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

from PyQt5.QtCore import pyqtSlot, pyqtProperty, QObject, pyqtSignal, QRegExp
from PyQt5.QtGui import QValidator
import os #For statvfs.
import urllib #To escape machine names for how they're saved to file.

import UM.Resources
import UM.Settings.ContainerRegistry
import UM.Settings.InstanceContainer

##  Are machine names valid?
#
#   Performs checks based on the length of the name.
class MachineNameValidator(QObject):
    def __init__(self, parent = None):
        super().__init__(parent)

        #Compute the validation regex for printer names. This is limited by the maximum file name length.
        try:
            filename_max_length = os.statvfs(UM.Resources.getDataStoragePath()).f_namemax
        except AttributeError: #Doesn't support statvfs. Probably because it's not a Unix system.
            filename_max_length = 255 #Assume it's Windows on NTFS.
        machine_name_max_length = filename_max_length - len("_current_settings.") - len(UM.Settings.ContainerRegistry.getMimeTypeForContainer(UM.Settings.InstanceContainer).preferredSuffix)
        # Characters that urllib.parse.quote_plus escapes count for 3! So now we
        # must devise a regex that allows only 3 normal characters or 1 special
        # character, and that up to [machine_name_max_length / 3] times.
        maximum_special_characters = int(machine_name_max_length / 12)
        unescaped = r"[a-zA-Z0-9_\-\.\/]"
        #single_length = r"[\u0000-\u007F]"
        #double_length = r"[\u0080-\u07FF]"
        #triple_length = r"[\u0800-\uFFFF]"
        #quadruple_length = r"[\u10000-\u10FFFF]"
        #self.machine_name_regex = r"((((" + unescaped + r"{0,3}|" + single_length + r"){0,2}" \
        #                          + r"|" + double_length + r"){0,2}" \
        #                          + r"|" + triple_length + r"){0,2}" \
        #                          + r"|" + quadruple_length + r"){0," + str(maximum_special_characters) + r"}"
        self.machine_name_regex = r"((" + unescaped + "){0,12}|.){0," + str(maximum_special_characters) + r"}"

    validationChanged = pyqtSignal()

    ##  Check if a specified machine name is allowed.
    #
    #   \param name The machine name to check.
    #   \param position The current position of the cursor in the text box.
    #   \return ``QValidator.Invalid`` if it's disallowed, or
    #   ``QValidator.Acceptable`` if it's allowed.
    def validate(self, name, position):
        #Check for file name length of the current settings container (which is the longest file we're saving with the name).
        try:
            filename_max_length = os.statvfs(UM.Resources.getDataStoragePath()).f_namemax
        except AttributeError: #Doesn't support statvfs. Probably because it's not a Unix system.
            filename_max_length = 255 #Assume it's Windows on NTFS.
        escaped_name = urllib.parse.quote_plus(name)
        current_settings_filename = escaped_name + "_current_settings." + UM.Settings.ContainerRegistry.getMimeTypeForContainer(UM.Settings.InstanceContainer).preferredSuffix
        if len(current_settings_filename) > filename_max_length:
            return QValidator.Invalid

        return QValidator.Acceptable #All checks succeeded.

    ##  Updates the validation state of a machine name text field.
    @pyqtSlot(str)
    def updateValidation(self, new_name):
        is_valid = self.validate(new_name, 0)
        if is_valid == QValidator.Acceptable:
            print("VALID")
            self.validation_regex = "^.*$" #Matches anything.
        else:
            print("BROKEN!")
            self.validation_regex = "a^" #Never matches (unless you manage to get "a" before the start of the string... good luck).
        self.validationChanged.emit()

    @pyqtProperty("QRegExp", notify=validationChanged)
    def machineNameRegex(self):
        print(self.machine_name_regex)
        return QRegExp(self.machine_name_regex)