From 83e7701eeefe3967d958778f4bc8ce60164ab784 Mon Sep 17 00:00:00 2001
From: rubenwardy <rw@rubenwardy.com>
Date: Tue, 12 Sep 2023 21:15:55 +0100
Subject: [PATCH] Add a super fast latest release API

---
 app/blueprints/api/endpoints.py | 45 ++++++++++++++++++++++++++++++++-
 app/flatpages/help/api.md       |  5 ++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/app/blueprints/api/endpoints.py b/app/blueprints/api/endpoints.py
index 16d2dbf8..e84aa329 100644
--- a/app/blueprints/api/endpoints.py
+++ b/app/blueprints/api/endpoints.py
@@ -21,7 +21,7 @@ from typing import List
 import flask_sqlalchemy
 from flask import request, jsonify, current_app, Response
 from flask_login import current_user, login_required
-from sqlalchemy import and_
+from sqlalchemy import and_, or_
 from sqlalchemy.orm import joinedload
 from sqlalchemy.sql.expression import func
 
@@ -826,3 +826,46 @@ def collection_view(author, name):
 	ret = collection.as_dict()
 	ret["items"] = [x.as_dict() for x in items]
 	return jsonify(ret)
+
+
+@bp.route("/api/updates/")
+def updates():
+	protocol_version = get_int_or_abort(request.args.get("protocol_version"))
+	minetest_version = request.args.get("engine_version")
+	if protocol_version or minetest_version:
+		version = MinetestRelease.get(minetest_version, protocol_version)
+	else:
+		version = None
+
+	# Subquery to get the latest release for each package
+	latest_release_query = (db.session.query(
+		PackageRelease.package_id,
+		func.max(PackageRelease.id).label('max_release_id'))
+			.select_from(PackageRelease)
+			.filter(PackageRelease.approved == True))
+
+	if version:
+		latest_release_query = (latest_release_query
+			.filter(or_(PackageRelease.min_rel_id == None,
+				PackageRelease.min_rel_id <= version.id))
+			.filter(or_(PackageRelease.max_rel_id == None,
+				PackageRelease.max_rel_id >= version.id)))
+
+	latest_release_subquery = (
+		latest_release_query
+		.group_by(PackageRelease.package_id)
+		.subquery()
+	)
+
+	# Get package id and latest release
+	query = (db.session.query(User.username, Package.name, latest_release_subquery.c.max_release_id)
+		.select_from(Package)
+		.join(User, Package.author)
+		.join(latest_release_subquery, Package.id == latest_release_subquery.c.package_id)
+		.filter(Package.state == PackageState.APPROVED)).all()
+
+	ret = {}
+	for author_username, package_name, release_id in query:
+		ret[f"{author_username}/{package_name}"] = release_id
+
+	return jsonify(ret)
diff --git a/app/flatpages/help/api.md b/app/flatpages/help/api.md
index 7220249f..ac099697 100644
--- a/app/flatpages/help/api.md
+++ b/app/flatpages/help/api.md
@@ -209,6 +209,11 @@ Supported query parameters:
             * `author`: author username
             * `name`: technical name
             * `type`: `mod`, `game`, or `txp`
+* GET `/api/updates/` (Look-up table)
+    * Returns a look-up table from package key (`author/name`) to latest release id
+    * Query arguments
+        * `protocol_version`:  Only show packages supported by this Minetest protocol version.
+        * `engine_version`:  Only show packages supported by this Minetest engine version, eg: `5.3.0`.
 * GET `/api/packages/<username>/<name>/releases/` (List)
     * Returns array of release dictionaries, see above, but without package info.
 * GET `/api/packages/<username>/<name>/releases/<id>/` (Read)