# Copyright (c) 2015 Ultimaker B.V.
# Cura is released under the terms of the LGPLv3 or higher.

import os.path

from UM.Application import Application
from UM.Math.Color import Color
from UM.PluginRegistry import PluginRegistry
from UM.Event import Event
from UM.View.View import View
from UM.Scene.Iterator.BreadthFirstIterator import BreadthFirstIterator

from UM.View.RenderBatch import RenderBatch
from UM.View.GL.OpenGL import OpenGL

from . import XRayPass

## View used to display a see-through version of objects with errors highlighted.
class XRayView(View):
    def __init__(self):
        super().__init__()

        self._xray_shader = None
        self._xray_pass = None
        self._xray_composite_shader = None
        self._composite_pass = None
        self._old_composite_shader = None
        self._old_layer_bindings = None

    def beginRendering(self):
        scene = self.getController().getScene()
        renderer = self.getRenderer()

        if not self._xray_shader:
            self._xray_shader = OpenGL.getInstance().createShaderProgram(os.path.join(PluginRegistry.getInstance().getPluginPath("XRayView"), "xray.shader"))
            self._xray_shader.setUniformValue("u_color", Color(*Application.getInstance().getTheme().getColor("xray").getRgb()))

        for node in BreadthFirstIterator(scene.getRoot()):
            if not node.render(renderer):
                if node.getMeshData() and node.isVisible():
                    renderer.queueNode(node,
                                       shader = self._xray_shader,
                                       type = RenderBatch.RenderType.Solid,
                                       blend_mode = RenderBatch.BlendMode.Additive,
                                       sort = -10,
                                       state_setup_callback = lambda gl: gl.glDepthFunc(gl.GL_ALWAYS),
                                       state_teardown_callback = lambda gl: gl.glDepthFunc(gl.GL_LESS)
                    )

    def endRendering(self):
        pass

    def event(self, event):
        if event.type == Event.ViewActivateEvent:
            if not self._xray_pass:
                # Currently the RenderPass constructor requires a size > 0
                # This should be fixed in RenderPass's constructor.
                self._xray_pass = XRayPass.XRayPass(1, 1)

            self.getRenderer().addRenderPass(self._xray_pass)

            if not self._xray_composite_shader:
                self._xray_composite_shader = OpenGL.getInstance().createShaderProgram(os.path.join(PluginRegistry.getInstance().getPluginPath("XRayView"), "xray_composite.shader"))
                theme = Application.getInstance().getTheme()
                self._xray_composite_shader.setUniformValue("u_background_color", Color(*theme.getColor("viewport_background").getRgb()))
                self._xray_composite_shader.setUniformValue("u_error_color", Color(*theme.getColor("xray_error").getRgb()))
                self._xray_composite_shader.setUniformValue("u_outline_color", Color(*theme.getColor("model_selection_outline").getRgb()))

            if not self._composite_pass:
                self._composite_pass = self.getRenderer().getRenderPass("composite")

            self._old_layer_bindings = self._composite_pass.getLayerBindings()
            self._composite_pass.setLayerBindings(["default", "selection", "xray"])
            self._old_composite_shader = self._composite_pass.getCompositeShader()
            self._composite_pass.setCompositeShader(self._xray_composite_shader)

        if event.type == Event.ViewDeactivateEvent:
            self.getRenderer().removeRenderPass(self._xray_pass)
            self._composite_pass.setLayerBindings(self._old_layer_bindings)
            self._composite_pass.setCompositeShader(self._old_composite_shader)
