# Copyright (c) 2018 Ultimaker B.V.
# Cura is released under the terms of the LGPLv3 or higher.

import re #Regular expressions for parsing escape characters in the settings.
import json

from UM.Settings.ContainerFormatError import ContainerFormatError
from UM.Settings.InstanceContainer import InstanceContainer
from UM.Logger import Logger
from UM.i18n import i18nCatalog
catalog = i18nCatalog("cura")

from cura.ReaderWriters.ProfileReader import ProfileReader, NoProfileException

class GCodeProfileReader(ProfileReader):
    """A class that reads profile data from g-code files.
    
    It reads the profile data from g-code files and stores it in a new profile.
    This class currently does not process the rest of the g-code in any way.
    """

    version = 3
    """The file format version of the serialized 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.
    """

    def __init__(self):
        """Initialises the g-code reader as a profile reader."""

        super().__init__()

    def read(self, file_name):
        """Reads a g-code file, loading the profile from it.
        
        :param file_name: The name of the file to read the profile from.
        :return: The profile that was in the specified file, if any. If the
            specified file was no g-code or contained no parsable profile,
            None  is returned.
        """

        if file_name.split(".")[-1] != "gcode":
            return None

        prefix = ";SETTING_" + str(GCodeProfileReader.version) + " "
        prefix_length = len(prefix)

        # Loading all settings from the file.
        # They are all at the end, but Python has no reverse seek any more since Python3.
        # TODO: Consider moving settings to the start?
        serialized = ""  # Will be filled with the serialized profile.
        try:
            with open(file_name, "r", encoding = "utf-8") as f:
                for line in f:
                    if line.startswith(prefix):
                        # Remove the prefix and the newline from the line and add it to the rest.
                        serialized += line[prefix_length : -1]
        except IOError as e:
            Logger.log("e", "Unable to open file %s for reading: %s", file_name, str(e))
            return None

        serialized = unescapeGcodeComment(serialized)
        serialized = serialized.strip()

        if not serialized:
            Logger.log("i", "No custom profile to import from this g-code: %s", file_name)
            raise NoProfileException()

        # serialized data can be invalid JSON
        try:
            json_data = json.loads(serialized)
        except Exception as e:
            Logger.log("e", "Could not parse serialized JSON data from g-code %s, error: %s", file_name, e)
            return None

        profiles = []
        global_profile = readQualityProfileFromString(json_data["global_quality"])

        # This is a fix for profiles created with 2.3.0 For some reason it added the "extruder" property to the
        # global profile.
        # The fix is simple and safe, as a global profile should never have the extruder entry.
        if global_profile.getMetaDataEntry("extruder", None) is not None:
            global_profile.setMetaDataEntry("extruder", None)
        profiles.append(global_profile)

        for profile_string in json_data.get("extruder_quality", []):
            profiles.append(readQualityProfileFromString(profile_string))
        return profiles


def unescapeGcodeComment(string: str) -> str:
    """Unescape a string which has been escaped for use in a gcode comment.
    
    :param string: The string to unescape.
    :return: The unescaped string.
    """

    # Un-escape the serialized profile.
    pattern = re.compile("|".join(GCodeProfileReader.escape_characters.keys()))

    # Perform the replacement with a regular expression.
    return pattern.sub(lambda m: GCodeProfileReader.escape_characters[re.escape(m.group(0))], string)


def readQualityProfileFromString(profile_string) -> InstanceContainer:
    """Read in a profile from a serialized string.
    
    :param profile_string: The profile data in serialized form.
    :return: The resulting Profile object or None if it could not be read.
    """

    # Create an empty profile - the id and name will be changed by the ContainerRegistry
    profile = InstanceContainer("")
    try:
        profile.deserialize(profile_string)
    except ContainerFormatError as e:
        Logger.log("e", "Corrupt profile in this g-code file: %s", str(e))
        return None
    except Exception as e:  # Not a valid g-code file.
        Logger.log("e", "Unable to serialise the profile: %s", str(e))
        return None
    return profile