"""Tests for the FastAPI server (``examples.api_server``).

These tests use FastAPI's TestClient and don't require a running server.
Skipped if fastapi is not installed.
"""

from __future__ import annotations

import pytest

try:
    from fastapi.testclient import TestClient
    HAS_FASTAPI = True
except ImportError:
    HAS_FASTAPI = False

import sys
from pathlib import Path
sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "examples"))

from palimseste.hf import HFPalimpsesteLM
from palimseste.lm import PalimpsesteConfig
import numpy as np

pytestmark = pytest.mark.skipif(not HAS_FASTAPI,
                                reason="fastapi not installed")


@pytest.fixture
def app_and_lm():
    cfg = PalimpsesteConfig(D=2000, context_window=16, kernel_radius=100,
                            temperature=0.3)
    lm = HFPalimpsesteLM(config=cfg, rng=np.random.default_rng(0))
    text = "bonjour salut je suis palimpseste. qui es-tu je suis un cortex. merci je vous en prie."
    lm.build_tokenizer(text)
    lm.train_on_text(text)
    from api_server import create_app
    app = create_app(lm)
    return app, lm


def test_health(app_and_lm):
    app, _ = app_and_lm
    client = TestClient(app)
    r = client.get("/health")
    assert r.status_code == 200
    data = r.json()
    assert data["status"] == "ok"
    assert "D" in data
    assert "|M|" in data


def test_stats(app_and_lm):
    app, _ = app_and_lm
    client = TestClient(app)
    r = client.get("/stats")
    assert r.status_code == 200
    data = r.json()
    assert "D" in data
    assert "n_traces" in data
    assert "vocab_size" in data
    assert "turns" in data


def test_chat(app_and_lm):
    app, _ = app_and_lm
    client = TestClient(app)
    r = client.post("/chat", json={"message": "bonjour"})
    assert r.status_code == 200
    data = r.json()
    assert "response" in data
    assert "elapsed_ms" in data
    assert isinstance(data["response"], str)


def test_teach(app_and_lm):
    app, lm = app_and_lm
    client = TestClient(app)
    n_before = len(lm.mem)
    r = client.post("/teach", json={"question": "what color is the sky",
                                     "answer": "blue"})
    assert r.status_code == 200
    data = r.json()
    assert data["success"] is True
    assert data["tokens_written"] > 0
    assert len(lm.mem) > n_before


def test_root_html(app_and_lm):
    app, _ = app_and_lm
    client = TestClient(app)
    r = client.get("/")
    assert r.status_code == 200
    assert "PALIMPSESTE" in r.text