/*
Copyright 2025 The Flux authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package utils

import (
	"context"

	"github.com/google/go-containerregistry/pkg/authn"

	"github.com/fluxcd/pkg/auth"
)

// delegatedAuthenticator is an authn.Authenticator that delegates
// calls for Authorization to a provided function.
type delegatedAuthenticator struct {
	authorizationFunc func() (*authn.AuthConfig, error)
}

// Authorization implements authn.Authenticator.
func (d *delegatedAuthenticator) Authorization() (*authn.AuthConfig, error) {
	return d.authorizationFunc()
}

// GetArtifactRegistryCredentials retrieves the registry credentials for the
// specified artifact repository and provider.
func GetArtifactRegistryCredentials(ctx context.Context, providerName string,
	artifactRepository string, opts ...auth.Option) (authn.Authenticator, error) {

	provider, err := ProviderByName[auth.ArtifactRegistryCredentialsProvider](providerName)
	if err != nil {
		return nil, err
	}

	// Fetch credentials lazily by wrapping the call to auth.GetArtifactRegistryCredentials
	// in a delegatedAuthenticator. This ensures that credentials are fresh when
	// Authorization() is called on the authn.Authenticator returned by this function.
	authorizationFunc := func() (*authn.AuthConfig, error) {
		authenticator, err := auth.GetArtifactRegistryCredentials(ctx, provider, artifactRepository, opts...)
		if err != nil {
			return nil, err
		}
		return authenticator.Authorization()
	}
	return &delegatedAuthenticator{authorizationFunc: authorizationFunc}, nil
}
