from __future__ import absolute_import, division, print_function, unicode_literals

import xml.dom

import css_parser

from . import cssrule
from .cssstyledeclaration import CSSStyleDeclaration
from .selectorlist import SelectorList

"""CSSStyleRule implements DOM Level 2 CSS CSSStyleRule."""

__all__ = ['CSSStyleRule']
__docformat__ = 'restructuredtext'
__version__ = '$Id$'

string_type = str


class CSSStyleRule(cssrule.CSSRule):
    """The CSSStyleRule object represents a ruleset specified (if any) in a CSS
    style sheet. It provides access to a declaration block as well as to the
    associated group of selectors.

    Format::

        : selector [ COMMA S* selector ]*
        LBRACE S* declaration [ ';' S* declaration ]* '}' S*
        ;
    """

    def __init__(self, selectorText=None, style=None, parentRule=None,
                 parentStyleSheet=None, readonly=False):
        """
        :Parameters:
            selectorText
                string parsed into selectorList
            style
                string parsed into CSSStyleDeclaration for this CSSStyleRule
            readonly
                if True allows setting of properties in constructor only
        """
        super(CSSStyleRule, self).__init__(parentRule=parentRule,
                                           parentStyleSheet=parentStyleSheet)

        self.selectorList = SelectorList()
        if selectorText:
            self.selectorText = selectorText

        if style:
            self.style = style
        else:
            self.style = CSSStyleDeclaration()

        self._readonly = readonly

    def __repr__(self):
        if self._namespaces:
            st = (self.selectorText, self._namespaces)
        else:
            st = self.selectorText
        return "css_parser.css.%s(selectorText=%r, style=%r)" % (
            self.__class__.__name__, st, self.style.cssText)

    def __str__(self):
        return "<css_parser.css.%s object selectorText=%r style=%r _namespaces=%r "\
               "at 0x%x>" % (self.__class__.__name__,
                             self.selectorText,
                             self.style.cssText,
                             self._namespaces,
                             id(self))

    def _getCssText(self):
        """Return serialized property cssText."""
        return css_parser.ser.do_CSSStyleRule(self)

    def _setCssText(self, cssText):
        """
        :param cssText:
            a parseable string or a tuple of (cssText, dict-of-namespaces)
        :exceptions:
            - :exc:`~xml.dom.NamespaceErr`:
              Raised if the specified selector uses an unknown namespace
              prefix.
            - :exc:`~xml.dom.SyntaxErr`:
              Raised if the specified CSS string value has a syntax error and
              is unparsable.
            - :exc:`~xml.dom.InvalidModificationErr`:
              Raised if the specified CSS string value represents a different
              type of rule than the current one.
            - :exc:`~xml.dom.HierarchyRequestErr`:
              Raised if the rule cannot be inserted at this point in the
              style sheet.
            - :exc:`~xml.dom.NoModificationAllowedErr`:
              Raised if the rule is readonly.
        """
        super(CSSStyleRule, self)._setCssText(cssText)

        # might be (cssText, namespaces)
        cssText, namespaces = self._splitNamespacesOff(cssText)
        try:
            # use parent style sheet ones if available
            namespaces = self.parentStyleSheet.namespaces
        except AttributeError:
            pass

        tokenizer = self._tokenize2(cssText)
        selectortokens = self._tokensupto2(tokenizer, blockstartonly=True)
        styletokens = self._tokensupto2(tokenizer, blockendonly=True)
        trail = self._nexttoken(tokenizer)
        if trail:
            self._log.error('CSSStyleRule: Trailing content: %s' %
                            self._valuestr(cssText), token=trail)
        elif not selectortokens:
            self._log.error('CSSStyleRule: No selector found: %r' %
                            self._valuestr(cssText))
        elif self._tokenvalue(selectortokens[0]).startswith('@'):
            self._log.error('CSSStyleRule: No style rule: %r' %
                            self._valuestr(cssText),
                            error=xml.dom.InvalidModificationErr)
        else:
            newSelectorList = SelectorList(parentRule=self)
            newStyle = CSSStyleDeclaration(parentRule=self)
            ok = True

            bracetoken = selectortokens.pop()
            if self._tokenvalue(bracetoken) != '{':
                ok = False
                self._log.error(
                    'CSSStyleRule: No start { of style declaration found: %r' %
                    self._valuestr(cssText), bracetoken)
            elif not selectortokens:
                ok = False
                self._log.error('CSSStyleRule: No selector found: %r.' %
                                self._valuestr(cssText), bracetoken)
            # SET
            newSelectorList.selectorText = (selectortokens,
                                            namespaces)

            if not styletokens:
                ok = False
                self._log.error(
                    'CSSStyleRule: No style declaration or "}" found: %r' %
                    self._valuestr(cssText))
            else:
                braceorEOFtoken = styletokens.pop()
                val, typ = self._tokenvalue(braceorEOFtoken), self._type(braceorEOFtoken)
                if val != '}' and typ != 'EOF':
                    ok = False
                    self._log.error('CSSStyleRule: No "}" after style '
                                    'declaration found: %r'
                                    % self._valuestr(cssText))
                else:
                    if 'EOF' == typ:
                        # add again as style needs it
                        styletokens.append(braceorEOFtoken)
                    # SET, may raise:
                    newStyle.cssText = styletokens

            if ok:
                self.selectorList = newSelectorList
                self.style = newStyle

    cssText = property(_getCssText, _setCssText,
                       doc="(DOM) The parsable textual representation of this "
                       "rule.")

    def __getNamespaces(self):
        """Uses children namespaces if not attached to a sheet, else the sheet's
        ones."""
        try:
            return self.parentStyleSheet.namespaces
        except AttributeError:
            return self.selectorList._namespaces

    _namespaces = property(__getNamespaces,
                           doc="If this Rule is attached to a CSSStyleSheet "
                               "the namespaces of that sheet are mirrored "
                               "here. While the Rule is not attached the "
                               "namespaces of selectorList are used.""")

    def _setSelectorList(self, selectorList):
        """
        :param selectorList: A SelectorList which replaces the current
            selectorList object
        """
        self._checkReadonly()
        selectorList._parentRule = self
        self._selectorList = selectorList

    _selectorList = None
    selectorList = property(lambda self: self._selectorList, _setSelectorList,
                            doc="The SelectorList of this rule.")

    def _setSelectorText(self, selectorText):
        """
        wrapper for css_parser SelectorList object

        :param selectorText:
            of type string, might also be a comma separated list
            of selectors
        :exceptions:
            - :exc:`~xml.dom.NamespaceErr`:
              Raised if the specified selector uses an unknown namespace
              prefix.
            - :exc:`~xml.dom.SyntaxErr`:
              Raised if the specified CSS string value has a syntax error
              and is unparsable.
            - :exc:`~xml.dom.NoModificationAllowedErr`:
              Raised if this rule is readonly.
        """
        self._checkReadonly()

        sl = SelectorList(selectorText=selectorText, parentRule=self)
        if sl.wellformed:
            self._selectorList = sl

    selectorText = property(lambda self: self._selectorList.selectorText,
                            _setSelectorText,
                            doc="(DOM) The textual representation of the "
                                "selector for the rule set.")

    def _setStyle(self, style):
        """
        :param style: A string or CSSStyleDeclaration which replaces the
            current style object.
        """
        self._checkReadonly()
        if isinstance(style, string_type):
            self._style = CSSStyleDeclaration(cssText=style, parentRule=self)
        else:
            style._parentRule = self
            self._style = style

    style = property(lambda self: self._style, _setStyle,
                     doc="(DOM) The declaration-block of this rule set.")

    type = property(lambda self: self.STYLE_RULE,
                    doc="The type of this rule, as defined by a CSSRule "
                        "type constant.")

    wellformed = property(lambda self: self.selectorList.wellformed)

    def _getValid(self):
        """Return whether the style declaration is valid."""
        return self.style.valid

    valid = property(_getValid,
                     doc='``True`` when the style declaration is true.')
