"""API-level tests for POST /api/funnels/trend (按日折线).

Repository dependency overridden with the in-memory fake — no Postgres.
"""

from __future__ import annotations

from datetime import date, timedelta

import pytest
from httpx import ASGITransport, AsyncClient

from app.api.funnels import get_repository
from app.main import app
from tests.conftest import FakeRepository


def _daily(uvs: list[int | None]) -> dict[str, int | None]:
    keys = ["start", "show", "detail", "order", "paid"]
    return {f"uv_{k}": uv for k, uv in zip(keys, uvs)}


def _dt(days_ago: int) -> str:
    return (date.today() - timedelta(days=days_ago)).strftime("%Y%m%d")


@pytest.fixture
def client_and_repo():
    repo = FakeRepository()
    app.dependency_overrides[get_repository] = lambda: repo
    transport = ASGITransport(app=app)
    client = AsyncClient(transport=transport, base_url="http://test")
    yield client, repo
    app.dependency_overrides.clear()


async def test_trend_default_window_returns_ascending_points(client_and_repo) -> None:
    client, repo = client_and_repo
    # 3 active days ending yesterday.
    for d in (3, 2, 1):
        repo.set_daily(_dt(d), _daily([1000 - d, 800 - d, 500 - d, 200 - d, 100 - d]))
    async with client:
        resp = await client.post("/api/funnels/trend", json={})
    assert resp.status_code == 200
    body = resp.json()
    assert body["data_status"] == "ready"
    dts = [p["dt"] for p in body["points"]]
    assert dts == [_dt(3), _dt(2), _dt(1)]  # ascending
    assert body["start_dt"] == _dt(3)
    assert body["end_dt"] == _dt(1)
    # each point carries the fixed 5-step funnel
    assert all(len(p["results"]) == 5 for p in body["points"])


async def test_trend_trims_leading_zero_days(client_and_repo) -> None:
    client, repo = client_and_repo
    repo.set_daily(_dt(5), _daily([0, 0, 0, 0, 0]))  # pre-launch
    repo.set_daily(_dt(4), _daily([0, 0, 0, 0, 0]))  # pre-launch
    repo.set_daily(_dt(3), _daily([900, 700, 400, 150, 80]))
    repo.set_daily(_dt(2), _daily([950, 720, 410, 160, 90]))
    repo.set_daily(_dt(1), _daily([0, 0, 0, 0, 0]))  # mid/trailing zero — kept
    async with client:
        resp = await client.post("/api/funnels/trend", json={})
    body = resp.json()
    dts = [p["dt"] for p in body["points"]]
    assert dts == [_dt(3), _dt(2), _dt(1)]  # leading zeros dropped, trailing zero kept
    assert body["start_dt"] == _dt(3)


async def test_trend_conversion_matches_funnel_口径(client_and_repo) -> None:
    client, repo = client_and_repo
    repo.set_daily(_dt(1), _daily([1000, 800, 500, 200, 100]))
    async with client:
        resp = await client.post("/api/funnels/trend", json={})
    rows = resp.json()["points"][0]["results"]
    assert rows[0]["conversion_rate"] is None  # step 1
    assert rows[1]["conversion_rate"] == pytest.approx(800 / 1000)
    assert rows[3]["conversion_rate"] == pytest.approx(200 / 500)


async def test_trend_custom_range_subsets(client_and_repo) -> None:
    client, repo = client_and_repo
    for d in (4, 3, 2, 1):
        repo.set_daily(_dt(d), _daily([1000, 800, 500, 200, 100]))
    start = (date.today() - timedelta(days=3)).isoformat()
    end = (date.today() - timedelta(days=2)).isoformat()
    async with client:
        resp = await client.post(
            "/api/funnels/trend", json={"start_dt": start, "end_dt": end}
        )
    dts = [p["dt"] for p in resp.json()["points"]]
    assert dts == [_dt(3), _dt(2)]


async def test_trend_no_data_is_missing(client_and_repo) -> None:
    client, _ = client_and_repo
    async with client:
        resp = await client.post("/api/funnels/trend", json={})
    body = resp.json()
    assert body["data_status"] == "missing"
    assert body["points"] == []
    assert body["start_dt"] is None and body["end_dt"] is None


async def test_trend_future_end_rejected(client_and_repo) -> None:
    client, _ = client_and_repo
    today = date.today().isoformat()
    async with client:
        resp = await client.post("/api/funnels/trend", json={"end_dt": today})
    assert resp.status_code == 422


async def test_trend_inverted_range_rejected(client_and_repo) -> None:
    client, _ = client_and_repo
    start = (date.today() - timedelta(days=1)).isoformat()
    end = (date.today() - timedelta(days=5)).isoformat()
    async with client:
        resp = await client.post(
            "/api/funnels/trend", json={"start_dt": start, "end_dt": end}
        )
    assert resp.status_code == 422