resource/cloudflare_zone: Add unicode support

Introduce unicode support for using zone names and ensure that the
schema comparison is performed after first converting both values to
unicode. This change ensures that the punycode and unicode values are
both stored as the unicode version to match what the Cloudflare API
returns.

Closes #399

cloudflare/resource_cloudflare_zone.go

@@ -3,10 +3,11 @@ package cloudflare
 import (
 	"fmt"
 	"log"
-	"regexp"
 	"strconv"
 	"strings"
 
+	"golang.org/x/net/idna"
+
 	cloudflare "github.com/cloudflare/cloudflare-go"
 	"github.com/hashicorp/terraform/helper/schema"
 	"github.com/hashicorp/terraform/helper/validation"
@@ -40,10 +41,10 @@ func resourceCloudflareZone() *schema.Resource {
 
 		Schema: map[string]*schema.Schema{
 			"zone": {
-				Type:         schema.TypeString,
-				Required:     true,
-				ForceNew:     true,
-				ValidateFunc: validation.StringMatch(regexp.MustCompile("^([a-zA-Z0-9][\\-a-zA-Z0-9]*\\.)+[\\-a-zA-Z0-9]{2,20}$"), ""),
+				Type:             schema.TypeString,
+				Required:         true,
+				ForceNew:         true,
+				DiffSuppressFunc: zoneDiffFunc,
 			},
 			"jump_start": {
 				Type:     schema.TypeBool,
@@ -264,3 +265,16 @@ func planNameForID(id string) string {
 	}
 	return ""
 }
+
+// zoneDiffFunc is a DiffSuppressFunc that accepts two strings and then converts
+// them to unicode before performing the comparison whether or not the value has
+// changed. This ensures that zones which could be either are evaluated
+// consistently and align with what the Cloudflare API returns.
+func zoneDiffFunc(k, old, new string, d *schema.ResourceData) bool {
+	var p *idna.Profile
+	p = idna.New()
+	unicodeOld, _ := p.ToUnicode(old)
+	unicodeNew, _ := p.ToUnicode(new)
+
+	return unicodeOld == unicodeNew
+}