import json, os, sys, urllib.request, urllib.parse, urllib.error

SECRETS = json.loads(os.environ.get("INTEGRATION_SECRETS", "{}"))
INPUTS = json.loads(os.environ.get("INTEGRATION_INPUTS", "{}"))
BASE = SECRETS.get("base_url", "https://api.crowdstrike.com").rstrip("/")


def token():
    data = urllib.parse.urlencode({"client_id": SECRETS.get("client_id", ""), "client_secret": SECRETS.get("client_secret", "")}).encode()
    req = urllib.request.Request(BASE + "/oauth2/token", data=data, headers={"Content-Type": "application/x-www-form-urlencoded", "Accept": "application/json"}, method="POST")
    with urllib.request.urlopen(req, timeout=30) as r:
        return json.loads(r.read()).get("access_token", "")


def call(method, path, tok, params=None, body=None):
    url = BASE + path
    if params:
        # params is a list of (key, value) tuples to allow repeated keys (e.g. ids)
        url += "?" + urllib.parse.urlencode(params)
    data = json.dumps(body).encode() if body is not None else None
    headers = {"Authorization": "Bearer " + tok, "Accept": "application/json"}
    if data is not None:
        headers["Content-Type"] = "application/json"
    req = urllib.request.Request(url, data=data, headers=headers, method=method)
    with urllib.request.urlopen(req, timeout=90) as r:
        raw = r.read()
        return json.loads(raw) if raw else {}


def csv(v):
    return [x.strip() for x in str(v or "").split(",") if x.strip()]


VERDICTS = ("true_positive", "false_positive", "ignored")


def main():
    tok = token()
    ids = csv(INPUTS.get("ids"))
    verdict = str(INPUTS.get("verdict") or "").strip()
    if verdict and verdict not in VERDICTS:
        raise ValueError("verdict must be one of " + ", ".join(VERDICTS) + ", got " + verdict)
    action_params = []
    if verdict:
        # The console's Resolution is read from these tags, and add_tag never
        # replaces one: drop the other two first, or a false positive turned
        # true positive would show both. Removing a tag the alert does not
        # carry is not an error worth stopping for — the add below is the call
        # that has to land.
        for other in VERDICTS:
            if other == verdict:
                continue
            try:
                call("PATCH", "/alerts/entities/alerts/v3", tok,
                     body={"action_parameters": [{"name": "remove_tag", "value": other}], "composite_ids": ids})
            except urllib.error.HTTPError:
                pass
        action_params.append({"name": "add_tag", "value": verdict})
    if INPUTS.get("status"):
        action_params.append({"name": "update_status", "value": str(INPUTS["status"])})
    if INPUTS.get("comment"):
        action_params.append({"name": "append_comment", "value": str(INPUTS["comment"])})
    if INPUTS.get("assign_to_uuid"):
        action_params.append({"name": "assign_to_uuid", "value": str(INPUTS["assign_to_uuid"])})
    if not action_params:
        raise ValueError("nothing to change: give a status, a verdict, a comment or an assignee")
    body = {"action_parameters": action_params, "composite_ids": ids}
    result = call("PATCH", "/alerts/entities/alerts/v3", tok, body=body)
    # Falcon answers 200 to an update it refused: the reasons sit in errors and
    # meta.writes.resources_affected stays at 0. Passing that on as a success
    # left an incident closed in Riposte and still open in the console.
    affected = ((result.get("meta") or {}).get("writes") or {}).get("resources_affected")
    if result.get("errors") or affected == 0:
        print(json.dumps({
            "error": "Falcon updated no alert" if affected == 0 else "Falcon refused part of the update",
            "resources_affected": affected,
            "errors": result.get("errors") or [],
            # The PATCH takes composite ids (<cid>:<id>), not the alert's bare id.
            "composite_ids": ids,
        }))
        sys.exit(1)
    print(json.dumps(result))


try:
    main()
except urllib.error.HTTPError as e:
    print(json.dumps({"error": "HTTP " + str(e.code), "detail": e.read().decode("utf-8", "replace")}))
    sys.exit(1)
except Exception as e:
    print(json.dumps({"error": str(e)}))
    sys.exit(1)