package main

import "fmt"

// Provider defines the interface for GeoIP data sources.
// Each provider knows how to fetch IPv4 CIDR blocks for a given country.
type Provider interface {
	// Name returns the human-readable name of this provider.
	Name() string

	// FetchCIDRs downloads and returns a slice of IPv4 CIDR strings
	// for the given ISO 3166-1 alpha-2 country code (lowercase).
	FetchCIDRs(countryCode string) ([]string, error)
}

// NewProvider creates a Provider by name.
// Supported providers: "ipverse", "ipdeny"
func NewProvider(name string) (Provider, error) {
	switch name {
	case "ipverse":
		return &IPverseProvider{}, nil
	case "ipdeny":
		return &IPDenyProvider{}, nil
	default:
		return nil, fmt.Errorf("unknown provider %q (supported: ipverse, ipdeny)", name)
	}
}