"""State machine transition tests (happy path + 409 invalid transitions)."""

from __future__ import annotations

import pytest

from app.statemachine import (
    InvalidTransition,
    STATES,
    TransitionContext,
    check_transition,
)


class TestStateMachineTransitions:
    """Test all valid transitions (happy path)."""

    def test_discovered_to_scored(self):
        ctx = TransitionContext(
            application_id="test",
            from_state="discovered",
            to_state="scored",
            has_score=True,
        )
        check_transition(ctx)  # should not raise

    def test_discovered_to_rejected(self):
        ctx = TransitionContext("test", "discovered", "rejected")
        check_transition(ctx)

    def test_scored_to_approved(self):
        ctx = TransitionContext("test", "scored", "approved")
        check_transition(ctx)

    def test_scored_to_rejected(self):
        ctx = TransitionContext("test", "scored", "rejected")
        check_transition(ctx)

    def test_approved_to_drafting(self):
        ctx = TransitionContext("test", "approved", "drafting")
        check_transition(ctx)

    def test_drafting_to_sent(self):
        ctx = TransitionContext(
            "test",
            "drafting",
            "sent",
            has_confirmed_approval=True,
            artifact_hash_match=True,
        )
        check_transition(ctx)

    def test_sent_to_interviewing(self):
        ctx = TransitionContext("test", "sent", "interviewing")
        check_transition(ctx)

    def test_interviewing_to_offer(self):
        ctx = TransitionContext("test", "interviewing", "offer")
        check_transition(ctx)

    def test_interviewing_to_closed(self):
        ctx = TransitionContext("test", "interviewing", "closed")
        check_transition(ctx)

    def test_offer_to_closed(self):
        ctx = TransitionContext("test", "offer", "closed")
        check_transition(ctx)

    def test_scored_to_expired(self):
        ctx = TransitionContext("test", "scored", "expired")
        check_transition(ctx)

    def test_approved_to_expired(self):
        ctx = TransitionContext("test", "approved", "expired")
        check_transition(ctx)


class TestStateMachineInvalidTransitions:
    """Test invalid transitions raise InvalidTransition."""

    def test_discovered_to_approved(self):
        ctx = TransitionContext("test", "discovered", "approved")
        with pytest.raises(InvalidTransition):
            check_transition(ctx)

    def test_discovered_to_sent(self):
        ctx = TransitionContext("test", "discovered", "sent")
        with pytest.raises(InvalidTransition):
            check_transition(ctx)

    def test_rejected_to_scored(self):
        ctx = TransitionContext("test", "rejected", "scored")
        with pytest.raises(InvalidTransition):
            check_transition(ctx)

    def test_closed_to_sent(self):
        ctx = TransitionContext("test", "closed", "sent")
        with pytest.raises(InvalidTransition):
            check_transition(ctx)

    def test_unknown_from_state(self):
        ctx = TransitionContext("test", "nonexistent", "scored")
        with pytest.raises(InvalidTransition):
            check_transition(ctx)

    def test_unknown_to_state(self):
        ctx = TransitionContext("test", "discovered", "nonexistent")
        with pytest.raises(InvalidTransition):
            check_transition(ctx)

    def test_drafting_to_sent_no_approval(self):
        """Guard: drafting -> sent requires confirmed approval."""
        ctx = TransitionContext(
            "test",
            "drafting",
            "sent",
            has_confirmed_approval=False,
            artifact_hash_match=False,
        )
        with pytest.raises(InvalidTransition) as exc_info:
            check_transition(ctx)
        assert "guard failed" in str(exc_info.value)

    def test_drafting_to_sent_hash_mismatch(self):
        """Guard: drafting -> sent requires hash match."""
        ctx = TransitionContext(
            "test",
            "drafting",
            "sent",
            has_confirmed_approval=True,
            artifact_hash_match=False,
        )
        with pytest.raises(InvalidTransition):
            check_transition(ctx)

    def test_discovered_to_scored_no_score(self):
        """Guard: discovered -> scored requires scoring completed (has_score)."""
        ctx = TransitionContext(
            "test",
            "discovered",
            "scored",
            has_score=False,
        )
        with pytest.raises(InvalidTransition) as exc_info:
            check_transition(ctx)
        assert "guard failed" in str(exc_info.value)


class TestStateMachineHelpers:
    def test_all_states_present(self):
        assert len(STATES) == 10

    def test_can_transition_valid(self):
        from app.statemachine import can_transition
        assert can_transition("discovered", "scored")
        assert can_transition("discovered", "rejected")

    def test_can_transition_invalid(self):
        from app.statemachine import can_transition
        assert not can_transition("discovered", "sent")
        assert not can_transition("closed", "discovered")