feat(claude-code-hooks): add PreCompact hook support for experimental.session.compacting event (#139)

src/hooks/claude-code-hooks/pre-compact.ts

@@ -0,0 +1,109 @@
+import type {
+  PreCompactInput,
+  PreCompactOutput,
+  ClaudeHooksConfig,
+} from "./types"
+import { findMatchingHooks, executeHookCommand, log } from "../../shared"
+import { DEFAULT_CONFIG } from "./plugin-config"
+import { isHookCommandDisabled, type PluginExtendedConfig } from "./config-loader"
+
+export interface PreCompactContext {
+  sessionId: string
+  cwd: string
+}
+
+export interface PreCompactResult {
+  context: string[]
+  elapsedMs?: number
+  hookName?: string
+  continue?: boolean
+  stopReason?: string
+  suppressOutput?: boolean
+  systemMessage?: string
+}
+
+export async function executePreCompactHooks(
+  ctx: PreCompactContext,
+  config: ClaudeHooksConfig | null,
+  extendedConfig?: PluginExtendedConfig | null
+): Promise<PreCompactResult> {
+  if (!config) {
+    return { context: [] }
+  }
+
+  const matchers = findMatchingHooks(config, "PreCompact", "*")
+  if (matchers.length === 0) {
+    return { context: [] }
+  }
+
+  const stdinData: PreCompactInput = {
+    session_id: ctx.sessionId,
+    cwd: ctx.cwd,
+    hook_event_name: "PreCompact",
+    hook_source: "opencode-plugin",
+  }
+
+  const startTime = Date.now()
+  let firstHookName: string | undefined
+  const collectedContext: string[] = []
+
+  for (const matcher of matchers) {
+    for (const hook of matcher.hooks) {
+      if (hook.type !== "command") continue
+
+      if (isHookCommandDisabled("PreCompact", hook.command, extendedConfig ?? null)) {
+        log("PreCompact hook command skipped (disabled by config)", { command: hook.command })
+        continue
+      }
+
+      const hookName = hook.command.split("/").pop() || hook.command
+      if (!firstHookName) firstHookName = hookName
+
+      const result = await executeHookCommand(
+        hook.command,
+        JSON.stringify(stdinData),
+        ctx.cwd,
+        { forceZsh: DEFAULT_CONFIG.forceZsh, zshPath: DEFAULT_CONFIG.zshPath }
+      )
+
+      if (result.exitCode === 2) {
+        log("PreCompact hook blocked", { hookName, stderr: result.stderr })
+        continue
+      }
+
+      if (result.stdout) {
+        try {
+          const output = JSON.parse(result.stdout) as PreCompactOutput
+
+          if (output.hookSpecificOutput?.additionalContext) {
+            collectedContext.push(...output.hookSpecificOutput.additionalContext)
+          } else if (output.context) {
+            collectedContext.push(...output.context)
+          }
+
+          if (output.continue === false) {
+            return {
+              context: collectedContext,
+              elapsedMs: Date.now() - startTime,
+              hookName: firstHookName,
+              continue: output.continue,
+              stopReason: output.stopReason,
+              suppressOutput: output.suppressOutput,
+              systemMessage: output.systemMessage,
+            }
+          }
+        } catch {
+          if (result.stdout.trim()) {
+            collectedContext.push(result.stdout.trim())
+          }
+        }
+      }
+    }
+  }
+
+  return {
+    context: collectedContext,
+    elapsedMs: Date.now() - startTime,
+    hookName: firstHookName,
+  }
+}