import {CachedFunction} from 'webext-storage-cache';

import elementReady from 'element-ready';

import type {NameWithOwner} from 'github-url-detection';

import api from './api.js';

import {extractCurrentBranchFromBranchPicker, getRepo} from './index.js';

import {branchSelector} from './selectors.js';

import GetDefaultBranch from './get-default-branch.gql';

const isCurrentRepo = (nameWithOwner: NameWithOwner): boolean => Boolean(getRepo()?.nameWithOwner === nameWithOwner);

// Do not make this function complicated. We're only optimizing for the repo root.

async function fromDOM(): Promise<string | undefined> {

if (!['', 'commits'].includes(getRepo()!.path)) {

return;

}

// We're on the default branch, so we can extract it from the current page. This exclusively happens on the exact pages:

// /user/repo

// /user/repo/commits (without further path)

const element = await elementReady(branchSelector);

if (!element) {

return;

}

return extractCurrentBranchFromBranchPicker(element);

}

async function fromAPI(repository: NameWithOwner): Promise<string> {

const [owner, name] = repository.split('/');

const response = await api.v4(GetDefaultBranch, {

variables: {

owner,

name,

},

});

return response.repository.defaultBranchRef.name;

}

// DO NOT use optional arguments/defaults in "cached functions" because they can't be memoized effectively

// https://github.com/sindresorhus/eslint-plugin-unicorn/issues/1864

export const defaultBranchOfRepo = new CachedFunction('default-branch', {

async updater(repository: NameWithOwner): Promise<string> {

if (!repository) {

throw new Error('getDefaultBranch was called on a non-repository page');

}

return (isCurrentRepo(repository) && await fromDOM()) || fromAPI(repository);

},

maxAge: {hours: 1},

staleWhileRevalidate: {days: 20},

});

export default async function getDefaultBranch(): Promise<string> {

return defaultBranchOfRepo.get(getRepo()!.nameWithOwner);

}