package config

import (
	"fmt"
	"os"
	"strings"

	"gopkg.in/yaml.v3"
)

type Config struct {
	Server   ServerConfig   `yaml:"server"`
	Database DatabaseConfig `yaml:"database"`
	Log      LogConfig      `yaml:"log"`
}

type ServerConfig struct {
	Address string `yaml:"address"`
}

type DatabaseConfig struct {
	URL string `yaml:"url"`
}

type LogConfig struct {
	Level  string `yaml:"level"`
	Format string `yaml:"format"`
}

func Default() Config {
	return Config{
		Server:   ServerConfig{Address: ":4533"},
		Database: DatabaseConfig{URL: ""},
		Log:      LogConfig{Level: "info", Format: "text"},
	}
}

func Load(path string) (Config, error) {
	cfg := Default()
	if path != "" {
		data, err := os.ReadFile(path)
		if err != nil {
			if !os.IsNotExist(err) {
				return cfg, fmt.Errorf("read config %q: %w", path, err)
			}
		} else if err := yaml.Unmarshal(data, &cfg); err != nil {
			return cfg, fmt.Errorf("parse config %q: %w", path, err)
		}
	}
	applyEnv(&cfg)
	return cfg, nil
}

func applyEnv(cfg *Config) {
	if v, ok := os.LookupEnv("SMARTMUSIC_SERVER_ADDRESS"); ok {
		cfg.Server.Address = v
	}
	if v, ok := os.LookupEnv("SMARTMUSIC_DATABASE_URL"); ok {
		cfg.Database.URL = v
	}
	if v, ok := os.LookupEnv("SMARTMUSIC_LOG_LEVEL"); ok {
		cfg.Log.Level = strings.ToLower(v)
	}
	if v, ok := os.LookupEnv("SMARTMUSIC_LOG_FORMAT"); ok {
		cfg.Log.Format = strings.ToLower(v)
	}
}