# Copyright (c) 2012 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import copy
import logging
import posixpath

from compiled_file_system import SingleFile, Unicode
from data_source import DataSource
from extensions_paths import JSON_TEMPLATES
from future import Future
from third_party.json_schema_compiler.json_parse import Parse


def _AddLevels(items, level):
  '''Add a 'level' key to each item in |items|. 'level' corresponds to how deep
  in |items| an item is. |level| sets the starting depth.
  '''
  for item in items:
    item['level'] = level
    if 'items' in item:
      _AddLevels(item['items'], level + 1)


def _AddAnnotations(items, path, parent=None):
  '''Add 'selected', 'child_selected' and 'related' properties to 
  |items| so that the sidenav can be expanded to show which menu item has 
  been selected and the related pages section can be drawn. 'related'
  is added to all items with the same parent as the selected item.
  If more than one item exactly matches the path, the deepest one is considered 
  'selected'. A 'parent' property is added to the selected path.
  
  Returns True if an item was marked 'selected'.
  '''
  for item in items:
    if 'items' in item:
      if _AddAnnotations(item['items'], path, item):
        item['child_selected'] = True
        return True

    if item.get('href', '') == path:
      item['selected'] = True
      if parent:
        item['parent'] = { 'title': parent.get('title', None), 
                          'href': parent.get('href', None) }
      
      for sibling in items:
        sibling['related'] = True
        
      return True

  return False


class SidenavDataSource(DataSource):
  '''Provides templates with access to JSON files used to create the side
  navigation bar.
  '''
  def __init__(self, server_instance, request):
    self._cache = server_instance.compiled_fs_factory.Create(
        server_instance.host_file_system_provider.GetTrunk(),
        self._CreateSidenavDict,
        SidenavDataSource)
    self._server_instance = server_instance
    self._request = request

  @SingleFile
  @Unicode
  def _CreateSidenavDict(self, _, content):
    items = Parse(content)
    # Start at level 2, the top <ul> element is level 1.
    _AddLevels(items, level=2)
    self._QualifyHrefs(items)
    return items

  def _QualifyHrefs(self, items):
    '''Force hrefs in |items| to either be absolute (http://...) or qualified
    (beginning with /, in which case it will be moved relative to |base_path|).
    Relative hrefs emit a warning and should be updated.
    '''
    for item in items:
      if 'items' in item:
        self._QualifyHrefs(item['items'])

      href = item.get('href')
      if href is not None and not href.startswith(('http://', 'https://')):
        if not href.startswith('/'):
          logging.warn('Paths in sidenav must be qualified. %s is not.' % href)
        else:
          href = href.lstrip('/')
        item['href'] = self._server_instance.base_path + href

  def Cron(self):
    return self._cache.GetFromFile(
        posixpath.join(JSON_TEMPLATES, 'chrome_sidenav.json'))

  def get(self, key):
    # TODO(mangini/kalman): Use |key| to decide which sidenav to use,
    # which will require a more complex Cron method.
    sidenav = self._cache.GetFromFile(
        posixpath.join(JSON_TEMPLATES, 'chrome_sidenav.json')).Get()
    sidenav = copy.deepcopy(sidenav)
    _AddAnnotations(sidenav,
                    self._server_instance.base_path + self._request.path)
    return sidenav