"""Load-bearing: a COMMISSIONED approach reaches the proposer, and gets no discount from the
deterministic validator (Trekk A3).

The seam this pins is the whole point of krav 1: a domain expert names an approach, and the
hypothesis prompt must actually carry it — otherwise the run merely *claims* to evaluate what was
ordered. Two detach points, and each must go RED on its own:

* drop the approach block from ``_build_messages`` -> the expert's label/description never reaches
  the model (``test_commissioned_approach_reaches_the_proposer``);
* let a commissioned approach bypass ``validate_proposal`` -> an expert's wish would outrank the
  deterministic gate (``test_commissioned_approach_gets_no_validator_discount``).

The control (``test_no_approach_keeps_the_base_prompt_byte_identical``) proves the addition is
inert when no mandate is given: a test that can only go green proves nothing.
"""

from __future__ import annotations

import pytest
from spikes._harness import FakeChatClient, message_texts

from portfolio_optimiser.budget import Budget, TokenMeter
from portfolio_optimiser.generate import _build_messages, generate_via_llm
from portfolio_optimiser.mandate import Approach
from portfolio_optimiser.reference_domain import load_reference_projects
from portfolio_optimiser.validator import Rejection, ValidatedProposal

_VALID = (
    '{"project_id":"FV42-GSV-E1","measure":"Reduce scope",'
    '"affected_items":[{"code":"05.2","quantity":4300,"unit_cost":215},'
    '{"code":"03.1","quantity":1800,"unit_cost":310}],"claimed_saving_nok":200000}'
)
#: Same shape and a value the IR itself accepts, but above the method cap (30% of the ~1.48M
#: affected total = ~445k) -> the DETERMINISTIC VALIDATOR is what must reject it, not the parser.
_INFEASIBLE = (
    '{"project_id":"FV42-GSV-E1","measure":"Reduce scope",'
    '"affected_items":[{"code":"05.2","quantity":4300,"unit_cost":215},'
    '{"code":"03.1","quantity":1800,"unit_cost":310}],"claimed_saving_nok":800000}'
)

_APPROACH = Approach(
    id="led-retrofit",
    label="LED retrofit of office lighting",
    description="Operations believes the fixtures are original and run far past their rated life.",
)


@pytest.fixture(scope="module")
def project():
    return load_reference_projects()[0]  # FV42-GSV-E1


def _meter() -> TokenMeter:
    return TokenMeter(Budget(max_tokens=10**9, max_rounds=20))


def test_commissioned_approach_reaches_the_proposer(project) -> None:
    """The expert's own words — label AND description — reach the hypothesis prompt VERBATIM.

    The description is the part the model cannot infer from cost data (it is the expert's reason
    for wanting this tried), so paraphrasing it away would quietly discard the domain knowledge.
    """
    text = message_texts(_build_messages(project, "ctx", approach=_APPROACH))[0]
    assert _APPROACH.label in text
    assert _APPROACH.description in text


def test_no_approach_keeps_the_base_prompt_byte_identical(project) -> None:
    """CONTROL: without a mandate the prompt is byte-identical to the pre-Trekk-A one, so every
    existing run and golden is untouched (mirrors ``prior_rejection=None``)."""
    base = message_texts(_build_messages(project, "ctx"))[0]
    assert base == message_texts(_build_messages(project, "ctx", approach=None))[0]
    assert "Propose ONE concrete cost-saving measure for this project." in base
    assert _APPROACH.label not in base


async def test_commissioned_approach_gets_no_validator_discount(project) -> None:
    """A commissioned approach whose numbers do not hold is REJECTED — the deterministic gate is
    blocking, and being asked for by a domain expert is not a reason to pass it.

    This is the one rule krav 1 must not be allowed to erode: the expert directs *what is
    evaluated*, never *what is approved*.
    """
    client = FakeChatClient(scripted=[_INFEASIBLE], default_reply=_INFEASIBLE)
    result = await generate_via_llm(
        client, project, "", _meter(), max_attempts=1, approach=_APPROACH
    )
    assert isinstance(result.outcome, Rejection)


async def test_commissioned_approach_still_validates_when_the_numbers_hold(project) -> None:
    """...and the same commissioned path DOES produce a validated proposal when the numbers are
    feasible — so the rejection above is the validator working, not the approach path being
    broken end to end."""
    client = FakeChatClient(scripted=[_VALID], default_reply=_VALID)
    result = await generate_via_llm(
        client, project, "", _meter(), max_attempts=1, approach=_APPROACH
    )
    assert isinstance(result.outcome, ValidatedProposal)
    assert _APPROACH.label in client.received_texts[0][0]  # it went through the commissioned prompt