# Copyright (c) 2022 Ultimaker B.V.
# Cura is released under the terms of the LGPLv3 or higher.
# modified by bigrep, 2024, to add a signal for the gcode hash

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

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.ContainerTree import ContainerTree
from UM.Signal import Signal

from UM.i18n import i18nCatalog

catalog = i18nCatalog("cura")


class GCodeWriter(MeshWriter):
    """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.
    """

    version = 3
    """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!
    """

    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.
    }
    """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.
    """

    _setting_keyword = ";SETTING_"

    gcodeHashed = Signal()

    def __init__(self):
        super().__init__(add_to_recent_files = False)

        self._application = Application.getInstance()

    def write(self, stream, nodes, mode = MeshWriter.OutputMode.TextMode):
        """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.
        """

        if mode != MeshWriter.OutputMode.TextMode:
            Logger.log("e", "GCodeWriter does not support non-text mode.")
            self.setInformation(catalog.i18nc("@error:not supported", "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"):
            self.setInformation(catalog.i18nc("@warning:status", "Please prepare G-code before exporting."))
            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)
            
            # bigrep modification write a hash to the end of the file, must be done here in case there are other post processors
            sha256_hash = hashlib.sha256()
            for gcode in gcode_list:
                sha256_hash.update(gcode.encode("utf-8"))
            hash_str = str(sha256_hash.hexdigest())
            stream.write(f";Checksum: {hash_str}")
            self.gcodeHashed.emit(hash_str)
            return True

        self.setInformation(catalog.i18nc("@warning:status", "Please prepare G-code before exporting."))
        return False

    def _serialiseSettings(self, stack):
        """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 stack: A container stack to serialise.
        :return: A serialised string of the settings.
        """
        container_registry = self._application.getContainerRegistry()

        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
        machine_definition_id_for_quality = ContainerTree.getInstance().machines[stack.definition.getId()].quality_definition
        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())
            quality_id = container_registry.uniqueName((stack.definition.getId() + "_" + quality_name).lower().replace(" ", "_"))
            container_with_profile = InstanceContainer(quality_id)
            container_with_profile.setName(quality_name)
            container_with_profile.setMetaDataEntry("type", "quality_changes")
            container_with_profile.setMetaDataEntry("quality_type", quality_type)
            if stack.getMetaDataEntry("position") is not None:  # For extruder stacks, the quality changes should include an intent category.
                container_with_profile.setMetaDataEntry("intent_category", stack.intent.getMetaDataEntry("intent_category", "default"))
            container_with_profile.setDefinition(machine_definition_id_for_quality)
            container_with_profile.setMetaDataEntry("setting_version", stack.quality.getMetaDataEntry("setting_version"))

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

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

        # Get the machine definition ID for quality profiles
        merged_global_instance_container.setMetaDataEntry("definition", machine_definition_id_for_quality)

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

        all_setting_keys = merged_global_instance_container.getAllKeys()
        for extruder in stack.extruderList:
            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())
                quality_id = container_registry.uniqueName((stack.definition.getId() + "_" + quality_name).lower().replace(" ", "_"))
                extruder_quality = InstanceContainer(quality_id)
                extruder_quality.setName(quality_name)
                extruder_quality.setMetaDataEntry("type", "quality_changes")
                extruder_quality.setMetaDataEntry("quality_type", quality_type)
                extruder_quality.setDefinition(machine_definition_id_for_quality)
                extruder_quality.setMetaDataEntry("setting_version", stack.quality.getMetaDataEntry("setting_version"))

            flat_extruder_quality = InstanceContainer.createMergedInstanceContainer(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
