import string, re
import PatternChecker
from DummyField import fields
from DateTime import DateTime
from threading import Thread
from urllib import urlopen
from urlparse import urljoin
from Errors import ValidationError

class ValidatorBase:
    """Even more minimalistic base class for validators.
    """
    property_names = ['enabled']

    message_names = []

    enabled = fields.CheckBoxField('enabled',
                                   title="Enabled",
                                   description=(
        "If a field is not enabled, it will considered to be not "
        "in the form during rendering or validation. Be careful "
        "when you change this state dynamically (in the TALES tab): "
        "a user could submit a field that since got disabled, or "
        "get a validation error as a field suddenly got enabled that "
        "wasn't there when the form was drawn."),
                                   default=1)

    def raise_error(self, error_key, field):
        raise ValidationError(error_key, field)

    def validate(self, field, key, REQUEST):
        pass # override in subclass

    def need_validate(self, field, key, REQUEST):
        """Default behavior is always validation.
        """
        return 1

class Validator(ValidatorBase):
    """Validates input and possibly transforms it to output.
    """
    property_names = ValidatorBase.property_names + ['external_validator']

    external_validator = fields.MethodField('external_validator',
                                            title="External Validator",
                                            description=(
        "When a method name is supplied, this method will be "
        "called each time this field is being validated. All other "
        "validation code is called first, however. The value (result of "
        "previous validation) and the REQUEST object will be passed as "
        "arguments to this method. Your method should return true if the "
        "validation succeeded. Anything else will cause "
        "'external_validator_failed' to be raised."),
                                            default="",
                                            required=0)

    message_names = ValidatorBase.message_names + ['external_validator_failed']

    external_validator_failed = "The input failed the external validator."

class StringBaseValidator(Validator):
    """Simple string validator.
    """
    property_names = Validator.property_names + ['required', 'whitespace_preserve']

    required = fields.CheckBoxField('required',
                                    title='Required',
                                    description=(
        "Checked if the field is required; the user has to fill in some "
        "data."),
                                    default=1)

    whitespace_preserve = fields.CheckBoxField('whitespace_preserve',
                                               title="Preserve whitespace",
                                               description=(
        "Checked if the field preserves whitespace. This means even "
        "just whitespace input is considered to be data."),
                                               default=0)

    message_names = Validator.message_names + ['required_not_found']

    required_not_found = 'Input is required but no input given.'

    def validate(self, field, key, REQUEST):
        value = REQUEST.get(key, "")
        if not field.get_value('whitespace_preserve'):
            value = string.strip(value)
        if field.get_value('required') and value == "":
            self.raise_error('required_not_found', field)
        return value

class StringValidator(StringBaseValidator):
    property_names = StringBaseValidator.property_names +\
                     ['unicode', 'max_length', 'truncate']

    unicode = fields.CheckBoxField('unicode',
                                   title='Unicode',
                                   description=(
        "Checked if the field delivers a unicode string instead of an "
        "8-bit string."),
                                   default=0)

    max_length = fields.IntegerField('max_length',
                                     title='Maximum length',
                                     description=(
        "The maximum amount of characters that can be entered in this "
        "field. If set to 0 or is left empty, there is no maximum. "
        "Note that this is server side validation."),
                                     default="",
                                     required=0)

    truncate = fields.CheckBoxField('truncate',
                                    title='Truncate',
                                    description=(
        "If checked, truncate the field if it receives more input than is "
        "allowed. The normal behavior in this case is to raise a validation "
        "error, but the text can be silently truncated instead."),
                                    default=0)

    message_names = StringBaseValidator.message_names +\
                    ['too_long']

    too_long = 'Too much input was given.'

    def validate(self, field, key, REQUEST):
        value = StringBaseValidator.validate(self, field, key, REQUEST)
        if field.get_value('unicode'):
            # use acquisition to get encoding of form
            value = unicode(value, field.get_form_encoding())

        max_length = field.get_value('max_length') or 0
        truncate = field.get_value('truncate')

        if max_length > 0 and len(value) > max_length:
            if truncate:
                value = value[:max_length]
            else:
                self.raise_error('too_long', field)
        return value

StringValidatorInstance = StringValidator()

class EmailValidator(StringValidator):
    message_names = StringValidator.message_names + ['not_email']

    not_email = 'You did not enter an email address.'

    # This regex allows for a simple username or a username in a
    # multi-dropbox (%). The host part has to be a normal fully
    # qualified domain name, allowing for 6 characters (.museum) as a
    # TLD.  No bang paths (uucp), no dotted-ip-addresses, no angle
    # brackets around the address (we assume these would be added by
    # some custom script if needed), and of course no characters that
    # don't belong in an e-mail address.
    pattern = re.compile('^[0-9a-zA-Z_&.%+-]+@([0-9a-zA-Z]([0-9a-zA-Z-]*[0-9a-zA-Z])?\.)+[a-zA-Z]{2,6}$')

    def validate(self, field, key, REQUEST):
        value = StringValidator.validate(self, field, key, REQUEST)
        if value == "" and not field.get_value('required'):
            return value

        if self.pattern.search(string.lower(value)) == None:
            self.raise_error('not_email', field)
        return value

EmailValidatorInstance = EmailValidator()

class PatternValidator(StringValidator):
    # does the real work
    checker = PatternChecker.PatternChecker()

    property_names = StringValidator.property_names +\
                     ['pattern']

    pattern = fields.StringField('pattern',
                                 title="Pattern",
                                 required=1,
                                 default="",
                                 description=(
        "The pattern the value should conform to. Patterns are "
        "composed of digits ('d'), alphabetic characters ('e') and "
        "alphanumeric characters ('f'). Any other character in the pattern "
        "should appear literally in the value in that place. Internal "
        "whitespace is checked as well but may be included in any amount. "
        "Example: 'dddd ee' is a Dutch zipcode (postcode). "
        "NOTE: currently experimental and details may change!")
                                 )

    message_names = StringValidator.message_names +\
                    ['pattern_not_matched']

    pattern_not_matched = "The entered value did not match the pattern."

    def validate(self, field, key, REQUEST):
        value = StringValidator.validate(self, field, key, REQUEST)
        if value == "" and not field.get_value('required'):
            return value
        value = self.checker.validate_value([field.get_value('pattern')],
                                            value)
        if value is None:
            self.raise_error('pattern_not_matched', field)
        return value

PatternValidatorInstance = PatternValidator()

class BooleanValidator(Validator):
    def validate(self, field, key, REQUEST):
        return not not REQUEST.get(key, 0)

BooleanValidatorInstance = BooleanValidator()

class IntegerValidator(StringBaseValidator):
    property_names = StringBaseValidator.property_names +\
                     ['start', 'end']

    start = fields.IntegerField('start',
                                title='Start',
                                description=(
        "The integer entered by the user must be larger than or equal to "
        "this value. If left empty, there is no minimum."),
                                default="",
                                required=0)

    end = fields.IntegerField('end',
                              title='End',
                              description=(
        "The integer entered by the user must be smaller than this "
        "value. If left empty, there is no maximum."),
                              default="",
                              required=0)

    message_names = StringBaseValidator.message_names +\
                    ['not_integer', 'integer_out_of_range']

    not_integer = 'You did not enter an integer.'
    integer_out_of_range = 'The integer you entered was out of range.'

    def validate(self, field, key, REQUEST):
        value = StringBaseValidator.validate(self, field, key, REQUEST)
        # we need to add this check again
        if value == "" and not field.get_value('required'):
            return value

        try:
            value = int(value)
        except ValueError:
            self.raise_error('not_integer', field)

        start = field.get_value('start')
        end = field.get_value('end')
        if start != "" and value < start:
            self.raise_error('integer_out_of_range', field)
        if end != "" and value >= end:
            self.raise_error('integer_out_of_range', field)
        return value

IntegerValidatorInstance = IntegerValidator()

class FloatValidator(StringBaseValidator):
    message_names = StringBaseValidator.message_names + ['not_float']

    not_float = "You did not enter a floating point number."

    def validate(self, field, key, REQUEST):
        value = StringBaseValidator.validate(self, field, key, REQUEST)
        if value == "" and not field.get_value('required'):
            return value

        try:
            value = float(value)
        except ValueError:
            self.raise_error('not_float', field)
        return value

FloatValidatorInstance = FloatValidator()

class LinesValidator(StringBaseValidator):
    property_names = StringBaseValidator.property_names +\
                     ['unicode', 'max_lines', 'max_linelength', 'max_length']

    unicode = fields.CheckBoxField('unicode',
                                   title='Unicode',
                                   description=(
        "Checked if the field delivers a unicode string instead of an "
        "8-bit string."),
                                   default=0)

    max_lines = fields.IntegerField('max_lines',
                                    title='Maximum lines',
                                    description=(
        "The maximum amount of lines a user can enter. If set to 0, "
        "or is left empty, there is no maximum."),
                                    default="",
                                    required=0)

    max_linelength = fields.IntegerField('max_linelength',
                                         title="Maximum length of line",
                                         description=(
        "The maximum length of a line. If set to 0 or is left empty, there "
        "is no maximum."),
                                         default="",
                                         required=0)

    max_length = fields.IntegerField('max_length',
                                     title="Maximum length (in characters)",
                                     description=(
        "The maximum total length in characters that the user may enter. "
        "If set to 0 or is left empty, there is no maximum."),
                                     default="",
                                     required=0)

    message_names = StringBaseValidator.message_names +\
                    ['too_many_lines', 'line_too_long', 'too_long']

    too_many_lines = 'You entered too many lines.'
    line_too_long = 'A line was too long.'
    too_long = 'You entered too many characters.'

    def validate(self, field, key, REQUEST):
        value = StringBaseValidator.validate(self, field, key, REQUEST)

        # we need to add this check again
        if value == "" and not field.get_value('required'):
            return []
        if field.get_value('unicode'):
            value = unicode(value, field.get_form_encoding())
        # check whether the entire input is too long
        max_length = field.get_value('max_length') or 0
        if max_length and len(value) > max_length:
            self.raise_error('too_long', field)
        # split input into separate lines
        lines = string.split(value, "\n")

        # check whether we have too many lines
        max_lines = field.get_value('max_lines') or 0
        if max_lines and len(lines) > max_lines:
            self.raise_error('too_many_lines', field)

        # strip extraneous data from lines and check whether each line is
        # short enough
        max_linelength = field.get_value('max_linelength') or 0
        result = []
        whitespace_preserve = field.get_value('whitespace_preserve')
        for line in lines:
            if not whitespace_preserve:
                line = string.strip(line)
            if max_linelength and len(line) > max_linelength:
                self.raise_error('line_too_long', field)
            result.append(line)

        return result

LinesValidatorInstance = LinesValidator()

class TextValidator(LinesValidator):
    def validate(self, field, key, REQUEST):
        value = LinesValidator.validate(self, field, key, REQUEST)
        # we need to add this check again
        if value == [] and not field.get_value('required'):
            return ""

        # join everything into string again with \n and return
        return string.join(value, "\n")

TextValidatorInstance = TextValidator()

class SelectionValidator(StringBaseValidator):

    property_names = StringBaseValidator.property_names +\
                     ['unicode']

    unicode = fields.CheckBoxField('unicode',
                                   title='Unicode',
                                   description=(
        "Checked if the field delivers a unicode string instead of an "
        "8-bit string."),
                                   default=0)

    message_names = StringBaseValidator.message_names +\
                    ['unknown_selection']

    unknown_selection = 'You selected an item that was not in the list.'

    def validate(self, field, key, REQUEST):
        value = StringBaseValidator.validate(self, field, key, REQUEST)

        if value == "" and not field.get_value('required'):
            return value

        # get the text and the value from the list of items
        for item in field.get_value('items'):
            if type(item) in [type(()), type([])]:
                item_text, item_value = item
            else:
                item_text = item
                item_value = item

            # check if the value is equal to the string/unicode version of
            # item_value; if that's the case, we can return the *original*
            # value in the list (not the submitted value). This way, integers
            # will remain integers.
            # XXX it is impossible with the UI currently to fill in unicode
            # items, but it's possible to do it with the TALES tab
            if field.get_value('unicode') and type(item_value) == type(u''):
                str_value = item_value.encode(field.get_form_encoding())
            else:
                str_value = str(item_value)

            if str_value == value:
                return item_value

        # if we didn't find the value, return error
        self.raise_error('unknown_selection', field)

SelectionValidatorInstance = SelectionValidator()

class MultiSelectionValidator(Validator):
    property_names = Validator.property_names + ['required', 'unicode']

    required = fields.CheckBoxField('required',
                                    title='Required',
                                    description=(
        "Checked if the field is required; the user has to fill in some "
        "data."),
                                    default=1)

    unicode = fields.CheckBoxField('unicode',
                                   title='Unicode',
                                   description=(
        "Checked if the field delivers a unicode string instead of an "
        "8-bit string."),
                                   default=0)

    message_names = Validator.message_names + ['required_not_found',
                                               'unknown_selection']

    required_not_found = 'Input is required but no input given.'
    unknown_selection = 'You selected an item that was not in the list.'

    def validate(self, field, key, REQUEST):
        values = REQUEST.get(key, [])
        # NOTE: a hack to deal with single item selections
        if type(values) is not type([]):
            # put whatever we got in a list
            values = [values]
        # if we selected nothing and entry is required, give error, otherwise
        # give entry list
        if len(values) == 0:
            if field.get_value('required'):
                self.raise_error('required_not_found', field)
            else:
                return values
        # convert everything to unicode if necessary
        if field.get_value('unicode'):
            values = [unicode(value, field.get_form_encoding())
                      for value in values]

        # create a dictionary of possible values
        value_dict = {}
        for item in field.get_value('items'):
            if type(item) in [type(()), type([])]:
                item_text, item_value = item
            else:
                item_text = item
                item_value = item
            value_dict[item_value] = 0

        # check whether all values are in dictionary
        result = []
        for value in values:
            # FIXME: hack to accept int values as well
            try:
                int_value = int(value)
            except ValueError:
                int_value = None
            if int_value is not None and value_dict.has_key(int_value):
                result.append(int_value)
                continue
            if value_dict.has_key(value):
                result.append(value)
                continue
            self.raise_error('unknown_selection', field)
        # everything checks out
        return result

MultiSelectionValidatorInstance = MultiSelectionValidator()

class FileValidator(Validator):
    def validate(self, field, key, REQUEST):
        return REQUEST.get(key, None)

FileValidatorInstance = FileValidator()

class LinkHelper:
    """A helper class to check if links are openable.
    """
    status = 0

    def __init__(self, link):
        self.link = link

    def open(self):
        try:
            urlopen(self.link)
        except:
            # all errors will definitely result in a failure
            pass
        else:
            # FIXME: would like to check for 404 errors and such?
            self.status = 1

class LinkValidator(StringValidator):
    property_names = StringValidator.property_names +\
                     ['check_link', 'check_timeout', 'link_type']

    check_link = fields.CheckBoxField('check_link',
                                      title='Check Link',
                                      description=(
        "Check whether the link is not broken."),
                                      default=0)

    check_timeout = fields.FloatField('check_timeout',
                                      title='Check Timeout',
                                      description=(
        "Maximum amount of seconds to check link. Required"),
                                      default=7.0,
                                      required=1)

    link_type = fields.ListField('link_type',
                                 title='Type of Link',
                                 default="external",
                                 size=1,
                                 items=[('External Link', 'external'),
                                        ('Internal Link', 'internal'),
                                        ('Relative Link', 'relative')],
                                 description=(
        "Define the type of the link. Required."),
                                 required=1)

    message_names = StringValidator.message_names + ['not_link']

    not_link = 'The specified link is broken.'

    def validate(self, field, key, REQUEST):
        value = StringValidator.validate(self, field, key, REQUEST)
        if value == "" and not field.get_value('required'):
            return value

        link_type = field.get_value('link_type')
        if link_type == 'internal':
            value = urljoin(REQUEST['BASE0'], value)
        elif link_type == 'relative':
            value = urljoin(REQUEST['URL1'], value)
        # otherwise must be external

        # FIXME: should try regular expression to do some more checking here?

        # if we don't need to check the link, we're done now
        if not field.get_value('check_link'):
            return value

        # resolve internal links using Zope's resolve_url
        if link_type in ['internal', 'relative']:
            try:
                REQUEST.resolve_url(value)
            except:
                self.raise_error('not_link', field)

        # check whether we can open the link
        link = LinkHelper(value)
        thread = Thread(target=link.open)
        thread.start()
        thread.join(field.get_value('check_timeout'))
        del thread
        if not link.status:
            self.raise_error('not_link', field)

        return value

LinkValidatorInstance = LinkValidator()

class DateTimeValidator(Validator):

    property_names = Validator.property_names + ['required',
                                                 'start_datetime',
                                                 'end_datetime',
                                                 'allow_empty_time']

    required = fields.CheckBoxField('required',
                                    title='Required',
                                    description=(
        "Checked if the field is required; the user has to enter something "
        "in the field."),
                                    default=1)

    start_datetime = fields.DateTimeField('start_datetime',
                                          title="Start datetime",
                                          description=(
        "The date and time entered must be later than or equal to "
        "this date/time. If left empty, no check is performed."),
                                          default=None,
                                          input_style="text",
                                          required=0)

    end_datetime = fields.DateTimeField('end_datetime',
                                        title="End datetime",
                                        description=(
        "The date and time entered must be earlier than "
        "this date/time. If left empty, no check is performed."),
                                        default=None,
                                        input_style="text",
                                        required=0)

    allow_empty_time = fields.CheckBoxField('allow_empty_time',
                                            title="Allow empty time",
                                            description=(
        "Allow time to be left empty. Time will default to midnight "
        "on that date."),
                                            default=0)

    message_names = Validator.message_names + ['required_not_found',
                                               'not_datetime',
                                               'datetime_out_of_range']

    required_not_found = 'Input is required but no input given.'
    not_datetime = 'You did not enter a valid date and time.'
    datetime_out_of_range = 'The date and time you entered were out of range.'

    def validate(self, field, key, REQUEST):
        try:
            year = field.validate_sub_field('year', REQUEST)
            month = field.validate_sub_field('month', REQUEST)
            day = field.validate_sub_field('day', REQUEST)

            if field.get_value('date_only'):
                hour = 0
                minute = 0
            elif field.get_value('allow_empty_time'):
                hour = field.validate_sub_field('hour', REQUEST)
                minute = field.validate_sub_field('minute', REQUEST)
                if hour == '' and minute == '':
                    hour = 0
                    minute = 0
                elif hour == '' or minute == '':
                    raise ValidationError('not_datetime', field)
            else:
                hour = field.validate_sub_field('hour', REQUEST)
                minute = field.validate_sub_field('minute', REQUEST)
        except ValidationError:
            self.raise_error('not_datetime', field)

        # handling of completely empty sub fields
        if ((year == '' and month == '' and day == '') and
            (field.get_value('date_only') or (hour == '' and minute == '')
            or (hour == 0 and minute == 0))):
            if field.get_value('required'):
                self.raise_error('required_not_found', field)
            else:
                # field is not required, return None for no entry
                return None
        # handling of partially empty sub fields; invalid datetime
        if ((year == '' or month == '' or day == '') or
            (not field.get_value('date_only') and
             (hour == '' or minute == ''))):
            self.raise_error('not_datetime', field)


        if field.get_value('ampm_time_style'):
            ampm = field.validate_sub_field('ampm', REQUEST)
            if field.get_value('allow_empty_time'):
                if ampm == '':
                    ampm = 'am'
            hour = int(hour)
            # handling not am or pm
            # handling hour > 12
            if ((ampm != 'am') and (ampm != 'pm')) or (hour > 12):
	        self.raise_error('not_datetime', field)
	    if (ampm == 'pm') and (hour == 0):
	        self.raise_error('not_datetime', field)
            elif ampm == 'pm' and hour < 12:
                hour += 12

        try:
            result = DateTime(int(year), int(month), int(day), hour, minute)
        # ugh, a host of string based exceptions
        except ('DateTimeError', 'Invalid Date Components', 'TimeError'):
            self.raise_error('not_datetime', field)

        # check if things are within range
        start_datetime = field.get_value('start_datetime')
        if (start_datetime is not None and
            result < start_datetime):
            self.raise_error('datetime_out_of_range', field)
        end_datetime = field.get_value('end_datetime')
        if (end_datetime is not None and
            result >= end_datetime):
            self.raise_error('datetime_out_of_range', field)

        return result

DateTimeValidatorInstance = DateTimeValidator()


class SuppressValidator(ValidatorBase):
    """A validator that is actually not used.
    """
    def need_validate(self, field, key, REQUEST):
        """Don't ever validate; suppress result in output.
        """
        return 0

SuppressValidatorInstance = SuppressValidator()
