// NewCmdStartBuild implements the OpenShift cli start-build command
func NewCmdStartBuild(fullName string, f *clientcmd.Factory, out io.Writer) *cobra.Command {
	webhooks := util.StringFlag{}
	webhooks.Default("none")

	cmd := &cobra.Command{
		Use:     "start-build (BUILDCONFIG | --from-build=BUILD)",
		Short:   "Starts a new build",
		Long:    startBuildLong,
		Example: fmt.Sprintf(startBuildExample, fullName),
		Run: func(cmd *cobra.Command, args []string) {
			err := RunStartBuild(f, out, cmd, args, webhooks)
			cmdutil.CheckErr(err)
		},
	}
	cmd.Flags().String("from-build", "", "Specify the name of a build which should be re-run")
	cmd.Flags().Bool("follow", false, "Start a build and watch its logs until it completes or fails")
	cmd.Flags().Var(&webhooks, "list-webhooks", "List the webhooks for the specified BuildConfig or build; accepts 'all', 'generic', or 'github'")
	cmd.Flags().String("from-webhook", "", "Specify a webhook URL for an existing BuildConfign to trigger")
	cmd.Flags().String("git-post-receive", "", "The contents of the post-receive hook to trigger a build")
	cmd.Flags().String("git-repository", "", "The path to the git repository for post-receive; defaults to the current directory")
	return cmd
}

// RunStartBuild contains all the necessary functionality for the OpenShift cli start-build command
func RunStartBuild(f *clientcmd.Factory, out io.Writer, cmd *cobra.Command, args []string, webhooks util.StringFlag) error {
	webhook := cmdutil.GetFlagString(cmd, "from-webhook")
	buildName := cmdutil.GetFlagString(cmd, "from-build")
	follow := cmdutil.GetFlagBool(cmd, "follow")

	switch {
	case len(webhook) > 0:
		if len(args) > 0 || len(buildName) > 0 {
			return cmdutil.UsageError(cmd, "The '--from-webhook' flag is incompatible with arguments or '--from-build'")
		}
		path := cmdutil.GetFlagString(cmd, "git-repository")
		postReceivePath := cmdutil.GetFlagString(cmd, "git-post-receive")
		repo := git.NewRepository()
		return RunStartBuildWebHook(f, out, webhook, path, postReceivePath, repo)
	case len(args) != 1 && len(buildName) == 0:
		return cmdutil.UsageError(cmd, "Must pass a name of a BuildConfig or specify build name with '--from-build' flag")
	}

	name := buildName
	isBuild := true
	if len(name) == 0 {
		name = args[0]
		isBuild = false
	}

	if webhooks.Provided() {
		return RunListBuildWebHooks(f, out, cmd.Out(), name, isBuild, webhooks.String())
	}

	client, _, err := f.Clients()
	if err != nil {
		return err
	}

	namespace, err := f.DefaultNamespace()
	if err != nil {
		return err
	}

	request := &buildapi.BuildRequest{
		ObjectMeta: kapi.ObjectMeta{Name: name},
	}
	var newBuild *buildapi.Build
	if isBuild {
		if newBuild, err = client.Builds(namespace).Clone(request); err != nil {
			return err
		}
	} else {
		if newBuild, err = client.BuildConfigs(namespace).Instantiate(request); err != nil {
			return err
		}
	}
	fmt.Fprintf(out, "%s\n", newBuild.Name)

	if follow {
		opts := buildapi.BuildLogOptions{
			Follow: true,
			NoWait: false,
		}
		rd, err := client.BuildLogs(namespace).Get(newBuild.Name, opts).Stream()
		if err != nil {
			return fmt.Errorf("error getting logs: %v", err)
		}
		defer rd.Close()
		_, err = io.Copy(out, rd)
		if err != nil {
			return fmt.Errorf("error streaming logs: %v", err)
		}
	}
	return nil
}