"""
Integration tests for the FastAPI HTTP server (HF Space entrypoint).

Uses FastAPI's TestClient (backed by httpx) to exercise all five endpoints:
  GET  /health
  GET  /tasks
  POST /reset
  POST /step
  GET  /state

These tests are self-contained: each test creates its own TestClient so there
is no shared mutable state between tests.
"""

import pytest
from fastapi.testclient import TestClient

from grid_env.Server.app import app


TASK_IDS = [
    "easy_single_pick",
    "medium_multi_item",
    "hard_restock_priority",
    "obstacle_course",
    "heavy_lifting",
    "stamina_run",
    "budget_run",
    "gauntlet",
]
ALL_ACTIONS = [
    "turn_left",
    "turn_right",
    "move_forward",
    "scan_bin",
    "pick_item",
    "pack_item",
    "recharge",
    "rest",
    "wait",
]


@pytest.fixture()
def client():
    """Fresh TestClient (and thus fresh WarehouseEnvService) per test."""
    # Re-import to get a fresh app instance each test.
    from grid_env.Server import app as app_module
    import importlib
    importlib.reload(app_module)
    with TestClient(app_module.app) as c:
        yield c


# ---------------------------------------------------------------------------
# GET /health
# ---------------------------------------------------------------------------

def test_health_returns_200(client):
    resp = client.get("/health")
    assert resp.status_code == 200


def test_health_has_required_keys(client):
    body = client.get("/health").json()
    assert "status" in body
    assert "task_id" in body
    assert "episode_id" in body


def test_health_status_is_ok(client):
    body = client.get("/health").json()
    assert body["status"] == "ok"


# ---------------------------------------------------------------------------
# GET /tasks
# ---------------------------------------------------------------------------

def test_tasks_returns_200(client):
    resp = client.get("/tasks")
    assert resp.status_code == 200


def test_tasks_has_tasks_key(client):
    body = client.get("/tasks").json()
    assert "tasks" in body
    assert isinstance(body["tasks"], list)


def test_tasks_returns_all(client):
    body = client.get("/tasks").json()
    ids = {t["task_id"] for t in body["tasks"]}
    assert ids == set(TASK_IDS)


# ---------------------------------------------------------------------------
# POST /reset
# ---------------------------------------------------------------------------

def test_reset_default_returns_200(client):
    resp = client.post("/reset", json={})
    assert resp.status_code == 200


def test_reset_response_has_observation_and_state(client):
    body = client.post("/reset", json={}).json()
    assert "observation" in body
    assert "state" in body


def test_reset_observation_has_task_id(client):
    body = client.post("/reset", json={"task_id": "easy_single_pick"}).json()
    assert body["observation"]["task_id"] == "easy_single_pick"


@pytest.mark.parametrize("task_id", TASK_IDS)
def test_reset_each_task(client, task_id):
    body = client.post("/reset", json={"task_id": task_id}).json()
    assert body["observation"]["task_id"] == task_id


def test_reset_with_seed_is_deterministic(client):
    """Same seed must produce the same initial battery level."""
    body1 = client.post("/reset", json={"task_id": "easy_single_pick", "seed": 42}).json()
    body2 = client.post("/reset", json={"task_id": "easy_single_pick", "seed": 42}).json()
    assert body1["observation"]["battery_level"] == body2["observation"]["battery_level"]


def test_reset_unknown_task_returns_404(client):
    resp = client.post("/reset", json={"task_id": "nonexistent_task"})
    assert resp.status_code == 404


# ---------------------------------------------------------------------------
# POST /step
# ---------------------------------------------------------------------------

def test_step_after_reset_returns_200(client):
    client.post("/reset", json={"task_id": "easy_single_pick"})
    resp = client.post("/step", json={"command": "wait"})
    assert resp.status_code == 200


def test_step_response_has_required_keys(client):
    client.post("/reset", json={"task_id": "easy_single_pick"})
    body = client.post("/step", json={"command": "wait"}).json()
    assert "observation" in body
    assert "reward" in body
    assert "done" in body
    assert "info" in body
    assert "state" in body


def test_step_done_is_bool(client):
    client.post("/reset", json={"task_id": "easy_single_pick"})
    body = client.post("/step", json={"command": "wait"}).json()
    assert isinstance(body["done"], bool)


@pytest.mark.parametrize("command", ALL_ACTIONS)
def test_step_all_commands_accepted(client, command):
    """Every valid command string should return 200."""
    client.post("/reset", json={"task_id": "easy_single_pick"})
    resp = client.post("/step", json={"command": command})
    assert resp.status_code == 200


def test_step_invalid_command_returns_400(client):
    client.post("/reset", json={"task_id": "easy_single_pick"})
    resp = client.post("/step", json={"command": "fly_to_mars"})
    assert resp.status_code == 400


def test_step_increments_step_count(client):
    client.post("/reset", json={"task_id": "easy_single_pick"})
    client.post("/step", json={"command": "wait"})
    body = client.post("/step", json={"command": "wait"}).json()
    assert body["state"]["step_count"] == 2


def test_step_episode_terminates(client):
    """Enough wait steps must eventually set done=True."""
    client.post("/reset", json={"task_id": "easy_single_pick"})
    done = False
    for _ in range(60):  # easy task max_steps is 40
        resp = client.post("/step", json={"command": "wait"})
        if resp.json()["done"]:
            done = True
            break
    assert done


def test_step_score_in_range_after_done(client):
    """score in info must be in [0, 1] after the episode ends."""
    client.post("/reset", json={"task_id": "easy_single_pick"})
    score = None
    for _ in range(60):
        body = client.post("/step", json={"command": "wait"}).json()
        if body["done"]:
            score = body["info"].get("score")
            break
    assert score is not None
    assert 0.0 <= score <= 1.0


# ---------------------------------------------------------------------------
# GET /state
# ---------------------------------------------------------------------------

def test_state_returns_200(client):
    resp = client.get("/state")
    assert resp.status_code == 200


def test_state_has_task_id(client):
    body = client.get("/state").json()
    assert "task_id" in body


def test_state_reflects_reset(client):
    client.post("/reset", json={"task_id": "medium_multi_item"})
    body = client.get("/state").json()
    assert body["task_id"] == "medium_multi_item"


def test_state_step_count_matches_steps_taken(client):
    client.post("/reset", json={"task_id": "easy_single_pick"})
    for _ in range(3):
        client.post("/step", json={"command": "wait"})
    body = client.get("/state").json()
    assert body["step_count"] == 3