# Copyright (c) 2017 Ultimaker B.V.
# Cura is released under the terms of the LGPLv3 or higher.

import re  # For escaping characters in the settings.
import json
import copy

from UM.Mesh.MeshWriter import MeshWriter
from UM.Logger import Logger
from UM.Application import Application
from UM.Settings.InstanceContainer import InstanceContainer

from cura.Machines.QualityManager import getMachineDefinitionIDForQualitySearch


##  Writes g-code to a file.
#
#   While this poses as a mesh writer, what this really does is take the g-code
#   in the entire scene and write it to an output device. Since the g-code of a
#   single mesh isn't separable from the rest what with rafts and travel moves
#   and all, it doesn't make sense to write just a single mesh.
#
#   So this plug-in takes the g-code that is stored in the root of the scene
#   node tree, adds a bit of extra information about the profiles and writes
#   that to the output device.
class GCodeWriter(MeshWriter):
    ##  The file format version of the serialised g-code.
    #
    #   It can only read settings with the same version as the version it was
    #   written with. If the file format is changed in a way that breaks reverse
    #   compatibility, increment this version number!
    version = 3

    ##  Dictionary that defines how characters are escaped when embedded in
    #   g-code.
    #
    #   Note that the keys of this dictionary are regex strings. The values are
    #   not.
    escape_characters = {
        re.escape("\\"): "\\\\",  # The escape character.
        re.escape("\n"): "\\n",   # Newlines. They break off the comment.
        re.escape("\r"): "\\r"    # Carriage return. Windows users may need this for visualisation in their editors.
    }

    _setting_keyword = ";SETTING_"

    def __init__(self):
        super().__init__()

        self._application = Application.getInstance()

    ##  Writes the g-code for the entire scene to a stream.
    #
    #   Note that even though the function accepts a collection of nodes, the
    #   entire scene is always written to the file since it is not possible to
    #   separate the g-code for just specific nodes.
    #
    #   \param stream The stream to write the g-code to.
    #   \param nodes This is ignored.
    #   \param mode Additional information on how to format the g-code in the
    #   file. This must always be text mode.
    def write(self, stream, nodes, mode = MeshWriter.OutputMode.TextMode):
        if mode != MeshWriter.OutputMode.TextMode:
            Logger.log("e", "GCodeWriter does not support non-text mode.")
            return False

        active_build_plate = Application.getInstance().getMultiBuildPlateModel().activeBuildPlate
        scene = Application.getInstance().getController().getScene()
        if not hasattr(scene, "gcode_dict"):
            return False
        gcode_dict = getattr(scene, "gcode_dict")
        gcode_list = gcode_dict.get(active_build_plate, None)
        if gcode_list is not None:
            has_settings = False
            for gcode in gcode_list:
                if gcode[:len(self._setting_keyword)] == self._setting_keyword:
                    has_settings = True
                stream.write(gcode)
            # Serialise the current container stack and put it at the end of the file.
            if not has_settings:
                settings = self._serialiseSettings(Application.getInstance().getGlobalContainerStack())
                stream.write(settings)
            return True

        return False

    ##  Create a new container with container 2 as base and container 1 written over it.
    def _createFlattenedContainerInstance(self, instance_container1, instance_container2):
        flat_container = InstanceContainer(instance_container2.getName())

        # The metadata includes id, name and definition
        flat_container.setMetaData(copy.deepcopy(instance_container2.getMetaData()))

        if instance_container1.getDefinition():
            flat_container.setDefinition(instance_container1.getDefinition().getId())

        for key in instance_container2.getAllKeys():
            flat_container.setProperty(key, "value", instance_container2.getProperty(key, "value"))

        for key in instance_container1.getAllKeys():
            flat_container.setProperty(key, "value", instance_container1.getProperty(key, "value"))

        return flat_container

    ##  Serialises a container stack to prepare it for writing at the end of the
    #   g-code.
    #
    #   The settings are serialised, and special characters (including newline)
    #   are escaped.
    #
    #   \param settings A container stack to serialise.
    #   \return A serialised string of the settings.
    def _serialiseSettings(self, stack):
        container_registry = self._application.getContainerRegistry()
        quality_manager = self._application.getQualityManager()

        prefix = self._setting_keyword + str(GCodeWriter.version) + " "  # The prefix to put before each line.
        prefix_length = len(prefix)

        quality_type = stack.quality.getMetaDataEntry("quality_type")
        container_with_profile = stack.qualityChanges
        if container_with_profile.getId() == "empty_quality_changes":
            # If the global quality changes is empty, create a new one
            quality_name = container_registry.uniqueName(stack.quality.getName())
            container_with_profile = quality_manager._createQualityChanges(quality_type, quality_name, stack, None)

        flat_global_container = self._createFlattenedContainerInstance(stack.userChanges, container_with_profile)
        # If the quality changes is not set, we need to set type manually
        if flat_global_container.getMetaDataEntry("type", None) is None:
            flat_global_container.setMetaDataEntry("type", "quality_changes")

        # Ensure that quality_type is set. (Can happen if we have empty quality changes).
        if flat_global_container.getMetaDataEntry("quality_type", None) is None:
            flat_global_container.setMetaDataEntry("quality_type", stack.quality.getMetaDataEntry("quality_type", "normal"))

        # Get the machine definition ID for quality profiles
        machine_definition_id_for_quality = getMachineDefinitionIDForQualitySearch(stack.definition)
        flat_global_container.setMetaDataEntry("definition", machine_definition_id_for_quality)

        serialized = flat_global_container.serialize()
        data = {"global_quality": serialized}

        all_setting_keys = flat_global_container.getAllKeys()
        for extruder in sorted(stack.extruders.values(), key = lambda k: int(k.getMetaDataEntry("position"))):
            extruder_quality = extruder.qualityChanges
            if extruder_quality.getId() == "empty_quality_changes":
                # Same story, if quality changes is empty, create a new one
                quality_name = container_registry.uniqueName(stack.quality.getName())
                extruder_quality = quality_manager._createQualityChanges(quality_type, quality_name, stack, None)

            flat_extruder_quality = self._createFlattenedContainerInstance(extruder.userChanges, extruder_quality)
            # If the quality changes is not set, we need to set type manually
            if flat_extruder_quality.getMetaDataEntry("type", None) is None:
                flat_extruder_quality.setMetaDataEntry("type", "quality_changes")

            # Ensure that extruder is set. (Can happen if we have empty quality changes).
            if flat_extruder_quality.getMetaDataEntry("position", None) is None:
                flat_extruder_quality.setMetaDataEntry("position", extruder.getMetaDataEntry("position"))

            # Ensure that quality_type is set. (Can happen if we have empty quality changes).
            if flat_extruder_quality.getMetaDataEntry("quality_type", None) is None:
                flat_extruder_quality.setMetaDataEntry("quality_type", extruder.quality.getMetaDataEntry("quality_type", "normal"))

            # Change the default definition
            flat_extruder_quality.setMetaDataEntry("definition", machine_definition_id_for_quality)

            extruder_serialized = flat_extruder_quality.serialize()
            data.setdefault("extruder_quality", []).append(extruder_serialized)

            all_setting_keys.update(flat_extruder_quality.getAllKeys())

        # Check if there is any profiles
        if not all_setting_keys:
            Logger.log("i", "No custom settings found, not writing settings to g-code.")
            return ""

        json_string = json.dumps(data)

        # Escape characters that have a special meaning in g-code comments.
        pattern = re.compile("|".join(GCodeWriter.escape_characters.keys()))

        # Perform the replacement with a regular expression.
        escaped_string = pattern.sub(lambda m: GCodeWriter.escape_characters[re.escape(m.group(0))], json_string)

        # Introduce line breaks so that each comment is no longer than 80 characters. Prepend each line with the prefix.
        result = ""

        # Lines have 80 characters, so the payload of each line is 80 - prefix.
        for pos in range(0, len(escaped_string), 80 - prefix_length):
            result += prefix + escaped_string[pos: pos + 80 - prefix_length] + "\n"
        return result