text: """
  
  resourceservice.py 
  
  This module contains functionality for interacting with resource models in
  the database.
  
  """
  
  from sqlalchemy import *
  from models import Resource, Category, resourcecategory
  import geoutils
  
  def search(database, search_params=None, limit=0, order_by='last_updated desc'):
      """
      Searches for one or more resources in the database using the specified parameters.
  
      Args:
          database: The current database context.
          limit: The maximum number of results to return.
          search_params: The dictionary of searching parameters to use.
          order_by: The ordering to use.
  
      Returns:
          A list of all resources matching the specified filtering criteria.
      """
  
      # Make sure we have at least some searching parameters, or failing that,
      # at least some sort of limit
      if (search_params is None or len(search_params) == 0) and limit <= 0:
          return None
  
      # Set up our base query
      query = database.session.query(Resource)
  
      # Store if we have location searching, which we'll use in our sorting
      has_location = False
  
      # Make sure we have some searching parameters!
      if search_params is not None and len(search_params) > 0:
  
          # "id" parameter - search against specific resource ID
          if 'id' in search_params:
              query = query.filter(Resource.id == search_params['id'])
  
          if 'visible' in search_params:
              query = query.filter(Resource.visible == search_params['visible'])
  
          # "search" parameter - text search against name/description/categories
          if 'search' in search_params and not search_params['search'].isspace():
              search_like_str = '%' + search_params['search'] + '%'
              query = query.filter(or_(Resource.name.like(search_like_str), 
                  Resource.description.like(search_like_str),
                  Resource.organization.like(search_like_str),
                  Resource.category_text.like(search_like_str)))
  
          # Category filtering - ensure at least one has been provided
          if 'categories' in search_params and len(search_params['categories']) > 0:
              query = query.filter(Resource.categories.any(
                  Category.id.in_(search_params['categories'])))
  
          # Location parameters ("lat", "long", "dist") - proximity filtering
          if 'dist' in search_params and \
              search_params['dist'] > 0 and \
              'lat' in search_params and \
              'long' in search_params:
  
              # Convert our overall distance value to kilometers
              dist_km = geoutils.miles2km(search_params['dist'])
  
              # Calculate our bounding box
              minLat, minLong, maxLat, maxLong = geoutils.boundingBox(search_params['lat'],
                  search_params['long'], dist_km)
  
              # Now apply filtering against that bounding box
              query = query.filter(Resource.latitude >= minLat, Resource.latitude <= maxLat)
              query = query.filter(Resource.longitude >= minLong, Resource.longitude <= maxLong)
  
              # Indicate we have location searching
              has_location = True
  
      # Apply ordering. If we have location searching sort by distance.
      # We determine this by summing up the absolute value of the
      # differences between the resource and search latitudes/longitudes.
      # The absolute value prevents differences with opposing signs
      # from cancelling each other out.
      # Otherwise, sort by whatever's provided.
      if has_location:
          query = query.order_by(
              func.abs(Resource.latitude - search_params['lat']) +
              func.abs(Resource.longitude - search_params['long']))
      elif order_by is not None and not order_by.isspace():
          query = query.order_by(order_by)
  
      # Apply limiting
      if limit > 0:
          query = query.limit(limit)
  
      return query.all()
  
  def save(database, resource):
      """
      Creates or modifies a resource.
  
      Args:
          database: The current database context.
          resource: The resource to save.
  
      Returns:
          A Boolean indicating if the operation succeeded.  If a pre-existing
          resource is being updated (as indicated by its ID) but it no longer
          exists in the database, the save will fail.
      """
      # TODO
      pass
  
  def delete(database, resource_id):
      """
      Deletes a resource.
  
      Args:
          database: The current database context.
          resource_id: The ID of the resource to delete.
  
      Returns:
          A Boolean indicating if the operation succeeded.
      """     
      # TODO
      pass
  