// Package cfg represents the overall wem application configuration.
package cfg

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

	"github.com/pelletier/go-toml"
)

const WemName = "wem"
const WemVersion = "0.8.3"

type WemConfig struct {
	CacheDir     string
	ProtonDir    string
	WineBuildDir string
	WineEnvDir   string
	WineSrcDir   string
}

func (w *WemConfig) ApplyArgs(cacheDir, protonDir, wineBuildDir, wineEnvDir, wineSrcDir string) {
	if cacheDir != "" {
		w.CacheDir = cacheDir
	}
	if protonDir != "" {
		w.ProtonDir = protonDir
	}
	if wineBuildDir != "" {
		w.WineBuildDir = wineBuildDir
	}
	if wineEnvDir != "" {
		w.WineEnvDir = wineEnvDir
	}
	if wineSrcDir != "" {
		w.WineSrcDir = wineSrcDir
	}
}

func (w *WemConfig) AsToml() (string, error) {
	b, err := toml.Marshal(w)
	if err != nil {
		return "", err
	}
	return string(b), nil
}

// EnsureDirs ensures that all dirs defined in
// the config exist, creating them as needed.
func (w *WemConfig) EnsureDirs() error {
	for _, dirPath := range []string{w.CacheDir, w.ProtonDir, w.WineBuildDir, w.WineEnvDir, w.WineSrcDir} {
		_, err := os.Stat(dirPath)
		if err != nil {
			err = os.MkdirAll(dirPath, 0755)
			if err != nil {
				return err
			}
		}
	}

	return nil
}

// Validate indicates if there are any missing config options.
func (w *WemConfig) Validate() error {
	if w.CacheDir == "" {
		return errors.New("CacheDir is not set")
	}
	if w.ProtonDir == "" {
		return errors.New("ProtonDir is not set")
	}
	if w.WineBuildDir == "" {
		return errors.New("WineBuildDir is not set")
	}
	if w.WineEnvDir == "" {
		return errors.New("WineEnvDir is not set")
	}
	if w.WineSrcDir == "" {
		return errors.New("WineSrcDir is not set")
	}
	return nil
}

func defaultWemConfig() string {
	c := fmt.Sprintf(`# Full path to the directory where archives should be cached to.
CacheDir = "%s/.local/share/wem/cache"

# Full path to the directory where Proton installations should go.
ProtonDir = "%s/.local/share/wem/proton"

# Full path to the directory where wem-built wine installations should go.
WineBuildDir = "%s/.local/share/wem/builds"

# Full path to the directory where wem envs will be created by default.
WineEnvDir = "%s/.local/share/wem/envs"

# Full path to the directory where wine source code is kept.
WineSrcDir = "%s/.local/share/wem/src"

`, os.Getenv("HOME"), os.Getenv("HOME"), os.Getenv("HOME"), os.Getenv("HOME"), os.Getenv("HOME"))
	return c
}

func CfgDir() string {
	return filepath.Join(os.Getenv("HOME"), ".config", "wem")
}

func GetConfig() (*WemConfig, error) {
	cfgPath := filepath.Join(CfgDir(), "wem.cfg")
	_, err := os.Stat(cfgPath)

	if err != nil {
		err = os.MkdirAll(filepath.Dir(cfgPath), 0755)
		if err != nil {
			return nil, err
		}
		f, err := os.Create(cfgPath)
		if err != nil {
			return nil, err
		}
		defer f.Close()

		// We do this instead of toml.Marshal()ing a struct because
		// it's nice to provide comments in the config file.
		f.WriteString(defaultWemConfig())
	}

	c, err := ioutil.ReadFile(cfgPath)
	if err != nil {
		return nil, err
	}

	cfgStr := os.ExpandEnv(string(c))
	wc := &WemConfig{}
	toml.Unmarshal([]byte(cfgStr), wc)

	err = wc.Validate()
	if err == nil {
		return wc, nil
	}
	return nil, err
}