/**
* Session state management for skill acknowledgments
*
* Tracks which skills have been suggested/injected in each conversation
* to avoid re-suggesting the same skills repeatedly. State is persisted
* per-conversation using conversation_id or session_id.
*/
import {
existsSync,
readFileSync,
writeFileSync,
mkdirSync,
renameSync
} from "fs";
import { join } from "path";
import type { SessionState } from "./types.js";
/**
* Extended session state with metadata
*/
interface ExtendedSessionState extends SessionState {
timestamp: number;
injectedSkills: string[];
injectionTimestamp: number;
}
/**
* Read acknowledged skills from session state file
*
* Returns list of skills that have been suggested/injected in previous
* turns of the current conversation.
*
* @param stateDir - State directory path (.claude/hooks/state)
* @param stateId - Conversation or session ID
* @returns Array of acknowledged skill names
*/
export function readAcknowledgedSkills(
stateDir: string,
stateId: string
): string[] {
const stateFile = join(stateDir, `${stateId}-skills-suggested.json`);
if (!existsSync(stateFile)) {
return [];
}
try {
const existing: ExtendedSessionState = JSON.parse(
readFileSync(stateFile, "utf-8")
);
return existing.acknowledgedSkills || [];
} catch {
// Invalid JSON, start fresh
return [];
}
}
/**
* Write session state to track acknowledged skills
*
* Uses atomic write pattern (write to temp file, then rename) to prevent
* corruption from concurrent hook invocations.
*
* @param stateDir - State directory path
* @param stateId - Conversation or session ID
* @param acknowledgedSkills - All skills acknowledged (existing + new)
* @param injectedSkills - Skills injected this turn
*/
export function writeSessionState(
stateDir: string,
stateId: string,
acknowledgedSkills: string[],
injectedSkills: string[]
): void {
try {
// Ensure state directory exists
mkdirSync(stateDir, { recursive: true });
const stateFile = join(stateDir, `${stateId}-skills-suggested.json`);
const tempFile = `${stateFile}.tmp`;
const stateData: ExtendedSessionState = {
timestamp: Date.now(),
acknowledgedSkills,
injectedSkills,
injectionTimestamp: Date.now()
};
// Atomic write: write to temp file, then rename
// This prevents corruption if multiple hooks run concurrently
writeFileSync(tempFile, JSON.stringify(stateData, null, 2));
// renameSync is atomic on POSIX systems - overwrites existing file atomically
renameSync(tempFile, stateFile);
} catch (err) {
// Don't fail the hook if state writing fails
console.error("Warning: Failed to write session state:", err);
}
}
