"""Reasoning effort: what goes out, and what does not.

The second half matters as much as the first. There is no field that works
everywhere -- OpenAI and vLLM read `reasoning_effort`, llama.cpp drops it
silently and reads only `chat_template_kwargs` -- so both are sent. That is only
safe because neither is sent at all until somebody chooses an effort, which is
what keeps an endpoint strict about unknown parameters working exactly as it
did.
"""

from __future__ import annotations

import pytest
from fastapi.testclient import TestClient
from sqlalchemy import select

from lembas.db.models import Chat, Connection, Model, User
from lembas.services import chat as chat_service

from .conftest import control_named


def _model(db, **capabilities) -> Model:
    connection = Connection(name="c", base_url="http://127.0.0.1:1", api_key_encrypted="")
    db.add(connection)
    db.commit()
    model = Model(
        connection_id=connection.id,
        model_id="m",
        capabilities_json={"reasoning": True, **capabilities},
    )
    db.add(model)
    db.commit()
    return model


def _chat(db, effort: str | None = None) -> Chat:
    model = _model(db)
    user = db.scalars(select(User)).first()
    chat = Chat(
        user_id=user.id,
        model_id=model.model_id,
        connection_id=model.connection_id,
        params_json={"reasoning_effort": effort} if effort is not None else {},
    )
    db.add(chat)
    db.commit()
    return chat


# --- What reaches the endpoint -----------------------------------------------
def test_an_effort_goes_out_in_both_forms(client: TestClient, db, registered):
    """One value, two fields. Neither endpoint family reads the other's."""
    chat = _chat(db, "high")

    body = chat_service.build_request(db, chat)

    assert body["reasoning_effort"] == "high"
    assert body["chat_template_kwargs"] == {"reasoning_effort": "high"}


def test_no_effort_means_neither_field(client: TestClient, db, registered):
    """The whole safety of sending both. A chat nobody has set an effort on is
    byte-for-byte the request it was before this existed, so a provider that
    refuses unknown parameters is untouched until somebody opts in."""
    chat = _chat(db)

    body = chat_service.build_request(db, chat)

    assert "reasoning_effort" not in body
    assert "chat_template_kwargs" not in body


def test_a_cleared_effort_means_neither_field(client: TestClient, db, registered):
    """Cleared is stored as None, like every other parameter here."""
    chat = _chat(db, None)

    body = chat_service.build_request(db, chat)

    assert "reasoning_effort" not in body


@pytest.mark.parametrize("junk", ["sudo", "HIGH ", "maximum", "1"])
def test_a_value_that_is_not_an_effort_is_not_sent(client: TestClient, db, registered, junk):
    """Never trusted from the row: it could predate a change to the list."""
    chat = _chat(db, junk)

    assert "reasoning_effort" not in chat_service.build_request(db, chat)


def test_existing_chat_template_kwargs_are_kept(client: TestClient, db, registered):
    """Merged rather than replaced, so a future caller setting something else
    there does not lose it."""
    body: dict = {"chat_template_kwargs": {"enable_thinking": True}}

    chat_service.apply_effort(body, "low")

    assert body["chat_template_kwargs"] == {"enable_thinking": True, "reasoning_effort": "low"}


# --- Setting it ---------------------------------------------------------------
def test_patching_the_effort_stores_it(client: TestClient, db, registered):
    chat = _chat(db)

    assert client.patch(
        f"/api/chats/{chat.id}", data={"reasoning_effort": "medium"}
    ).status_code == 204

    db.refresh(chat)
    assert chat.params_json["reasoning_effort"] == "medium"


def test_an_empty_effort_clears_it(client: TestClient, db, registered):
    chat = _chat(db, "high")

    client.patch(f"/api/chats/{chat.id}", data={"reasoning_effort": ""})

    db.refresh(chat)
    assert chat.params_json["reasoning_effort"] is None


def test_an_unknown_effort_leaves_the_old_one(client: TestClient, db, registered):
    """Ignored, not refused: a typo should not cost the setting you had."""
    chat = _chat(db, "low")

    client.patch(f"/api/chats/{chat.id}", data={"reasoning_effort": "extreme"})

    db.refresh(chat)
    assert chat.params_json["reasoning_effort"] == "low"


def test_the_control_only_appears_on_a_reasoning_model(client: TestClient, db, registered):
    """The flag has existed with no reader since the beginning; this is its
    first job. Offering the control everywhere would offer a setting that does
    nothing almost everywhere."""
    chat = _chat(db)
    assert "data-effort" in client.get(f"/chat/{chat.id}").text

    model = db.scalars(select(Model)).one()
    model.capabilities_json = {"reasoning": False}
    db.commit()

    assert "data-effort" not in client.get(f"/chat/{chat.id}").text


# --- The per-model default ----------------------------------------------------
def test_a_new_chat_starts_from_the_models_defaults(client: TestClient, db, registered):
    """`Model.params_json` has claimed to do this since it was added and did it
    nowhere. It is empty on every existing row, so honouring it changes nothing
    until an administrator sets something."""
    model = _model(db)
    model.params_json = {"reasoning_effort": "high"}
    db.commit()

    client.post("/api/chats/start", data={"content": "hello", "model_id": "m"})

    chat = db.scalars(select(Chat)).one()
    assert chat.params_json["reasoning_effort"] == "high"


def test_a_model_with_no_defaults_starts_a_plain_chat(client: TestClient, db, registered):
    _model(db)

    client.post("/api/chats/start", data={"content": "hello", "model_id": "m"})

    assert db.scalars(select(Chat)).one().params_json == {}


# --- Choosable before the first prompt ---------------------------------------
def test_the_effort_select_carries_its_own_verb(client: TestClient, db, registered):
    """The same invariant the mode select needs, for the same reason.

    Both were built on `form="…"` pointing at an empty sibling form holding the
    `hx-patch`, and both therefore wrote nothing at all: `form=` scopes the
    values a request carries, it does not route the event that starts one.
    """
    chat = _chat(db)

    select = control_named(client.get(f"/chat/{chat.id}").text, "reasoning_effort")
    assert select["hx-patch"] == f"/api/chats/{chat.id}"
    assert select["form"] == "chat-params-form"


def test_the_effort_is_offered_before_there_is_a_chat(client: TestClient, db, registered):
    """Otherwise it is a setting you can only reach once it is too late to use.

    On the new-chat screen there is nothing to PATCH, so it is an ordinary field
    of the composer's form and carries no verb -- `_new_chat` reads it.
    """
    _model(db)

    select = control_named(client.get("/chat").text, "reasoning_effort")
    assert "hx-patch" not in select
    assert "form" not in select


def test_starting_a_chat_with_an_effort_stores_it(client: TestClient, db, registered):
    _model(db)

    client.post(
        "/api/chats/start",
        data={"content": "hello", "model_id": "m", "reasoning_effort": "low"},
    )

    assert db.scalars(select(Chat)).one().params_json["reasoning_effort"] == "low"


def test_an_explicit_effort_beats_the_models_default(client: TestClient, db, registered):
    """An inherited value is a starting point, not a ceiling."""
    model = _model(db)
    model.params_json = {"reasoning_effort": "high"}
    db.commit()

    client.post(
        "/api/chats/start",
        data={"content": "hello", "model_id": "m", "reasoning_effort": "low"},
    )

    assert db.scalars(select(Chat)).one().params_json["reasoning_effort"] == "low"


def test_a_nonsense_effort_at_the_start_falls_back(client: TestClient, db, registered):
    model = _model(db)
    model.params_json = {"reasoning_effort": "high"}
    db.commit()

    client.post(
        "/api/chats/start",
        data={"content": "hello", "model_id": "m", "reasoning_effort": "extreme"},
    )

    assert db.scalars(select(Chat)).one().params_json["reasoning_effort"] == "high"