"""Tests for solver.mates.generator -- synthetic mate generator."""

from __future__ import annotations

from solver.mates.generator import SyntheticMateGenerator, generate_mate_training_batch
from solver.mates.primitives import MateType

# ---------------------------------------------------------------------------
# SyntheticMateGenerator
# ---------------------------------------------------------------------------


class TestSyntheticMateGenerator:
    """SyntheticMateGenerator core functionality."""

    def test_generate_basic(self) -> None:
        """Generate a simple assembly with mates."""
        gen = SyntheticMateGenerator(seed=42)
        bodies, mates, result = gen.generate(3)
        assert len(bodies) == 3
        assert len(mates) > 0
        assert result.analysis is not None

    def test_deterministic_with_seed(self) -> None:
        """Same seed produces same output."""
        gen1 = SyntheticMateGenerator(seed=123)
        _, mates1, _ = gen1.generate(3)

        gen2 = SyntheticMateGenerator(seed=123)
        _, mates2, _ = gen2.generate(3)

        assert len(mates1) == len(mates2)
        for m1, m2 in zip(mates1, mates2, strict=True):
            assert m1.mate_type == m2.mate_type
            assert m1.ref_a.body_id == m2.ref_a.body_id

    def test_grounded(self) -> None:
        """Grounded assembly should work."""
        gen = SyntheticMateGenerator(seed=42)
        bodies, _mates, result = gen.generate(3, grounded=True)
        assert len(bodies) == 3
        assert result.analysis is not None

    def test_revolute_produces_two_mates(self) -> None:
        """A revolute joint should reverse-map to 2 mates."""
        gen = SyntheticMateGenerator(seed=42)
        _bodies, mates, _result = gen.generate(2)
        # 2 bodies -> 1 revolute joint -> 2 mates (concentric + coincident)
        assert len(mates) == 2
        mate_types = {m.mate_type for m in mates}
        assert MateType.CONCENTRIC in mate_types
        assert MateType.COINCIDENT in mate_types


class TestReverseMapping:
    """Reverse mapping from joints to mates."""

    def test_revolute_mapping(self) -> None:
        """REVOLUTE -> Concentric + Coincident."""
        gen = SyntheticMateGenerator(seed=42)
        _bodies, mates, _result = gen.generate(2)
        types = [m.mate_type for m in mates]
        assert MateType.CONCENTRIC in types
        assert MateType.COINCIDENT in types

    def test_round_trip_analysis(self) -> None:
        """Generated mates round-trip through analysis successfully."""
        gen = SyntheticMateGenerator(seed=42)
        _bodies, _mates, result = gen.generate(4)
        assert result.analysis is not None
        assert result.labels is not None
        # Should produce joints from the mates
        assert len(result.joints) > 0


class TestNoiseInjection:
    """Noise injection mechanisms."""

    def test_redundant_injection(self) -> None:
        """Redundant prob > 0 produces more mates than clean version."""
        gen_clean = SyntheticMateGenerator(seed=42, redundant_prob=0.0)
        _, mates_clean, _ = gen_clean.generate(4)

        gen_noisy = SyntheticMateGenerator(seed=42, redundant_prob=1.0)
        _, mates_noisy, _ = gen_noisy.generate(4)

        assert len(mates_noisy) > len(mates_clean)

    def test_missing_injection(self) -> None:
        """Missing prob > 0 produces fewer mates than clean version."""
        gen_clean = SyntheticMateGenerator(seed=42, missing_prob=0.0)
        _, mates_clean, _ = gen_clean.generate(4)

        gen_noisy = SyntheticMateGenerator(seed=42, missing_prob=0.5)
        _, mates_noisy, _ = gen_noisy.generate(4)

        # With 50% drop rate on 6 mates, very likely to drop at least one
        assert len(mates_noisy) <= len(mates_clean)

    def test_incompatible_injection(self) -> None:
        """Incompatible prob > 0 adds mates with wrong geometry."""
        gen = SyntheticMateGenerator(seed=42, incompatible_prob=1.0)
        _, mates, _ = gen.generate(3)
        # Should have extra mates beyond the clean count
        gen_clean = SyntheticMateGenerator(seed=42)
        _, mates_clean, _ = gen_clean.generate(3)
        assert len(mates) > len(mates_clean)


# ---------------------------------------------------------------------------
# generate_mate_training_batch
# ---------------------------------------------------------------------------


class TestGenerateMateTrainingBatch:
    """Batch generation function."""

    def test_batch_structure(self) -> None:
        """Each example has required keys."""
        examples = generate_mate_training_batch(batch_size=3, seed=42)
        assert len(examples) == 3
        for ex in examples:
            assert "bodies" in ex
            assert "mates" in ex
            assert "patterns" in ex
            assert "labels" in ex
            assert "n_bodies" in ex
            assert "n_mates" in ex
            assert "n_joints" in ex

    def test_batch_deterministic(self) -> None:
        """Same seed produces same batch."""
        batch1 = generate_mate_training_batch(batch_size=5, seed=99)
        batch2 = generate_mate_training_batch(batch_size=5, seed=99)
        for ex1, ex2 in zip(batch1, batch2, strict=True):
            assert ex1["n_bodies"] == ex2["n_bodies"]
            assert ex1["n_mates"] == ex2["n_mates"]

    def test_batch_grounded_ratio(self) -> None:
        """Batch respects grounded_ratio parameter."""
        # All grounded
        examples = generate_mate_training_batch(batch_size=5, seed=42, grounded_ratio=1.0)
        assert len(examples) == 5

    def test_batch_with_noise(self) -> None:
        """Batch with noise injection runs without error."""
        examples = generate_mate_training_batch(
            batch_size=3,
            seed=42,
            redundant_prob=0.3,
            missing_prob=0.1,
        )
        assert len(examples) == 3
        for ex in examples:
            assert ex["n_mates"] >= 0