from uuid import uuid4

import pytest
from fastapi.testclient import TestClient
from sqlalchemy.orm import Session

from models.simulation_result import SimulationResult
from services.simulation import run_simulation


@pytest.fixture
def client(api_client: TestClient) -> TestClient:
    return api_client


def test_run_simulation_function_generates_samples():
    params = [
        {"name": "grade", "value": 1.8, "distribution": "normal", "std_dev": 0.2},
        {
            "name": "recovery",
            "value": 0.9,
            "distribution": "uniform",
            "min": 0.8,
            "max": 0.95,
        },
    ]
    results = run_simulation(params, iterations=5, seed=123)
    assert isinstance(results, list)
    assert len(results) == 5
    assert results[0]["iteration"] == 1


def test_simulation_endpoint_no_params(client: TestClient):
    scenario_payload = {
        "name": f"NoParamScenario-{uuid4()}",
        "description": "No parameters run",
    }
    scenario_resp = client.post("/api/scenarios/", json=scenario_payload)
    assert scenario_resp.status_code == 200
    scenario_id = scenario_resp.json()["id"]

    resp = client.post(
        "/api/simulations/run",
        json={"scenario_id": scenario_id, "parameters": [], "iterations": 10},
    )
    assert resp.status_code == 400
    assert resp.json()["detail"] == "No parameters provided"


def test_simulation_endpoint_success(
    client: TestClient, db_session: Session
):
    scenario_payload = {
        "name": f"SimScenario-{uuid4()}",
        "description": "Simulation test",
    }
    scenario_resp = client.post("/api/scenarios/", json=scenario_payload)
    assert scenario_resp.status_code == 200
    scenario_id = scenario_resp.json()["id"]

    params = [
        {"name": "param1", "value": 2.5, "distribution": "normal", "std_dev": 0.5}
    ]
    payload = {
        "scenario_id": scenario_id,
        "parameters": params,
        "iterations": 10,
        "seed": 42,
    }

    resp = client.post("/api/simulations/run", json=payload)
    assert resp.status_code == 200
    data = resp.json()
    assert data["scenario_id"] == scenario_id
    assert len(data["results"]) == 10
    assert data["summary"]["count"] == 10

    db_session.expire_all()
    persisted = (
        db_session.query(SimulationResult)
        .filter(SimulationResult.scenario_id == scenario_id)
        .all()
    )
    assert len(persisted) == 10


def test_simulation_endpoint_uses_stored_parameters(client: TestClient):
    scenario_payload = {
        "name": f"StoredParams-{uuid4()}",
        "description": "Stored parameter simulation",
    }
    scenario_resp = client.post("/api/scenarios/", json=scenario_payload)
    assert scenario_resp.status_code == 200
    scenario_id = scenario_resp.json()["id"]

    parameter_payload = {
        "scenario_id": scenario_id,
        "name": "grade",
        "value": 1.5,
    }
    param_resp = client.post("/api/parameters/", json=parameter_payload)
    assert param_resp.status_code == 200

    resp = client.post(
        "/api/simulations/run",
        json={"scenario_id": scenario_id, "iterations": 3, "seed": 7},
    )
    assert resp.status_code == 200
    data = resp.json()
    assert data["summary"]["count"] == 3
    assert len(data["results"]) == 3