refactor(claude-code-plugin-loader): split loader.ts into per-type loaders

Extract plugin component loading into dedicated modules:
- discovery.ts: plugin directory detection
- plugin-path-resolver.ts: path resolution logic
- agent-loader.ts, command-loader.ts, hook-loader.ts
- mcp-server-loader.ts, skill-loader.ts

src/features/claude-code-plugin-loader/discovery.ts

@@ -0,0 +1,180 @@
+import { existsSync, readFileSync } from "fs"
+import { homedir } from "os"
+import { join } from "path"
+import { log } from "../../shared/logger"
+import type {
+  InstalledPluginsDatabase,
+  PluginInstallation,
+  PluginManifest,
+  LoadedPlugin,
+  PluginLoadResult,
+  PluginLoadError,
+  PluginScope,
+  ClaudeSettings,
+  PluginLoaderOptions,
+} from "./types"
+
+function getPluginsBaseDir(): string {
+  if (process.env.CLAUDE_PLUGINS_HOME) {
+    return process.env.CLAUDE_PLUGINS_HOME
+  }
+  return join(homedir(), ".claude", "plugins")
+}
+
+function getInstalledPluginsPath(): string {
+  return join(getPluginsBaseDir(), "installed_plugins.json")
+}
+
+function loadInstalledPlugins(): InstalledPluginsDatabase | null {
+  const dbPath = getInstalledPluginsPath()
+  if (!existsSync(dbPath)) {
+    return null
+  }
+
+  try {
+    const content = readFileSync(dbPath, "utf-8")
+    return JSON.parse(content) as InstalledPluginsDatabase
+  } catch (error) {
+    log("Failed to load installed plugins database", error)
+    return null
+  }
+}
+
+function getClaudeSettingsPath(): string {
+  if (process.env.CLAUDE_SETTINGS_PATH) {
+    return process.env.CLAUDE_SETTINGS_PATH
+  }
+  return join(homedir(), ".claude", "settings.json")
+}
+
+function loadClaudeSettings(): ClaudeSettings | null {
+  const settingsPath = getClaudeSettingsPath()
+  if (!existsSync(settingsPath)) {
+    return null
+  }
+
+  try {
+    const content = readFileSync(settingsPath, "utf-8")
+    return JSON.parse(content) as ClaudeSettings
+  } catch (error) {
+    log("Failed to load Claude settings", error)
+    return null
+  }
+}
+
+function loadPluginManifest(installPath: string): PluginManifest | null {
+  const manifestPath = join(installPath, ".claude-plugin", "plugin.json")
+  if (!existsSync(manifestPath)) {
+    return null
+  }
+
+  try {
+    const content = readFileSync(manifestPath, "utf-8")
+    return JSON.parse(content) as PluginManifest
+  } catch (error) {
+    log(`Failed to load plugin manifest from ${manifestPath}`, error)
+    return null
+  }
+}
+
+function derivePluginNameFromKey(pluginKey: string): string {
+  const atIndex = pluginKey.indexOf("@")
+  return atIndex > 0 ? pluginKey.substring(0, atIndex) : pluginKey
+}
+
+function isPluginEnabled(
+  pluginKey: string,
+  settingsEnabledPlugins: Record<string, boolean> | undefined,
+  overrideEnabledPlugins: Record<string, boolean> | undefined,
+): boolean {
+  if (overrideEnabledPlugins && pluginKey in overrideEnabledPlugins) {
+    return overrideEnabledPlugins[pluginKey]
+  }
+  if (settingsEnabledPlugins && pluginKey in settingsEnabledPlugins) {
+    return settingsEnabledPlugins[pluginKey]
+  }
+  return true
+}
+
+function extractPluginEntries(
+  db: InstalledPluginsDatabase,
+): Array<[string, PluginInstallation | undefined]> {
+  if (db.version === 1) {
+    return Object.entries(db.plugins).map(([key, installation]) => [key, installation])
+  }
+  return Object.entries(db.plugins).map(([key, installations]) => [key, installations[0]])
+}
+
+export function discoverInstalledPlugins(options?: PluginLoaderOptions): PluginLoadResult {
+  const db = loadInstalledPlugins()
+  const settings = loadClaudeSettings()
+  const plugins: LoadedPlugin[] = []
+  const errors: PluginLoadError[] = []
+
+  if (!db || !db.plugins) {
+    return { plugins, errors }
+  }
+
+  const settingsEnabledPlugins = settings?.enabledPlugins
+  const overrideEnabledPlugins = options?.enabledPluginsOverride
+
+  for (const [pluginKey, installation] of extractPluginEntries(db)) {
+    if (!installation) continue
+
+    if (!isPluginEnabled(pluginKey, settingsEnabledPlugins, overrideEnabledPlugins)) {
+      log(`Plugin disabled: ${pluginKey}`)
+      continue
+    }
+
+    const { installPath, scope, version } = installation
+
+    if (!existsSync(installPath)) {
+      errors.push({
+        pluginKey,
+        installPath,
+        error: "Plugin installation path does not exist",
+      })
+      continue
+    }
+
+    const manifest = loadPluginManifest(installPath)
+    const pluginName = manifest?.name || derivePluginNameFromKey(pluginKey)
+
+    const loadedPlugin: LoadedPlugin = {
+      name: pluginName,
+      version: version || manifest?.version || "unknown",
+      scope: scope as PluginScope,
+      installPath,
+      pluginKey,
+      manifest: manifest ?? undefined,
+    }
+
+    if (existsSync(join(installPath, "commands"))) {
+      loadedPlugin.commandsDir = join(installPath, "commands")
+    }
+    if (existsSync(join(installPath, "agents"))) {
+      loadedPlugin.agentsDir = join(installPath, "agents")
+    }
+    if (existsSync(join(installPath, "skills"))) {
+      loadedPlugin.skillsDir = join(installPath, "skills")
+    }
+
+    const hooksPath = join(installPath, "hooks", "hooks.json")
+    if (existsSync(hooksPath)) {
+      loadedPlugin.hooksPath = hooksPath
+    }
+
+    const mcpPath = join(installPath, ".mcp.json")
+    if (existsSync(mcpPath)) {
+      loadedPlugin.mcpPath = mcpPath
+    }
+
+    plugins.push(loadedPlugin)
+    log(`Discovered plugin: ${pluginName}@${version} (${scope})`, {
+      installPath,
+      hasManifest: !!manifest,
+    })
+  }
+
+  return { plugins, errors }
+}