# Copyright (c) 2016 Ultimaker B.V.
# Cura is released under the terms of the AGPLv3 or higher.

from UM.Mesh.MeshWriter import MeshWriter
from UM.Logger import Logger
from UM.Application import Application
from UM.Settings.InstanceContainer import InstanceContainer #To create a complete setting profile to store in the g-code.
import re #For escaping characters in the settings.

##  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 = 2

    ##  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.
    }

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

    def write(self, stream, node, mode = MeshWriter.OutputMode.TextMode):
        if mode != MeshWriter.OutputMode.TextMode:
            Logger.log("e", "GCode Writer does not support non-text mode.")
            return False

        scene = Application.getInstance().getController().getScene()
        gcode_list = getattr(scene, "gcode_list")
        if gcode_list:
            for gcode in gcode_list:
                stream.write(gcode)
            # Serialise the current container stack and put it at the end of the file.
            settings = self._serialiseSettings(Application.getInstance().getGlobalContainerStack())
            stream.write(settings)
            return True

        return False

    ##  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, settings):
        prefix = ";SETTING_" + str(GCodeWriter.version) + " "  # The prefix to put before each line.
        prefix_length = len(prefix)

        global_stack = Application.getInstance().getGlobalContainerStack()
        container_with_profile = global_stack.findContainer({"type": "quality"})
        serialized = container_with_profile.serialize()

        # 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.
        serialized = pattern.sub(lambda m: GCodeWriter.escape_characters[re.escape(m.group(0))], serialized)

        # 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(serialized), 80 - prefix_length):
            result += prefix + serialized[pos : pos + 80 - prefix_length] + "\n"
        serialized = result

        return serialized