module ModelTags

  include Radiant::Taggable

  class TagError < StandardError; end

  desc %{ }
  tag 'model' do |tag|
    raise TagError, "'#{tag.name}' tag must contain a 'name' attribute." unless tag.attr['name']
    tag.locals.model = tag.attr['name'].classify.constantize
    tag.locals.user = "x" # XXX TODO XXX
    tag.expand
  end

  desc %{ }
  tag 'model:find' do |tag|
    parms = Hash.new
    records = []

    if tag.attr['id']
      # if id was given then return that record
      records[0] = tag.locals.model.find tag.attr['id']
    else
      # searching for a set of records based on the given parameters
      [:order, :limit, :offset ].each do |p|
        if tag.attr[p] || tag.attr[p.to_s]
          parms[p] = tag.attr[p] || tag.attr[p.to_s]
        end
      end
      # -- combine conditions with r:filters:conditions
      conditions = get_conditions(tag)
      parms[:conditions] = conditions if conditions

      # now we have the conditions and such
      if tag.attr['distinct']
        # if dictinct records are queried
        # TODO XXX : ditinct(...) should be secured
        sql = "select distinct(#{tag.attr['distinct']}) from #{tag.locals.model.table_name} "
        if parms[:conditions]
          sql += " where (#{parms[:conditions]}) "
        end
        if parms[:order]
          sql += " order by #{parms[:order]} "
        end
        if parms[:limit]
          sql += " limit #{parms[:limit]} "
        end
        records = tag.locals.model.find_by_sql sql
      else
        # lookup records based on the parameters
        records = tag.locals.model.find(:all,parms)
      end
    end
    tag.locals.records = records
    tag.expand
  end

  desc %{ }
  tag 'model:find:each' do |tag|
    # -- each --
    result = []
    if non_empty(tag)
      records = tag.locals.records
      records.each do |record|
        tag.locals.record = record
        result << tag.expand
      end
    end
    result
  end

  desc %{ }
  tag 'model:find:each:value' do |tag|
    ret = nil
    if tag.attr['name']
      ret = tag.locals.record[tag.attr['name']]
    end

    # resulting value may be changed with these two attributes:
    # - if_found, - unless_found
    if_or_unless_value(tag,ret)
  end


  desc %{ }
  tag 'model:find:count' do |tag|
    if non_empty(tag)
      tag.locals.records.size.to_s
    else
      "0"
    end
  end

  desc %{ }
  tag 'model:find:if_returned' do |tag|
    # -- each --
    if non_empty(tag)
      tag.expand
    end
  end

  desc %{ }
  tag 'model:find:unless_returned' do |tag|
    # -- each --
    unless non_empty(tag)
      tag.expand
    end
  end

  # ---------------------------------------------------------
  # Calculated values, generated by Model or Entity functions

  desc %{ }
  tag 'function' do |tag|
    if tag.attr['name']
      if tag.locals.model.respond_to?("function_is_allowed_to?") &&
         tag.locals.model.function_is_allowed_to?(tag.attr['name'],tag.locals.user) # XXX TODO XXX
        parms = tag.attr['params'].split(",") if tag.attr['params']
        c = get_conditions(tag)
        ret = tag.locals.model.send(tag.attr['name'],parms,c)
        # calcval may return string, array and hash
        tag.locals.calcval = ret
        tag.locals.calcvals = ret
        tag.expand
      end
    end
  end

  desc %{ }
  tag 'each:function' do |tag|
    if tag.attr['name']
      if tag.locals.record.respond_to?("function_is_allowed_to?") &&
         tag.locals.record.function_is_allowed_to?(tag.attr['name'],tag.locals.user) # XXX TODO XXX
        parms = tag.attr['params'].split(",") if tag.attr['params']
        c = get_conditions(tag)
        ret = tag.locals.record.send(tag.attr['name'],parms,c)
        # calcval may return string, array and hash
        tag.locals.calcval = ret
        tag.locals.calcvals = ret
        tag.expand
      end
    end
  end

  desc %{  }
  tag 'function:each' do |tag|
    if tag.locals.calcvals && tag.locals.calcvals.size > 0
      result = []
      tag.locals.calcvals.each do |r|
        tag.locals.calcval = r
        result << tag.expand
      end
      result
    end
  end

  desc %{ }
  tag 'function:each:value' do |tag|
    ret = calcval_value(tag)

    # resulting value may be changed with these two attributes:
    # - if_found, - unless_found
    if_or_unless_value(tag,ret)
  end

  desc %{ }
  tag 'function:count' do |tag|
    calcval_count(tag)
  end

  desc %{ }
  tag 'function:if_returned' do |tag|
    if calcval_non_empty(tag)
      tag.expand
    end
  end

  # ------------------------------------------------------------------------
  # A group of entities may be stored in the session. That I call container.
  # These need a special controller that has access to session data.

  desc %{ }
  tag 'add_item_to' do |tag|
    model_name     = tag.locals.model.to_s if tag.locals.model
    model_name   ||= "String"
    #  --
    action         = tag.attr['action'] || "/container/add_item_to"
    update_value   = tag.attr['container'] || "#{model_name}_container"
    url            = tag.attr['url'] || '/'
    quantity       = tag.attr['quantity'] || "1"
    text           = tag.expand
    # -- parameters --
    id               = tag.locals.record['id'] if tag.locals.record
    id             ||= tag.locals.calcval['id'] if (tag.locals.calcval && tag.locals.calcval['id'])
    id_param         = %{eid: '#{id}'}
    url_param        = %{url: '#{url}'}
    container_param  = %{container: '#{update_value}'}
    model_param      = %{model: '#{tag.locals.model.to_s}'}
    quantity_param   = %{quantity: '#{quantity}'}
    # -- construnct javascript --
    parameters   = %{{#{id_param}, #{url_param}, #{container_param}, #{model_param}, #{quantity_param}}}
    oncomplete   = %{function(request){new Effect.Highlight(&quot;#{update_value}&quot;,{duration:0.5});}}
    options      = %{{asynchronous:true, evalScripts:true, onComplete:#{oncomplete}, parameters:#{parameters}}}
    ajax_updater = %{ <a href="#" onclick="new Ajax.Updater('#{update_value}', '#{action}', #{options}); return false;">#{text}</a> }
  end

  desc %{ }
  tag 'remove_item_from' do |tag|
    model_name     = tag.locals.model.to_s if tag.locals.model
    model_name   ||= "String"
    #  --
    action         = tag.attr['action'] || "/container/remove_item_from"
    update_value   = tag.attr['container'] || "#{model_name}_container"
    url            = tag.attr['url'] || '/'
    quantity       = tag.attr['quantity'] || "1"
    text           = tag.expand
    # -- parameters --
    id               = tag.locals.record['id'] if tag.locals.record
    id             ||= tag.locals.calcval['id'] if (tag.locals.calcval && tag.locals.calcval['id'])
    id_param         = %{eid: '#{id}'}
    url_param        = %{url: '#{url}'}
    container_param  = %{container: '#{update_value}'}
    model_param      = %{model: '#{tag.locals.model.to_s}'}
    quantity_param   = %{quantity: '#{quantity}'}
    # -- construnct javascript --
    parameters   = %{{#{id_param}, #{url_param}, #{container_param}, #{model_param}, #{quantity_param}}}
    oncomplete   = %{function(request){new Effect.Highlight(&quot;#{update_value}&quot;,{duration:0.5});}}
    options      = %{{asynchronous:true, evalScripts:true, onComplete:#{oncomplete}, parameters:#{parameters}}}
    ajax_updater = %{ <a href="#" onclick="new Ajax.Updater('#{update_value}', '#{action}', #{options}); return false;">#{text}</a> }
  end

  desc %{ }
  tag 'container_item' do |tag|
    model_name = nil
    model      = tag.locals.model
    id         = nil
    request    = tag.globals.page.request
    # --
    if request
      if request.parameters['model']
        model_name  = request.parameters['model']
        model       = model_name.classify.constantize if model_name
      end
      id = request.parameters['eid']
      # --
      tag.locals.model      = model
      tag.locals.id         = id
      tag.locals.quantity   = request.parameters['quantity']
      tag.locals.container  = request.parameters['container']
      tag.locals.url        = request.parameters['url']
    end
    tag.locals.record = model.find(id) if (model && id)
    if tag.locals.record
      tag.expand
    end
  end

  # -----------------------------------------------------
  # Code duplication for clarity. One tag would do for both
  # container_item and model:find:each

  desc %{ }
  tag 'container_item:value' do |tag|
    ret = nil
    if tag.attr['name']
      ret = tag.locals.record[tag.attr['name']]
    end

    # resulting value may be changed with these two attributes:
    # - if_found, - unless_found
    if_or_unless_value(tag,ret)
  end

  # this tag is placed here in order to make functions work
  # on the container_items, so
  # container_item:each:function may be used
  desc %{ }
  tag 'container_item:each' do |tag|
    tag.expand
  end

  desc %{ }
  tag 'container_item:quantity' do |tag|
    tag.locals.quantity.to_s
  end

  desc %{ }
  tag 'container_item:subtotal_for' do |tag|
    total_for = tag.attr['field'] || 'price'
    suppress = (tag.attr['suppress_if_zero'] && tag.attr['suppress_if_zero'] == "true") ? true : false
    subtotal = 0.0
    quantity = tag.locals.quantity.to_f || 1.0
    if tag.locals.record
      subtotal = tag.locals.record[total_for].to_f
    end
    if subtotal>0.0
      suppress = false
    end
    if suppress
      nil
    else
      (subtotal * quantity).to_s
    end
  end

private

  def calcval_value(tag)
    ret = nil
    if tag.attr['name']
      ret = tag.locals.calcval[tag.attr['name']]
    else
      ret = tag.locals.calcval
    end
    ret
  end

  def calcval_count(tag)
    if tag.locals.calcvals
      tag.locals.calcvals.size.to_s
    else
      "0"
    end
  end

  def calcval_non_empty(tag)
    # treats nil, empty array, and empty string the same way
    ( tag.locals.calcvals &&
      tag.locals.calcvals.respond_to?("size") &&
      tag.locals.calcvals.size>0
     ) ||
     (
      tag.locals.calcval &&
      tag.locals.calcval.respond_to?("length") &&
      tag.locals.calcval.length>0
     )
  end

  def non_empty(tag)
    records = tag.locals.records
    records && records.size>0
  end

  def get_conditions(tag)
    ret = tag.locals.conditions
    if tag.attr['conditions']
      if tag.locals.conditions
        ret = "#{tag.attr['conditions']} AND #{tag.locals.conditions}"
      else
        ret = tag.attr['conditions']
      end
    end
    ret
  end

  def if_or_unless_value(tag,ret)
    newret = ret.to_s
    if tag.attr['if_found'] && ret && ret.length > 0
      newret = tag.attr['if_found']
    end
    if tag.attr['unless_found'] && (!ret || ret.length == 0)
      newret = tag.attr['unless_found']
    end
    newret
  end
end