mugit @ f70e150

package config

import (

	"errors"

	"fmt"

	"os"

	"path/filepath"

	"strings"

	"time"

	"gopkg.in/yaml.v2"

)

var (

	ErrConfigNotFound = errors.New("no config file found")

	ErrUnsetEnv       = errors.New("environment variable is not set")

	ErrFileNotFound   = errors.New("provided file path is invalid")

)

type ServerConfig struct {

	Host string `yaml:"host"`

	Port int    `yaml:"port"`

}

type MetaConfig struct {

	Title       string `yaml:"title"`

	Description string `yaml:"description"`

	Host        string `yaml:"host"`

	Modt        string `yaml:"modt"`

}

type RepoConfig struct {

	Dir     string   `yaml:"dir"`

	Readmes []string `yaml:"readmes"`

}

type SSHConfig struct {

	Enable  bool     `yaml:"enable"`

	User    string   `yaml:"user"`

	Keys    []string `yaml:"keys"`

	LogFile string   `yaml:"log_file"`

}

type MirrorConfig struct {

	Enable      bool          `yaml:"enable"`

	Interval    time.Duration `yaml:"interval"`

	GithubToken string        `yaml:"github_token"`

}

type CacheConfig struct {

	HomePage time.Duration `yaml:"home_page"`

	Readme   time.Duration `yaml:"readme"`

	Diff     time.Duration `yaml:"diff"`

}

type Config struct {

	Server ServerConfig `yaml:"server"`

	Meta   MetaConfig   `yaml:"meta"`

	Repo   RepoConfig   `yaml:"repo"`

	SSH    SSHConfig    `yaml:"ssh"`

	Mirror MirrorConfig `yaml:"mirror"`

	Cache  CacheConfig  `yaml:"cache"`

}

func Load(fpath string) (*Config, error) {

	configBytes, err := os.ReadFile(fpath)

	if err != nil {

		return nil, err

	}

	var config Config

	if cerr := yaml.Unmarshal(configBytes, &config); cerr != nil {

		return nil, fmt.Errorf("parsing config: %w", cerr)

	}

	if config.Repo.Dir, err = filepath.Abs(config.Repo.Dir); err != nil {

		return nil, err

	}

	config.ensureDefaults()

	if perr := config.parseValues(); perr != nil {

		return nil, perr

	}

	if verr := config.validate(); verr != nil {

		return nil, verr

	}

	return &config, nil

}

// PathOrDefault uses userPath, if it's "", or invalid path, will default to one of those(in priority order)

// 1. ./config.yaml

// 2. /etc/mugit.yaml

// 3. /var/lib/mugit/config.yaml

func PathOrDefault(userPath string) string {

	return pathOrDefaultWithCandidates(userPath, []string{

		"./config.yaml",

		"/etc/mugit.yaml",

		"/var/lib/mugit/config.yaml",

	})

}

func pathOrDefaultWithCandidates(path string, candidates []string) string {

	if isFileExists(path) {

		return path

	}

	for _, fpath := range candidates {

		if isFileExists(fpath) {

			return fpath

		}

	}

	return ""

}

func (c *Config) ensureDefaults() {

	// http

	if c.Server.Port == 0 {

		c.Server.Port = 8080

	}

	// meta

	if c.Meta.Title == "" {

		c.Meta.Title = "my mugit"

	}

	// repos

	if len(c.Repo.Readmes) == 0 {

		c.Repo.Readmes = []string{

			"README.md", "readme.md",

			"README.html", "readme.html",

			"README.txt", "readme.txt",

			"readme",

		}

	}

	// ssh

	if c.SSH.User == "" {

		c.SSH.User = "git"

	}

	if c.SSH.LogFile == "" {

		c.SSH.LogFile = filepath.Join(c.Repo.Dir, "mugit-ssh.log")

	}

	// mirroring

	if c.Mirror.Interval == 0 {

		c.Mirror.Interval = 8 * time.Hour

	}

	// cache

	if c.Cache.HomePage == 0 {

		c.Cache.HomePage = 5 * time.Minute

	}

	if c.Cache.Readme == 0 {

		c.Cache.Readme = 1 * time.Minute

	}

	if c.Cache.Diff == 0 {

		c.Cache.Diff = 15 * time.Minute

	}

}

func (c *Config) parseValues() error {

	if c.Mirror.Enable {

		ghToken, err := parseValue(c.Mirror.GithubToken)

		if err != nil {

			return err

		}

		c.Mirror.GithubToken = ghToken

	}

	return nil

}

func parseValue(value string) (string, error) {

	envPrefix := "$env:"

	filePrefix := "$file:"

	switch {

	case strings.HasPrefix(value, envPrefix):

		env := os.Getenv(os.ExpandEnv(value[len(envPrefix):]))

		if env == "" {

			return "", ErrUnsetEnv

		}

		return env, nil

	case strings.HasPrefix(value, filePrefix):

		// supports only absolute paths

		fpath := value[len(filePrefix):]

		if !isFileExists(fpath) {

			return "", ErrFileNotFound

		}

		data, err := os.ReadFile(fpath)

		if err != nil {

			return "", err

		}

		return strings.TrimSpace(string(data)), nil

	default:

		return value, nil

	}

}

func isFileExists(path string) bool {

	_, err := os.Stat(path)

	return err == nil

}

func isDirExists(path string) bool {

	i, err := os.Stat(path)

	if err != nil {

		return false

	}

	return i.IsDir()

}