feat: add theme support for code editor

- Add light theme with GitHub-inspired colors
- Add high contrast theme with VS Code high contrast colors
- Dynamically switch themes when user changes app theme
- Use CodeMirror Compartment for efficient theme reconfiguration
- Support dark, light, high-contrast, and custom (uses dark) themes

src/lib/components/editor/CodeEditor.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
   import { onMount, onDestroy } from "svelte";
   import { EditorView, basicSetup } from "codemirror";
-  import { EditorState } from "@codemirror/state";
+  import { EditorState, Compartment } from "@codemirror/state";
   import { keymap } from "@codemirror/view";
   import { oneDark } from "@codemirror/theme-one-dark";
   import { javascript } from "@codemirror/lang-javascript";
@@ -32,7 +32,10 @@
   import { toml } from "@codemirror/legacy-modes/mode/toml";
   import { dockerFile } from "@codemirror/legacy-modes/mode/dockerfile";
   import { powerShell } from "@codemirror/legacy-modes/mode/powershell";
+  import { HighlightStyle, syntaxHighlighting } from "@codemirror/language";
+  import { tags } from "@lezer/highlight";
   import { editorStore } from "$lib/stores/editor";
+  import { configStore } from "$lib/stores/config";
   import type { EditorTab } from "$lib/types/editor";
   import type { Extension } from "@codemirror/state";
 
@@ -40,6 +43,274 @@
 
   let editorContainer: HTMLDivElement;
   let view: EditorView | null = null;
+  let themeCompartment = new Compartment();
+
+  // Subscribe to theme changes
+  const config = configStore.config;
+
+  // Light theme
+  const lightTheme = EditorView.theme(
+    {
+      "&": {
+        backgroundColor: "#ffffff",
+        color: "#24292e",
+      },
+      ".cm-content": {
+        caretColor: "#24292e",
+      },
+      ".cm-cursor, .cm-dropCursor": {
+        borderLeftColor: "#24292e",
+      },
+      "&.cm-focused .cm-selectionBackground, .cm-selectionBackground, .cm-content ::selection": {
+        backgroundColor: "#c8d3f5",
+      },
+      ".cm-panels": {
+        backgroundColor: "#f6f8fa",
+        color: "#24292e",
+      },
+      ".cm-panels.cm-panels-top": {
+        borderBottom: "1px solid #e1e4e8",
+      },
+      ".cm-panels.cm-panels-bottom": {
+        borderTop: "1px solid #e1e4e8",
+      },
+      ".cm-searchMatch": {
+        backgroundColor: "#ffdf5d",
+        outline: "1px solid #c4a000",
+      },
+      ".cm-searchMatch.cm-searchMatch-selected": {
+        backgroundColor: "#c4a000",
+      },
+      ".cm-activeLine": {
+        backgroundColor: "#f6f8fa",
+      },
+      ".cm-selectionMatch": {
+        backgroundColor: "#c8d3f5",
+      },
+      ".cm-matchingBracket, .cm-nonmatchingBracket": {
+        backgroundColor: "#c8d3f5",
+        outline: "1px solid #888",
+      },
+      ".cm-gutters": {
+        backgroundColor: "#f6f8fa",
+        color: "#6a737d",
+        border: "none",
+        borderRight: "1px solid #e1e4e8",
+      },
+      ".cm-activeLineGutter": {
+        backgroundColor: "#e1e4e8",
+      },
+      ".cm-foldPlaceholder": {
+        backgroundColor: "transparent",
+        border: "none",
+        color: "#6a737d",
+      },
+      ".cm-tooltip": {
+        border: "1px solid #e1e4e8",
+        backgroundColor: "#ffffff",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:before": {
+        borderTopColor: "transparent",
+        borderBottomColor: "transparent",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:after": {
+        borderTopColor: "#ffffff",
+        borderBottomColor: "#ffffff",
+      },
+      ".cm-tooltip-autocomplete": {
+        "& > ul > li[aria-selected]": {
+          backgroundColor: "#e1e4e8",
+          color: "#24292e",
+        },
+      },
+    },
+    { dark: false }
+  );
+
+  const lightHighlightStyle = HighlightStyle.define([
+    { tag: tags.keyword, color: "#d73a49" },
+    {
+      tag: [tags.name, tags.deleted, tags.character, tags.propertyName, tags.macroName],
+      color: "#6f42c1",
+    },
+    { tag: [tags.function(tags.variableName), tags.labelName], color: "#6f42c1" },
+    { tag: [tags.color, tags.constant(tags.name), tags.standard(tags.name)], color: "#005cc5" },
+    { tag: [tags.definition(tags.name), tags.separator], color: "#24292e" },
+    {
+      tag: [
+        tags.typeName,
+        tags.className,
+        tags.number,
+        tags.changed,
+        tags.annotation,
+        tags.modifier,
+        tags.self,
+        tags.namespace,
+      ],
+      color: "#e36209",
+    },
+    {
+      tag: [
+        tags.operator,
+        tags.operatorKeyword,
+        tags.url,
+        tags.escape,
+        tags.regexp,
+        tags.link,
+        tags.special(tags.string),
+      ],
+      color: "#032f62",
+    },
+    { tag: [tags.meta, tags.comment], color: "#6a737d" },
+    { tag: tags.strong, fontWeight: "bold" },
+    { tag: tags.emphasis, fontStyle: "italic" },
+    { tag: tags.strikethrough, textDecoration: "line-through" },
+    { tag: tags.link, color: "#032f62", textDecoration: "underline" },
+    { tag: tags.heading, fontWeight: "bold", color: "#005cc5" },
+    { tag: [tags.atom, tags.bool, tags.special(tags.variableName)], color: "#005cc5" },
+    { tag: [tags.processingInstruction, tags.string, tags.inserted], color: "#22863a" },
+    { tag: tags.invalid, color: "#cb2431" },
+  ]);
+
+  // High contrast theme
+  const highContrastTheme = EditorView.theme(
+    {
+      "&": {
+        backgroundColor: "#000000",
+        color: "#ffffff",
+      },
+      ".cm-content": {
+        caretColor: "#ffffff",
+      },
+      ".cm-cursor, .cm-dropCursor": {
+        borderLeftColor: "#ffffff",
+        borderLeftWidth: "2px",
+      },
+      "&.cm-focused .cm-selectionBackground, .cm-selectionBackground, .cm-content ::selection": {
+        backgroundColor: "#264f78",
+      },
+      ".cm-panels": {
+        backgroundColor: "#000000",
+        color: "#ffffff",
+      },
+      ".cm-panels.cm-panels-top": {
+        borderBottom: "2px solid #ffffff",
+      },
+      ".cm-panels.cm-panels-bottom": {
+        borderTop: "2px solid #ffffff",
+      },
+      ".cm-searchMatch": {
+        backgroundColor: "#515c6a",
+        outline: "2px solid #ffff00",
+      },
+      ".cm-searchMatch.cm-searchMatch-selected": {
+        backgroundColor: "#ffff00",
+        color: "#000000",
+      },
+      ".cm-activeLine": {
+        backgroundColor: "#1a1a1a",
+      },
+      ".cm-selectionMatch": {
+        backgroundColor: "#264f78",
+      },
+      ".cm-matchingBracket, .cm-nonmatchingBracket": {
+        backgroundColor: "#515c6a",
+        outline: "2px solid #ffff00",
+      },
+      ".cm-gutters": {
+        backgroundColor: "#000000",
+        color: "#858585",
+        border: "none",
+        borderRight: "2px solid #ffffff",
+      },
+      ".cm-activeLineGutter": {
+        backgroundColor: "#1a1a1a",
+        color: "#ffffff",
+      },
+      ".cm-foldPlaceholder": {
+        backgroundColor: "transparent",
+        border: "none",
+        color: "#ffff00",
+      },
+      ".cm-tooltip": {
+        border: "2px solid #ffffff",
+        backgroundColor: "#000000",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:before": {
+        borderTopColor: "transparent",
+        borderBottomColor: "transparent",
+      },
+      ".cm-tooltip .cm-tooltip-arrow:after": {
+        borderTopColor: "#000000",
+        borderBottomColor: "#000000",
+      },
+      ".cm-tooltip-autocomplete": {
+        "& > ul > li[aria-selected]": {
+          backgroundColor: "#264f78",
+          color: "#ffffff",
+        },
+      },
+    },
+    { dark: true }
+  );
+
+  const highContrastHighlightStyle = HighlightStyle.define([
+    { tag: tags.keyword, color: "#569cd6", fontWeight: "bold" },
+    {
+      tag: [tags.name, tags.deleted, tags.character, tags.propertyName, tags.macroName],
+      color: "#9cdcfe",
+    },
+    { tag: [tags.function(tags.variableName), tags.labelName], color: "#dcdcaa" },
+    { tag: [tags.color, tags.constant(tags.name), tags.standard(tags.name)], color: "#4fc1ff" },
+    { tag: [tags.definition(tags.name), tags.separator], color: "#ffffff" },
+    {
+      tag: [
+        tags.typeName,
+        tags.className,
+        tags.number,
+        tags.changed,
+        tags.annotation,
+        tags.modifier,
+        tags.self,
+        tags.namespace,
+      ],
+      color: "#4ec9b0",
+    },
+    {
+      tag: [
+        tags.operator,
+        tags.operatorKeyword,
+        tags.url,
+        tags.escape,
+        tags.regexp,
+        tags.link,
+        tags.special(tags.string),
+      ],
+      color: "#d4d4d4",
+    },
+    { tag: [tags.meta, tags.comment], color: "#6a9955" },
+    { tag: tags.strong, fontWeight: "bold" },
+    { tag: tags.emphasis, fontStyle: "italic" },
+    { tag: tags.strikethrough, textDecoration: "line-through" },
+    { tag: tags.link, color: "#3794ff", textDecoration: "underline" },
+    { tag: tags.heading, fontWeight: "bold", color: "#569cd6" },
+    { tag: [tags.atom, tags.bool, tags.special(tags.variableName)], color: "#569cd6" },
+    { tag: [tags.processingInstruction, tags.string, tags.inserted], color: "#ce9178" },
+    { tag: tags.invalid, color: "#f44747" },
+  ]);
+
+  function getThemeExtension(theme: string): Extension {
+    switch (theme) {
+      case "light":
+        return [lightTheme, syntaxHighlighting(lightHighlightStyle)];
+      case "high-contrast":
+        return [highContrastTheme, syntaxHighlighting(highContrastHighlightStyle)];
+      case "dark":
+      case "custom":
+      default:
+        return oneDark;
+    }
+  }
 
   function getLanguageExtension(language: string): Extension {
     const languageMap: Record<string, () => Extension> = {
@@ -84,6 +355,8 @@
   function createEditor() {
     if (!editorContainer) return;
 
+    const currentTheme = $config.theme;
+
     const saveKeymap = keymap.of([
       {
         key: "Mod-s",
@@ -105,7 +378,7 @@
       doc: tab.content,
       extensions: [
         basicSetup,
-        oneDark,
+        themeCompartment.of(getThemeExtension(currentTheme)),
         getLanguageExtension(tab.language),
         saveKeymap,
         updateListener,
@@ -120,10 +393,6 @@
           ".cm-content": {
             fontFamily: "'JetBrains Mono', 'Fira Code', 'Consolas', monospace",
           },
-          ".cm-gutters": {
-            backgroundColor: "var(--bg-secondary)",
-            borderRight: "1px solid var(--border-color)",
-          },
         }),
       ],
     });
@@ -141,6 +410,13 @@
     }
   }
 
+  // Watch for theme changes and update the editor
+  $: if (view && $config.theme) {
+    view.dispatch({
+      effects: themeCompartment.reconfigure(getThemeExtension($config.theme)),
+    });
+  }
+
   onMount(() => {
     createEditor();
   });