import logging, types, re
from gae import template, webapp, db
from django.template import TemplateSyntaxError, InvalidTemplateLibrary, VariableDoesNotExist
from django.template.defaultfilters import stringfilter
from django.template.defaulttags import LoadNode
from django.template import get_library
from django import template as django_template
from gae.translation import translate as _
from gae.config import get_config
from gae.tools import prepare_url_vars

def node_rule(base_obj, rules):
    '''
    Decorator for logged users only.

    Args:
      rules - list of rules for users who have access (supported: admin)
    '''
    def wrap(handler_method):
        cls = type("NewNode", (base_obj,), {'render': handler_method, 'rules': rules})
        def tag_func(parser, token):
            return cls.handle_token(parser, token)
        tag_func.__name__ = handler_method.__name__
        return tag_func
    return wrap

class BaseNode(django_template.Node):
    """Base class for simplify creation of template tags"""
    rules = []

    def __init__(self, **kvargs):
        # set alla passed values to current class
        for name, value in kvargs.items():
            setattr(self, name, value)

    @classmethod
    def handle_token(cls, parser, token):
        """
        Class method to parse template tag and return a Node.
        Syntax defined into 'rules' class property.

        Syntex:
            {% get_xxx %}
            {% get_xxx as [varname] %}
            {% get_xxx for [object] as [varname] %}
            {% get_xxx for [model] [object_id] as [varname] %}
        """
        tokens = token.split_contents()[1:]
        # call tag without parameters
        if len(tokens) == 0:
            return cls()
        # convert one rule to tuple of rules
        if (type(cls.rules) == types.StringType):
            cls.rules = (cls.rules, )
        rules = [rule.strip().split(" ") for rule in cls.rules]
        # find rules for current tag by number of arguments
        rules = [rule for rule in rules if len(rule) == len(tokens)]
        # convert rules from line to list
        # match correct syntax for tag
        rule_found = None
        for rule in rules:
            rule_found = True
            for a, b in zip(rule, tokens):
                if not (a == b or (a.startswith('[') and a.endswith(']'))):
                    rule_found = None
            if rule_found:
                rule_found = rule
                break
        # rule not found
        if not rule_found:
            raise django_template.TemplateSyntaxError("Incorrect arguments in %r template tag" % token.split_contents()[0])
        # get params for class
        params = dict([(a[1:-1], b) for a, b in zip(rule_found, tokens) if a.startswith('[') and a.endswith(']')])
        # create object instance
        return cls(**params)

    def get_object(self, context):
        '''Return object based on parameter: object_instance or object_type and object_id'''
        try:
            # restore object by variable name
            if self.object_instance:
                obj = django_template.resolve_variable(self.object_instance, context)
            # get object by id
            elif self.object_type is not None and self.object_id is not None:
                # TODO: need import module before using
                obj = getattr(self.object_type, 'get_by_id')(int(self.object_id))
            else:
                obj = None
        except (AttributeError, VariableDoesNotExist), err:
            obj = None
        return obj

    @staticmethod
    def get_var(context, var_name):
        '''Return object based on parameter: object_instance or object_type and object_id'''
        try:
            # restore object by variable name
            obj = django_template.resolve_variable(var_name, context)
        except (AttributeError, VariableDoesNotExist), err:
            logging.warn("Template variable '%s' does not exists" % var_name)
            obj = None
        return obj


class UrlNode(django_template.Node):
    def __init__(self, params):
        self.full_tag = "{%% tag %s %%}" % " ".join(params)
        if len(params) == 0:
            raise django_template.TemplateSyntaxError("You need pass arguments to 'url' template tag")
        try:
            self.app, self.tag = params[0].split('.')
        except:
            raise django_template.TemplateSyntaxError("You need pass first argument in format 'app_name.url_tag_name' for '%s'" % self.full_tag)
        self.params = {}
        if len(params) > 1:
            try:
                self.params = dict([param.split("=") for param in params[1:]])
            except:
                raise django_template.TemplateSyntaxError("You need pass arguments in format 'arg1=value1 arg2=value2' for '%s'" % self.full_tag)

    def render(self, context):
        # resolve variables
        params = {}
        for k, v in self.params.items():
            params[k] = BaseNode.get_var(context, v)
            if params[k] is None:
                raise django_template.TemplateSyntaxError("Variable '%s' not defined for '%s'" % (v, self.full_tag))
            # use key name or id if passed models object
            if isinstance(params[k], db.Model):
                params[k] = params[k].key().name() or params[k].key().id() or params[k].key()
        # search in global urls mapping
        for url in get_config("site.urls", []):
            if url.get('map', "") == self.app:
                url_prefix = url.get('url') or ""
                # search in mapped application
                for url in get_config("%s.urls" % self.app, []):
                    if url.get('tag', "") == self.tag:
                        return "/%s%s" % (url_prefix, self._make_url(url.get('url') or "", params))
        # mapped action not found
        raise django_template.TemplateSyntaxError("Url not found for '%s'" % self.full_tag)

    def _make_url(self, url, vars={}):
        # convert url to style "%(blog)s/new"
        url_with_placemarks = prepare_url_vars(url, "%(\\1)s")
        try:
            # insert values from dictionary to string
            return url_with_placemarks % vars
        except KeyError:
            raise django_template.TemplateSyntaxError("Not all required arguments passed to '%s'" % self.full_tag)


register = template.create_template_register()

@register.simple_tag
def back_url():
    '''Return url to previous page'''
    return webapp.instance.back_url()

@register.simple_tag
def current_url():
    '''Return current page address'''
    return webapp.instance.request.path

@register.tag
@node_rule(BaseNode, ('[text]', '[text] [app_name]'))
def translate(self, context):
    '''Return translated text'''
    text = self.get_var(context, self.text)
    if hasattr(self, "app_name"):
        return _(text, self.app_name)
    return _(text)

@register.tag
def url(parser, token):
    try:
        params = token.split_contents()[1:]
    except ValueError:
        raise django_template.TemplateSyntaxError, "%r tag requires an arguments" % token.contents.split()[0]
    return UrlNode(params)

@register.filter(name='translate')
@stringfilter
def filter_translate(text):
    '''Return translated text'''
    return _(text)

@register.filter
def debug(content):
    return "Type: %s. Properties: %s" % (type(content), dir(content))

@register.tag
@node_rule(BaseNode, ('[paginator]',))
def show_pages(self, context):
    '''Return pagination links'''
    paginator = self.get_var(context, self.paginator)
    return template.render('common/show_pages.html', {"paginator": paginator})

from gae.template.tag_elif import do_if
register.tag("if", do_if)