import platform
import re
import urllib2
import urlparse

from django.core.exceptions import ValidationError
from django.utils.translation import ugettext_lazy as _
from django.utils.encoding import smart_unicode
from django.utils.ipv6 import is_valid_ipv6_address

# These values, if given to validate(), will trigger the self.required check.
EMPTY_VALUES = (None, '', [], (), {})

try:
    from django.conf import settings
    URL_VALIDATOR_USER_AGENT = settings.URL_VALIDATOR_USER_AGENT
except ImportError:
    # It's OK if Django settings aren't configured.
    URL_VALIDATOR_USER_AGENT = 'Django (http://www.djangoproject.com/)'

class RegexValidator(object):
    regex = ''
    message = _(u'Enter a valid value.')
    code = 'invalid'

    def __init__(self, regex=None, message=None, code=None):
        if regex is not None:
            self.regex = regex
        if message is not None:
            self.message = message
        if code is not None:
            self.code = code

        # Compile the regex if it was not passed pre-compiled.
        if isinstance(self.regex, basestring):
            self.regex = re.compile(self.regex)

    def __call__(self, value):
        """
        Validates that the input matches the regular expression.
        """
        if not self.regex.search(smart_unicode(value)):
            raise ValidationError(self.message, code=self.code)

class URLValidator(RegexValidator):
    regex = re.compile(
        r'^(?:http|ftp)s?://' # http:// or https://
        r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}\.?)|' #domain...
        r'localhost|' #localhost...
        r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' # ...or ip
        r'(?::\d+)?' # optional port
        r'(?:/?|[/?]\S+)$', re.IGNORECASE)

    def __init__(self, verify_exists=False,
                 validator_user_agent=URL_VALIDATOR_USER_AGENT):
        super(URLValidator, self).__init__()
        self.verify_exists = verify_exists
        self.user_agent = validator_user_agent

    def __call__(self, value):
        try:
            super(URLValidator, self).__call__(value)
        except ValidationError, e:
            # Trivial case failed. Try for possible IDN domain
            if value:
                value = smart_unicode(value)
                scheme, netloc, path, query, fragment = urlparse.urlsplit(value)
                try:
                    netloc = netloc.encode('idna') # IDN -> ACE
                except UnicodeError: # invalid domain part
                    raise e
                url = urlparse.urlunsplit((scheme, netloc, path, query, fragment))
                super(URLValidator, self).__call__(url)
            else:
                raise
        else:
            url = value

        if self.verify_exists:
            import warnings
            warnings.warn(
                "The URLField verify_exists argument has intractable security "
                "and performance issues. Accordingly, it has been deprecated.",
                DeprecationWarning
                )

            headers = {
                "Accept": "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5",
                "Accept-Language": "en-us,en;q=0.5",
                "Accept-Charset": "ISO-8859-1,utf-8;q=0.7,*;q=0.7",
                "Connection": "close",
                "User-Agent": self.user_agent,
            }
            url = url.encode('utf-8')
            broken_error = ValidationError(
                _(u'This URL appears to be a broken link.'), code='invalid_link')
            try:
                req = urllib2.Request(url, None, headers)
                req.get_method = lambda: 'HEAD'
                #Create an opener that does not support local file access
                opener = urllib2.OpenerDirector()

                #Don't follow redirects, but don't treat them as errors either
                error_nop = lambda *args, **kwargs: True
                http_error_processor = urllib2.HTTPErrorProcessor()
                http_error_processor.http_error_301 = error_nop
                http_error_processor.http_error_302 = error_nop
                http_error_processor.http_error_307 = error_nop

                handlers = [urllib2.UnknownHandler(),
                            urllib2.HTTPHandler(),
                            urllib2.HTTPDefaultErrorHandler(),
                            urllib2.FTPHandler(),
                            http_error_processor]
                try:
                    import ssl
                except ImportError:
                    # Python isn't compiled with SSL support
                    pass
                else:
                    handlers.append(urllib2.HTTPSHandler())
                map(opener.add_handler, handlers)
                opener.http_error_301 = lambda: True
                if platform.python_version_tuple() >= (2, 6):
                    opener.open(req, timeout=10)
                else:
                    opener.open(req)
            except ValueError:
                raise ValidationError(_(u'Enter a valid URL.'), code='invalid')
            except: # urllib2.URLError, httplib.InvalidURL, etc.
                raise broken_error


def validate_integer(value):
    try:
        int(value)
    except (ValueError, TypeError):
        raise ValidationError('')

class EmailValidator(RegexValidator):

    def __call__(self, value):
        try:
            super(EmailValidator, self).__call__(value)
        except ValidationError, e:
            # Trivial case failed. Try for possible IDN domain-part
            if value and u'@' in value:
                parts = value.split(u'@')
                try:
                    parts[-1] = parts[-1].encode('idna')
                except UnicodeError:
                    raise e
                super(EmailValidator, self).__call__(u'@'.join(parts))
            else:
                raise

email_re = re.compile(
    r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*"  # dot-atom
    r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-011\013\014\016-\177])*"' # quoted-string
    r')@((?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?$)'  # domain
    r'|\[(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}\]$', re.IGNORECASE)  # literal form, ipv4 address (SMTP 4.1.3)
validate_email = EmailValidator(email_re, _(u'Enter a valid e-mail address.'), 'invalid')

slug_re = re.compile(r'^[-\w]+$')
validate_slug = RegexValidator(slug_re, _(u"Enter a valid 'slug' consisting of letters, numbers, underscores or hyphens."), 'invalid')

ipv4_re = re.compile(r'^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$')
validate_ipv4_address = RegexValidator(ipv4_re, _(u'Enter a valid IPv4 address.'), 'invalid')

def validate_ipv6_address(value):
    if not is_valid_ipv6_address(value):
        raise ValidationError(_(u'Enter a valid IPv6 address.'), code='invalid')

def validate_ipv46_address(value):
    try:
        validate_ipv4_address(value)
    except ValidationError:
        try:
            validate_ipv6_address(value)
        except ValidationError:
            raise ValidationError(_(u'Enter a valid IPv4 or IPv6 address.'), code='invalid')

ip_address_validator_map = {
    'both': ([validate_ipv46_address], _('Enter a valid IPv4 or IPv6 address.')),
    'ipv4': ([validate_ipv4_address], _('Enter a valid IPv4 address.')),
    'ipv6': ([validate_ipv6_address], _('Enter a valid IPv6 address.')),
}

def ip_address_validators(protocol, unpack_ipv4):
    """
    Depending on the given parameters returns the appropriate validators for
    the GenericIPAddressField.

    This code is here, because it is exactly the same for the model and the form field.
    """
    if protocol != 'both' and unpack_ipv4:
        raise ValueError(
            "You can only use `unpack_ipv4` if `protocol` is set to 'both'")
    try:
        return ip_address_validator_map[protocol.lower()]
    except KeyError:
        raise ValueError("The protocol '%s' is unknown. Supported: %s"
                         % (protocol, ip_address_validator_map.keys()))

comma_separated_int_list_re = re.compile('^[\d,]+$')
validate_comma_separated_integer_list = RegexValidator(comma_separated_int_list_re, _(u'Enter only digits separated by commas.'), 'invalid')


class BaseValidator(object):
    compare = lambda self, a, b: a is not b
    clean   = lambda self, x: x
    message = _(u'Ensure this value is %(limit_value)s (it is %(show_value)s).')
    code = 'limit_value'

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

    def __call__(self, value):
        cleaned = self.clean(value)
        params = {'limit_value': self.limit_value, 'show_value': cleaned}
        if self.compare(cleaned, self.limit_value):
            raise ValidationError(
                self.message % params,
                code=self.code,
                params=params,
            )

class MaxValueValidator(BaseValidator):
    compare = lambda self, a, b: a > b
    message = _(u'Ensure this value is less than or equal to %(limit_value)s.')
    code = 'max_value'

class MinValueValidator(BaseValidator):
    compare = lambda self, a, b: a < b
    message = _(u'Ensure this value is greater than or equal to %(limit_value)s.')
    code = 'min_value'

class MinLengthValidator(BaseValidator):
    compare = lambda self, a, b: a < b
    clean   = lambda self, x: len(x)
    message = _(u'Ensure this value has at least %(limit_value)d characters (it has %(show_value)d).')
    code = 'min_length'

class MaxLengthValidator(BaseValidator):
    compare = lambda self, a, b: a > b
    clean   = lambda self, x: len(x)
    message = _(u'Ensure this value has at most %(limit_value)d characters (it has %(show_value)d).')
    code = 'max_length'