import { loadRepoById } from "../repos";
import type { WebhookEvent } from "../events/emit";
import { repoHub } from "./hub-do";
import { toJsonText } from "./protocol";

const MAX_TEXT = 200;
const MAX_COMMITS = 20;

/** Event types agents can subscribe to: webhook events plus coordination changes. */
export const AGENT_EVENT_TYPES = [
  "push",
  "create",
  "delete",
  "issues",
  "issue_comment",
  "pull_request",
  "pull_request_review",
  "pull_request_review_comment",
  "release",
  "workflow_run",
  "claims",
] as const;

function pick(source: unknown, keys: string[]): Record<string, unknown> {
  if (typeof source !== "object" || source === null) return {};
  const out: Record<string, unknown> = {};
  for (const key of keys) {
    const value: unknown = Reflect.get(source, key);
    if (typeof value === "string") out[key] = value.slice(0, MAX_TEXT);
    else if (typeof value === "number" || typeof value === "boolean" || value === null) out[key] = value;
  }
  return out;
}

/** A bounded summary of a webhook payload: enough to react to, never whole bodies or diffs. */
export function summarizeEvent(event: WebhookEvent, payload: Record<string, unknown>): Record<string, unknown> {
  const sender = pick(payload.sender, ["login"]);
  const base = { action: typeof payload.action === "string" ? payload.action : null, sender: sender.login ?? null };
  switch (event) {
    case "push": {
      const commits = Array.isArray(payload.commits) ? payload.commits.slice(0, MAX_COMMITS) : [];
      return {
        ...base,
        ...pick(payload, ["ref", "before", "after", "created", "deleted"]),
        commits: commits.map((commit: unknown) => pick(commit, ["id", "message"])),
      };
    }
    case "pull_request":
      return { ...base, pull_request: pick(payload.pull_request, ["number", "title", "state", "merged", "html_url"]) };
    case "pull_request_review":
      return {
        ...base,
        review: pick(payload.review, ["state", "body", "commit_id"]),
        pull_request: pick(payload.pull_request, ["number", "html_url"]),
      };
    case "workflow_run":
      return {
        ...base,
        workflow_run: pick(payload.workflow_run, [
          "run_number",
          "name",
          "event",
          "head_sha",
          "head_branch",
          "status",
          "conclusion",
          "html_url",
        ]),
      };
    case "issues":
    case "issue_comment":
      return {
        ...base,
        issue: pick(payload.issue, ["number", "title", "html_url"]),
        comment: pick(payload.comment, ["body"]),
      };
    default:
      return { ...base, ...pick(payload, ["ref", "ref_type"]) };
  }
}

/** Queue-consumer hook: forwards a repository's webhook event to its MCP coordination hub. */
export async function publishRepoEvent(
  repoId: string,
  event: WebhookEvent,
  payload: Record<string, unknown>,
): Promise<void> {
  if (!(AGENT_EVENT_TYPES as readonly string[]).includes(event)) return;
  const repo = await loadRepoById(repoId);
  if (!repo) return;
  try {
    await repoHub(repo.id).publish(
      repo.id,
      `${repo.owner_name}/${repo.name}`,
      event,
      toJsonText(summarizeEvent(event, payload)),
    );
  } catch (error) {
    console.error("MCP event fan-out failed", error);
  }
}