import pytest

from app.services import youtube_client


class FakeResponse:
    def __init__(self, status_code, payload):
        self.status_code = status_code
        self._payload = payload
        self.text = str(payload)

    def json(self):
        return self._payload


class FakeClient:
    def __init__(self, responses):
        self._responses = list(responses)

    def __enter__(self):
        return self

    def __exit__(self, *args):
        return False

    def get(self, url, params=None, headers=None):
        return self._responses.pop(0)


def _credentials():
    class Cred:
        token = "fake-token"

    return Cred()


def test_fetch_subscriptions_paginates(monkeypatch):
    page1 = FakeResponse(
        200,
        {
            "items": [
                {
                    "id": "subA",
                    "snippet": {
                        "title": "Channel A",
                        "description": "desc a",
                        "resourceId": {"channelId": "chanA"},
                        "thumbnails": {"high": {"url": "http://thumb/a.jpg"}},
                    },
                }
            ],
            "nextPageToken": "page2",
        },
    )
    page2 = FakeResponse(
        200,
        {
            "items": [
                {
                    "snippet": {
                        "title": "Channel B",
                        "description": "desc b",
                        "resourceId": {"channelId": "chanB"},
                        "thumbnails": {"default": {"url": "http://thumb/b.jpg"}},
                    }
                }
            ]
        },
    )

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([page1, page2]))

    result = youtube_client.fetch_subscriptions(_credentials())

    assert [r["youtube_channel_id"] for r in result] == ["chanA", "chanB"]
    assert result[0]["youtube_subscription_id"] == "subA"
    assert result[0]["thumbnail_url"] == "http://thumb/a.jpg"
    assert result[1]["thumbnail_url"] == "http://thumb/b.jpg"


def test_fetch_subscriptions_raises_on_quota_exceeded(monkeypatch):
    response = FakeResponse(
        403,
        {"error": {"message": "Quota exceeded", "errors": [{"reason": "quotaExceeded"}]}},
    )
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([response]))

    with pytest.raises(youtube_client.YouTubeQuotaExceeded):
        youtube_client.fetch_subscriptions(_credentials())


def test_fetch_playlist_video_ids(monkeypatch):
    response = FakeResponse(
        200,
        {
            "items": [
                {"contentDetails": {"videoId": "vid1"}},
                {"contentDetails": {"videoId": "vid2"}},
            ]
        },
    )
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([response]))

    result = youtube_client.fetch_playlist_video_ids(_credentials(), "UUplaylist", 10)

    assert result == ["vid1", "vid2"]


def test_fetch_playlist_video_ids_returns_empty_on_404(monkeypatch):
    response = FakeResponse(404, {"error": {"message": "playlist not found"}})
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([response]))

    result = youtube_client.fetch_playlist_video_ids(_credentials(), "UUplaylist", 10)

    assert result == []


def test_fetch_playlist_video_ids_paginates(monkeypatch):
    page1 = FakeResponse(
        200,
        {
            "items": [{"contentDetails": {"videoId": f"vid{i}"}} for i in range(50)],
            "nextPageToken": "page2",
        },
    )
    page2 = FakeResponse(
        200,
        {"items": [{"contentDetails": {"videoId": f"vid{i}"}} for i in range(50, 80)]},
    )
    seen = []

    class RecordingClient(FakeClient):
        def get(self, url, params=None, headers=None):
            seen.append({"url": url, "params": params})
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: RecordingClient([page1, page2]))

    result = youtube_client.fetch_playlist_video_ids(_credentials(), "UUplaylist", 80)

    assert result == [f"vid{i}" for i in range(80)]
    assert len(seen) == 2
    assert seen[0]["params"]["maxResults"] == 50
    assert "pageToken" not in seen[0]["params"]
    assert seen[1]["params"]["maxResults"] == 30
    assert seen[1]["params"]["pageToken"] == "page2"
    assert seen[0]["params"]["part"] == "contentDetails"
    assert seen[1]["params"]["part"] == "contentDetails"


def test_fetch_playlist_video_ids_stops_at_safety_cap(monkeypatch):
    page = FakeResponse(
        200,
        {"items": [{"contentDetails": {"videoId": "vid"}}], "nextPageToken": "next"},
    )
    seen = []

    class RecordingClient(FakeClient):
        def get(self, url, params=None, headers=None):
            seen.append(params)
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: RecordingClient([page] * 100))

    result = youtube_client.fetch_playlist_video_ids(_credentials(), "UUplaylist", 10000)

    assert len(result) == youtube_client.MAX_PLAYLIST_PAGES
    assert len(seen) == youtube_client.MAX_PLAYLIST_PAGES
    assert "pageToken" not in seen[0]
    assert seen[1]["pageToken"] == "next"


def _page_items(video_ids, next_token=None):
    payload = {"items": [{"contentDetails": {"videoId": vid}} for vid in video_ids]}
    if next_token:
        payload["nextPageToken"] = next_token
    return FakeResponse(200, payload)


def test_fetch_playlist_video_ids_incremental_returns_only_unknown(monkeypatch):
    page = _page_items(["new1", "known1", "new2", "known2"])
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([page]))

    result = youtube_client.fetch_playlist_video_ids_incremental(
        _credentials(), "UUplaylist", known_ids={"known1", "known2"}, max_results=10, stop_threshold=50
    )

    assert result == ["new1", "new2"]


def test_fetch_playlist_video_ids_incremental_stops_on_known_run(monkeypatch):
    page1 = _page_items([f"known{i}" for i in range(50)], next_token="page2")
    page2 = _page_items(["new1", "new2"], next_token="page3")
    seen = []

    class RecordingClient(FakeClient):
        def get(self, url, params=None, headers=None):
            seen.append(params)
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: RecordingClient([page1, page2]))

    result = youtube_client.fetch_playlist_video_ids_incremental(
        _credentials(), "UUplaylist", known_ids={f"known{i}" for i in range(50)}, max_results=10, stop_threshold=50
    )

    assert result == []
    assert len(seen) == 1  # page2 never requested


def test_fetch_playlist_video_ids_incremental_known_run_crosses_pages(monkeypatch):
    page1 = _page_items(["new1"] + [f"known{i}" for i in range(49)], next_token="page2")
    page2 = _page_items([f"known{i}" for i in range(49, 60)], next_token="page3")
    seen = []

    class RecordingClient(FakeClient):
        def get(self, url, params=None, headers=None):
            seen.append(params)
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: RecordingClient([page1, page2]))

    result = youtube_client.fetch_playlist_video_ids_incremental(
        _credentials(), "UUplaylist", known_ids={f"known{i}" for i in range(60)}, max_results=10, stop_threshold=50
    )

    assert result == ["new1"]
    assert len(seen) == 2  # stopped mid-page-2, page3 never requested


def test_fetch_playlist_video_ids_incremental_stops_at_cap(monkeypatch):
    pages = [_page_items([f"vid{page * 50 + i}" for i in range(50)], next_token=f"p{page + 2}") for page in range(6)]
    seen = []

    class RecordingClient(FakeClient):
        def get(self, url, params=None, headers=None):
            seen.append(params)
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: RecordingClient(pages))

    result = youtube_client.fetch_playlist_video_ids_incremental(
        _credentials(), "UUplaylist", known_ids=set(), max_results=200, stop_threshold=50
    )

    assert len(result) == 200
    assert len(seen) == 4


def test_fetch_playlist_video_ids_incremental_empty_on_404(monkeypatch):
    response = FakeResponse(404, {"error": {"message": "playlist not found"}})
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([response]))

    result = youtube_client.fetch_playlist_video_ids_incremental(
        _credentials(), "UUplaylist", known_ids=set(), max_results=10, stop_threshold=50
    )

    assert result == []


def test_fetch_playlist_video_ids_incremental_dedupes_new_ids(monkeypatch):
    page = _page_items(["new1", "new1", "known1"])
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([page]))

    result = youtube_client.fetch_playlist_video_ids_incremental(
        _credentials(), "UUplaylist", known_ids={"known1"}, max_results=10, stop_threshold=50
    )

    assert result == ["new1"]


def test_fetch_videos_details(monkeypatch):
    response = FakeResponse(
        200,
        {
            "items": [
                {
                    "id": "vid1",
                    "snippet": {
                        "channelId": "chanA",
                        "title": "Title 1",
                        "description": "desc",
                        "publishedAt": "2026-09-10T12:00:00Z",
                        "thumbnails": {"high": {"url": "http://thumb/1.jpg"}},
                    },
                    "contentDetails": {"duration": "PT10M5S"},
                }
            ]
        },
    )
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([response]))

    result = youtube_client.fetch_videos_details(_credentials(), ["vid1"])

    assert len(result) == 1
    assert result[0]["youtube_video_id"] == "vid1"
    assert result[0]["youtube_channel_id"] == "chanA"
    assert result[0]["duration_iso8601"] == "PT10M5S"
    assert result[0]["thumbnail_url"] == "http://thumb/1.jpg"


def test_unsubscribe_success(monkeypatch):
    response = FakeResponse(204, {})
    seen = {}

    class FakeDeleteClient(FakeClient):
        def delete(self, url, params=None, headers=None):
            seen["params"] = params
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeDeleteClient([response]))

    youtube_client.unsubscribe(_credentials(), "sub123")

    assert seen["params"] == {"id": "sub123"}


def test_unsubscribe_already_gone_is_not_an_error(monkeypatch):
    response = FakeResponse(404, {"error": {"message": "not found"}})

    class FakeDeleteClient(FakeClient):
        def delete(self, url, params=None, headers=None):
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeDeleteClient([response]))

    youtube_client.unsubscribe(_credentials(), "sub123")  # must not raise


def test_unsubscribe_insufficient_scope(monkeypatch):
    response = FakeResponse(
        403,
        {"error": {"message": "Request had insufficient authentication scopes.", "errors": [{"reason": "forbidden"}]}},
    )

    class FakeDeleteClient(FakeClient):
        def delete(self, url, params=None, headers=None):
            return self._responses.pop(0)

    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeDeleteClient([response]))

    with pytest.raises(youtube_client.YouTubeInsufficientScope):
        youtube_client.unsubscribe(_credentials(), "sub123")


def test_fetch_uploads_playlists_batches(monkeypatch):
    response = FakeResponse(
        200,
        {
            "items": [
                {
                    "id": "chanA",
                    "contentDetails": {"relatedPlaylists": {"uploads": "UUchanA"}},
                    "statistics": {"subscriberCount": "12345"},
                },
                {
                    "id": "chanB",
                    "contentDetails": {"relatedPlaylists": {"uploads": "UUchanB"}},
                    "statistics": {"hiddenSubscriberCount": True},
                },
                {"id": "chanC", "contentDetails": {"relatedPlaylists": {"uploads": "UUchanC"}}},
                {"id": "chanD", "contentDetails": {"relatedPlaylists": {}}, "statistics": {"subscriberCount": "42"}},
            ]
        },
    )
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([response]))

    result = youtube_client.fetch_uploads_playlists(_credentials(), ["chanA", "chanB", "chanC", "chanD"])

    assert result == {
        "chanA": {"uploads_playlist_id": "UUchanA", "subscriber_count": 12345},
        "chanB": {"uploads_playlist_id": "UUchanB", "subscriber_count": None},
        "chanC": {"uploads_playlist_id": "UUchanC", "subscriber_count": None},
        "chanD": {"uploads_playlist_id": None, "subscriber_count": 42},
    }


def test_fetch_uploads_playlists_subscriber_count_not_an_int_is_none(monkeypatch):
    response = FakeResponse(
        200,
        {
            "items": [
                {
                    "id": "chanA",
                    "contentDetails": {"relatedPlaylists": {"uploads": "UUchanA"}},
                    "statistics": {"subscriberCount": "not-a-number"},
                }
            ]
        },
    )
    monkeypatch.setattr(youtube_client.httpx, "Client", lambda timeout: FakeClient([response]))

    result = youtube_client.fetch_uploads_playlists(_credentials(), ["chanA"])

    assert result == {"chanA": {"uploads_playlist_id": "UUchanA", "subscriber_count": None}}