// Copyright (C) MongoDB, Inc. 2017-present.
//
// 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
//
// Based on github.com/aws/aws-sdk-go by Amazon.com, Inc. with code from:
// - github.com/aws/aws-sdk-go/blob/v1.34.28/aws/credentials/static_provider.go
// - github.com/aws/aws-sdk-go/blob/v1.34.28/aws/credentials/credentials.go
// See THIRD-PARTY-NOTICES for original license terms

package awsv4

import (
	"errors"
)

// StaticProviderName provides a name of Static provider
const StaticProviderName = "StaticProvider"

var (
	// ErrStaticCredentialsEmpty is emitted when static credentials are empty.
	ErrStaticCredentialsEmpty = errors.New("EmptyStaticCreds: static credentials are empty")
)

// A Value is the AWS credentials value for individual credential fields.
type Value struct {
	// AWS Access key ID
	AccessKeyID string

	// AWS Secret Access Key
	SecretAccessKey string

	// AWS Session Token
	SessionToken string

	// Provider used to get credentials
	ProviderName string
}

// HasKeys returns if the credentials Value has both AccessKeyID and
// SecretAccessKey value set.
func (v Value) HasKeys() bool {
	return len(v.AccessKeyID) != 0 && len(v.SecretAccessKey) != 0
}

// A StaticProvider is a set of credentials which are set programmatically,
// and will never expire.
type StaticProvider struct {
	Value
}

// Retrieve returns the credentials or error if the credentials are invalid.
func (s *StaticProvider) Retrieve() (Value, error) {
	if s.AccessKeyID == "" || s.SecretAccessKey == "" {
		return Value{ProviderName: StaticProviderName}, ErrStaticCredentialsEmpty
	}

	if len(s.Value.ProviderName) == 0 {
		s.Value.ProviderName = StaticProviderName
	}
	return s.Value, nil
}