"""Unit tests for RecipeMeshCache."""
from __future__ import annotations

from unittest.mock import MagicMock

import numpy as np
import pytest

from presa_mano.clients.open3dmodel_cache import RecipeMesh, RecipeMeshCache


def _verts_tris():
    verts = np.array([[0.,0.,0.],[1.,0.,0.],[0.,1.,0.]])
    tris  = np.array([[0,1,2]], dtype=np.int32)
    return verts, tris


def _mock_client(stl_bytes_by_id: dict[str, tuple[bytes, str]]):
    """Mock client whose get_stl_bytes returns the registered (bytes, etag)
    for each recipe_id, and counts calls."""
    m = MagicMock()
    m._call_count = {}
    def _get(recipe_id: str):
        m._call_count[recipe_id] = m._call_count.get(recipe_id, 0) + 1
        return stl_bytes_by_id[recipe_id]
    m.get_stl_bytes.side_effect = _get
    return m


def test_cache_miss_then_hit(monkeypatch):
    verts, tris = _verts_tris()
    monkeypatch.setattr(
        "presa_mano.clients.open3dmodel_cache.parse_stl_bytes",
        lambda b: (verts, tris),
    )
    client = _mock_client({"r1": (b"STL1", "etag-A")})
    cache = RecipeMeshCache(client=client, capacity=4)

    m1 = cache.get("r1")
    assert isinstance(m1, RecipeMesh)
    np.testing.assert_array_equal(m1.vertices, verts)
    np.testing.assert_array_equal(m1.triangles, tris)
    assert m1.etag == "etag-A"
    assert client._call_count["r1"] == 1

    # secondo accesso: la cache valida l'etag (refetch dei bytes, sempre)
    # ma evita il parse -> identity preserved sull'oggetto RecipeMesh.
    m2 = cache.get("r1")
    assert m2 is m1
    assert client._call_count["r1"] == 2


def test_cache_etag_change_refetches(monkeypatch):
    verts, tris = _verts_tris()
    monkeypatch.setattr(
        "presa_mano.clients.open3dmodel_cache.parse_stl_bytes",
        lambda b: (verts, tris),
    )
    client = MagicMock()
    seq = iter([(b"STL_OLD", "etag-A"), (b"STL_NEW", "etag-B")])
    client.get_stl_bytes.side_effect = lambda rid: next(seq)
    cache = RecipeMeshCache(client=client, capacity=4)
    cache.get("r1")
    m2 = cache.get("r1")
    assert m2.etag == "etag-B"
    assert client.get_stl_bytes.call_count == 2


def test_cache_lru_evicts_oldest(monkeypatch):
    verts, tris = _verts_tris()
    monkeypatch.setattr(
        "presa_mano.clients.open3dmodel_cache.parse_stl_bytes",
        lambda b: (verts, tris),
    )
    client = _mock_client({
        f"r{i}": (f"S{i}".encode(), f"e{i}") for i in range(10)
    })
    cache = RecipeMeshCache(client=client, capacity=3)
    cache.get("r1"); cache.get("r2"); cache.get("r3")
    # r1 e' il piu' vecchio
    cache.get("r4")  # evict r1
    cache.get("r1")  # miss -> re-fetch (call_count va a 2)
    assert client._call_count["r1"] == 2


def test_cache_get_uses_overrideable_client(monkeypatch):
    """`get(recipe_id, client=other)` permette di passare un client fresco
    (utile quando PUT /api/config cambia base_url)."""
    verts, tris = _verts_tris()
    monkeypatch.setattr(
        "presa_mano.clients.open3dmodel_cache.parse_stl_bytes",
        lambda b: (verts, tris),
    )
    default_client = _mock_client({"r1": (b"S1", "e1")})
    override_client = _mock_client({"r1": (b"S2", "e2")})
    cache = RecipeMeshCache(client=default_client, capacity=2)

    m = cache.get("r1", client=override_client)
    assert m.etag == "e2"
    assert default_client._call_count.get("r1", 0) == 0
    assert override_client._call_count["r1"] == 1