package docker

 
 import (
 	"encoding/json"

 	"fmt"

 	"github.com/dotcloud/docker/utils"

 	"io/ioutil"

 	"os"

 	"path/filepath"

 	"sort"

 	"strings"

 )
 

 const DEFAULTTAG = "latest"

 type TagStore struct {

 	path         string
 	graph        *Graph

 	Repositories map[string]Repository

 }
 

 type Repository map[string]string

 func NewTagStore(path string, graph *Graph) (*TagStore, error) {

 	abspath, err := filepath.Abs(path)
 	if err != nil {
 		return nil, err
 	}

 	store := &TagStore{

 		path:         abspath,
 		graph:        graph,

 		Repositories: make(map[string]Repository),

 	}

 	// Load the json file if it exists, otherwise create it.
 	if err := store.Reload(); os.IsNotExist(err) {
 		if err := store.Save(); err != nil {
 			return nil, err
 		}
 	} else if err != nil {

 		return nil, err
 	}
 	return store, nil
 }
 

 func (store *TagStore) Save() error {

 	// Store the json ball
 	jsonData, err := json.Marshal(store)
 	if err != nil {
 		return err
 	}
 	if err := ioutil.WriteFile(store.path, jsonData, 0600); err != nil {
 		return err
 	}
 	return nil
 }
 

 func (store *TagStore) Reload() error {

 	jsonData, err := ioutil.ReadFile(store.path)
 	if err != nil {
 		return err
 	}
 	if err := json.Unmarshal(jsonData, store); err != nil {
 		return err
 	}
 	return nil
 }
 

 func (store *TagStore) LookupImage(name string) (*Image, error) {

 	// FIXME: standardize on returning nil when the image doesn't exist, and err for everything else
 	// (so we can pass all errors here)
 	repos, tag := utils.ParseRepositoryTag(name)
 	if tag == "" {
 		tag = DEFAULTTAG
 	}
 	img, err := store.GetImage(repos, tag)

 	if err != nil {

 		return nil, err
 	} else if img == nil {
 		if img, err = store.graph.Get(name); err != nil {

 			return nil, err
 		}
 	}
 	return img, nil
 }
 

 // Return a reverse-lookup table of all the names which refer to each image
 // Eg. {"43b5f19b10584": {"base:latest", "base:v1"}}

 func (store *TagStore) ByID() map[string][]string {
 	byID := make(map[string][]string)

 	for repoName, repository := range store.Repositories {
 		for tag, id := range repository {
 			name := repoName + ":" + tag

 			if _, exists := byID[id]; !exists {
 				byID[id] = []string{name}

 			} else {

 				byID[id] = append(byID[id], name)
 				sort.Strings(byID[id])

 			}
 		}
 	}

 	return byID

 }
 
 func (store *TagStore) ImageName(id string) string {

 	if names, exists := store.ByID()[id]; exists && len(names) > 0 {

 		return names[0]
 	}

 	return utils.TruncateID(id)

 }
 

 func (store *TagStore) DeleteAll(id string) error {

 	names, exists := store.ByID()[id]

 	if !exists || len(names) == 0 {
 		return nil
 	}
 	for _, name := range names {
 		if strings.Contains(name, ":") {
 			nameParts := strings.Split(name, ":")

 			if _, err := store.Delete(nameParts[0], nameParts[1]); err != nil {

 				return err
 			}
 		} else {

 			if _, err := store.Delete(name, ""); err != nil {

 				return err
 			}
 		}
 	}
 	return nil
 }
 

 func (store *TagStore) Delete(repoName, tag string) (bool, error) {
 	deleted := false

 	if err := store.Reload(); err != nil {

 		return false, err

 	}
 	if r, exists := store.Repositories[repoName]; exists {
 		if tag != "" {
 			if _, exists2 := r[tag]; exists2 {
 				delete(r, tag)
 				if len(r) == 0 {
 					delete(store.Repositories, repoName)
 				}

 				deleted = true

 			} else {

 				return false, fmt.Errorf("No such tag: %s:%s", repoName, tag)

 			}
 		} else {
 			delete(store.Repositories, repoName)

 			deleted = true

 		}
 	} else {
 		fmt.Errorf("No such repository: %s", repoName)
 	}

 	return deleted, store.Save()

 }
 

 func (store *TagStore) Set(repoName, tag, imageName string, force bool) error {
 	img, err := store.LookupImage(imageName)
 	if err != nil {
 		return err
 	}

 	if tag == "" {

 		tag = DEFAULTTAG

 	}

 	if err := validateRepoName(repoName); err != nil {
 		return err
 	}
 	if err := validateTagName(tag); err != nil {
 		return err

 	}

 	if err := store.Reload(); err != nil {
 		return err
 	}

 	var repo Repository

 	if r, exists := store.Repositories[repoName]; exists {
 		repo = r
 	} else {

 		repo = make(map[string]string)

 		if old, exists := store.Repositories[repoName]; exists && !force {

 			return fmt.Errorf("Conflict: Tag %s:%s is already set to %s", repoName, tag, old)

 		}

 		store.Repositories[repoName] = repo
 	}

 	repo[tag] = img.ID

 	return store.Save()
 }
 

 func (store *TagStore) Get(repoName string) (Repository, error) {

 	if err := store.Reload(); err != nil {
 		return nil, err
 	}
 	if r, exists := store.Repositories[repoName]; exists {
 		return r, nil
 	}
 	return nil, nil
 }
 

 func (store *TagStore) GetImage(repoName, tagOrID string) (*Image, error) {

 	repo, err := store.Get(repoName)
 	if err != nil {
 		return nil, err
 	} else if repo == nil {
 		return nil, nil
 	}

 	if revision, exists := repo[tagOrID]; exists {
 		return store.graph.Get(revision)
 	}
 	// If no matching tag is found, search through images for a matching image id

 	for _, revision := range repo {

 		if strings.HasPrefix(revision, tagOrID) {

 			return store.graph.Get(revision)
 		}
 	}

 	return nil, nil
 }

 
 // Validate the name of a repository
 func validateRepoName(name string) error {
 	if name == "" {
 		return fmt.Errorf("Repository name can't be empty")
 	}
 	return nil
 }
 
 // Validate the name of a tag
 func validateTagName(name string) error {
 	if name == "" {
 		return fmt.Errorf("Tag name can't be empty")
 	}
 	if strings.Contains(name, "/") || strings.Contains(name, ":") {
 		return fmt.Errorf("Illegal tag name: %s", name)
 	}
 	return nil
 }