packages/plugins/sdk/src/define-plugin.ts

/**
 * `definePlugin` — the top-level helper for authoring a Paperclip plugin.
 *
 * Plugin authors call `definePlugin()` and export the result as the default
 * export from their worker entrypoint. The host imports the worker module,
 * calls `setup()` with a `PluginContext`, and from that point the plugin
 * responds to events, jobs, webhooks, and UI requests through the context.
 *
 * @see PLUGIN_SPEC.md §14.1 — Example SDK Shape
 *
 * @example
 * ```ts
 * // dist/worker.ts
 * import { definePlugin } from "@paperclipai/plugin-sdk";
 *
 * export default definePlugin({
 *   async setup(ctx) {
 *     ctx.logger.info("Linear sync plugin starting");
 *
 *     // Subscribe to events
 *     ctx.events.on("issue.created", async (event) => {
 *       const config = await ctx.config.get();
 *       await ctx.http.fetch(`https://api.linear.app/...`, {
 *         method: "POST",
 *         headers: { Authorization: `Bearer ${await ctx.secrets.resolve(config.apiKeyRef as string)}` },
 *         body: JSON.stringify({ title: event.payload.title }),
 *       });
 *     });
 *
 *     // Register a job handler
 *     ctx.jobs.register("full-sync", async (job) => {
 *       ctx.logger.info("Running full-sync job", { runId: job.runId });
 *       // ... sync logic
 *     });
 *
 *     // Register data for the UI
 *     ctx.data.register("sync-health", async ({ companyId }) => {
 *       const state = await ctx.state.get({
 *         scopeKind: "company",
 *         scopeId: String(companyId),
 *         stateKey: "last-sync",
 *       });
 *       return { lastSync: state };
 *     });
 *   },
 * });
 * ```
 */

import type { PluginContext } from "./types.js";

// ---------------------------------------------------------------------------
// Health check result
// ---------------------------------------------------------------------------

/**
 * Optional plugin-reported diagnostics returned from the `health()` RPC method.
 *
 * @see PLUGIN_SPEC.md §13.2 — `health`
 */
export interface PluginHealthDiagnostics {
  /** Machine-readable status: `"ok"` | `"degraded"` | `"error"`. */
  status: "ok" | "degraded" | "error";
  /** Human-readable description of the current health state. */
  message?: string;
  /** Plugin-reported key-value diagnostics (e.g. connection status, queue depth). */
  details?: Record<string, unknown>;
}

// ---------------------------------------------------------------------------
// Config validation result
// ---------------------------------------------------------------------------

/**
 * Result returned from the `validateConfig()` RPC method.
 *
 * @see PLUGIN_SPEC.md §13.3 — `validateConfig`
 */
export interface PluginConfigValidationResult {
  /** Whether the config is valid. */
  ok: boolean;
  /** Non-fatal warnings about the config. */
  warnings?: string[];
  /** Validation errors (populated when `ok` is `false`). */
  errors?: string[];
}

// ---------------------------------------------------------------------------
// Webhook handler input
// ---------------------------------------------------------------------------

/**
 * Input received by the plugin worker's `handleWebhook` handler.
 *
 * @see PLUGIN_SPEC.md §13.7 — `handleWebhook`
 */
export interface PluginWebhookInput {
  /** Endpoint key matching the manifest declaration. */
  endpointKey: string;
  /** Inbound request headers. */
  headers: Record<string, string | string[]>;
  /** Raw request body as a UTF-8 string. */
  rawBody: string;
  /** Parsed JSON body (if applicable and parseable). */
  parsedBody?: unknown;
  /** Unique request identifier for idempotency checks. */
  requestId: string;
}

// ---------------------------------------------------------------------------
// Plugin definition
// ---------------------------------------------------------------------------

/**
 * The plugin definition shape passed to `definePlugin()`.
 *
 * The only required field is `setup`, which receives the `PluginContext` and
 * is where the plugin registers its handlers (events, jobs, data, actions,
 * tools, etc.).
 *
 * All other lifecycle hooks are optional. If a hook is not implemented the
 * host applies default behaviour (e.g. restarting the worker on config change
 * instead of calling `onConfigChanged`).
 *
 * @see PLUGIN_SPEC.md §13 — Host-Worker Protocol
 */
export interface PluginDefinition {
  /**
   * Called once when the plugin worker starts up, after `initialize` completes.
   *
   * This is where the plugin registers all its handlers: event subscriptions,
   * job handlers, data/action handlers, and tool registrations. Registration
   * must be synchronous after `setup` resolves — do not register handlers
   * inside async callbacks that may resolve after `setup` returns.
   *
   * @param ctx - The full plugin context provided by the host
   */
  setup(ctx: PluginContext): Promise<void>;

  /**
   * Called when the host wants to know if the plugin is healthy.
   *
   * The host polls this on a regular interval and surfaces the result in the
   * plugin health dashboard. If not implemented, the host infers health from
   * worker process liveness.
   *
   * @see PLUGIN_SPEC.md §13.2 — `health`
   */
  onHealth?(): Promise<PluginHealthDiagnostics>;

  /**
   * Called when the operator updates the plugin's instance configuration at
   * runtime, without restarting the worker.
   *
   * If not implemented, the host restarts the worker to apply the new config.
   *
   * @param newConfig - The newly resolved configuration
   * @see PLUGIN_SPEC.md §13.4 — `configChanged`
   */
  onConfigChanged?(newConfig: Record<string, unknown>): Promise<void>;

  /**
   * Called when the host is about to shut down the plugin worker.
   *
   * The worker has at most 10 seconds (configurable via plugin config) to
   * finish in-flight work and resolve this promise. After the deadline the
   * host sends SIGTERM, then SIGKILL.
   *
   * @see PLUGIN_SPEC.md §12.5 — Graceful Shutdown Policy
   */
  onShutdown?(): Promise<void>;

  /**
   * Called to validate the current plugin configuration.
   *
   * The host calls this:
   * - after the plugin starts (to surface config errors immediately)
   * - after the operator saves a new config (to validate before persisting)
   * - via the "Test Connection" button in the settings UI
   *
   * @param config - The configuration to validate
   * @see PLUGIN_SPEC.md §13.3 — `validateConfig`
   */
  onValidateConfig?(config: Record<string, unknown>): Promise<PluginConfigValidationResult>;

  /**
   * Called to handle an inbound webhook delivery.
   *
   * The host routes `POST /api/plugins/:pluginId/webhooks/:endpointKey` to
   * this handler. The plugin is responsible for signature verification using
   * a resolved secret ref.
   *
   * If not implemented but webhooks are declared in the manifest, the host
   * returns HTTP 501 for webhook deliveries.
   *
   * @param input - Webhook delivery metadata and payload
   * @see PLUGIN_SPEC.md §13.7 — `handleWebhook`
   */
  onWebhook?(input: PluginWebhookInput): Promise<void>;
}

// ---------------------------------------------------------------------------
// PaperclipPlugin — the sealed object returned by definePlugin()
// ---------------------------------------------------------------------------

/**
 * The sealed plugin object returned by `definePlugin()`.
 *
 * Plugin authors export this as the default export from their worker
 * entrypoint. The host imports it and calls the lifecycle methods.
 *
 * @see PLUGIN_SPEC.md §14 — SDK Surface
 */
export interface PaperclipPlugin {
  /** The original plugin definition passed to `definePlugin()`. */
  readonly definition: PluginDefinition;
}

// ---------------------------------------------------------------------------
// definePlugin — top-level factory
// ---------------------------------------------------------------------------

/**
 * Define a Paperclip plugin.
 *
 * Call this function in your worker entrypoint and export the result as the
 * default export. The host will import the module and call lifecycle methods
 * on the returned object.
 *
 * @param definition - Plugin lifecycle handlers
 * @returns A sealed `PaperclipPlugin` object for the host to consume
 *
 * @example
 * ```ts
 * import { definePlugin } from "@paperclipai/plugin-sdk";
 *
 * export default definePlugin({
 *   async setup(ctx) {
 *     ctx.logger.info("Plugin started");
 *     ctx.events.on("issue.created", async (event) => {
 *       // handle event
 *     });
 *   },
 *
 *   async onHealth() {
 *     return { status: "ok" };
 *   },
 * });
 * ```
 *
 * @see PLUGIN_SPEC.md §14.1 — Example SDK Shape
 */
export function definePlugin(definition: PluginDefinition): PaperclipPlugin {
  return Object.freeze({ definition });
}