package config

import (
	"fmt"

	mcdslconfig "git.wntrmute.dev/kyle/mcdsl/config"
)

// Config is the top-level MCNS configuration.
type Config struct {
	mcdslconfig.Base
	DNS DNSConfig `toml:"dns"`
}

// DNSConfig holds the DNS server settings.
type DNSConfig struct {
	ListenAddr string   `toml:"listen_addr"`
	Upstreams  []string `toml:"upstreams"`
}

// Load reads a TOML config file, applies environment variable overrides
// (MCNS_ prefix), sets defaults, and validates required fields.
func Load(path string) (*Config, error) {
	cfg, err := mcdslconfig.Load[Config](path, "MCNS")
	if err != nil {
		return nil, err
	}

	// Apply DNS defaults.
	if cfg.DNS.ListenAddr == "" {
		cfg.DNS.ListenAddr = ":53"
	}
	if len(cfg.DNS.Upstreams) == 0 {
		cfg.DNS.Upstreams = []string{"1.1.1.1:53", "8.8.8.8:53"}
	}

	return cfg, nil
}

// Validate implements the mcdsl config.Validator interface.
func (c *Config) Validate() error {
	if c.Database.Path == "" {
		return fmt.Errorf("database.path is required")
	}
	if c.MCIAS.ServerURL == "" {
		return fmt.Errorf("mcias.server_url is required")
	}
	if c.Server.TLSCert == "" {
		return fmt.Errorf("server.tls_cert is required")
	}
	if c.Server.TLSKey == "" {
		return fmt.Errorf("server.tls_key is required")
	}
	return nil
}