package config

import (
	"fmt"
	"strings"

	"github.com/spf13/viper"
)

// Load loads configuration from file and environment variables
func Load(configPath string) (*Config, error) {
	v := viper.New()

	// Set config file if provided
	if configPath != "" {
		v.SetConfigFile(configPath)
	} else {
		// Look for config.yaml in current directory and /etc/gohoarder
		v.SetConfigName("config")
		v.SetConfigType("yaml")
		v.AddConfigPath(".")
		v.AddConfigPath("/etc/gohoarder")
		v.AddConfigPath("$HOME/.gohoarder")
	}

	// Set environment variable prefix
	v.SetEnvPrefix("GOHOARDER")
	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
	v.AutomaticEnv()

	// Read config file
	if err := v.ReadInConfig(); err != nil {
		// If no config file found, use defaults
		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
			return nil, fmt.Errorf("failed to read config file: %w", err)
		}
	}

	// Start with defaults
	cfg := Default()

	// Unmarshal into config struct
	if err := v.Unmarshal(cfg); err != nil {
		return nil, fmt.Errorf("failed to unmarshal config: %w", err)
	}

	// Validate configuration
	if err := cfg.Validate(); err != nil {
		return nil, fmt.Errorf("config validation failed: %w", err)
	}

	return cfg, nil
}