import type * as getCompare from '#lib/lexicons/dev/knotless/getCompare.ts';
import type * as getTemplate from '#lib/lexicons/dev/knotless/getTemplate.ts';
import type * as listBranches from '#lib/lexicons/dev/knotless/listBranches.ts';
import type { PageLoad } from './$types';
import type { AtUriString } from '@atproto/lex';
import { branches, repoPage, xrpc } from '#lib/data.ts';

/**
 * Opening a pull: the branch to merge into
 * (`?base=`, the default branch if not given), the repository to bring a
 * branch in from (`?head=`, this one or a fork) and the branch
 * (`?branch=`); what it brings in, once chosen; and the template a pull
 * there is asked to follow. With `?expand=1`, as a branch's Compare & pull
 * links, the form to open it shows at once rather than on asking.
 */
export const load: PageLoad = async (event) => {
	const p = event.url.searchParams;
	const { repo, answer } = await repoPage<typeof getCompare.main>(event, 'dev.knotless.getCompare');
	const base = p.get('base') || repo.defaultBranch;
	const head = (p.get('head') || repo.uri) as AtUriString;
	const branch = p.get('branch') || '';
	const quiet = { ...event, setHeaders: () => {} };
	const [bases, from, compared, template] = await Promise.all([
		branches(event),
		xrpc<typeof listBranches.main>(
			quiet,
			'dev.knotless.listBranches',
			{ repo: head, limit: 1000 },
			true
		),
		branch
			? xrpc<typeof getCompare.main>(
					quiet,
					'dev.knotless.getCompare',
					{ repo: repo.uri, base, head, branch },
					true
				)
			: null,
		xrpc<typeof getTemplate.main>(
			quiet,
			'dev.knotless.getTemplate',
			{ repo: repo.uri, kind: 'pull', base },
			true
		).catch(() => null)
	]);
	return {
		repo,
		heads: answer.heads,
		base,
		head,
		branch,
		bases,
		branches: from?.branches.map((b) => b.name) ?? [],
		changes: compared?.changes ?? null,
		template: template?.template ?? '',
		expand: p.get('expand') === '1'
	};
};