import os
import pytest
from unittest.mock import MagicMock, patch
from PIL import ImageDraw

# display_manager imports the hardware rgbmatrix module at import time unless
# EMULATOR=true. Use the emulator (same convention as
# test_display_dirty_tracking.py) so this file collects standalone instead of
# relying on collection order — the tests below patch RGBMatrix/
# RGBMatrixOptions explicitly, so the underlying binding doesn't matter here.
os.environ.setdefault("EMULATOR", "true")

from src.display_manager import DisplayManager

@pytest.fixture
def mock_rgb_matrix():
    """Mock the rgbmatrix library."""
    with patch('src.display_manager.RGBMatrix') as mock_matrix, \
         patch('src.display_manager.RGBMatrixOptions') as mock_options, \
         patch('src.display_manager.freetype'):
        
        # Setup matrix instance mock
        matrix_instance = MagicMock()
        matrix_instance.width = 128
        matrix_instance.height = 32
        matrix_instance.CreateFrameCanvas.return_value = MagicMock()
        matrix_instance.Clear = MagicMock()
        matrix_instance.SetImage = MagicMock()
        mock_matrix.return_value = matrix_instance
        
        yield {
            'matrix_class': mock_matrix,
            'options_class': mock_options,
            'matrix_instance': matrix_instance
        }

class TestDisplayManagerInitialization:
    """Test DisplayManager initialization."""
    
    def test_init_hardware_mode(self, test_config, mock_rgb_matrix):
        """Test initialization in hardware mode."""
        # Ensure EMULATOR env var is not set
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(test_config)
            
            assert dm.width == 128
            assert dm.height == 32
            assert dm.matrix is not None
            
            # Verify options were set correctly
            mock_rgb_matrix['options_class'].assert_called()
            options = mock_rgb_matrix['options_class'].return_value
            assert options.rows == 32
            assert options.cols == 64
            assert options.chain_length == 2
            
    def test_init_emulator_mode(self, test_config):
        """Test initialization in emulator mode."""
        # Set EMULATOR env var and patch the import
        with patch.dict('os.environ', {'EMULATOR': 'true'}), \
             patch('src.display_manager.RGBMatrix') as mock_matrix, \
             patch('src.display_manager.RGBMatrixOptions') as mock_options:
            
            # Setup matrix instance
            matrix_instance = MagicMock()
            matrix_instance.width = 128
            matrix_instance.height = 32
            mock_matrix.return_value = matrix_instance
            
            dm = DisplayManager(test_config)
            
            assert dm.width == 128
            assert dm.height == 32
            mock_matrix.assert_called()


class TestDisplayManagerDrawing:
    """Test drawing operations."""
    
    def test_clear(self, test_config, mock_rgb_matrix):
        """Test clear operation."""
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(test_config)
            dm.clear()
            # clear() calls Clear() multiple times (offscreen_canvas, current_canvas, matrix)
            assert dm.matrix.Clear.called
            
    def test_draw_text(self, test_config, mock_rgb_matrix):
        """Text drawn through draw_text must actually light pixels."""
        from PIL import Image, ImageDraw, ImageFont
        import src.display_manager as dm_mod
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            DisplayManager._instance = None
            dm = DisplayManager(test_config, suppress_test_pattern=True)
            # The fixture replaces the module's freetype with a MagicMock,
            # which breaks draw_text's isinstance(font, freetype.Face) check
            # (and silently swallows the draw). Give the mock a real class so
            # isinstance works and the PIL path is taken.
            dm_mod.freetype.Face = type("_FakeFace", (), {})
            # Start from a known-black canvas so the assertion below can only
            # pass if draw_text itself lit something.
            dm.image = Image.new('RGB', (dm.width, dm.height))
            dm.draw = ImageDraw.Draw(dm.image)

            dm.draw_text("Test", 0, 0, font=ImageFont.load_default())

            assert dm.image.convert("L").getbbox() is not None, \
                "draw_text lit no pixels"
            
    def test_draw_image(self, test_config, mock_rgb_matrix):
        """Test image drawing."""
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(test_config)
            
            # DisplayManager doesn't have draw_image method
            # It uses SetImage on canvas in update_display()
            # Just verify DisplayManager can handle image operations
            from PIL import Image
            test_image = Image.new('RGB', (64, 32))
            dm.image = test_image
            dm.draw = ImageDraw.Draw(dm.image)
            
            # Verify image was set
            assert dm.image is not None


class TestDisplayManagerResourceManagement:
    """Test resource management."""

    def test_cleanup(self, test_config, mock_rgb_matrix):
        """Test cleanup operation."""
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(test_config)
            dm.cleanup()

            dm.matrix.Clear.assert_called()


class TestDisplayManagerDoubleSided:
    """Double-sided mode: render once at logical size, tile across the chain."""

    def _config(self, **double_sided):
        """Build a config (physical 128x32) with the given double_sided block."""
        return {
            'display': {
                'hardware': {
                    'rows': 32, 'cols': 64, 'chain_length': 2, 'parallel': 1,
                    'hardware_mapping': 'adafruit-hat-pwm', 'brightness': 90,
                },
                'runtime': {'gpio_slowdown': 2},
                'double_sided': double_sided,
            },
            'timezone': 'UTC',
            'plugin_system': {'plugins_directory': 'plugins'},
        }

    def _captured_physical(self, mock_rgb_matrix):
        """Return the image handed to the canvas on the last update_display()."""
        canvas = mock_rgb_matrix['matrix_instance'].CreateFrameCanvas.return_value
        return canvas.SetImage.call_args[0][0]

    def test_horizontal_reports_logical_dimensions(self, mock_rgb_matrix):
        """Plugins see the per-screen size, not the full physical chain."""
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(enabled=True, copies=2, axis='horizontal'),
                                suppress_test_pattern=True)
            # Physical chain is 128x32; two side-by-side copies -> logical 64x32.
            assert dm.matrix.width == 64
            assert dm.matrix.height == 32
            assert (dm.width, dm.height) == (64, 32)
            assert dm.image.size == (64, 32)

    def test_horizontal_tiles_image_across_chain(self, mock_rgb_matrix):
        """The logical screen is duplicated left/right into a full-chain frame."""
        from PIL import Image
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(enabled=True, copies=2, axis='horizontal'),
                                suppress_test_pattern=True)
            logical = Image.new('RGB', (64, 32), (0, 0, 0))
            logical.putpixel((5, 5), (255, 0, 0))
            dm.image = logical
            dm.update_display()

            physical = self._captured_physical(mock_rgb_matrix)
            assert physical.size == (128, 32)
            assert physical.getpixel((5, 5)) == (255, 0, 0)
            assert physical.getpixel((69, 5)) == (255, 0, 0)  # copy shifted +64

    def test_vertical_axis_tiles_stacked(self, mock_rgb_matrix):
        """Vertical axis stacks copies (for panels on parallel outputs)."""
        from PIL import Image
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(enabled=True, copies=2, axis='vertical'),
                                suppress_test_pattern=True)
            # 128x32 split vertically -> logical 128x16.
            assert (dm.matrix.width, dm.matrix.height) == (128, 16)
            logical = Image.new('RGB', (128, 16), (0, 0, 0))
            logical.putpixel((10, 3), (0, 255, 0))
            dm.image = logical
            dm.update_display()

            physical = self._captured_physical(mock_rgb_matrix)
            assert physical.size == (128, 32)
            assert physical.getpixel((10, 3)) == (0, 255, 0)
            assert physical.getpixel((10, 19)) == (0, 255, 0)  # copy shifted +16

    def test_indivisible_dimension_disables_mode(self, mock_rgb_matrix):
        """A physical size that doesn't divide evenly falls back to single."""
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(enabled=True, copies=3, axis='horizontal'),
                                suppress_test_pattern=True)
            assert dm._double_sided is None  # 128 % 3 != 0
            assert dm.matrix.width == 128
            assert dm.image.size == (128, 32)

    def test_disabled_blits_logical_image_unchanged(self, mock_rgb_matrix):
        """With the feature off, the rendered image is sent through untouched."""
        from PIL import Image
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(enabled=False), suppress_test_pattern=True)
            assert dm._double_sided is None
            img = Image.new('RGB', (128, 32))
            dm.image = img
            dm.update_display()
            assert self._captured_physical(mock_rgb_matrix) is img

    def test_brightness_write_forwards_through_proxy(self, mock_rgb_matrix):
        """Setting brightness via the proxy reaches the real matrix."""
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(enabled=True, copies=2, axis='horizontal'),
                                suppress_test_pattern=True)
            assert dm.set_brightness(70) is True
            assert mock_rgb_matrix['matrix_instance'].brightness == 70


class TestDisplayManagerOrientation:
    """The orientation setting composes onto pixel_mapper_config for panels
    mounted upside down, without disturbing a custom pixel_mapper_config."""

    def _config(self, **hardware_overrides):
        config = {
            'display': {
                'hardware': {
                    'rows': 32, 'cols': 64, 'chain_length': 2, 'parallel': 1,
                    'hardware_mapping': 'adafruit-hat-pwm', 'brightness': 90,
                },
                'runtime': {'gpio_slowdown': 2},
            },
            'timezone': 'UTC',
            'plugin_system': {'plugins_directory': 'plugins'},
        }
        config['display']['hardware'].update(hardware_overrides)
        return config

    def test_default_orientation_leaves_pixel_mapper_config_untouched(self, mock_rgb_matrix):
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            DisplayManager(self._config(), suppress_test_pattern=True)
            options = mock_rgb_matrix['options_class'].return_value
            assert options.pixel_mapper_config == ''

    def test_orientation_180_appends_rotate_mapper(self, mock_rgb_matrix):
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            DisplayManager(self._config(orientation='180'), suppress_test_pattern=True)
            options = mock_rgb_matrix['options_class'].return_value
            assert options.pixel_mapper_config == 'Rotate:180'

    def test_orientation_180_composes_with_existing_pixel_mapper_config(self, mock_rgb_matrix):
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            DisplayManager(self._config(orientation='180', pixel_mapper_config='U-mapper'),
                           suppress_test_pattern=True)
            options = mock_rgb_matrix['options_class'].return_value
            assert options.pixel_mapper_config == 'U-mapper;Rotate:180'


class TestDisplayManagerPi5Guard:
    """On a Pi 5 the library returns no matrix for settings its RP1 path can't
    drive, and the binding doesn't check, so the process would crash on its next
    call. DisplayManager has to refuse before creating the matrix and fall back."""

    def _config(self, **hardware_overrides):
        config = {
            'display': {
                'hardware': {
                    'rows': 48, 'cols': 96, 'chain_length': 1, 'parallel': 1,
                    'hardware_mapping': 'regular', 'brightness': 90,
                },
                'runtime': {'gpio_slowdown': 2},
            },
            'timezone': 'UTC',
            'plugin_system': {'plugins_directory': 'plugins'},
        }
        config['display']['hardware'].update(hardware_overrides)
        return config

    @pytest.fixture
    def board(self, tmp_path, monkeypatch):
        from src import pi5_matrix_support

        def set_model(model):
            path = tmp_path / 'model'
            path.write_bytes(model.encode() + b'\x00')
            monkeypatch.setattr(pi5_matrix_support, 'MODEL_PATH', str(path))
        return set_model

    def test_unsupported_setting_on_pi5_never_creates_the_matrix(self, mock_rgb_matrix, board):
        board('Raspberry Pi 5 Model B Rev 1.0')
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(row_address_type=5), suppress_test_pattern=True)
        mock_rgb_matrix['matrix_class'].assert_not_called()
        assert dm.matrix is None

    def test_supported_setting_on_pi5_creates_the_matrix(self, mock_rgb_matrix, board):
        board('Raspberry Pi 5 Model B Rev 1.0')
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(row_address_type=2), suppress_test_pattern=True)
        mock_rgb_matrix['matrix_class'].assert_called_once()
        assert dm.matrix is not None

    def test_other_boards_are_left_to_the_library(self, mock_rgb_matrix, board):
        board('Raspberry Pi 4 Model B Rev 1.5')
        DisplayManager._instance = None
        with patch.dict('os.environ', {'EMULATOR': 'false'}):
            dm = DisplayManager(self._config(row_address_type=5), suppress_test_pattern=True)
        mock_rgb_matrix['matrix_class'].assert_called_once()
        assert dm.matrix is not None