package config

import (
	"fmt"
	"net/netip"

	"go.uber.org/multierr"
)

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

	// TrustedProxies lists IPs/CIDRs (e.g. of a fronting nginx) allowed to set
	// X-Forwarded-For/X-Real-IP when gin resolves the client IP. Empty means no
	// forwarded header is trusted, and the raw remote address is used instead.
	TrustedProxies []string `yaml:"trusted_proxies"`
}

func (sc *ServerConfig) Validate() error {
	var err error

	if sc.Address == "" {
		err = multierr.Append(err, fmt.Errorf("address is missing"))
	}

	for _, proxy := range sc.TrustedProxies {
		if _, parseErr := netip.ParsePrefix(proxy); parseErr == nil {
			continue
		}
		if _, parseErr := netip.ParseAddr(proxy); parseErr == nil {
			continue
		}
		err = multierr.Append(err, fmt.Errorf("invalid trusted_proxies entry %q: must be an IP or CIDR", proxy))
	}

	return err
}