"""The Maker composes at a desk: image saved, graph tried, no measurement."""
import io

import pytest
from PIL import Image
from sqlalchemy import select

from src.backend.config import settings
from src.backend.models.orm.measurement import Measurement
from src.backend.models.orm.recipe import RecipeVersion
from src.backend.models.orm.task import RecipeSubtask, RecipeTask
from src.backend.models.orm.vision import VisionReferenceImage
from src.backend.tests.conftest import auth_headers, create_test_recipe


def an_image() -> bytes:
    buffer = io.BytesIO()
    Image.new("L", (64, 64), color=0).save(buffer, format="PNG")
    return buffer.getvalue()


async def recipe_parts(db_session, recipe_id: int):
    """`create_test_recipe` returns only the recipe: here it is broken apart."""
    version = (await db_session.execute(
        select(RecipeVersion).where(
            RecipeVersion.recipe_id == recipe_id,
            RecipeVersion.is_current == True,  # noqa: E712
        )
    )).scalar_one()
    task = (await db_session.execute(
        select(RecipeTask).where(RecipeTask.version_id == version.id)
    )).scalars().first()
    subtask = (await db_session.execute(
        select(RecipeSubtask).where(RecipeSubtask.task_id == task.id)
    )).scalars().first()
    return version, task, subtask


@pytest.fixture
def worker_says(monkeypatch):
    def _install(outputs: dict):
        async def fake_call(image_bytes: bytes, graph: dict) -> dict:
            return {"outputs": outputs, "failures": [],
                    "engine_version": "b" * 40, "duration_ms": 7}
        monkeypatch.setattr(
            "src.backend.services.vision_service._call_worker", fake_call,
        )
    return _install


@pytest.fixture(autouse=True)
def redirect_uploads(monkeypatch, tmp_path):
    """Keep reference images out of the real repo tree during tests.

    `settings.upload_path` is `parents[2] / self.upload_dir`, and pathlib
    replaces the left operand of `/` when the right one is absolute - so
    redirecting the bare `upload_dir` setting to pytest's absolute `tmp_path`
    is enough to redirect the resolved path too.
    """
    monkeypatch.setattr(settings, "upload_dir", str(tmp_path))


@pytest.mark.asyncio
async def test_a_reference_image_keeps_its_provenance(
    client, db_session, maker_user,
):
    recipe = await create_test_recipe(db_session, maker_user.id)
    version, task, subtask = await recipe_parts(db_session, recipe.id)
    await db_session.commit()

    response = await client.post(
        "/api/vision/reference-images",
        headers=auth_headers(maker_user),
        files={"image": ("ref.png", an_image(), "image/png")},
        data={"task_id": str(task.id), "note": "sample part"},
    )

    assert response.status_code == 200
    saved = (await db_session.execute(
        select(VisionReferenceImage)
    )).scalars().one()
    assert saved.task_id == task.id
    assert saved.note == "sample part"
    assert saved.acquired_at is not None
    assert saved.path


@pytest.mark.asyncio
async def test_preview_runs_the_graph_and_saves_no_measurement(
    client, db_session, maker_user, worker_says,
):
    recipe = await create_test_recipe(db_session, maker_user.id)
    version, task, subtask = await recipe_parts(db_session, recipe.id)
    task.task_type = "camera_measure"
    task.vision_json = {"schema_version": 1, "name": "p", "tools": []}
    subtask.vision_output = "t1.diameter"
    await db_session.commit()
    worker_says({"t1.diameter": 42.0})

    response = await client.post(
        "/api/vision/preview",
        headers=auth_headers(maker_user),
        files={"image": ("ref.png", an_image(), "image/png")},
        data={"task_id": str(task.id)},
    )

    assert response.status_code == 200
    assert response.json()["outputs"]["t1.diameter"] == 42.0
    # This is the whole point of this test: composing does not measure.
    assert (await db_session.execute(select(Measurement))).scalars().all() == []