import json
import os
import random
import threading
import time
import uuid
from contextlib import contextmanager
from pathlib import Path

import jwt as pyjwt
import pytest
import requests
import sseclient
from pytest import ExitCode


def pytest_collection_modifyitems(items):
    early = []
    rest = []
    for item in items:
        if "Step01PreInit" in item.nodeid or "Step02LazyInit" in item.nodeid:
            early.append(item)
        else:
            rest.append(item)
    items[:] = early + rest


@pytest.hookimpl(trylast=True)
def pytest_sessionfinish(session, exitstatus):
    if exitstatus in (ExitCode.NO_TESTS_COLLECTED, 5):
        session.exitstatus = ExitCode.OK


class _SessionWithBase(requests.Session):
    def __init__(self, base: str, default_timeout: float = 30):
        super().__init__()
        self._base = base.rstrip("/")
        self._default_timeout = default_timeout

    def request(self, method, url, *args, **kwargs):
        if url.startswith("http://") or url.startswith("https://"):
            full = url
        else:
            path = url if url.startswith("/") else f"/{url}"
            full = f"{self._base}{path}"
        kwargs.setdefault("timeout", self._default_timeout)
        return super().request(method, full, *args, **kwargs)


@pytest.fixture(scope="session")
def base_url():
    return os.environ.get("BASE_URL", "http://detections:8080")


@pytest.fixture(scope="session")
def http_client(base_url):
    return _SessionWithBase(base_url, 30)


@pytest.fixture(scope="session")
def jwt_secret():
    return os.environ.get("JWT_SECRET", "")


@pytest.fixture(scope="session")
def jwt_token(jwt_secret):
    if not jwt_secret:
        return ""
    return pyjwt.encode(
        {"sub": "test-user", "exp": int(time.time()) + 3600},
        jwt_secret,
        algorithm="HS256",
    )


@pytest.fixture(scope="session")
def auth_headers(jwt_token):
    return {"Authorization": f"Bearer {jwt_token}"} if jwt_token else {}


@pytest.fixture
def channel_id():
    return str(uuid.uuid4())


@pytest.fixture(scope="session")
def image_detect(http_client, auth_headers):
    def _detect(image_bytes, filename="img.jpg", config=None, timeout=30):
        cid = str(uuid.uuid4())
        headers = {**auth_headers, "X-Channel-Id": cid}
        detections = []
        errors = []
        done = threading.Event()
        connected = threading.Event()

        def _listen():
            try:
                with http_client.get(
                    f"/detect/events/{cid}",
                    stream=True,
                    timeout=timeout + 2,
                    headers=auth_headers,
                ) as resp:
                    resp.raise_for_status()
                    connected.set()
                    for ev in sseclient.SSEClient(resp).events():
                        if not ev.data or not str(ev.data).strip():
                            continue
                        data = json.loads(ev.data)
                        if data.get("mediaStatus") == "AIProcessing":
                            detections.extend(data.get("annotations", []))
                        if data.get("mediaStatus") in ("AIProcessed", "Error"):
                            break
            except BaseException as e:
                errors.append(e)
            finally:
                connected.set()
                done.set()

        th = threading.Thread(target=_listen, daemon=True)
        th.start()
        connected.wait(timeout=5)

        data_form = {}
        if config:
            data_form["config"] = config

        t0 = time.perf_counter()
        r = http_client.post(
            "/detect/image",
            files={"file": (filename, image_bytes, "image/jpeg")},
            data=data_form,
            headers=headers,
            timeout=timeout,
        )
        done.wait(timeout=timeout)
        elapsed_ms = (time.perf_counter() - t0) * 1000.0

        assert r.status_code == 202, f"Expected 202, got {r.status_code}: {r.text}"
        assert not errors, f"SSE errors: {errors}"

        th.join(timeout=1)
        return detections, elapsed_ms

    return _detect


@pytest.fixture
def sse_client_factory(http_client, auth_headers):
    @contextmanager
    def _open(channel_id: str):
        with http_client.get(
            f"/detect/events/{channel_id}",
            stream=True,
            timeout=600,
            headers=auth_headers,
        ) as resp:
            resp.raise_for_status()
            yield sseclient.SSEClient(resp)

    return _open


@pytest.fixture(scope="session")
def mock_loader_url():
    return os.environ.get("MOCK_LOADER_URL", "http://mock-loader:8080")


@pytest.fixture(scope="session")
def mock_annotations_url():
    return os.environ.get("MOCK_ANNOTATIONS_URL", "http://mock-annotations:8081")


@pytest.fixture(scope="session", autouse=True)
def wait_for_services(base_url, mock_loader_url, mock_annotations_url):
    urls = [
        f"{base_url}/health",
        f"{mock_loader_url}/mock/status",
        f"{mock_annotations_url}/mock/status",
    ]
    deadline = time.time() + 120
    while time.time() < deadline:
        ok = True
        for u in urls:
            try:
                r = requests.get(u, timeout=5)
                if r.status_code != 200:
                    ok = False
                    break
            except OSError:
                ok = False
                break
        if ok:
            return
        time.sleep(2)
    pytest.fail("services not ready within 120s")


@pytest.fixture(autouse=True)
def reset_mocks(mock_loader_url, mock_annotations_url):
    requests.post(f"{mock_loader_url}/mock/reset", timeout=10)
    requests.post(f"{mock_annotations_url}/mock/reset", timeout=10)
    yield


def _media_dir() -> Path:
    return Path(os.environ.get("MEDIA_DIR", "/media"))


def _read_media(name: str) -> bytes:
    p = _media_dir() / name
    if not p.is_file():
        pytest.skip(f"missing {p}")
    return p.read_bytes()


@pytest.fixture(scope="session")
def media_dir():
    return str(_media_dir())


@pytest.fixture(scope="session")
def image_small():
    return _read_media("image_small.jpg")


@pytest.fixture(scope="session")
def image_large():
    return _read_media("image_large.JPG")


@pytest.fixture(scope="session")
def image_dense():
    return _read_media("image_dense01.jpg")


@pytest.fixture(scope="session")
def image_dense_02():
    return _read_media("image_dense02.jpg")


@pytest.fixture(scope="session")
def image_different_types():
    return _read_media("image_different_types.jpg")


@pytest.fixture(scope="session")
def image_empty_scene():
    return _read_media("image_empty_scene.jpg")


@pytest.fixture(scope="session")
def video_short_path():
    return str(_media_dir() / "video_test01.mp4")


@pytest.fixture(scope="session")
def video_short_02_path():
    return str(_media_dir() / "video_short02.mp4")


@pytest.fixture(scope="session")
def video_long_path():
    return str(_media_dir() / "video_long03.mp4")


@pytest.fixture(scope="session")
def empty_image():
    return b""


@pytest.fixture(scope="session")
def corrupt_image():
    random.seed(42)
    return random.randbytes(1024)


@pytest.fixture(scope="module")
def warm_engine(http_client, image_small, auth_headers):
    deadline = time.time() + 120
    last_status = None
    consecutive_errors = 0

    while time.time() < deadline:
        cid = str(uuid.uuid4())
        headers = {**auth_headers, "X-Channel-Id": cid}
        done = threading.Event()

        def _listen(cid=cid):
            try:
                with http_client.get(
                    f"/detect/events/{cid}",
                    stream=True,
                    timeout=35,
                    headers=auth_headers,
                ) as resp:
                    resp.raise_for_status()
                    for ev in sseclient.SSEClient(resp).events():
                        if not ev.data or not str(ev.data).strip():
                            continue
                        data = json.loads(ev.data)
                        if data.get("mediaStatus") == "AIProcessed":
                            break
            except Exception:
                pass
            finally:
                done.set()

        th = threading.Thread(target=_listen, daemon=True)
        th.start()
        time.sleep(0.1)

        try:
            r = http_client.post(
                "/detect/image",
                files={"file": ("warm.jpg", image_small, "image/jpeg")},
                headers=headers,
            )
            last_status = r.status_code
            if r.status_code == 202:
                done.wait(timeout=30)
                th.join(timeout=1)
                return
            if r.status_code >= 500:
                consecutive_errors += 1
                if consecutive_errors >= 5:
                    pytest.fail(
                        f"engine warm-up aborted: {consecutive_errors} consecutive "
                        f"HTTP {last_status} errors — server is broken, not starting up"
                    )
            else:
                consecutive_errors = 0
        except OSError:
            consecutive_errors = 0

        th.join(timeout=1)
        time.sleep(2)

    pytest.fail(f"engine warm-up timed out after 120s (last status: {last_status})")