from __future__ import annotations

import pytest

from app.core.request_limits import RequestBodyLimitMiddleware


def _scope(headers: list[tuple[bytes, bytes]] | None = None) -> dict:
    return {
        "type": "http",
        "asgi": {"version": "3.0"},
        "http_version": "1.1",
        "method": "POST",
        "scheme": "http",
        "path": "/upload",
        "raw_path": b"/upload",
        "query_string": b"",
        "headers": headers or [],
        "client": ("127.0.0.1", 12345),
        "server": ("testserver", 80),
    }


async def _consume_body(scope, receive, send) -> None:
    while True:
        message = await receive()
        if message["type"] == "http.disconnect":
            return
        if not message.get("more_body", False):
            break
    await send({"type": "http.response.start", "status": 200, "headers": []})
    await send({"type": "http.response.body", "body": b"ok", "more_body": False})


@pytest.mark.asyncio
async def test_request_body_limit_rejects_oversized_content_length() -> None:
    sent = []
    received = False

    async def receive():
        nonlocal received
        received = True
        return {"type": "http.request", "body": b"", "more_body": False}

    async def send(message):
        sent.append(message)

    middleware = RequestBodyLimitMiddleware(_consume_body, max_bytes=5)
    await middleware(_scope([(b"content-length", b"6")]), receive, send)

    assert sent[0]["status"] == 413
    assert b"no-store" in dict(sent[0]["headers"])[b"cache-control"]
    assert received is False


@pytest.mark.asyncio
async def test_request_body_limit_rejects_oversized_chunked_body() -> None:
    sent = []
    chunks = iter([
        {"type": "http.request", "body": b"123", "more_body": True},
        {"type": "http.request", "body": b"456", "more_body": True},
        {"type": "http.request", "body": b"", "more_body": False},
    ])

    async def receive():
        return next(chunks)

    async def send(message):
        sent.append(message)

    middleware = RequestBodyLimitMiddleware(_consume_body, max_bytes=5)
    await middleware(_scope(), receive, send)

    assert sent[0]["status"] == 413
    assert b"Request body too large" in sent[1]["body"]
    assert sent[1]["more_body"] is False


@pytest.mark.asyncio
async def test_request_body_limit_allows_body_at_limit() -> None:
    sent = []
    chunks = iter([
        {"type": "http.request", "body": b"12345", "more_body": False},
    ])

    async def receive():
        return next(chunks)

    async def send(message):
        sent.append(message)

    middleware = RequestBodyLimitMiddleware(_consume_body, max_bytes=5)
    await middleware(_scope(), receive, send)

    assert sent[0]["status"] == 200
    assert sent[1]["body"] == b"ok"