pi-multifx-pedal/tests/test_midi_integration.py

"""Integration tests for MIDI controller — PC, CC, expression pedal.

Tests the full chain from MIDI handler → PedalApp callbacks →
preset manager → pipeline parameter control.
"""
from __future__ import annotations

from typing import Any

import pytest

from midi.handler import (
    MIDIHandler,
    MIDIEvent,
    CC_EXPRESSION,
    RT_CLOCK,
    RT_START,
    RT_STOP,
    CONTROL_CHANGE,
    PROGRAM_CHANGE,
    NOTE_ON,
)
from presets.manager import PresetManager
from presets.types import FXBlock, FXType, MIDIMapping, Preset


# ═══════════════════════════════════════════════════════════════════
# Fixtures
# ═══════════════════════════════════════════════════════════════════


class MockPipeline:
    """Minimal mock of AudioPipeline for testing MIDI integration."""

    def __init__(self) -> None:
        self._master_volume = 0.8
        self._bypassed = False
        self._loaded_preset: Preset | None = None

    def load_preset(self, preset: Preset) -> None:
        self._loaded_preset = preset


@pytest.fixture
def preset_manager(tmp_path: Any) -> PresetManager:
    """PresetManager with a temp directory."""
    pm = PresetManager(preset_dir=str(tmp_path / "presets"))
    return pm


@pytest.fixture
def mock_pipeline() -> MockPipeline:
    return MockPipeline()


@pytest.fixture
def handler() -> MIDIHandler:
    """MIDIHandler with no hardware interfaces."""
    h = MIDIHandler()
    return h


# ═══════════════════════════════════════════════════════════════════
# CC callback lambda tests (the bugfix)
# ═══════════════════════════════════════════════════════════════════


class TestCCLambdaClosure:
    """Verify that register_cc closures capture the CC number correctly.

    This was the root cause bug: _on_midi_cc received the MIDI channel
    instead of the CC number, breaking expression pedal and preset mappings.
    """

    def test_lambda_captures_cc_number(self, handler: MIDIHandler) -> None:
        """Each registered CC callback should know its CC number."""
        results: list[int] = []

        # Simulate what PedalApp._wire_midi_callbacks does
        for cc in range(128):
            handler.register_cc(cc, lambda val, ch, cc_num=cc: results.append(cc_num))

        # Fire a few CCs through dispatch
        handler.dispatch(MIDIEvent(type="cc", cc_number=0, cc_value=64))
        handler.dispatch(MIDIEvent(type="cc", cc_number=11, cc_value=100))
        handler.dispatch(MIDIEvent(type="cc", cc_number=74, cc_value=50))
        handler.dispatch(MIDIEvent(type="cc", cc_number=127, cc_value=127))

        assert results == [0, 11, 74, 127]

    def test_expression_pedal_identified_correctly(self, handler: MIDIHandler) -> None:
        """Expression pedal (CC #11) should be distinguishable from other CCs."""
        results: list[tuple[int, int, int]] = []

        # Register callbacks like PedalApp does
        for cc in range(128):
            handler.register_cc(
                cc, lambda val, ch, cc_num=cc: results.append((val, cc_num, ch))
            )

        # Send expression pedal CC on MIDI channel 0
        handler.dispatch(
            MIDIEvent(type="cc", cc_number=CC_EXPRESSION, cc_value=64, channel=0)
        )

        assert len(results) == 1
        val, cc_num, ch = results[0]
        assert cc_num == CC_EXPRESSION  # Should be 11, not the MIDI channel
        assert val == 64
        assert ch == 0

    def test_midi_channel_preserved(self, handler: MIDIHandler) -> None:
        """MIDI channel should still be passed correctly."""
        results: list[tuple[int, int, int]] = []

        for cc in range(128):
            handler.register_cc(
                cc, lambda val, ch, cc_num=cc: results.append((val, cc_num, ch))
            )

        # CC#7 on MIDI channel 5
        handler.dispatch(MIDIEvent(type="cc", cc_number=7, cc_value=100, channel=5))

        assert len(results) == 1
        val, cc_num, ch = results[0]
        assert cc_num == 7
        assert val == 100
        assert ch == 5


# ═══════════════════════════════════════════════════════════════════
# PedalApp callback tests
# ═══════════════════════════════════════════════════════════════════


class TestPedalAppMIDICallbacks:
    """Test the PedalApp-level MIDI callback logic in isolation."""

    def test_on_midi_pc_selects_preset(
        self, preset_manager: PresetManager, mock_pipeline: MockPipeline
    ) -> None:
        """Simulate PedalApp._on_midi_pc — PC message should select a preset."""
        from main import PedalApp

        # Create a preset to select
        preset = Preset(name="Test", bank=1, program=2)
        preset_manager.save(preset)

        # Simulate PedalApp callback by calling preset_manager.midi_pc directly
        # (same as PedalApp._on_midi_pc does)
        result = preset_manager.midi_pc(channel=1, program=2)

        assert result.name == "Test"
        assert result.bank == 1
        assert result.program == 2
        assert preset_manager.current_bank == 1
        assert preset_manager.current_program == 2

    def test_on_midi_pc_creates_blank_on_empty_slot(
        self, preset_manager: PresetManager, mock_pipeline: MockPipeline
    ) -> None:
        """Selecting an empty slot via PC should create a blank preset."""
        result = preset_manager.midi_pc(channel=2, program=0)

        assert result is not None
        assert result.bank == 2
        assert result.program == 0
        assert result.name == "New Bank 2 #0"

    def test_expression_pedal_sets_master_volume(
        self, mock_pipeline: MockPipeline
    ) -> None:
        """CC#11 = expression pedal → master volume update."""
        # Simulate PedalApp._on_midi_cc with our fixed signature
        from main import PedalApp

        app = PedalApp.__new__(PedalApp)
        app.pipeline = mock_pipeline
        app.presets = None  # Not needed for expression pedal path

        # Call with CC#11 = expression pedal
        app._on_midi_cc(value=64, cc_number=11, channel=0)

        # Master volume should be 64/127 ≈ 0.504
        assert mock_pipeline._master_volume == pytest.approx(64.0 / 127.0)

    def test_expression_pedal_full_sweep(
        self, mock_pipeline: MockPipeline
    ) -> None:
        """Full expression pedal sweep from heel to toe."""
        from main import PedalApp

        app = PedalApp.__new__(PedalApp)
        app.pipeline = mock_pipeline
        app.presets = None

        values = [0, 32, 64, 96, 127]
        expected = [0.0, 32 / 127, 64 / 127, 96 / 127, 127 / 127]

        for val, exp in zip(values, expected):
            app._on_midi_cc(value=val, cc_number=11, channel=0)
            assert mock_pipeline._master_volume == pytest.approx(exp)

    def test_cc_updates_preset_mapping(
        self, preset_manager: PresetManager, mock_pipeline: MockPipeline
    ) -> None:
        """CC should update a parameter mapped in the preset's MIDI mappings."""
        from main import PedalApp

        # Create a preset with a MIDI mapping for delay feedback on CC#14
        delay_param_key = "delay.feedback"
        preset = Preset(
            name="Delay Test",
            bank=0,
            program=0,
            chain=[
                FXBlock(fx_type=FXType.DELAY, params={"feedback": 0.5, "mix": 0.3}),
            ],
            midi_mappings={
                delay_param_key: MIDIMapping(
                    cc_number=14, channel=0, min_val=0.0, max_val=1.0
                ),
            },
        )
        preset_manager.save(preset)
        preset_manager.midi_pc(channel=0, program=0)  # Select it

        # Set up PedalApp-like context
        app = PedalApp.__new__(PedalApp)
        app.pipeline = mock_pipeline
        app.presets = preset_manager

        # We need to track if the preset's param was updated.
        # _on_midi_cc logs the mapping but doesn't apply changes to the
        # pipeline yet — that's a future enhancement. For now, verify
        # the callback completes without error and the mapping is found.

        # CC#14 = delay.feedback = 100/127
        app._on_midi_cc(value=100, cc_number=14, channel=0)

        # At minimum, it shouldn't crash. The pipeline's master_volume
        # should remain unchanged (CC#14 is not expression pedal).
        assert mock_pipeline._master_volume == 0.8

    def test_cc_mapping_only_matches_correct_cc(
        self, preset_manager: PresetManager, mock_pipeline: MockPipeline
    ) -> None:
        """CC that doesn't match any mapping should not affect anything."""
        from main import PedalApp

        preset = Preset(
            name="Test",
            bank=0,
            program=0,
            midi_mappings={"reverb.mix": MIDIMapping(cc_number=14)},
        )
        preset_manager.save(preset)
        preset_manager.midi_pc(channel=0, program=0)

        app = PedalApp.__new__(PedalApp)
        app.pipeline = mock_pipeline
        app.presets = preset_manager

        # CC#99 has no mapping — should be no-op
        app._on_midi_cc(value=64, cc_number=99, channel=0)
        # CC#14 has a mapping — should be found
        app._on_midi_cc(value=64, cc_number=14, channel=0)

        # Both should complete without error
        assert mock_pipeline._master_volume == 0.8

    def test_no_pipeline_no_crash(self) -> None:
        """CC handler should not crash if pipeline or presets are missing."""
        from main import PedalApp

        app = PedalApp.__new__(PedalApp)
        app.pipeline = None
        app.presets = None

        # These should be no-ops
        app._on_midi_cc(value=64, cc_number=11, channel=0)
        app._on_midi_pc(channel=0, program=0)


# ═══════════════════════════════════════════════════════════════════
# Full parse → dispatch → callback chain tests
# ═══════════════════════════════════════════════════════════════════


class TestFullMIDIChain:
    """End-to-end: raw MIDI bytes → handler → callback → application logic."""

    def test_pc_full_chain(self, preset_manager: PresetManager) -> None:
        """PC message bytes → handler → preset change."""
        handler = MIDIHandler()
        handler.set_pc_callback(lambda ch, pg: preset_manager.midi_pc(ch, pg))

        # Save a preset at bank 3, program 1
        preset_manager.save(Preset(name="PC Test", bank=3, program=1))

        # Send MIDI Program Change: channel=3, program=1
        ev = handler.parse(bytes([PROGRAM_CHANGE | 3, 1]))
        assert ev is not None
        handler.dispatch(ev)

        assert preset_manager.current_bank == 3
        assert preset_manager.current_program == 1

        loaded = preset_manager.load(3, 1)
        assert loaded.name == "PC Test"

    def test_expression_full_chain(self, mock_pipeline: MockPipeline) -> None:
        """CC#11 bytes → handler → expression pedal → master volume."""
        handler = MIDIHandler()
        results: list[tuple[int, int, int]] = []

        # Register like PedalApp does — lambda captures CC#11
        for cc in range(128):
            handler.register_cc(
                cc, lambda val, ch, cc_num=cc: results.append((val, cc_num, ch))
            )

        # Send CC#11 = expression pedal, value 96
        ev = handler.parse(bytes([CONTROL_CHANGE | 0, CC_EXPRESSION, 96]))
        assert ev is not None
        assert ev.type == "cc"
        assert ev.cc_number == CC_EXPRESSION
        assert ev.cc_value == 96
        handler.dispatch(ev)

        # Verify the lambda was called with correct CC number
        assert len(results) == 1
        val, cc_num, ch = results[0]
        assert cc_num == 11  # CC#11, not MIDI channel
        assert val == 96

    def test_midi_channel_preserved_through_chain(self) -> None:
        """MIDI channel should survive parse → dispatch."""
        handler = MIDIHandler()
        results: list[tuple[int, int, int]] = []

        for cc in range(128):
            handler.register_cc(
                cc, lambda val, ch, cc_num=cc: results.append((val, cc_num, ch))
            )

        # CC#7 on MIDI channel 15
        ev = handler.parse(bytes([CONTROL_CHANGE | 15, 7, 100]))
        assert ev is not None
        handler.dispatch(ev)

        assert len(results) == 1
        val, cc_num, ch = results[0]
        assert val == 100
        assert cc_num == 7
        assert ch == 15  # MIDI channel preserved

    def test_pc_different_banks(self, preset_manager: PresetManager) -> None:
        """PC messages targeting different banks should switch correctly."""
        handler = MIDIHandler()
        handler.set_pc_callback(lambda ch, pg: preset_manager.midi_pc(ch, pg))

        # Save presets in different banks
        preset_manager.save(Preset(name="Bank 0", bank=0, program=0))
        preset_manager.save(Preset(name="Bank 3", bank=3, program=2))
        preset_manager.save(Preset(name="Bank 7", bank=7, program=1))

        # Switch to bank 3, program 2
        ev = handler.parse(bytes([PROGRAM_CHANGE | 3, 2]))
        assert ev is not None
        handler.dispatch(ev)
        assert preset_manager.current_bank == 3
        assert preset_manager.current_program == 2
        assert preset_manager.load(3, 2).name == "Bank 3"

        # Switch to bank 0, program 0
        ev = handler.parse(bytes([PROGRAM_CHANGE | 0, 0]))
        assert ev is not None
        handler.dispatch(ev)
        assert preset_manager.current_bank == 0
        assert preset_manager.current_program == 0
        assert preset_manager.load(0, 0).name == "Bank 0"


# ═══════════════════════════════════════════════════════════════════
# Expression pedal edge cases
# ═══════════════════════════════════════════════════════════════════


class TestExpressionPedalEdgeCases:
    """Expression pedal boundary conditions."""

    def test_expression_min_value(self, mock_pipeline: MockPipeline) -> None:
        """CC#11 value 0 should set master volume to 0."""
        from main import PedalApp

        app = PedalApp.__new__(PedalApp)
        app.pipeline = mock_pipeline
        app.presets = None

        app._on_midi_cc(value=0, cc_number=11, channel=0)
        assert mock_pipeline._master_volume == 0.0

    def test_expression_max_value(self, mock_pipeline: MockPipeline) -> None:
        """CC#11 value 127 should set master volume to 1.0."""
        from main import PedalApp

        app = PedalApp.__new__(PedalApp)
        app.pipeline = mock_pipeline
        app.presets = None

        app._on_midi_cc(value=127, cc_number=11, channel=0)
        assert mock_pipeline._master_volume == 1.0

    def test_expression_above_127_clipped_by_handler(self) -> None:
        """CC value >127 should be clipped at parse time."""
        handler = MIDIHandler()

        # MIDI protocol constrains to 7-bit, but verify parse handles it
        ev = handler.parse(bytes([CONTROL_CHANGE | 0, 11, 127]))
        assert ev is not None
        assert ev.cc_value <= 127

    def test_expression_on_wrong_channel_still_works(
        self, mock_pipeline: MockPipeline
    ) -> None:
        """Expression pedal (CC#11) should work on any MIDI channel."""
        from main import PedalApp

        app = PedalApp.__new__(PedalApp)
        app.pipeline = mock_pipeline
        app.presets = None

        # Expression on MIDI channel 7
        app._on_midi_cc(value=100, cc_number=11, channel=7)
        assert mock_pipeline._master_volume == pytest.approx(100.0 / 127.0)


# ═══════════════════════════════════════════════════════════════════
# Program Change edge cases
# ═══════════════════════════════════════════════════════════════════


class TestProgramChangeEdgeCases:
    """Program Change boundary conditions."""

    def test_pc_program_127_valid(self, preset_manager: PresetManager) -> None:
        """Program 127 (max for MIDI) gets clamped to PRESETS_PER_BANK-1."""
        preset_manager.save(Preset(name="Max PG", bank=0, program=127))
        result = preset_manager.midi_pc(channel=0, program=127)
        # program is clamped to PRESETS_PER_BANK - 1 = 3
        assert result.program == 3

    def test_pc_program_clamped(self, preset_manager: PresetManager) -> None:
        """Program > 127 should be clamped to 3 (PRESETS_PER_BANK-1)."""
        # midi_pc calls _select_and_activate which clamps program
        # to [0, PRESETS_PER_BANK-1] = [0, 3]
        # So program=127 becomes 3
        result = preset_manager.midi_pc(channel=0, program=127)
        assert result.program == 3  # Clamped to max index

    def test_pc_rapid_switching(self, preset_manager: PresetManager) -> None:
        """Rapid PC messages should switch presets without error."""
        handler = MIDIHandler()
        handler.set_pc_callback(lambda ch, pg: preset_manager.midi_pc(ch, pg))

        for bank in range(4):
            for prog in range(4):
                preset_manager.save(
                    Preset(name=f"Rapid B{bank}P{prog}", bank=bank, program=prog)
                )

        # Rapid-fire PC messages
        import time

        for bank in range(4):
            for prog in range(4):
                ev = handler.parse(bytes([PROGRAM_CHANGE | bank, prog]))
                assert ev is not None
                handler.dispatch(ev)
                time.sleep(0.001)  # Small yield between dispatches

        # Should end on the last one
        assert preset_manager.current_bank == 3
        assert preset_manager.current_program == 3