package config

import (
	"fmt"
	"github.com/pelletier/go-toml/v2"
	"io/ioutil"
	"os"
	"path/filepath"
)

type Config[T any] struct {
	Name       string
	Filename   string
	ConfigFile *string
	Config     T
}

func getConfigDir(n string) string {
	// Find config directory

	// Linux (XDG base directory specification compliant)
	if xdg_config_home := os.Getenv("XDG_CONFIG_HOME"); xdg_config_home != "" {
		return filepath.Join(xdg_config_home, n)
	}

	return filepath.Join(os.Getenv("HOME"), ".config", n)
}

func (c *Config[T]) Get() (bool, error) {
	configDir := getConfigDir(c.Name)

	err := os.MkdirAll(configDir, 0755)
	if err != nil {
		return false, fmt.Errorf("Could not create config directory: %w", err)
	}

	configFilepath := filepath.Join(configDir, c.Filename+".toml")
	c.ConfigFile = &configFilepath

	// open file, creating it if empty
	configFile, err := os.OpenFile(*c.ConfigFile, os.O_RDWR|os.O_CREATE, 0644)
	defer configFile.Close()

	if err != nil {
		return false, fmt.Errorf("Could not open config file: %w", err)
	}

	fi, err := configFile.Stat()
	if err != nil {
		return false, fmt.Errorf("Could not get config file size: %w", err)
	}

	if fi.Size() == 0 {
		// if file is empty, write default config
		data, err := toml.Marshal(c.Config)
		if err != nil {
			return false, fmt.Errorf("Could not write default config to file: %w", err)
		}
		configFile.Write(data)
		// return nil as the user must edit the config file
		return true, nil
	} else {
		// try to parse config file
		data, err := ioutil.ReadAll(configFile)
		if err != nil {
			return false, fmt.Errorf("Could not read data from config file: %w", err)
		}
		err = toml.Unmarshal(data, &c.Config)
		if err != nil {
			return false, fmt.Errorf("Could not parse config file contents: %w", err)
		}
		return false, nil
	}

}

func (c *Config[T]) Write() error {
	data, err := toml.Marshal(c.Config)
	if err != nil {
		return fmt.Errorf("Could not marshal config: %w", err)
	}

	configFile, err := os.OpenFile(*c.ConfigFile, os.O_RDWR, 0644)
	defer configFile.Close()

	_, err = configFile.Write(data)
	if err != nil {
		return fmt.Errorf("Could not write to config file: %w", err)
	}
	return nil
}