Remind reviewers in Slack about open GitHub pull requests

import datetime
from clickruntime import on_trigger, credentials, http, notify

REPO = "acme/app"
CHANNEL = "#code-review"
HOURS = 24
GH_TO_EMAIL = {"kchen": "kim@acme.com", "vlee": "vik@acme.com"}

def gh(method, path, **kw):
    resp = http.request(method, f"https://api.github.com{path}", headers={
        "Authorization": f"Bearer {credentials.connection('github', 'work')}",
        "Accept": "application/vnd.github+json"}, **kw)
    resp.raise_for_status()
    return resp.json() if resp.content else None

def slack_id(email):
    r = http.get("https://slack.com/api/users.lookupByEmail", params={"email": email},
                 headers={"Authorization": f"Bearer {credentials.connection('slack', 'work')}"}).json()
    return r["user"]["id"] if r.get("ok") else None

@on_trigger
def run(event):
    if datetime.datetime.utcnow().weekday() >= 5:
        return {"skipped": "weekend"}
    now = datetime.datetime.utcnow()
    owed = {}
    for pr in gh("GET", f"/repos/{REPO}/pulls", params={"state": "open", "per_page": 100}):
        if pr["draft"]:
            continue
        age = now - datetime.datetime.strptime(pr["updated_at"], "%Y-%m-%dT%H:%M:%SZ")
        if age.total_seconds() < HOURS * 3600:
            continue
        for r in pr["requested_reviewers"]:
            owed.setdefault(r["login"], []).append(f"{pr['title']} (<{pr['html_url']}|#{pr['number']}>), {age.days or 1} day{'s' if age.days > 1 else ''}")
    if not owed:
        return {"waiting": 0}
    lines = []
    for login, prs in owed.items():
        uid = slack_id(GH_TO_EMAIL[login]) if login in GH_TO_EMAIL else None
        lines.append(f"{f'<@{uid}>' if uid else login}: " + " · ".join(prs))
    notify.slack("Pull requests waiting for review:\n" + "\n".join(lines), channel=CHANNEL)
    return {"reviewers": len(owed)}