package cli

import (
	"errors"
	"fmt"

	"github.com/mitchellh/go-homedir"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
)

// configName is the base name of the optional configuration file looked
// up in the config directory; viper tries every extension it supports, so
// ~/.sneak.yaml, ~/.sneak.json, ~/.sneak.toml, and so on all work.
const configName = ".sneak"

// loadConfig runs before every command. It reads the optional
// configuration file into a.config and makes environment variables
// available through it. The file is the one named by --config, or else
// configName in Params.ConfigDir, which defaults to the user's home
// directory. A missing default file is not an error; a file that is named
// explicitly but missing, or one that cannot be parsed, is.
func (a *app) loadConfig(cmd *cobra.Command, _ []string) error {
	configDir := a.params.ConfigDir
	if configDir == "" {
		home, err := homedir.Dir()
		if err != nil {
			return fmt.Errorf("finding home directory: %w", err)
		}

		configDir = home
	}

	config := viper.New()
	config.AddConfigPath(configDir)
	config.SetConfigName(configName)
	config.AutomaticEnv()

	if a.configFile != "" {
		config.SetConfigFile(a.configFile)
	}

	err := config.ReadInConfig()

	_, isNotFound := errors.AsType[viper.ConfigFileNotFoundError](err)
	if isNotFound {
		a.config = config

		return nil
	}

	if err != nil {
		return fmt.Errorf("reading config file: %w", err)
	}

	a.config = config

	_, err = fmt.Fprintln(
		cmd.ErrOrStderr(), "Using config file:", config.ConfigFileUsed(),
	)

	return err
}

// configFileUsed returns the path of the configuration file that
// loadConfig read, or an empty string if there was none.
func (a *app) configFileUsed() string {
	if a.config == nil {
		return ""
	}

	return a.config.ConfigFileUsed()
}