"""API tests for the admission queue endpoints and changed /api/v1/query admission.

Covers docs/QUEUE_SPECIFICATION.md section 11 "API tests": response shapes,
status codes, no-store header, cookie issuance on join, credential fields
rejected on queue endpoints, implicit join on query while idle, 409 for a
non-holder.
"""

from __future__ import annotations

import asyncio
from pathlib import Path

import httpx
import pytest
from httpx import ASGITransport

from backend.admission import AdmissionController
from backend.app import create_app, SESSION_COOKIE_NAME
from backend.artifacts import ArtifactStore
from backend.containers import FakeContainerManager
from backend.dev.fake_peer import ScriptedContainerPeer
from backend.model import FakeModelAdapter
from backend.settings import Settings

from tests.backend.conftest import make_test_confluence_client_factory


class FakeClock:
    def __init__(self, start: float = 0.0):
        self._now = start

    def __call__(self) -> float:
        return self._now

    def advance(self, seconds: float) -> None:
        self._now += seconds


def build_app(
    tmp_path: Path,
    scenario: str = "standard",
    admission_controller=None,
    query_timeout_seconds: float = 30.0,
    cleanup_timeout_seconds: float = 5.0,
    queue_max_length: int = 20,
):
    settings = Settings(
        approved_confluence_origins=["https://approved.example.com"],
        query_timeout_seconds=query_timeout_seconds,
        cleanup_timeout_seconds=cleanup_timeout_seconds,
        queue_max_length=queue_max_length,
    )
    store = ArtifactStore(tmp_path / "artifacts")
    container_mgr = FakeContainerManager(lambda: ScriptedContainerPeer(scenario=scenario))
    model_adapter = FakeModelAdapter()
    conf_factory = make_test_confluence_client_factory()

    app = create_app(
        settings=settings,
        container_manager=container_mgr,
        artifact_store=store,
        model_adapter=model_adapter,
        confluence_client_factory=conf_factory,
        admission_controller=admission_controller,
    )
    return app, store, container_mgr


QUERY_PAYLOAD = {
    "prompt": "How do I deploy service X?",
    "credentials": {"url": "https://approved.example.com", "pat": "valid-pat"},
}
ORIGIN = {"Origin": "http://testserver"}


@pytest.mark.asyncio
async def test_queue_join_response_shape_and_cookie(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        resp = await client.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert resp.status_code == 200
        assert resp.headers.get("Cache-Control") == "no-store"
        assert SESSION_COOKIE_NAME in resp.cookies

        data = resp.json()
        assert set(data.keys()) == {
            "ticket_id",
            "status",
            "position",
            "ahead",
            "eta_seconds",
            "reservation_expires_in_seconds",
            "runner",
        }
        assert data["status"] == "ready"
        assert data["position"] == 1
        assert data["ahead"] == 0
        assert data["eta_seconds"] is None
        assert data["reservation_expires_in_seconds"] == 45
        assert data["runner"] == "reserved"


@pytest.mark.asyncio
async def test_queue_join_idempotent(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        first = (await client.post("/api/v1/queue/join", json={}, headers=ORIGIN)).json()
        second = (await client.post("/api/v1/queue/join", json={}, headers=ORIGIN)).json()
        assert first["ticket_id"] == second["ticket_id"]


@pytest.mark.asyncio
async def test_queue_join_rejects_credential_fields(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        resp = await client.post(
            "/api/v1/queue/join",
            json={"credentials": {"url": "https://approved.example.com", "pat": "x"}},
            headers=ORIGIN,
        )
        assert resp.status_code == 400
        assert resp.json()["error"]["code"] == "invalid_input"

        resp = await client.post("/api/v1/queue/join", json={"pat": "secret-token"}, headers=ORIGIN)
        assert resp.status_code == 400
        assert resp.json()["error"]["code"] == "invalid_input"
        assert "secret-token" not in resp.text


@pytest.mark.asyncio
async def test_queue_join_origin_enforcement(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        resp = await client.post("/api/v1/queue/join", json={})
        assert resp.status_code == 403
        assert resp.json()["error"]["code"] == "origin_denied"


@pytest.mark.asyncio
async def test_queue_status_404_without_ticket_then_ready(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        # Bootstrap a session cookie without ever joining.
        await client.get("/")
        resp = await client.get("/api/v1/queue/status")
        assert resp.status_code == 404
        assert resp.json()["error"]["code"] == "ticket_not_found"
        assert resp.headers.get("Cache-Control") == "no-store"

        join_data = (await client.post("/api/v1/queue/join", json={}, headers=ORIGIN)).json()

        status_resp = await client.get("/api/v1/queue/status")
        assert status_resp.status_code == 200
        status_data = status_resp.json()
        assert status_data["ticket_id"] == join_data["ticket_id"]
        assert status_data["status"] == "ready"


@pytest.mark.asyncio
async def test_queue_leave_204_always_and_drops_ticket(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        # No ticket yet: still 204.
        resp = await client.delete("/api/v1/queue/ticket", headers=ORIGIN)
        assert resp.status_code == 204

        await client.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        resp = await client.delete("/api/v1/queue/ticket", headers=ORIGIN)
        assert resp.status_code == 204

        status_resp = await client.get("/api/v1/queue/status")
        assert status_resp.status_code == 404

        # Idempotent second leave.
        resp = await client.delete("/api/v1/queue/ticket", headers=ORIGIN)
        assert resp.status_code == 204


@pytest.mark.asyncio
async def test_queue_leave_origin_enforcement(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        resp = await client.delete("/api/v1/queue/ticket")
        assert resp.status_code == 403
        assert resp.json()["error"]["code"] == "origin_denied"


@pytest.mark.asyncio
async def test_queue_full_503(tmp_path: Path):
    app, _, _ = build_app(tmp_path, queue_max_length=1)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as reserved_client, \
            httpx.AsyncClient(transport=transport, base_url="http://testserver") as queued_client, \
            httpx.AsyncClient(transport=transport, base_url="http://testserver") as overflow_client:
        r1 = await reserved_client.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert r1.json()["status"] == "ready"

        r2 = await queued_client.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert r2.json()["status"] == "queued"

        r3 = await overflow_client.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert r3.status_code == 503
        assert r3.json()["error"]["code"] == "queue_full"


@pytest.mark.asyncio
async def test_query_implicit_join_while_idle_then_idle_again_after(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as client:
        resp = await client.post("/api/v1/query", json=QUERY_PAYLOAD, headers=ORIGIN)
        assert resp.status_code == 200

    # Promotion/idle recovery happens after cleanup; a fresh session should
    # immediately be admitted as "ready" (idle) and see a recorded estimate.
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as probe:
        probe_resp = await probe.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        data = probe_resp.json()
        assert data["status"] == "ready"
        assert data["eta_seconds"] is not None
        assert data["eta_seconds"] >= 0


@pytest.mark.asyncio
async def test_query_409_busy_for_non_holder_session(tmp_path: Path):
    app, _, _ = build_app(tmp_path)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as holder, \
            httpx.AsyncClient(transport=transport, base_url="http://testserver") as intruder:
        join_resp = await holder.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert join_resp.json()["status"] == "ready"

        # A different session, holding no reservation, is refused without
        # disturbing the queue.
        busy_resp = await intruder.post("/api/v1/query", json=QUERY_PAYLOAD, headers=ORIGIN)
        assert busy_resp.status_code == 409
        assert busy_resp.json()["error"]["code"] == "busy"

        status_after = await holder.get("/api/v1/queue/status")
        assert status_after.json()["status"] == "ready"

        # The holder itself can now claim and run.
        ok_resp = await holder.post("/api/v1/query", json=QUERY_PAYLOAD, headers=ORIGIN)
        assert ok_resp.status_code == 200


@pytest.mark.asyncio
async def test_query_busy_while_running_and_promotes_after_cleanup(tmp_path: Path):
    app, _, _ = build_app(
        tmp_path, scenario="timeout", query_timeout_seconds=0.2, cleanup_timeout_seconds=2.0
    )
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as running_client, \
            httpx.AsyncClient(transport=transport, base_url="http://testserver") as other_client, \
            httpx.AsyncClient(transport=transport, base_url="http://testserver") as probe_client:
        task = asyncio.create_task(
            running_client.post("/api/v1/query", json=QUERY_PAYLOAD, headers=ORIGIN)
        )
        await asyncio.sleep(0.05)

        busy_resp = await other_client.post("/api/v1/query", json=QUERY_PAYLOAD, headers=ORIGIN)
        assert busy_resp.status_code == 409
        assert busy_resp.json()["error"]["code"] == "busy"

        # Runner times out, cleanup runs, and the runner returns to idle;
        # the timed-out run's duration is still recorded (failure counts).
        timeout_resp = await asyncio.wait_for(task, timeout=10.0)
        assert timeout_resp.status_code == 504

        probe_resp = await probe_client.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert probe_resp.json()["status"] == "ready"


@pytest.mark.asyncio
async def test_reservation_expiry_query_after_window_is_busy(tmp_path: Path):
    # The query request itself is what discovers the expiry (spec section 3,
    # "Claim"): the reserved session sending the query after the window gets
    # 409, and the ticket is dropped as a side effect of that request.
    clock = FakeClock(0.0)
    admission = AdmissionController(
        reservation_seconds=1.0, heartbeat_seconds=30.0, max_queue_length=5, clock=clock
    )
    app, _, _ = build_app(tmp_path, admission_controller=admission)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as holder:
        join_resp = await holder.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert join_resp.json()["status"] == "ready"

        clock.advance(2.0)

        query_resp = await holder.post("/api/v1/query", json=QUERY_PAYLOAD, headers=ORIGIN)
        assert query_resp.status_code == 409
        assert query_resp.json()["error"]["code"] == "busy"


@pytest.mark.asyncio
async def test_reservation_expiry_status_poll_is_ticket_not_found(tmp_path: Path):
    # Spec section 8: "Reservation expires -> ticket dropped, next promoted;
    # next status is 404; rejoin once." Polling after the window discovers
    # the expiry itself and reports ticket_not_found rather than "ready".
    clock = FakeClock(0.0)
    admission = AdmissionController(
        reservation_seconds=1.0, heartbeat_seconds=30.0, max_queue_length=5, clock=clock
    )
    app, _, _ = build_app(tmp_path, admission_controller=admission)
    transport = ASGITransport(app=app)
    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as holder:
        join_resp = await holder.post("/api/v1/queue/join", json={}, headers=ORIGIN)
        assert join_resp.json()["status"] == "ready"

        clock.advance(2.0)

        status_resp = await holder.get("/api/v1/queue/status")
        assert status_resp.status_code == 404
        assert status_resp.json()["error"]["code"] == "ticket_not_found"

        # Once discovered, the runner is idle again (queue was empty), so a
        # fresh query from any session -- including this one, now indistinct
        # from a walk-up -- is admitted by implicit join.
        query_resp = await holder.post("/api/v1/query", json=QUERY_PAYLOAD, headers=ORIGIN)
        assert query_resp.status_code == 200