"""Absolute-deadline contracts for the killable HTTP control helper."""

from __future__ import annotations

import base64
import io
import json
import subprocess
import threading
import time
import urllib.request
from http.server import BaseHTTPRequestHandler, HTTPServer

import pytest

from testing.tests.test_hermes_scm_broker_support import _load


class _Handler(BaseHTTPRequestHandler):
    def _respond(self):
        if self.path == "/slow":
            time.sleep(10)
        if self.path == "/redirect":
            self.send_response(302)
            self.send_header("Location", "http://127.0.0.1:1/evil")
            self.send_header("Content-Length", "0")
            self.end_headers()
            return
        status = 404 if self.path == "/missing" else 200
        body = b"x" * 64 if self.path == "/large" else b'{"ok":true}'
        self.send_response(status)
        self.send_header("Content-Type", "application/json")
        self.send_header("Content-Length", str(len(body)))
        self.end_headers()
        self.wfile.write(body)

    do_GET = _respond
    do_POST = _respond

    def log_message(self, *_args):
        return


@pytest.fixture(scope="module")
def server():
    value = HTTPServer(("127.0.0.1", 0), _Handler)
    thread = threading.Thread(target=value.serve_forever, daemon=True)
    thread.start()
    yield f"http://127.0.0.1:{value.server_port}"
    value.shutdown()


def _control(url: str, **overrides):
    value = {
        "url": url,
        "method": "GET",
        "headers": {"Accept": "application/json"},
        "body": "",
        "maximum": 1024,
        "timeout": 10,
    }
    value.update(overrides)
    return value


def test_child_exchange_round_trips_and_reports_http_errors(server):
    module = _load("deadline_http")
    result = module._child_exchange(_control(server + "/ok"))
    assert (result.status, result.content_type) == (200, "application/json")
    assert result.body == b'{"ok":true}'

    posted = module._child_exchange(
        _control(
            server + "/ok",
            method="POST",
            body=base64.b64encode(b'{"a":1}').decode(),
        )
    )
    assert posted.status == 200

    missing = module._child_exchange(_control(server + "/missing"))
    assert missing.status == 404


def test_child_exchange_rejects_redirects_and_oversized_responses(server):
    module = _load("deadline_http")
    with pytest.raises(Exception):
        module._child_exchange(_control(server + "/redirect"))
    with pytest.raises(ValueError, match="too large"):
        module._child_exchange(_control(server + "/large", maximum=8))


@pytest.mark.parametrize(
    "overrides",
    [
        {"url": 1},
        {"method": None},
        {"headers": ["not", "dict"]},
        {"headers": {"Accept": 5}},
        {"body": b"raw"},
        {"maximum": "big"},
        {"maximum": -1},
        {"maximum": 4 * 1024 * 1024},
        {"timeout": "soon"},
        {"timeout": 0},
        {"timeout": 121},
    ],
)
def test_child_exchange_rejects_invalid_control_documents(overrides):
    module = _load("deadline_http")
    control = _control("http://127.0.0.1:1/")
    control.update(overrides)
    with pytest.raises(ValueError, match="invalid control"):
        module._child_exchange(control)


def test_child_exchange_rejects_bad_or_oversized_encoded_bodies():
    module = _load("deadline_http")
    with pytest.raises(ValueError):
        module._child_exchange(_control("http://127.0.0.1:1/", body="!!not-b64!!"))
    huge = base64.b64encode(b"x" * (module.MAX_CONTROL_BYTES + 1)).decode()
    with pytest.raises(ValueError, match="request too large"):
        module._child_exchange(_control("http://127.0.0.1:1/", body=huge))


def test_read_response_enforces_deadline_and_size():
    module = _load("deadline_http")

    class Reader:
        def __init__(self, body: bytes):
            self.stream = io.BytesIO(body)

        def read(self, limit: int):
            return self.stream.read(limit)

    with pytest.raises(TimeoutError):
        module._read_response(Reader(b"abc"), 10, time.monotonic() - 1)
    with pytest.raises(ValueError, match="too large"):
        module._read_response(Reader(b"abcdef"), 4, time.monotonic() + 5)
    value = module._read_response(Reader(b"abc"), 10, time.monotonic() + 5)
    assert value == b"abc"


def _run_child_main(module, monkeypatch, raw: bytes) -> dict:
    stdin = type("Stdin", (), {"buffer": io.BytesIO(raw)})()
    stdout = io.StringIO()
    monkeypatch.setattr(module.sys, "stdin", stdin)
    monkeypatch.setattr(module.sys, "stdout", stdout)
    code = module._child_main()
    return code, json.loads(stdout.getvalue())


def test_child_main_reports_success_and_failure_documents(monkeypatch, server):
    module = _load("deadline_http")
    code, output = _run_child_main(
        module, monkeypatch, json.dumps(_control(server + "/ok")).encode()
    )
    assert code == 0 and output["ok"] is True
    assert base64.b64decode(output["body"]) == b'{"ok":true}'

    for raw in (
        b"x" * (module.MAX_CONTROL_BYTES + 1),
        b"not json",
        b"[1,2]",
    ):
        code, output = _run_child_main(module, monkeypatch, raw)
        assert code == 1 and output == {"ok": False}


class _FakeProcess:
    def __init__(self, output: bytes, returncode: int = 0):
        self.args = ["fake-child"]
        self.pid = 0
        self.returncode = returncode
        self.output = output
        self.stdin_payload = None

    def communicate(self, payload=None, timeout=None):
        self.stdin_payload = payload
        return self.output, b""


def _fake_popen(output: bytes, returncode: int = 0):
    def popen(*_args, **_kwargs):
        return _FakeProcess(output, returncode)

    return popen


def _success_output(body: bytes, **overrides) -> bytes:
    value = {
        "ok": True,
        "status": 200,
        "content_type": "application/json",
        "body": base64.b64encode(body).decode("ascii"),
    }
    value.update(overrides)
    return json.dumps(value).encode()


def test_exchange_validates_bounds_and_request_body():
    module = _load("deadline_http")
    request = urllib.request.Request("https://scm.bstein.dev/api/v1/x")
    with pytest.raises(module.PolicyError, match="bounds are invalid"):
        module.exchange(request, maximum=1, timeout=0)
    with pytest.raises(module.PolicyError, match="bounds are invalid"):
        module.exchange(request, maximum=-1, timeout=10)
    request.data = "not-bytes"
    with pytest.raises(module.PolicyError, match="safe size"):
        module.exchange(request, maximum=1, timeout=10)
    request.data = b"x" * (module.MAX_CONTROL_BYTES + 1)
    with pytest.raises(module.PolicyError, match="safe size"):
        module.exchange(request, maximum=1, timeout=10)


def test_exchange_returns_result_and_enforces_response_limit():
    module = _load("deadline_http")
    request = urllib.request.Request(
        "https://scm.bstein.dev/api/v1/x", data=b"{}", method="POST"
    )
    result = module.exchange(
        request, maximum=64, timeout=10, popen=_fake_popen(_success_output(b"body"))
    )
    assert (result.status, result.content_type, result.body) == (
        200,
        "application/json",
        b"body",
    )
    with pytest.raises(module.PolicyError, match="safe size"):
        module.exchange(
            request,
            maximum=2,
            timeout=10,
            popen=_fake_popen(_success_output(b"body")),
        )


@pytest.mark.parametrize(
    ("output", "returncode", "match"),
    [
        (b"", 1, "request failed"),
        (b"x" * (4 * 1024 * 1024 + 1), 0, "request failed"),
        (b"not json", 0, "invalid evidence"),
        (b'{"ok":false}', 0, "invalid evidence"),
        (b"[1]", 0, "invalid evidence"),
        (b'{"ok":true}', 0, "invalid evidence"),
        (b'{"ok":true,"status":"200","content_type":"a","body":""}', 0, "invalid evidence"),
        (b'{"ok":true,"status":200,"content_type":"a","body":"!!"}', 0, "invalid evidence"),
    ],
    ids=[
        "empty-error",
        "oversized-output",
        "invalid-json",
        "false-result",
        "array-result",
        "missing-fields",
        "empty-body",
        "invalid-body",
    ],
)
def test_exchange_rejects_invalid_helper_evidence(output, returncode, match):
    module = _load("deadline_http")
    request = urllib.request.Request("https://scm.bstein.dev/api/v1/x")
    with pytest.raises(module.PolicyError, match=match):
        module.exchange(
            request, maximum=64, timeout=10, popen=_fake_popen(output, returncode)
        )


def test_exchange_kills_the_helper_when_the_deadline_expires(server):
    module = _load("deadline_http")
    request = urllib.request.Request(server + "/slow")
    started = time.monotonic()
    with pytest.raises(module.PolicyError, match="deadline exceeded"):
        module.exchange(request, maximum=64, timeout=1.0)
    assert time.monotonic() - started < 5


def test_exchange_fails_before_spawn_wait_when_time_is_exhausted(monkeypatch):
    module = _load("deadline_http")
    request = urllib.request.Request("https://scm.bstein.dev/api/v1/x")
    killed = []
    monkeypatch.setattr(module.os, "killpg", lambda pid, sig: killed.append((pid, sig)))
    clock = iter([0.0, 1_000_000.0, 1_000_000.0, 1_000_000.0])
    monkeypatch.setattr(module.time, "monotonic", lambda: next(clock))
    with pytest.raises(module.PolicyError, match="deadline exceeded"):
        module.exchange(
            request, maximum=64, timeout=10, popen=_fake_popen(_success_output(b""))
        )
    assert killed


def test_terminate_tolerates_already_finished_helpers():
    module = _load("deadline_http")
    process = subprocess.Popen(
        ["/bin/true"], start_new_session=True, stdout=subprocess.DEVNULL
    )
    process.wait()
    module._terminate(process)
    assert process.returncode == 0


def test_child_entrypoint_round_trip_through_real_subprocess(server):
    module = _load("deadline_http")
    request = urllib.request.Request(server + "/ok")
    result = module.exchange(request, maximum=1024, timeout=20)
    assert result.status == 200 and result.body == b'{"ok":true}'


def test_open_bounded_adapts_result_to_the_urlopen_interface():
    module = _load("deadline_http")
    request = urllib.request.Request("https://scm.bstein.dev/api/v1/x")
    with module.open_bounded(
        request, maximum=64, timeout=10, popen=_fake_popen(_success_output(b"body"))
    ) as response:
        assert response.status == 200
        assert response.headers.get_content_type() == "application/json"
        assert response.read(2) == b"bo"
        assert response.read() == b"dy"