import { type } from "arktype";
import type { ToolContext } from "./server.ts";
import { execute, tool } from "./shared.ts";

interface GiteaPull {
  number: number; html_url: string; title: string; body?: string | null;
  state: string; draft?: boolean; merged?: boolean; allow_maintainer_edit?: boolean;
  head?: { sha: string; ref: string; repo?: { full_name: string } | null };
  base?: { ref: string; repo?: { full_name: string } };
  user?: { login: string }; assignees?: Array<{ login: string }>;
  labels?: Array<string | { name?: string }>;
}

export const PullRequestInfo = type({
  pull_number: type.number.describe("The pull request number to fetch"),
});

export function PullRequestInfoTool(ctx: ToolContext) {
  return tool({
    name: "get_pull_request",
    description:
      "Retrieve PR metadata (title, body, state, branches, author, labels). " +
      "Example: `get_pull_request({ pull_number: 1234 })`. To checkout a PR branch locally, use checkout_pr instead.",
    parameters: PullRequestInfo,
    execute: execute(async ({ pull_number }) => {
      const r = await ctx.gitea.request(
        "GET /repos/{owner}/{repo}/pulls/{index}",
        { owner: ctx.repo.owner, repo: ctx.repo.name, index: pull_number }
      );
      const data = r.data as GiteaPull;
      const isFork = data.head?.repo?.full_name !== data.base?.repo?.full_name;
      return {
        number: data.number, url: data.html_url, title: data.title, body: data.body,
        state: data.state, draft: data.draft, merged: data.merged,
        maintainerCanModify: data.allow_maintainer_edit,
        base: data.base?.ref, head: data.head?.ref, isFork,
        author: data.user?.login,
        assignees: data.assignees?.map((a) => a.login).filter((n): n is string => n !== undefined),
        labels: data.labels
          ?.map((l) => (typeof l === "string" ? l : l.name))
          .filter((n): n is string => n !== undefined),
        closingIssues: [],
      };
    }),
  });
}