feat: Add cross-platform detection (Claude Code + OpenCode support)

packages/specflow/src/lib/platform.ts

@@ -0,0 +1,171 @@
+/**
+ * Platform Detection Module
+ * 
+ * Detects the current AI platform (Claude Code vs OpenCode) and provides
+ * platform-agnostic path resolution.
+ * 
+ * Priority Order:
+ * 1. PAI_DIR environment variable (explicit override)
+ * 2. OPENCODE_DIR environment variable (OpenCode specific)
+ * 3. Directory structure detection (~/.claude vs ~/.opencode)
+ * 4. Manual fallback with error
+ * 
+ * @module lib/platform
+ */
+
+import { homedir } from "os";
+import { existsSync } from "fs";
+
+export type Platform = "claudecode" | "opencode" | "unknown";
+
+export interface PlatformInfo {
+  platform: Platform;
+  rootDir: string;
+  skillsDir: string;
+  memoryDir: string;
+  executionDir: string;
+  projectsDir: string;
+}
+
+/**
+ * Detects the current platform based on environment variables and directory structure.
+ * 
+ * @returns Platform identifier
+ */
+export function detectPlatform(): Platform {
+  // Priority 1: PAI_DIR environment variable (legacy Claude Code)
+  if (process.env.PAI_DIR) {
+    return "claudecode";
+  }
+
+  // Priority 2: OPENCODE_DIR environment variable
+  if (process.env.OPENCODE_DIR) {
+    return "opencode";
+  }
+
+  // Priority 3: Directory structure detection
+  const home = homedir();
+  const claudeDir = `${home}/.claude`;
+  const opencodeDir = `${home}/.opencode`;
+
+  // Check which directory exists
+  if (existsSync(claudeDir)) {
+    return "claudecode";
+  }
+  if (existsSync(opencodeDir)) {
+    return "opencode";
+  }
+
+  return "unknown";
+}
+
+/**
+ * Gets the root directory for the current platform.
+ * 
+ * @returns Absolute path to platform root directory
+ * @throws Error if platform cannot be detected
+ */
+export function getRootDir(): string {
+  const platform = detectPlatform();
+  const home = homedir();
+
+  switch (platform) {
+    case "claudecode":
+      return process.env.PAI_DIR || `${home}/.claude`;
+    case "opencode":
+      return process.env.OPENCODE_DIR || `${home}/.opencode`;
+    case "unknown":
+      throw new Error(
+        "Platform detection failed. Set PAI_DIR or OPENCODE_DIR environment variable, " +
+        "or ensure ~/.claude or ~/.opencode directory exists."
+      );
+  }
+}
+
+/**
+ * Gets complete platform information including all standard directories.
+ * 
+ * @returns PlatformInfo object with all resolved paths
+ */
+export function getPlatformInfo(): PlatformInfo {
+  const platform = detectPlatform();
+  const rootDir = getRootDir();
+
+  return {
+    platform,
+    rootDir,
+    skillsDir: `${rootDir}/skills`,
+    memoryDir: `${rootDir}/MEMORY`,
+    executionDir: `${rootDir}/MEMORY/execution`,
+    projectsDir: `${rootDir}/MEMORY/projects`,
+  };
+}
+
+/**
+ * Resolves a relative path to an absolute path based on platform root.
+ * 
+ * @param relativePath - Path relative to platform root (e.g., "skills/SpecFlow")
+ * @returns Absolute path
+ */
+export function resolvePath(relativePath: string): string {
+  const rootDir = getRootDir();
+
+  // Handle paths that already start with /
+  if (relativePath.startsWith("/")) {
+    return relativePath;
+  }
+
+  // Handle paths that start with ~/
+  if (relativePath.startsWith("~/")) {
+    const home = homedir();
+    return `${home}/${relativePath.slice(2)}`;
+  }
+
+  return `${rootDir}/${relativePath}`;
+}
+
+/**
+ * Gets the feature execution directory for a given feature name.
+ * 
+ * @param featureName - Name of the feature (e.g., "contact-enrichment")
+ * @returns Absolute path to feature execution directory
+ */
+export function getFeatureDir(featureName: string): string {
+  const { executionDir } = getPlatformInfo();
+  return `${executionDir}/Features/${featureName}`;
+}
+
+/**
+ * Gets the project directory for a given project name.
+ * 
+ * @param projectName - Name of the project (e.g., "specflow-bundle")
+ * @returns Absolute path to project directory
+ */
+export function getProjectDir(projectName: string): string {
+  const { projectsDir } = getPlatformInfo();
+  return `${projectsDir}/${projectName}`;
+}
+
+/**
+ * Gets the specs directory for a given feature.
+ * 
+ * @param featureName - Name of the feature
+ * @returns Absolute path to specs directory
+ */
+export function getSpecsDir(featureName: string): string {
+  return `${getFeatureDir(featureName)}/specs`;
+}
+
+/**
+ * Checks if running on OpenCode platform.
+ */
+export function isOpenCode(): boolean {
+  return detectPlatform() === "opencode";
+}
+
+/**
+ * Checks if running on Claude Code platform.
+ */
+export function isClaudeCode(): boolean {
+  return detectPlatform() === "claudecode";
+}