feat: Implement AI chat history models and parsers for GitHub Copilot

Author: Marvin Zhang

packages/ai/src/models/application.ts

@@ -0,0 +1,52 @@
+/**
+ * Application and workspace hierarchy models for AI Chat processing
+ *
+ * Defines the three-level hierarchy:
+ * Application (VS Code app) -> Workspace (project) -> Session (chat)
+ */
+
+export interface ApplicationMetadata {
+  discovered_workspaces_count?: number;
+  parsing_errors?: string[];
+  total_sessions_discovered?: number;
+  discovery_timestamp?: string;
+  [key: string]: unknown; // Allow additional properties
+}
+
+/**
+ * Application information (VS Code app type)
+ * Top level of the hierarchy: Application -> Workspace -> Session
+ */
+export interface ApplicationInfo {
+  /** Unique application identifier */
+  id: string;
+  /** Human-readable application name */
+  name: string;
+  /** Path to the application's data directory */
+  path: string;
+  /** Name of the AI agent */
+  agent: string;
+  /** Optional: number of workspaces in this application */
+  workspaceCount?: number;
+  /** Additional metadata */
+  metadata?: ApplicationMetadata;
+}
+
+/**
+ * Lightweight workspace information (without sessions)
+ * Used for workspace discovery and listing within an application
+ */
+export interface WorkspaceInfo {
+  /** Unique workspace identifier (within the application) */
+  id: string;
+  /** Human-readable workspace name */
+  name: string;
+  /** Path to the workspace */
+  path?: string;
+  /** Parent application identifier */
+  applicationId: string;
+  /** Optional: number of sessions in this workspace */
+  sessionCount?: number;
+  /** Additional metadata */
+  metadata?: ApplicationMetadata;
+}

packages/ai/src/models/index.ts

@@ -9,6 +9,7 @@
  */
 
 // Re-export all models from their respective files
-export * from './chat-message.js';
-export * from './chat-session.js';
+export * from './application.js';
 export * from './workspace.js';
+export * from './chat-session.js';
+export * from './chat-message.js';

packages/ai/src/models/workspace.ts

@@ -13,7 +13,7 @@ export interface WorkspaceMetadata {
   [key: string]: unknown; // Allow additional properties
 }
 
-// TypeScript interface
+// TypeScript interface for full workspace with sessions
 export interface Workspace {
   /** Name of the AI agent */
   agent: string;

packages/ai/src/parsers/base.ts

@@ -0,0 +1,44 @@
+/**
+ * Abstract base class for AI assistant chat history parsers
+ *
+ * Provides a common interface for parsing chat history from various AI coding assistants
+ * like GitHub Copilot, Cursor, Claude Code, etc.
+ * 
+ * Supports three-level hierarchy: Application -> Workspace -> Session
+ */
+
+import type { ChatSession, ApplicationInfo, WorkspaceInfo } from '../models/index.js';
+import { Logger, ConsoleLogger } from './utils.js';
+
+/**
+ * Abstract base class for AI assistant parsers
+ */
+export abstract class BaseParser {
+  protected logger: Logger;
+
+  protected constructor(logger?: Logger) {
+    this.logger = logger || new ConsoleLogger();
+  }
+
+  /**
+   * Get all available applications (VS Code installations) for this AI assistant
+   * Returns lightweight application info without workspaces or sessions
+   */
+  abstract getApplications(): Promise<ApplicationInfo[]>;
+
+  /**
+   * Get all workspaces from a specific application
+   * Returns lightweight workspace info without sessions
+   */
+  abstract getWorkspaces(applicationId: string): Promise<WorkspaceInfo[]>;
+
+  /**
+   * Get all chat sessions from a specific workspace within an application
+   */
+  abstract getChatSessions(applicationId: string, workspaceId: string): Promise<ChatSession[]>;
+
+  /**
+   * Parse a single chat session by session ID
+   */
+  protected abstract parseChatSession(applicationId: string, workspaceId: string, sessionId: string): Promise<ChatSession | null>;
+}