import path from "node:path";
import { describe, expect, test } from "vitest";

import {
  GitUpdateService,
  UPDATE_REMOTE_URL,
  type CommandResult,
  type CommandRunner,
} from "../../src/updater/git-update-service.js";

function result(stdout = "", code = 0, stderr = ""): CommandResult {
  return { code, stdout, stderr };
}

function fakeRunner(responses: Map<string, CommandResult>): CommandRunner {
  return async (command, args) =>
    responses.get(`${command} ${args.join(" ")}`) ??
    result("", 1, "unexpected command");
}

describe("GitUpdateService", () => {
  test("checks the currently checked-out branch", async () => {
    const root = path.resolve(".");
    const runner = fakeRunner(
      new Map([
        ["git branch --show-current", result("feature/demo\n")],
        [
          `git fetch --quiet ${UPDATE_REMOTE_URL} +refs/heads/feature/demo:refs/remotes/xo-updater/feature/demo`,
          result(),
        ],
        ["git rev-parse HEAD", result("aaa\n")],
        ["git rev-parse refs/remotes/xo-updater/feature/demo", result("bbb\n")],
        ["git status --porcelain", result()],
        ["git merge-base --is-ancestor aaa bbb", result()],
        ["git log -1 --format=%s bbb", result("Useful update\n")],
      ]),
    );

    const update = await new GitUpdateService(root, runner).check();

    expect(update).toMatchObject({
      status: "available",
      branch: "feature/demo",
      currentCommit: "aaa",
      targetCommit: "bbb",
      canApply: true,
    });
  });

  test("reports an available update but blocks applying over local changes", async () => {
    const root = path.resolve(".");
    const runner = fakeRunner(
      new Map([
        ["git branch --show-current", result("main\n")],
        [
          `git fetch --quiet ${UPDATE_REMOTE_URL} +refs/heads/main:refs/remotes/xo-updater/main`,
          result(),
        ],
        ["git rev-parse HEAD", result("aaa\n")],
        ["git rev-parse refs/remotes/xo-updater/main", result("bbb\n")],
        ["git status --porcelain", result(" M src/example.ts\n")],
        ["git merge-base --is-ancestor aaa bbb", result()],
        ["git log -1 --format=%s bbb", result("Update\n")],
      ]),
    );

    const update = await new GitUpdateService(root, runner).check();

    expect(update).toMatchObject({ status: "available", canApply: false });
  });

  test("does not replace commits when the local branch is ahead", async () => {
    const root = path.resolve(".");
    const runner = fakeRunner(
      new Map([
        ["git branch --show-current", result("main\n")],
        [
          `git fetch --quiet ${UPDATE_REMOTE_URL} +refs/heads/main:refs/remotes/xo-updater/main`,
          result(),
        ],
        ["git rev-parse HEAD", result("bbb\n")],
        ["git rev-parse refs/remotes/xo-updater/main", result("aaa\n")],
        ["git status --porcelain", result()],
        ["git merge-base --is-ancestor bbb aaa", result("", 1)],
        ["git merge-base --is-ancestor aaa bbb", result()],
      ]),
    );

    await expect(
      new GitUpdateService(root, runner).check(),
    ).resolves.toMatchObject({
      status: "up-to-date",
      branch: "main",
      currentCommit: "bbb",
    });
  });
});