text: # -*- coding: utf-8  -*-
  #
  # Copyright (C) 2012-2016 Ben Kurtovic <ben.kurtovic@gmail.com>
  #
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the "Software"), to deal
  # in the Software without restriction, including without limitation the rights
  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  # copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  # SOFTWARE.
  
  from __future__ import unicode_literals
  from collections import defaultdict
  import re
  
  from . import HTMLEntity, Node, Text
  from .extras import Parameter
  from ..compat import range, str
  from ..utils import parse_anything
  
  __all__ = ["Template"]
  
  FLAGS = re.DOTALL | re.UNICODE
  
  class Template(Node):
      """Represents a template in wikicode, like ``{{foo}}``."""
  
      def __init__(self, name, params=None):
          super(Template, self).__init__()
          self._name = name
          if params:
              self._params = params
          else:
              self._params = []
  
      def __unicode__(self):
          if self.params:
              params = "|".join([str(param) for param in self.params])
              return "{{" + str(self.name) + "|" + params + "}}"
          else:
              return "{{" + str(self.name) + "}}"
  
      def __children__(self):
          yield self.name
          for param in self.params:
              if param.showkey:
                  yield param.name
              yield param.value
  
      def __showtree__(self, write, get, mark):
          write("{{")
          get(self.name)
          for param in self.params:
              write("    | ")
              mark()
              get(param.name)
              write("    = ")
              mark()
              get(param.value)
          write("}}")
  
      def _surface_escape(self, code, char):
          """Return *code* with *char* escaped as an HTML entity.
  
          The main use of this is to escape pipes (``|``) or equal signs (``=``)
          in parameter names or values so they are not mistaken for new
          parameters.
          """
          replacement = str(HTMLEntity(value=ord(char)))
          for node in code.filter_text(recursive=False):
              if char in node:
                  code.replace(node, node.replace(char, replacement), False)
  
      def _select_theory(self, theories):
          """Return the most likely spacing convention given different options.
  
          Given a dictionary of convention options as keys and their occurrence
          as values, return the convention that occurs the most, or ``None`` if
          there is no clear preferred style.
          """
          if theories:
              values = tuple(theories.values())
              best = max(values)
              confidence = float(best) / sum(values)
              if confidence >= 0.75:
                  return tuple(theories.keys())[values.index(best)]
  
      def _get_spacing_conventions(self, use_names):
          """Try to determine the whitespace conventions for parameters.
  
          This will examine the existing parameters and use
          :meth:`_select_theory` to determine if there are any preferred styles
          for how much whitespace to put before or after the value.
          """
          before_theories = defaultdict(lambda: 0)
          after_theories = defaultdict(lambda: 0)
          for param in self.params:
              if use_names:
                  component = str(param.name)
              else:
                  component = str(param.value)
              match = re.search(r"^(\s*).*?(\s*)$", component, FLAGS)
              before, after = match.group(1), match.group(2)
              before_theories[before] += 1
              after_theories[after] += 1
  
          before = self._select_theory(before_theories)
          after = self._select_theory(after_theories)
          return before, after
  
      def _blank_param_value(self, value):
          """Remove the content from *value* while keeping its whitespace.
  
          Replace *value*\ 's nodes with two text nodes, the first containing
          whitespace from before its content and the second containing whitespace
          from after its content.
          """
          match = re.search(r"^(\s*).*?(\s*)$", str(value), FLAGS)
          value.nodes = [Text(match.group(1)), Text(match.group(2))]
  
      def _fix_dependendent_params(self, i):
          """Unhide keys if necessary after removing the param at index *i*."""
          if not self.params[i].showkey:
              for param in self.params[i + 1:]:
                  if not param.showkey:
                      param.showkey = True
  
      def _remove_exact(self, needle, keep_field):
          """Remove a specific parameter, *needle*, from the template."""
          for i, param in enumerate(self.params):
              if param is needle:
                  if keep_field:
                      self._blank_param_value(param.value)
                  else:
                      self._fix_dependendent_params(i)
                      self.params.pop(i)
                  return
          raise ValueError(needle)
  
      def _should_remove(self, i, name):
          """Look ahead for a parameter with the same name, but hidden.
  
          If one exists, we should remove the given one rather than blanking it.
          """
          if self.params[i].showkey:
              following = self.params[i + 1:]
              better_matches = [after.name.strip() == name and not after.showkey
                                for after in following]
              return any(better_matches)
          return False
  
      @property
      def name(self):
          """The name of the template, as a :class:`.Wikicode` object."""
          return self._name
  
      @property
      def params(self):
          """The list of parameters contained within the template."""
          return self._params
  
      @name.setter
      def name(self, value):
          self._name = parse_anything(value)
  
      def has(self, name, ignore_empty=False):
          """Return ``True`` if any parameter in the template is named *name*.
  
          With *ignore_empty*, ``False`` will be returned even if the template
          contains a parameter with the name *name*, if the parameter's value
          is empty. Note that a template may have multiple parameters with the
          same name, but only the last one is read by the MediaWiki parser.
          """
          name = str(name).strip()
          for param in self.params:
              if param.name.strip() == name:
                  if ignore_empty and not param.value.strip():
                      continue
                  return True
          return False
  
      has_param = lambda self, name, ignore_empty=False: \
                  self.has(name, ignore_empty)
      has_param.__doc__ = "Alias for :meth:`has`."
  
      def get(self, name):
          """Get the parameter whose name is *name*.
  
          The returned object is a :class:`.Parameter` instance. Raises
          :exc:`ValueError` if no parameter has this name. Since multiple
          parameters can have the same name, we'll return the last match, since
          the last parameter is the only one read by the MediaWiki parser.
          """
          name = str(name).strip()
          for param in reversed(self.params):
              if param.name.strip() == name:
                  return param
          raise ValueError(name)
  
      def add(self, name, value, showkey=None, before=None,
              preserve_spacing=True):
          """Add a parameter to the template with a given *name* and *value*.
  
          *name* and *value* can be anything parsable by
          :func:`.utils.parse_anything`; pipes and equal signs are automatically
          escaped from *value* when appropriate.
  
          If *name* is already a parameter in the template, we'll replace its
          value.
  
          If *showkey* is given, this will determine whether or not to show the
          parameter's name (e.g., ``{{foo|bar}}``'s parameter has a name of
          ``"1"`` but it is hidden); otherwise, we'll make a safe and intelligent
          guess.
  
          If *before* is given (either a :class:`.Parameter` object or a name),
          then we will place the parameter immediately before this one.
          Otherwise, it will be added at the end. If *before* is a name and
          exists multiple times in the template, we will place it before the last
          occurrence. If *before* is not in the template, :exc:`ValueError` is
          raised. The argument is ignored if *name* is an existing parameter.
  
          If *preserve_spacing* is ``True``, we will try to preserve whitespace
          conventions around the parameter, whether it is new or we are updating
          an existing value. It is disabled for parameters with hidden keys,
          since MediaWiki doesn't strip whitespace in this case.
          """
          name, value = parse_anything(name), parse_anything(value)
          self._surface_escape(value, "|")
  
          if self.has(name):
              self.remove(name, keep_field=True)
              existing = self.get(name)
              if showkey is not None:
                  existing.showkey = showkey
              if not existing.showkey:
                  self._surface_escape(value, "=")
              nodes = existing.value.nodes
              if preserve_spacing and existing.showkey:
                  for i in range(2):  # Ignore empty text nodes
                      if not nodes[i]:
                          nodes[i] = None
                  existing.value = parse_anything([nodes[0], value, nodes[1]])
              else:
                  existing.value = value
              return existing
  
          if showkey is None:
              if Parameter.can_hide_key(name):
                  int_name = int(str(name))
                  int_keys = set()
                  for param in self.params:
                      if not param.showkey:
                          int_keys.add(int(str(param.name)))
                  expected = min(set(range(1, len(int_keys) + 2)) - int_keys)
                  if expected == int_name:
                      showkey = False
                  else:
                      showkey = True
              else:
                  showkey = True
          if not showkey:
              self._surface_escape(value, "=")
  
          if preserve_spacing and showkey:
              before_n, after_n = self._get_spacing_conventions(use_names=True)
              before_v, after_v = self._get_spacing_conventions(use_names=False)
              name = parse_anything([before_n, name, after_n])
              value = parse_anything([before_v, value, after_v])
  
          param = Parameter(name, value, showkey)
          if before:
              if not isinstance(before, Parameter):
                  before = self.get(before)
              self.params.insert(self.params.index(before), param)
          else:
              self.params.append(param)
          return param
  
      def remove(self, param, keep_field=False):
          """Remove a parameter from the template, identified by *param*.
  
          If *param* is a :class:`.Parameter` object, it will be matched exactly,
          otherwise it will be treated like the *name* argument to :meth:`has`
          and :meth:`get`.
  
          If *keep_field* is ``True``, we will keep the parameter's name, but
          blank its value. Otherwise, we will remove the parameter completely.
  
          When removing a parameter with a hidden name, subsequent parameters
          with hidden names will be made visible. For example, removing ``bar``
          from ``{{foo|bar|baz}}`` produces ``{{foo|2=baz}}`` because
          ``{{foo|baz}}`` is incorrect.
  
          If the parameter shows up multiple times in the template and *param* is
          not a :class:`.Parameter` object, we will remove all instances of it
          (and keep only one if *keep_field* is ``True`` - either the one with a
          hidden name, if it exists, or the first instance).
          """
          if isinstance(param, Parameter):
              return self._remove_exact(param, keep_field)
  
          name = str(param).strip()
          removed = False
          to_remove = []
  
          for i, param in enumerate(self.params):
              if param.name.strip() == name:
                  if keep_field:
                      if self._should_remove(i, name):
                          to_remove.append(i)
                      else:
                          self._blank_param_value(param.value)
                          keep_field = False
                  else:
                      self._fix_dependendent_params(i)
                      to_remove.append(i)
                  if not removed:
                      removed = True
  
          if not removed:
              raise ValueError(name)
          for i in reversed(to_remove):
              self.params.pop(i)
  