package chartutil

import (
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"

	"github.com/kubernetes/helm/pkg/proto/hapi/chart"
)

const (
	// ChartfileName is the default Chart file name.
	ChartfileName = "Chart.yaml"
	// ValuesfileName is the default values file name.
	ValuesfileName = "values.yaml"
	// TemplatesDir is the relative directory name for templates.
	TemplatesDir = "templates"
	// ChartsDir is the relative directory name for charts dependencies.
	ChartsDir = "charts"
)

const defaultValues = `# Default values for %s.
# This is a YAML-formatted file.
# Declare name/value pairs to be passed into your templates.
# name: value
`

// Create creates a new chart in a directory.
//
// Inside of dir, this will create a directory based on the name of
// chartfile.Name. It will then write the Chart.yaml into this directory and
// create the (empty) appropriate directories.
//
// The returned string will point to the newly created directory. It will be
// an absolute path, even if the provided base directory was relative.
//
// If dir does not exist, this will return an error.
// If Chart.yaml or any directories cannot be created, this will return an
// error. In such a case, this will attempt to clean up by removing the
// new chart directory.
func Create(chartfile *chart.Metadata, dir string) (string, error) {
	path, err := filepath.Abs(dir)
	if err != nil {
		return path, err
	}

	if fi, err := os.Stat(path); err != nil {
		return path, err
	} else if !fi.IsDir() {
		return path, fmt.Errorf("no such directory %s", path)
	}

	n := chartfile.Name
	cdir := filepath.Join(path, n)
	if fi, err := os.Stat(cdir); err == nil && !fi.IsDir() {
		return cdir, fmt.Errorf("file %s already exists and is not a directory", cdir)
	}
	if err := os.MkdirAll(cdir, 0755); err != nil {
		return cdir, err
	}

	if err := SaveChartfile(filepath.Join(cdir, ChartfileName), chartfile); err != nil {
		return cdir, err
	}

	val := []byte(fmt.Sprintf(defaultValues, chartfile.Name))
	if err := ioutil.WriteFile(filepath.Join(cdir, ValuesfileName), val, 0644); err != nil {
		return cdir, err
	}

	for _, d := range []string{TemplatesDir, ChartsDir} {
		if err := os.MkdirAll(filepath.Join(cdir, d), 0755); err != nil {
			return cdir, err
		}
	}
	return cdir, nil
}