package aws

import (
	"os"
	"strings"
	"unicode"

	"github.com/mitchellh/goamz/aws"
)

type Config struct {
	AccessKey string `mapstructure:"access_key"`
	SecretKey string `mapstructure:"secret_key"`
	Region    string `mapstructure:"region"`
}

// AWSAuth returns a valid aws.Auth object for access to AWS services, or
// an error if the authentication couldn't be resolved.
//
// TODO(mitchellh): Test in some way.
func (c *Config) AWSAuth() (aws.Auth, error) {
	auth, err := aws.GetAuth(c.AccessKey, c.SecretKey)
	if err == nil {
		// Store the accesskey and secret that we got...
		c.AccessKey = auth.AccessKey
		c.SecretKey = auth.SecretKey
	}

	return auth, err
}

// AWSRegion returns the configured region.
//
// TODO(mitchellh): Test in some way.
func (c *Config) AWSRegion() (aws.Region, error) {
	if c.Region != "" {
		return aws.Regions[c.Region], nil
	}

	if v := os.Getenv("AWS_REGION"); v != "" {
		return aws.Regions[v], nil
	}

	md, err := aws.GetMetaData("placement/availability-zone")
	if err != nil {
		return aws.Region{}, err
	}

	region := strings.TrimRightFunc(string(md), unicode.IsLetter)
	return aws.Regions[region], nil
}