package config

import (
	"fmt"
	"github.com/spf13/viper"
)

// Config stores all configuration for the application.
// The values are read by viper from a config file or environment variables.
type Config struct {
	Title          string `mapstructure:"title"`
	DefaultFile    string `mapstructure:"default_file"`
	ShowTOC        bool   `mapstructure:"show_toc"`
}

// LoadConfig reads configuration from file or environment variables.
func LoadConfig() (config Config, err error) {
	viper.AddConfigPath(".")
	viper.SetConfigName("config")
	viper.SetConfigType("toml")

	// Set default values
	viper.SetDefault("title", "GemReader")
	viper.SetDefault("default_file", "")
	viper.SetDefault("show_toc", false)

	viper.AutomaticEnv()

	if err = viper.ReadInConfig(); err != nil {
		// Don't return error if config file doesn't exist, just use defaults
		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
			// Config file not found, proceed with defaults
			err = nil
		} else {
			return config, fmt.Errorf("error reading config file: %w", err)
		}
	}

	if err = viper.Unmarshal(&config); err != nil {
		return config, fmt.Errorf("error parsing config file: %w", err)
	}

	return config, nil
}