package credentials

import (
	"errors"
	"os"

	"github.com/alibabacloud-go/tea/tea"
)

type envProvider struct{}

var providerEnv = new(envProvider)

const (
	// EnvVarAccessKeyId is a name of ALIBABA_CLOUD_ACCESS_KEY_Id
	EnvVarAccessKeyId = "ALIBABA_CLOUD_ACCESS_KEY_Id"
	// EnvVarAccessKeySecret is a name of ALIBABA_CLOUD_ACCESS_KEY_SECRET
	EnvVarAccessKeySecret = "ALIBABA_CLOUD_ACCESS_KEY_SECRET"
)

func newEnvProvider() Provider {
	return &envProvider{}
}

func (p *envProvider) resolve() (*Config, error) {
	accessKeyId, ok1 := os.LookupEnv(EnvVarAccessKeyId)
	accessKeySecret, ok2 := os.LookupEnv(EnvVarAccessKeySecret)
	if !ok1 || !ok2 {
		return nil, nil
	}
	if accessKeyId == "" {
		return nil, errors.New(EnvVarAccessKeyId + " cannot be empty")
	}
	if accessKeySecret == "" {
		return nil, errors.New(EnvVarAccessKeySecret + " cannot be empty")
	}
	config := &Config{
		Type:            tea.String("access_key"),
		AccessKeyId:     tea.String(accessKeyId),
		AccessKeySecret: tea.String(accessKeySecret),
	}
	return config, nil
}