From 3b71c0f64a2d1c4b9845dfc36d9b65720a516a91 Mon Sep 17 00:00:00 2001
From: Jaco Greeff <jacogr@gmail.com>
Date: Wed, 21 Aug 2019 09:52:56 +0200
Subject: [PATCH] Check Enum index before value on construct (#1329)

---
 packages/types/src/codec/Enum.spec.ts | 80 ++++++++++++++++++++++++---
 packages/types/src/codec/Enum.ts      | 17 +++---
 2 files changed, 80 insertions(+), 17 deletions(-)

diff --git a/packages/types/src/codec/Enum.spec.ts b/packages/types/src/codec/Enum.spec.ts
index 559fcfa600..1b90cdf8b0 100644
--- a/packages/types/src/codec/Enum.spec.ts
+++ b/packages/types/src/codec/Enum.spec.ts
@@ -234,20 +234,82 @@ describe('Enum', (): void => {
           new Enum(['foo', 'bar'], 1).eq('foo')
         ).toBe(false);
       });
+
+      it('has isNone set, with correct index (i.e. no values are used)', (): void => {
+        const test = new Enum(['foo', 'bar'], 1);
+
+        expect(test.isNone).toBe(true);
+        expect(test.index).toEqual(1);
+      });
     });
   });
 
-  describe('toRawType', (): void => {
-    it('has a sane output for basic enums', (): void => {
-      expect(
-        new Enum(['foo', 'bar']).toRawType()
-      ).toEqual(JSON.stringify({ _enum: ['foo', 'bar'] }));
+  describe('index construction', (): void => {
+    it('creates enum where index is specified', (): void => {
+      const Test = Enum.with({
+        A: U32,
+        B: U32
+      });
+      const test = new Test(new U32(123), 1);
+
+      expect(test.type).toEqual('B');
+      expect((test.value as U32).toNumber()).toEqual(123);
     });
 
-    it('has a sane output for types enums', (): void => {
-      expect(
-        new Enum({ foo: Text, bar: U32 }).toRawType()
-      ).toEqual(JSON.stringify({ _enum: { foo: 'Text', bar: 'u32' } }));
+    it('creates enum when value is an enum', (): void => {
+      const Test = Enum.with({
+        A: U32,
+        B: U32
+      });
+      const test = new Test(new Test(123, 1));
+
+      expect(test.type).toEqual('B');
+      expect((test.value as U32).toNumber()).toEqual(123);
+    });
+
+    it('creates via enum with nested enums as the value', (): void => {
+      const Nest = Enum.with({
+        C: U32,
+        D: U32
+      });
+      const Test = Enum.with({
+        A: U32,
+        B: Nest
+      });
+      const test = new Test(new Nest(123, 1), 1);
+
+      expect(test.type).toEqual('B');
+      expect((test.value as Enum).type).toEqual('D');
+      expect(((test.value as Enum).value as U32).toNumber()).toEqual(123);
+    });
+  });
+
+  describe('outputs', (): void => {
+    describe('toRawType', (): void => {
+      it('has a sane output for basic enums', (): void => {
+        expect(
+          new Enum(['foo', 'bar']).toRawType()
+        ).toEqual(JSON.stringify({ _enum: ['foo', 'bar'] }));
+      });
+
+      it('has a sane output for typed enums', (): void => {
+        expect(
+          new Enum({ foo: Text, bar: U32 }).toRawType()
+        ).toEqual(JSON.stringify({ _enum: { foo: 'Text', bar: 'u32' } }));
+      });
+    });
+
+    describe('toHex', (): void => {
+      it('has a proper hex representation & length', (): void => {
+        const Test = Enum.with({
+          A: Text,
+          B: U32
+        });
+        const test = new Test(123, 1);
+
+        expect(test.toHex()).toEqual('0x017b000000');
+        expect(test.encodedLength).toEqual(1 + 4);
+      });
     });
   });
 });
diff --git a/packages/types/src/codec/Enum.ts b/packages/types/src/codec/Enum.ts
index 04ac4904fd..90a553fcd2 100644
--- a/packages/types/src/codec/Enum.ts
+++ b/packages/types/src/codec/Enum.ts
@@ -11,7 +11,8 @@ import { mapToTypeMap } from './utils';
 import Base from './Base';
 import Struct from './Struct';
 
-interface EnumConstructor<T = Codec> {
+// export interface, this is used in Enum.with, so required as public by TS
+export interface EnumConstructor<T = Codec> {
   new(value?: any, index?: number): T;
 }
 
@@ -61,7 +62,7 @@ export default class Enum extends Base<Codec> {
 
   private _isBasic: boolean;
 
-  public constructor (def: Record<string, InterfaceTypes | Constructor> | string[], value?: any, index?: number | Enum) {
+  public constructor (def: Record<string, InterfaceTypes | Constructor> | string[], value?: any, index?: number) {
     const defInfo = extractDef(def);
     const decoded = Enum.decodeEnum(defInfo.def, value, index);
 
@@ -73,13 +74,13 @@ export default class Enum extends Base<Codec> {
     this._index = this._indexes.indexOf(decoded.index) || 0;
   }
 
-  private static decodeEnum (def: TypesDef, value?: any, index?: number | Enum): Decoded {
-    if (value instanceof Enum) {
-      return Enum.createValue(def, value._index, value.raw);
-    } else if (index instanceof Enum) {
-      return Enum.createValue(def, index._index, index.raw);
-    } else if (isNumber(index)) {
+  private static decodeEnum (def: TypesDef, value?: any, index?: number): Decoded {
+    // NOTE We check the index path first, before looking at values - this allows treating
+    // the optional indexes before anything else, more-specific > less-specific
+    if (isNumber(index)) {
       return Enum.createValue(def, index, value);
+    } else if (value instanceof Enum) {
+      return Enum.createValue(def, value._index, value.raw);
     }
 
     // Or else, we just look at `value`