package main

import (
	// Standard
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"regexp"
	"runtime"
)

// getConfigDir figures out the path of the configuration directory.
// Uses env variables appropriate for the OS, or uses the user provided path.
func getConfigDir() (string, error) {
	var envName string
	var path []string

	// User-provided directory takes priority over default directory.
	if flagConfigDir != "" {
		return flagConfigDir, nil
	}

	switch runtime.GOOS {
	case "linux", "darwin":
		envName = "HOME"
		path = []string{".config", "launcher"}
	case "windows":
		envName = "USERPROFILE"
		path = []string{"launcher"}
	default:
		return "", fmt.Errorf("Unknown OS: %s", runtime.GOOS)
	}

	home := os.Getenv(envName)
	if home == "" {
		return "", fmt.Errorf("%s is not set", envName)
	}
	path = append([]string{home}, path...)
	configDir := filepath.Join(path...)
	return configDir, nil
}


// getCommandsetFiles find the home directory and retrieves YAML files
// not hidden.
func getCommandsetFiles() ([]string, error) {
	dir, err := getConfigDir()
	if err != nil {
		return nil, err
	}

	fileInfos, err := ioutil.ReadDir(dir)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%s\n", err)
		os.Exit(1)
	}

	// No filenamer starting with '.', and no filenames not ending in
	// ".yaml" or ".yml".
	var filenames []string
	var filename string
	for _, entry := range fileInfos {
		fName := entry.Name()
		// Shortest considered file would by something like 'a.yml',
		// 5 characters.
		if len(fName) < 5 || fName[0] == '.' {
			continue
		}

		if m, _ := regexp.Match("(?i)\\.ya?ml", []byte(fName)); m {
			filename = filepath.Join(dir, entry.Name())
			filenames = append(filenames, filename)
		}
	}
	return filenames, nil
}