml"
	resp, err := http.Get(indexURL)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	var r IndexFile

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

	if err := yaml.Unmarshal(b, &r); err != nil {
		return err
	}

	return ioutil.WriteFile(indexFilePath, b, 0644)
}

// UnmarshalYAML unmarshals the index file
func (i *IndexFile) UnmarshalYAML(unmarshal func(interface{}) error) error {
	var refs map[string]*ChartRef
	if err := unmarshal(&refs); err != nil {
		return err
	}
	i.Entries = refs
	return nil
}

func (i *IndexFile) addEntry(name string, url string) ([]byte, error) {
	if i.Entries == nil {
		i.Entries = make(map[string]*ChartRef)
	}
	entry := ChartRef{Name: name, URL: url}
	i.Entries[name] = &entry
	out, err := yaml.Marshal(&i.Entries)
	if err != nil {
		return nil, err
	}

	return out, nil
}

// LoadIndexFile takes a file at the given path and returns an IndexFile object
func LoadIndexFile(path string) (*IndexFile, error) {
	b, err := ioutil.ReadFile(path)
	if err != nil {
		return nil, err
	}

	indexfile := NewIndexFile()
	err = yaml.Unmarshal(b, indexfile)
	if err != nil {
		return nil, err
	}

	return indexfile, nil
}