// processGet handles a charm file GET request after authentication.
// It returns the bundle path, the requested file path (if any), whether the
// default charm icon has been requested and an error.
func (h *charmsHandler) processGet(r *http.Request, st *state.State) (
	archivePath string,
	fileArg string,
	serveIcon bool,
	err error,
) {
	errRet := func(err error) (string, string, bool, error) {
		return "", "", false, err
	}

	query := r.URL.Query()

	// Retrieve and validate query parameters.
	curlString := query.Get("url")
	if curlString == "" {
		return errRet(errors.Errorf("expected url=CharmURL query argument"))
	}
	curl, err := charm.ParseURL(curlString)
	if err != nil {
		return errRet(errors.Trace(err))
	}
	fileArg = query.Get("file")
	if fileArg != "" {
		fileArg = path.Clean(fileArg)
	} else if query.Get("icon") == "1" {
		serveIcon = true
		fileArg = "icon.svg"
	}

	// Ensure the working directory exists.
	tmpDir := filepath.Join(h.dataDir, "charm-get-tmp")
	if err = os.MkdirAll(tmpDir, 0755); err != nil {
		return errRet(errors.Annotate(err, "cannot create charms tmp directory"))
	}

	// Use the storage to retrieve and save the charm archive.
	storage := storage.NewStorage(st.ModelUUID(), st.MongoSession())
	ch, err := st.Charm(curl)
	if err != nil {
		return errRet(errors.Annotate(err, "cannot get charm from state"))
	}

	reader, _, err := storage.Get(ch.StoragePath())
	if err != nil {
		return errRet(errors.Annotate(err, "cannot get charm from model storage"))
	}
	defer reader.Close()

	charmFile, err := ioutil.TempFile(tmpDir, "charm")
	if err != nil {
		return errRet(errors.Annotate(err, "cannot create charm archive file"))
	}
	if _, err = io.Copy(charmFile, reader); err != nil {
		cleanupFile(charmFile)
		return errRet(errors.Annotate(err, "error processing charm archive download"))
	}

	charmFile.Close()
	return charmFile.Name(), fileArg, serveIcon, nil
}

func (s *migrateCharmStorageSuite) testMigrateCharmStorage(c *gc.C, curl *charm.URL, agentConfig agent.Config) {
	curlPlaceholder := charm.MustParseURL("cs:quantal/dummy-1")
	err := s.State.AddStoreCharmPlaceholder(curlPlaceholder)
	c.Assert(err, jc.ErrorIsNil)

	curlPending := charm.MustParseURL("cs:quantal/missing-123")
	_, err = s.State.PrepareStoreCharmUpload(curlPending)
	c.Assert(err, jc.ErrorIsNil)

	var storagePath string
	var called bool
	s.PatchValue(upgrades.StateAddCharmStoragePaths, func(st *state.State, storagePaths map[*charm.URL]string) error {
		c.Assert(storagePaths, gc.HasLen, 1)
		for k, v := range storagePaths {
			c.Assert(k.String(), gc.Equals, curl.String())
			storagePath = v
		}
		called = true
		return nil
	})
	err = upgrades.MigrateCharmStorage(s.State, agentConfig)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(called, jc.IsTrue)

	storage := storage.NewStorage(s.State.EnvironUUID(), s.State.MongoSession())
	r, length, err := storage.Get(storagePath)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(r, gc.NotNil)
	defer r.Close()
	c.Assert(length, gc.Equals, int64(3))
	data, err := ioutil.ReadAll(r)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(string(data), gc.Equals, "abc")
}

func (s *charmsSuite) TestUploadRepackagesNestedArchives(c *gc.C) {
	// Make a clone of the dummy charm in a nested directory.
	rootDir := c.MkDir()
	dirPath := filepath.Join(rootDir, "subdir1", "subdir2")
	err := os.MkdirAll(dirPath, 0755)
	c.Assert(err, jc.ErrorIsNil)
	dir := testcharms.Repo.ClonedDir(dirPath, "dummy")
	// Now tweak the path the dir thinks it is in and bundle it.
	dir.Path = rootDir
	tempFile, err := ioutil.TempFile(c.MkDir(), "charm")
	c.Assert(err, jc.ErrorIsNil)
	defer tempFile.Close()
	defer os.Remove(tempFile.Name())
	err = dir.ArchiveTo(tempFile)
	c.Assert(err, jc.ErrorIsNil)

	// Try reading it as a bundle - should fail due to nested dirs.
	_, err = charm.ReadCharmArchive(tempFile.Name())
	c.Assert(err, gc.ErrorMatches, `archive file "metadata.yaml" not found`)

	// Now try uploading it - should succeeed and be repackaged.
	resp, err := s.uploadRequest(c, s.charmsURI(c, "?series=quantal"), true, tempFile.Name())
	c.Assert(err, jc.ErrorIsNil)
	expectedURL := charm.MustParseURL("local:quantal/dummy-1")
	s.assertUploadResponse(c, resp, expectedURL.String())
	sch, err := s.State.Charm(expectedURL)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(sch.URL(), gc.DeepEquals, expectedURL)
	c.Assert(sch.Revision(), gc.Equals, 1)
	c.Assert(sch.IsUploaded(), jc.IsTrue)

	// Get it from the storage and try to read it as a bundle - it
	// should succeed, because it was repackaged during upload to
	// strip nested dirs.
	storage := storage.NewStorage(s.State.EnvironUUID(), s.State.MongoSession())
	reader, _, err := storage.Get(sch.StoragePath())
	c.Assert(err, jc.ErrorIsNil)
	defer reader.Close()

	data, err := ioutil.ReadAll(reader)
	c.Assert(err, jc.ErrorIsNil)
	downloadedFile, err := ioutil.TempFile(c.MkDir(), "downloaded")
	c.Assert(err, jc.ErrorIsNil)
	defer downloadedFile.Close()
	defer os.Remove(downloadedFile.Name())
	err = ioutil.WriteFile(downloadedFile.Name(), data, 0644)
	c.Assert(err, jc.ErrorIsNil)

	bundle, err := charm.ReadCharmArchive(downloadedFile.Name())
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(bundle.Revision(), jc.DeepEquals, sch.Revision())
	c.Assert(bundle.Meta(), jc.DeepEquals, sch.Meta())
	c.Assert(bundle.Config(), jc.DeepEquals, sch.Config())
}

func (s *RepoSuite) AssertCharmUploaded(c *gc.C, curl *charm.URL) {
	ch, err := s.State.Charm(curl)
	c.Assert(err, jc.ErrorIsNil)

	storage := storage.NewStorage(s.State.EnvironUUID(), s.State.MongoSession())
	r, _, err := storage.Get(ch.StoragePath())
	c.Assert(err, jc.ErrorIsNil)
	defer r.Close()

	digest, _, err := utils.ReadSHA256(r)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(ch.BundleSha256(), gc.Equals, digest)
}

func (s *charmsSuite) TestUploadRespectsLocalRevision(c *gc.C) {
	// Make a dummy charm dir with revision 123.
	dir := testcharms.Repo.ClonedDir(c.MkDir(), "dummy")
	dir.SetDiskRevision(123)
	// Now bundle the dir.
	tempFile, err := ioutil.TempFile(c.MkDir(), "charm")
	c.Assert(err, jc.ErrorIsNil)
	defer tempFile.Close()
	defer os.Remove(tempFile.Name())
	err = dir.ArchiveTo(tempFile)
	c.Assert(err, jc.ErrorIsNil)

	// Now try uploading it and ensure the revision persists.
	resp, err := s.uploadRequest(c, s.charmsURI(c, "?series=quantal"), true, tempFile.Name())
	c.Assert(err, jc.ErrorIsNil)
	expectedURL := charm.MustParseURL("local:quantal/dummy-123")
	s.assertUploadResponse(c, resp, expectedURL.String())
	sch, err := s.State.Charm(expectedURL)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(sch.URL(), gc.DeepEquals, expectedURL)
	c.Assert(sch.Revision(), gc.Equals, 123)
	c.Assert(sch.IsUploaded(), jc.IsTrue)

	// First rewind the reader, which was reset but BundleTo() above.
	_, err = tempFile.Seek(0, 0)
	c.Assert(err, jc.ErrorIsNil)

	// Finally, verify the SHA256.
	expectedSHA256, _, err := utils.ReadSHA256(tempFile)
	c.Assert(err, jc.ErrorIsNil)

	c.Assert(sch.BundleSha256(), gc.Equals, expectedSHA256)

	storage := storage.NewStorage(s.State.EnvironUUID(), s.State.MongoSession())
	reader, _, err := storage.Get(sch.StoragePath())
	c.Assert(err, jc.ErrorIsNil)
	defer reader.Close()
	downloadedSHA256, _, err := utils.ReadSHA256(reader)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(downloadedSHA256, gc.Equals, expectedSHA256)
}

// downloadCharm downloads the given charm name from the provider storage and
// saves the corresponding zip archive to the given charmArchivePath.
func (h *charmsHandler) downloadCharm(st *state.State, curl *charm.URL, charmArchivePath string) error {
	storage := storage.NewStorage(st.ModelUUID(), st.MongoSession())
	ch, err := st.Charm(curl)
	if err != nil {
		return errors.Annotate(err, "cannot get charm from state")
	}

	// In order to avoid races, the archive is saved in a temporary file which
	// is then atomically renamed. The temporary file is created in the
	// charm cache directory so that we can safely assume the rename source and
	// target live in the same file system.
	cacheDir := filepath.Dir(charmArchivePath)
	if err = os.MkdirAll(cacheDir, 0755); err != nil {
		return errors.Annotate(err, "cannot create the charms cache")
	}
	tempCharmArchive, err := ioutil.TempFile(cacheDir, "charm")
	if err != nil {
		return errors.Annotate(err, "cannot create charm archive temp file")
	}
	defer tempCharmArchive.Close()

	// Use the storage to retrieve and save the charm archive.
	reader, _, err := storage.Get(ch.StoragePath())
	if err != nil {
		defer cleanupFile(tempCharmArchive)
		return errors.Annotate(err, "cannot get charm from model storage")
	}
	defer reader.Close()

	if _, err = io.Copy(tempCharmArchive, reader); err != nil {
		defer cleanupFile(tempCharmArchive)
		return errors.Annotate(err, "error processing charm archive download")
	}
	tempCharmArchive.Close()
	if err = os.Rename(tempCharmArchive.Name(), charmArchivePath); err != nil {
		defer cleanupFile(tempCharmArchive)
		return errors.Annotate(err, "error renaming the charm archive")
	}
	return nil
}

func uploadCharms(config UploadBinariesConfig) error {
	storage := config.GetStateStorage(config.State)
	usedCharms := getUsedCharms(config.Model)
	charmUploader := config.GetCharmUploader(config.Target)

	for _, charmUrl := range usedCharms.Values() {
		logger.Debugf("send charm %s to target", charmUrl)

		curl, err := charm.ParseURL(charmUrl)
		if err != nil {
			return errors.Annotate(err, "bad charm URL")
		}

		path, err := config.GetCharmStoragePath(config.State, curl)
		if err != nil {
			return errors.Trace(err)
		}

		reader, _, err := storage.Get(path)
		if err != nil {
			return errors.Annotate(err, "cannot get charm from storage")
		}
		defer reader.Close()

		content, cleanup, err := streamThroughTempFile(reader)
		if err != nil {
			return errors.Trace(err)
		}
		defer cleanup()

		if _, err := charmUploader.UploadCharm(curl, content); err != nil {
			return errors.Annotate(err, "cannot upload charm")
		}
	}
	return nil
}