package aws

import (
	"fmt"
	"net/url"
	"regexp"
	"strings"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/awserr"
	"github.com/aws/aws-sdk-go/service/iam"

	"github.com/hashicorp/terraform/helper/schema"
)

func resourceAwsIamRolePolicy() *schema.Resource {
	return &schema.Resource{
		// PutRolePolicy API is idempotent, so these can be the same.
		Create: resourceAwsIamRolePolicyPut,
		Update: resourceAwsIamRolePolicyPut,

		Read:   resourceAwsIamRolePolicyRead,
		Delete: resourceAwsIamRolePolicyDelete,

		Schema: map[string]*schema.Schema{
			"policy": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
			},
			"name": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
					// https://github.com/boto/botocore/blob/2485f5c/botocore/data/iam/2010-05-08/service-2.json#L8291-L8296
					value := v.(string)
					if len(value) > 128 {
						errors = append(errors, fmt.Errorf(
							"%q cannot be longer than 128 characters", k))
					}
					if !regexp.MustCompile("^[\\w+=,.@-]+$").MatchString(value) {
						errors = append(errors, fmt.Errorf(
							"%q must match [\\w+=,.@-]", k))
					}
					return
				},
			},
			"role": &schema.Schema{
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
			},
		},
	}
}

func resourceAwsIamRolePolicyPut(d *schema.ResourceData, meta interface{}) error {
	iamconn := meta.(*AWSClient).iamconn

	request := &iam.PutRolePolicyInput{
		RoleName:       aws.String(d.Get("role").(string)),
		PolicyName:     aws.String(d.Get("name").(string)),
		PolicyDocument: aws.String(d.Get("policy").(string)),
	}

	if _, err := iamconn.PutRolePolicy(request); err != nil {
		return fmt.Errorf("Error putting IAM role policy %s: %s", *request.PolicyName, err)
	}

	d.SetId(fmt.Sprintf("%s:%s", *request.RoleName, *request.PolicyName))
	return nil
}

func resourceAwsIamRolePolicyRead(d *schema.ResourceData, meta interface{}) error {
	iamconn := meta.(*AWSClient).iamconn

	role, name := resourceAwsIamRolePolicyParseId(d.Id())

	request := &iam.GetRolePolicyInput{
		PolicyName: aws.String(name),
		RoleName:   aws.String(role),
	}

	var err error
	getResp, err := iamconn.GetRolePolicy(request)
	if err != nil {
		if iamerr, ok := err.(awserr.Error); ok && iamerr.Code() == "NoSuchEntity" { // XXX test me
			d.SetId("")
			return nil
		}
		return fmt.Errorf("Error reading IAM policy %s from role %s: %s", name, role, err)
	}

	if getResp.PolicyDocument == nil {
		return fmt.Errorf("GetRolePolicy returned a nil policy document")
	}

	policy, err := url.QueryUnescape(*getResp.PolicyDocument)
	if err != nil {
		return err
	}
	return d.Set("policy", policy)
}

func resourceAwsIamRolePolicyDelete(d *schema.ResourceData, meta interface{}) error {
	iamconn := meta.(*AWSClient).iamconn

	role, name := resourceAwsIamRolePolicyParseId(d.Id())

	request := &iam.DeleteRolePolicyInput{
		PolicyName: aws.String(name),
		RoleName:   aws.String(role),
	}

	if _, err := iamconn.DeleteRolePolicy(request); err != nil {
		return fmt.Errorf("Error deleting IAM role policy %s: %s", d.Id(), err)
	}
	return nil
}

func resourceAwsIamRolePolicyParseId(id string) (roleName, policyName string) {
	parts := strings.SplitN(id, ":", 2)
	roleName = parts[0]
	policyName = parts[1]
	return
}