feat(renderer): add Mode 2031 dark/light theme detection

packages/core/src/renderer.ts

@@ -429,6 +429,7 @@ export class CliRenderer extends EventEmitter implements RenderContext {
   private _cachedPalette: TerminalColors | null = null
   private _paletteDetectionPromise: Promise<TerminalColors> | null = null
   private _onDestroy?: () => void
+  private _themeMode: "dark" | "light" | null = null
 
   private inputHandlers: ((sequence: string) => boolean)[] = []
   private prependedInputHandlers: ((sequence: string) => boolean)[] = []
@@ -848,6 +849,10 @@ export class CliRenderer extends EventEmitter implements RenderContext {
     return this._capabilities
   }
 
+  public get themeMode(): "dark" | "light" | null {
+    return this._themeMode
+  }
+
   public getDebugInputs(): Array<{ timestamp: string; sequence: string }> {
     return [...this._debugInputs]
   }
@@ -1060,6 +1065,24 @@ export class CliRenderer extends EventEmitter implements RenderContext {
     return false
   }).bind(this)
 
+  private themeModeHandler: (sequence: string) => boolean = ((sequence: string) => {
+    if (sequence === "\x1b[?997;1n") {
+      if (this._themeMode !== "dark") {
+        this._themeMode = "dark"
+        this.emit("theme_mode", "dark")
+      }
+      return true
+    }
+    if (sequence === "\x1b[?997;2n") {
+      if (this._themeMode !== "light") {
+        this._themeMode = "light"
+        this.emit("theme_mode", "light")
+      }
+      return true
+    }
+    return false
+  }).bind(this)
+
   private setupInput(): void {
     for (const handler of this.prependedInputHandlers) {
       this.addInputHandler(handler)
@@ -1078,6 +1101,7 @@ export class CliRenderer extends EventEmitter implements RenderContext {
     })
     this.addInputHandler(this.capabilityHandler)
     this.addInputHandler(this.focusHandler)
+    this.addInputHandler(this.themeModeHandler)
     this.addInputHandler((sequence: string) => {
       return this._keyHandler.processInput(sequence)
     })

packages/core/src/types.ts

@@ -44,12 +44,15 @@ export enum DebugOverlayCorner {
 
 export type WidthMethod = "wcwidth" | "unicode"
 
+export type ThemeMode = "dark" | "light"
+
 export interface RendererEvents {
   resize: (width: number, height: number) => void
   key: (data: Buffer) => void
   "memory:snapshot": (snapshot: { heapUsed: number; heapTotal: number; arrayBuffers: number }) => void
   selection: (selection: Selection) => void
   "debugOverlay:toggle": (enabled: boolean) => void
+  theme_mode: (mode: ThemeMode) => void
 }
 
 export interface RenderContext extends EventEmitter {

packages/core/src/zig/terminal.zig

@@ -165,8 +165,7 @@ pub fn resetState(self: *Terminal, tty: anytype) !void {
     }
 
     if (self.state.color_scheme_updates) {
-        try tty.writeAll(ansi.ANSI.colorSchemeReset);
-        self.state.color_scheme_updates = false;
+        try self.setColorSchemeUpdates(tty, false);
     }
 
     self.setTerminalTitle(tty, "");
@@ -270,6 +269,11 @@ pub fn enableDetectedFeatures(self: *Terminal, tty: anytype, use_kitty_keyboard:
     if (self.caps.focus_tracking) {
         try self.setFocusTracking(tty, true);
     }
+
+    if (self.caps.color_scheme_updates) {
+        try self.setColorSchemeUpdates(tty, true);
+        try tty.writeAll(ansi.ANSI.colorSchemeRequest);
+    }
 }
 
 fn checkEnvironmentOverrides(self: *Terminal) void {
@@ -488,6 +492,12 @@ pub fn setModifyOtherKeys(self: *Terminal, tty: anytype, enable: bool) !void {
     self.state.modify_other_keys = enable;
 }
 
+pub fn setColorSchemeUpdates(self: *Terminal, tty: anytype, enable: bool) !void {
+    const seq = if (enable) ansi.ANSI.colorSchemeSet else ansi.ANSI.colorSchemeReset;
+    try tty.writeAll(seq);
+    self.state.color_scheme_updates = enable;
+}
+
 /// The responses look like these:
 /// kitty - '\x1B[?1016;2$y\x1B[?2027;0$y\x1B[?2031;2$y\x1B[?1004;1$y\x1B[?2026;2$y\x1B[1;2R\x1B[1;3R\x1BP>|kitty(0.40.1)\x1B\\\x1B[?0u\x1B_Gi=1;EINVAL:Zero width/height not allowed\x1B\\\x1B[?62;c'
 /// ghostty - '\x1B[?1016;1$y\x1B[?2027;1$y\x1B[?2031;2$y\x1B[?1004;1$y\x1B[?2004;2$y\x1B[?2026;2$y\x1B[1;1R\x1B[1;1R\x1BP>|ghostty 1.1.3\x1B\\\x1B[?0u\x1B_Gi=1;OK\x1B\\\x1B[?62;22c'