from __future__ import annotations

import unittest
from datetime import datetime, timedelta, timezone
from types import SimpleNamespace

from govoplan_poll.backend.mutation_plans import (
    MAX_RETIREMENT_RESPONDENT_IDS,
    PollMutationPlanError,
    decide_existing_response_impact,
    normalize_retirement_selector,
    plan_poll_update,
    plan_response_retirement,
)


def poll(**overrides: object) -> SimpleNamespace:
    values = {
        "status": "open",
        "kind": "availability",
        "title": "Availability",
        "description": None,
        "visibility": "private",
        "result_visibility": "organizer",
        "context_module": "scheduling",
        "context_resource_type": "scheduling_request",
        "context_resource_id": "request-1",
        "workflow_state": "collecting",
        "workflow_steps": [],
        "allow_anonymous": False,
        "allow_response_update": True,
        "min_choices": 1,
        "max_choices": 2,
        "opens_at": None,
        "closes_at": None,
        "metadata_": {},
    }
    values.update(overrides)
    return SimpleNamespace(**values)


def response(
    response_id: str,
    *,
    deleted_at: datetime | None = None,
    idempotency_key: str | None = None,
) -> SimpleNamespace:
    metadata = {}
    if idempotency_key is not None:
        metadata["response_retirement"] = {
            "idempotency_key": idempotency_key
        }
    return SimpleNamespace(
        id=response_id,
        deleted_at=deleted_at,
        metadata_=metadata,
    )


class PollMutationPlanTests(unittest.TestCase):
    def test_poll_update_is_planned_before_mutation_and_preserves_responses(
        self,
    ) -> None:
        item = poll()
        plan = plan_poll_update(
            item,  # type: ignore[arg-type]
            {
                "title": "Revised",
                "context_resource_id": "request-2",
                "max_choices": 1,
            },
            active_option_count=2,
        )

        self.assertEqual("Availability", item.title)
        self.assertEqual("preserve", plan.response_decision.disposition)
        plan.apply(item)
        self.assertEqual("Revised", item.title)
        self.assertEqual("request-2", item.context_resource_id)
        self.assertEqual(1, item.max_choices)

    def test_poll_update_rejects_invalid_window_without_mutation(self) -> None:
        item = poll(opens_at=datetime.now(timezone.utc))
        with self.assertRaisesRegex(
            PollMutationPlanError,
            "closes_at must be after opens_at",
        ):
            plan_poll_update(
                item,  # type: ignore[arg-type]
                {"closes_at": item.opens_at - timedelta(minutes=1)},
                active_option_count=2,
            )
        self.assertIsNone(item.closes_at)

    def test_existing_response_decision_table(self) -> None:
        cases = (
            ("option_content", True, True, "invalidate_affected_answers"),
            ("option_remove", True, False, "reject"),
            ("option_reorder", True, False, "preserve"),
            ("participant_remove", True, False, "retire"),
            ("poll_policy_or_scope", True, False, "preserve"),
            ("option_remove", False, False, "preserve"),
        )
        for change, has_responses, allow_updates, expected in cases:
            with self.subTest(change=change, has_responses=has_responses):
                decision = decide_existing_response_impact(
                    change,  # type: ignore[arg-type]
                    has_active_responses=has_responses,
                    allow_response_update=allow_updates,
                )
                self.assertEqual(expected, decision.disposition)

    def test_retirement_selector_is_deduplicated_and_bounded(self) -> None:
        selector = normalize_retirement_selector(
            respondent_ids=(" person-1 ", "person-1", ""),
            invitation_id=None,
            reason=" participant removed ",
            idempotency_key=" request:participant:removed ",
        )
        self.assertEqual(("person-1",), selector.respondent_ids)
        self.assertEqual("participant removed", selector.reason)

        with self.assertRaisesRegex(
            PollMutationPlanError,
            "too many participant identities",
        ):
            normalize_retirement_selector(
                respondent_ids=tuple(
                    f"person-{index}"
                    for index in range(MAX_RETIREMENT_RESPONDENT_IDS + 1)
                ),
                invitation_id=None,
                reason="participant removed",
                idempotency_key="bounded",
            )

    def test_retirement_replay_precedes_new_active_response(self) -> None:
        retired_at = datetime.now(timezone.utc) - timedelta(minutes=1)
        already_retired = response(
            "response-old",
            deleted_at=retired_at,
            idempotency_key="remove-1",
        )
        newly_submitted = response("response-new")

        plan = plan_response_retirement(
            (already_retired, newly_submitted),
            idempotency_key="remove-1",
            now=datetime.now(timezone.utc),
        )

        self.assertEqual("replay", plan.disposition)
        self.assertEqual(("response-old",), tuple(item.id for item in plan.responses))
        plan.apply(
            reason="participant removed",
            idempotency_key="remove-1",
            metadata={},
        )
        self.assertIsNone(newly_submitted.deleted_at)


if __name__ == "__main__":
    unittest.main()