From 9bff7be222aa27040fcb2f795103a1824239453b Mon Sep 17 00:00:00 2001
From: German Zargaryan <2526045+germanz@users.noreply.github.com>
Date: Thu, 1 Jul 2021 17:03:35 +0200
Subject: [PATCH] MINOR: Fix theme extends to respect multiple image textures
 (#2230)

Signed-off-by: German Zargaryan <2526045+germanz@users.noreply.github.com>
---
 @here/harp-mapview/lib/ThemeLoader.ts      | 38 ++++++++++++-
 @here/harp-mapview/test/ThemeLoaderTest.ts | 65 ++++++++++++++++++++++
 2 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/@here/harp-mapview/lib/ThemeLoader.ts b/@here/harp-mapview/lib/ThemeLoader.ts
index b0948844e3..4c0307f50d 100644
--- a/@here/harp-mapview/lib/ThemeLoader.ts
+++ b/@here/harp-mapview/lib/ThemeLoader.ts
@@ -10,6 +10,7 @@ import { isJsonExpr } from "@here/harp-datasource-protocol";
 import {
     Definitions,
     FlatTheme,
+    ImageTexture,
     isJsonExprReference,
     Style,
     Styles,
@@ -524,7 +525,42 @@ export class ThemeLoader {
         } else if (theme.styles) {
             styles = { ...theme.styles };
         }
-        return { ...baseTheme, ...theme, definitions, styles };
+
+        return {
+            ...baseTheme,
+            ...theme,
+            // Due to nested structure of the images/textures it needs a
+            // deep merge with a duplicate exclusion.
+            ...ThemeLoader.mergeImageTextures(theme, baseTheme),
+            definitions,
+            styles
+        };
+    }
+
+    private static mergeImageTextures(
+        theme: Theme,
+        baseTheme: Theme
+    ): Pick<FlatTheme, "images" | "imageTextures"> {
+        const images = { ...baseTheme.images, ...theme.images };
+        let imageTextures: ImageTexture[] = [];
+
+        if (!baseTheme.imageTextures && theme.imageTextures) {
+            imageTextures = theme.imageTextures;
+        } else if (baseTheme.imageTextures && !theme.imageTextures) {
+            imageTextures = baseTheme.imageTextures;
+        } else if (baseTheme.imageTextures && theme.imageTextures) {
+            imageTextures = theme.imageTextures.slice();
+            baseTheme.imageTextures.forEach(val => {
+                if (!imageTextures.find(({ name }) => name === val.name)) {
+                    imageTextures.push(val);
+                }
+            });
+        }
+
+        return {
+            images,
+            imageTextures
+        };
     }
 
     private static convertFlatTheme(theme: Theme | FlatTheme): Theme {
diff --git a/@here/harp-mapview/test/ThemeLoaderTest.ts b/@here/harp-mapview/test/ThemeLoaderTest.ts
index 1324e43ef5..9c96c89499 100644
--- a/@here/harp-mapview/test/ThemeLoaderTest.ts
+++ b/@here/harp-mapview/test/ThemeLoaderTest.ts
@@ -306,6 +306,71 @@ describe("ThemeLoader", function () {
             assert.deepEqual(result.definitions!.roadColor, { type: "color", value: "#fff" });
             assert.deepEqual(result.definitions!.waterColor, { type: "color", value: "#0f0" });
         });
+        it("supports multiple inheritance with textures", async function () {
+            const inheritedTheme: Theme = {
+                extends: [
+                    {
+                        images: {
+                            foo: {
+                                url: "icons://maki_icons.png",
+                                preload: true
+                            },
+                            baz: {
+                                url: "icons://maki_icons.png",
+                                preload: true
+                            }
+                        },
+                        imageTextures: [
+                            {
+                                name: "foo",
+                                image: "foo"
+                            },
+                            {
+                                name: "baz",
+                                image: "baz"
+                            }
+                        ]
+                    },
+                    {
+                        images: {
+                            bar: {
+                                url: "icons://maki_icons.png",
+                                preload: true
+                            },
+                            baz: {
+                                url: "icons://override.png",
+                                atlas: "icons://icons/maki_icons.json",
+                                preload: true
+                            }
+                        },
+                        imageTextures: [
+                            {
+                                name: "bar",
+                                image: "bar"
+                            },
+                            {
+                                name: "baz",
+                                image: "baz"
+                            }
+                        ]
+                    }
+                ]
+            };
+
+            const result = await ThemeLoader.load(inheritedTheme);
+            assert.exists(result.images?.foo);
+            assert.exists(result.images?.bar);
+            assert.exists(result.images?.baz);
+
+            assert.equal(result.images?.baz.url, "icons://override.png");
+            assert.exists(result.images?.baz.atlas);
+
+            assert.deepEqual(result.imageTextures?.map(imageTexture => imageTexture.name).sort(), [
+                "bar",
+                "baz",
+                "foo"
+            ]);
+        });
     });
 
     describe("#load support for inheritance and optional reference resolving", function () {