/*
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 session

import (
	"fmt"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/credentials/stscreds"
	"github.com/aws/aws-sdk-go/aws/request"
	awssess "github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/sts"
	ctrl "sigs.k8s.io/controller-runtime"
)

// Config contains configuration to create a new AWS provider.
type Config struct {
	AssumeRole string
	Region     string
	APIRetries int
}

var log = ctrl.Log.WithName("provider").WithName("aws")

// New creates a new aws session based on the supported input methods.
// https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html#specifying-credentials
func New(sak, aks, region, role string, stsprovider STSProvider) (*awssess.Session, error) {
	config := aws.NewConfig()
	sessionOpts := awssess.Options{
		Config: *config,
	}
	if sak != "" && aks != "" {
		sessionOpts.Config.Credentials = credentials.NewStaticCredentials(aks, sak, "")
		sessionOpts.SharedConfigState = awssess.SharedConfigDisable
	}
	sess, err := awssess.NewSessionWithOptions(sessionOpts)
	if err != nil {
		return nil, fmt.Errorf("unable to create aws session: %w", err)
	}
	if region != "" {
		log.V(1).Info("using region", "region", region)
		sess.Config.WithRegion(region)
	}

	if role != "" {
		log.V(1).Info("assuming role", "role", role)
		stsclient := stsprovider(sess)
		sess.Config.WithCredentials(stscreds.NewCredentialsWithClient(stsclient, role))
	}
	sess.Handlers.Build.PushBack(request.WithAppendUserAgent("external-secrets"))
	return sess, nil
}

type STSProvider func(*awssess.Session) stscreds.AssumeRoler

func DefaultSTSProvider(sess *awssess.Session) stscreds.AssumeRoler {
	return sts.New(sess)
}