From 2d145e7c9473b48dc7ee1879deaa4d28053fbca5 Mon Sep 17 00:00:00 2001
From: I-Al-Istannen <i-al-istannen@users.noreply.github.com>
Date: Mon, 24 Oct 2022 17:31:34 +0200
Subject: [PATCH] Check for new versions at startup

---
 PFERD/__main__.py   |  7 ++++++
 PFERD/cli/parser.py |  5 +++++
 PFERD/update.py     | 53 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 65 insertions(+)
 create mode 100644 PFERD/update.py

diff --git a/PFERD/__main__.py b/PFERD/__main__.py
index 4faeb13..19f5a21 100644
--- a/PFERD/__main__.py
+++ b/PFERD/__main__.py
@@ -5,6 +5,8 @@ import os
 import sys
 from pathlib import Path
 
+from PFERD.update import check_for_updates
+
 from .auth import AuthLoadError
 from .cli import PARSER, ParserLoadError, load_default_section
 from .config import Config, ConfigDumpError, ConfigLoadError, ConfigOptionError
@@ -134,6 +136,11 @@ def main() -> None:
             loop.run_until_complete(asyncio.sleep(1))
             loop.close()
         else:
+            log.explain_topic("Checking for updates")
+            if not args.skip_update_check:
+                asyncio.run(check_for_updates())
+            else:
+                log.explain("Update check skipped due to configuration option")
             asyncio.run(pferd.run(args.debug_transforms))
     except (ConfigOptionError, AuthLoadError) as e:
         log.unlock()
diff --git a/PFERD/cli/parser.py b/PFERD/cli/parser.py
index e753023..2868d38 100644
--- a/PFERD/cli/parser.py
+++ b/PFERD/cli/parser.py
@@ -151,6 +151,11 @@ PARSER.add_argument(
     action="version",
     version=f"{NAME} {VERSION} (https://github.com/Garmelon/PFERD)",
 )
+PARSER.add_argument(
+    "--skip-update-check",
+    action="store_true",
+    help="disable automatic update checks at startup"
+)
 PARSER.add_argument(
     "--config", "-c",
     type=Path,
diff --git a/PFERD/update.py b/PFERD/update.py
new file mode 100644
index 0000000..ff86368
--- /dev/null
+++ b/PFERD/update.py
@@ -0,0 +1,53 @@
+from dataclasses import dataclass
+import ssl
+from typing import Optional
+import aiohttp
+import certifi
+
+from .version import NAME, VERSION
+from .logging import log
+
+
+@dataclass
+class PferdUpdate:
+    release_url: str
+    version: str
+
+
+def _build_session() -> aiohttp.ClientSession:
+    return aiohttp.ClientSession(
+        headers={"User-Agent": f"{NAME}/{VERSION}"},
+        connector=aiohttp.TCPConnector(ssl=ssl.create_default_context(cafile=certifi.where())),
+        timeout=aiohttp.ClientTimeout(
+            total=15 * 60,
+            connect=10,
+            sock_connect=10,
+            sock_read=10,
+        )
+    )
+
+
+async def check_for_updates() -> None:
+    if new_version := await get_newer_version():
+        log.warn(
+            f"{NAME} version out of date. "
+            + f"You are running version {VERSION!r} but {new_version.version!r} was found on GitHub."
+        )
+        log.warn_contd(f"You can download it on GitHub: {new_version.release_url}")
+    else:
+        log.explain("No update found")
+
+
+async def get_newer_version() -> Optional[PferdUpdate]:
+    async with _build_session() as session:
+        async with session.get(
+            "https://api.github.com/repos/Garmelon/Pferd/releases/latest",
+            headers={"Accept": "application/vnd.github+json"}
+        ) as response:
+            release_information = await response.json()
+            tag_name: str = release_information["tag_name"]
+            tag_name = tag_name.removeprefix("v")
+            if VERSION == tag_name:
+                return None
+
+            return PferdUpdate(release_url=release_information["html_url"], version=tag_name)