"""Datoka Hooks HTTP example. Python 3.10+, standard library only.
Usage: python send-http.py ACCESS_FILE STABLE_EVENT_ID PAYLOAD_FILE
Retry manually with the same event ID and unchanged payload file.
"""
import json
import re
import sys
from pathlib import Path
from urllib.error import HTTPError
from urllib.request import HTTPRedirectHandler, Request, build_opener

ORIGIN = "https://datoka-hooks-test.bhazarstudio.workers.dev"

class NoRedirect(HTTPRedirectHandler):
    def redirect_request(self, req, fp, code, msg, headers, newurl):
        return None

def inputs(args):
    if len(args) != 3:
        raise ValueError("usage")
    access_file, event_id, payload_file = args
    access = json.loads(Path(access_file).read_text(encoding="utf-8-sig"))
    if not isinstance(access, dict) or access.get("origin", ORIGIN) != ORIGIN:
        raise ValueError("invalid_access")
    if not re.fullmatch(r"pub-[a-f0-9]{32}", access.get("hookId", "")):
        raise ValueError("invalid_hook")
    if not re.fullmatch(r"[a-f0-9]{64}", access.get("token", "")):
        raise ValueError("invalid_token")
    if not re.fullmatch(r"[A-Za-z0-9][A-Za-z0-9._:-]{0,127}", event_id):
        raise ValueError("invalid_event_id")
    with Path(payload_file).open("rb") as source:
        body = source.read(65537)
    if len(body) > 65536:
        raise ValueError("body_too_large")
    json.loads(body.decode("utf-8"))
    return access, event_id, body

def send_http(access, event_id, body, opener=None):
    # Preserve the original bytes. Never follow redirects with the bearer token.
    request = Request(
        ORIGIN + "/v1/hooks/" + access["hookId"] + "/events",
        data=body, method="POST",
        headers={"Authorization": "Bearer " + access["token"],
                 "Content-Type": "application/json",
                 "X-Datoka-Event-Id": event_id})
    client = opener if opener is not None else build_opener(NoRedirect())
    try:
        with client.open(request, timeout=20) as response:
            if response.status != 202:
                raise ValueError("unexpected_status")
            result = json.loads(response.read(1048577))
    except HTTPError as error:
        # Do not print raw errors, URLs, response bodies or credentials.
        status = error.code
        error.close()
        raise ValueError("hooks_http_" + str(status)) from None
    return {key: result.get(key) for key in ("deliveryId", "state", "attempts")}

def main(args=None):
    try:
        result = send_http(*inputs(sys.argv[1:] if args is None else args))
        print(json.dumps(result, indent=2))
        return 0
    except Exception:
        print("Submission not confirmed. Check access, receiver and quota. "
              "Retry with the SAME event ID and unchanged JSON file. "
              "HTTP 202 means accepted, not delivered.", file=sys.stderr)
        return 1

if __name__ == "__main__":
    sys.exit(main())