feat(floating-ai): step 2 — create section registry + FloatingChatContext

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/renderer/context/FloatingChatContext.tsx

@@ -0,0 +1,176 @@
+import {
+  createContext,
+  useContext,
+  useCallback,
+  useEffect,
+  useState,
+  useRef,
+  type ReactNode,
+  type RefObject,
+} from 'react';
+
+// ---------- Types ----------
+
+export interface AISection {
+  id: string; // e.g. "project-tasks", "tasks-list", "timeline-chart"
+  label: string; // Human-readable, e.g. "Tasks", "Project Timeline"
+  ref: RefObject<HTMLElement | null>;
+  projectId?: string; // If section is project-scoped
+}
+
+interface FloatingChatState {
+  isOpen: boolean;
+  activeSectionId: string | null;
+  position: { x: number; y: number; width: number };
+  morphTargetId: string | null;
+  projectId?: string;
+}
+
+interface FloatingChatContextValue {
+  // State
+  state: FloatingChatState;
+  sections: Map<string, AISection>;
+
+  // Section registry
+  registerSection: (section: AISection) => void;
+  unregisterSection: (id: string) => void;
+
+  // Actions
+  openAtSection: (sectionId: string) => void;
+  moveToSection: (sectionId: string) => void;
+  close: () => void;
+  setMorphTarget: (id: string | null) => void;
+}
+
+// ---------- Constants ----------
+
+const CHAT_WIDTH = 380;
+const CHAT_HEIGHT = 420;
+const PADDING = 16;
+
+// ---------- Position computation ----------
+
+function computeAnchorPosition(
+  sectionRef: RefObject<HTMLElement | null>,
+): { x: number; y: number; width: number } {
+  const el = sectionRef.current;
+  if (!el) return { x: PADDING, y: PADDING, width: CHAT_WIDTH };
+
+  const rect = el.getBoundingClientRect();
+
+  // Anchor to top-right of section, offset inward
+  let x = rect.right - CHAT_WIDTH - PADDING;
+  let y = rect.top + PADDING;
+
+  // Edge-collision clamping
+  x = Math.max(PADDING, Math.min(x, window.innerWidth - CHAT_WIDTH - PADDING));
+  y = Math.max(
+    PADDING,
+    Math.min(y, window.innerHeight - CHAT_HEIGHT - PADDING),
+  );
+
+  return { x, y, width: CHAT_WIDTH };
+}
+
+// ---------- Context ----------
+
+const FloatingChatCtx = createContext<FloatingChatContextValue | null>(null);
+
+export function useFloatingChat(): FloatingChatContextValue {
+  const ctx = useContext(FloatingChatCtx);
+  if (!ctx)
+    throw new Error('useFloatingChat must be used within FloatingChatProvider');
+  return ctx;
+}
+
+// Convenience hook for pages to register a section
+export function useAISection(section: AISection): void {
+  const { registerSection, unregisterSection } = useFloatingChat();
+
+  useEffect(() => {
+    registerSection(section);
+    return () => unregisterSection(section.id);
+  }, [section.id, registerSection, unregisterSection]);
+}
+
+// ---------- Provider ----------
+
+export function FloatingChatProvider({ children }: { children: ReactNode }) {
+  const sectionsRef = useRef<Map<string, AISection>>(new Map());
+  const [sections, setSections] = useState<Map<string, AISection>>(new Map());
+  const [state, setState] = useState<FloatingChatState>({
+    isOpen: false,
+    activeSectionId: null,
+    position: { x: 0, y: 0, width: CHAT_WIDTH },
+    morphTargetId: null,
+  });
+
+  const registerSection = useCallback((section: AISection) => {
+    sectionsRef.current.set(section.id, section);
+    setSections(new Map(sectionsRef.current));
+  }, []);
+
+  const unregisterSection = useCallback((id: string) => {
+    sectionsRef.current.delete(id);
+    setSections(new Map(sectionsRef.current));
+  }, []);
+
+  const openAtSection = useCallback((sectionId: string) => {
+    const section = sectionsRef.current.get(sectionId);
+    if (!section) return;
+
+    const position = computeAnchorPosition(section.ref);
+
+    setState({
+      isOpen: true,
+      activeSectionId: sectionId,
+      position,
+      morphTargetId: null,
+      projectId: section.projectId,
+    });
+  }, []);
+
+  const moveToSection = useCallback((sectionId: string) => {
+    const section = sectionsRef.current.get(sectionId);
+    if (!section) return;
+
+    const position = computeAnchorPosition(section.ref);
+
+    setState((prev) => ({
+      ...prev,
+      activeSectionId: sectionId,
+      position,
+      projectId: section.projectId,
+    }));
+  }, []);
+
+  const close = useCallback(() => {
+    setState((prev) => ({
+      ...prev,
+      isOpen: false,
+      activeSectionId: null,
+      morphTargetId: null,
+    }));
+  }, []);
+
+  const setMorphTarget = useCallback((id: string | null) => {
+    setState((prev) => ({ ...prev, morphTargetId: id }));
+  }, []);
+
+  return (
+    <FloatingChatCtx.Provider
+      value={{
+        state,
+        sections,
+        registerSection,
+        unregisterSection,
+        openAtSection,
+        moveToSection,
+        close,
+        setMorphTarget,
+      }}
+    >
+      {children}
+    </FloatingChatCtx.Provider>
+  );
+}