require 'puppet'
require 'puppet/rails/param_name'
require 'puppet/rails/param_value'
require 'puppet/rails/puppet_tag'
require 'puppet/rails/benchmark'
require 'puppet/util/rails/collection_merger'

class Puppet::Rails::Resource < ActiveRecord::Base
  include Puppet::Util::CollectionMerger
  include Puppet::Util::ReferenceSerializer
  include Puppet::Rails::Benchmark

  has_many :param_values, :dependent => :destroy, :class_name => "Puppet::Rails::ParamValue"
  has_many :param_names, :through => :param_values, :class_name => "Puppet::Rails::ParamName"

  has_many :resource_tags, :dependent => :destroy, :class_name => "Puppet::Rails::ResourceTag"
  has_many :puppet_tags, :through => :resource_tags, :class_name => "Puppet::Rails::PuppetTag"

  belongs_to :source_file
  belongs_to :host

  @tags = {}
  def self.tags
    @tags
  end

  # Determine the basic details on the resource.
  def self.rails_resource_initial_args(resource)
    result = [:type, :title, :line].inject({}) do |hash, param|
      # 'type' isn't a valid column name, so we have to use another name.
      to = (param == :type) ? :restype : param
      if value = resource.send(param)
        hash[to] = value
      end
      hash
    end

    # We always want a value here, regardless of what the resource has,
    # so we break it out separately.
    result[:exported] = resource.exported || false

    result
  end

  def add_resource_tag(tag)
    pt = Puppet::Rails::PuppetTag.accumulate_by_name(tag)
    resource_tags.build(:puppet_tag => pt)
  end

  def file
    (f = self.source_file) ? f.filename : nil
  end

  def file=(file)
    self.source_file = Puppet::Rails::SourceFile.find_or_create_by_filename(file)
  end

  def title
    unserialize_value(self[:title])
  end

  def params_list
    @params_list ||= []
  end

  def params_list=(params)
    @params_list = params
  end

  def add_param_to_list(param)
    params_list << param
  end

  def tags_list
    @tags_list ||= []
  end

  def tags_list=(tags)
    @tags_list = tags
  end

  def add_tag_to_list(tag)
    tags_list << tag
  end

  def [](param)
    if param == 'id'
      super
    else
      super || parameter(param)
    end
  end

  # Make sure this resource is equivalent to the provided Parser resource.
  def merge_parser_resource(resource)
    accumulate_benchmark("Individual resource merger", :attributes) { merge_attributes(resource) }
    accumulate_benchmark("Individual resource merger", :parameters) { merge_parameters(resource) }
    accumulate_benchmark("Individual resource merger", :tags) { merge_tags(resource) }
    save
  end

  def merge_attributes(resource)
    args = self.class.rails_resource_initial_args(resource)
    args.each do |param, value|
      self[param] = value unless resource[param] == value
    end

    # Handle file specially
    self.file = resource.file if (resource.file and  (!resource.file or self.file != resource.file))
  end

  def merge_parameters(resource)
    catalog_params = {}
    resource.each do |param, value|
      catalog_params[param.to_s] = value
    end

    db_params = {}

    deletions = []
    params_list.each do |value|
      # First remove any parameters our catalog resource doesn't have at all.
      deletions << value['id'] and next unless catalog_params.include?(value['name'])

      # Now store them for later testing.
      db_params[value['name']] ||= []
      db_params[value['name']] << value
    end

    # Now get rid of any parameters whose value list is different.
    # This might be extra work in cases where an array has added or lost
    # a single value, but in the most common case (a single value has changed)
    # this makes sense.
    db_params.each do |name, value_hashes|
      values = value_hashes.collect { |v| v['value'] }

      value_hashes.each { |v| deletions << v['id'] } unless value_compare(catalog_params[name], values)
    end

    # Perform our deletions.
    Puppet::Rails::ParamValue.delete(deletions) unless deletions.empty?

    # Lastly, add any new parameters.
    catalog_params.each do |name, value|
      next if db_params.include?(name) && ! db_params[name].find{ |val| deletions.include?( val["id"] ) }
      values = value.is_a?(Array) ? value : [value]

      values.each do |v|
        param_values.build(:value => serialize_value(v), :line => resource.line, :param_name => Puppet::Rails::ParamName.accumulate_by_name(name))
      end
    end
  end

  # Make sure the tag list is correct.
  def merge_tags(resource)
    in_db = []
    deletions = []
    resource_tags = resource.tags
    tags_list.each do |tag|
      deletions << tag['id'] and next unless resource_tags.include?(tag['name'])
      in_db << tag['name']
    end
    Puppet::Rails::ResourceTag.delete(deletions) unless deletions.empty?

    (resource_tags - in_db).each do |tag|
      add_resource_tag(tag)
    end
  end

  def value_compare(v,db_value)
    v = [v] unless v.is_a?(Array)

    v == db_value
  end

  def name
    ref
  end

  def parameter(param)
    if pn = param_names.find_by_name(param)
      return (pv = param_values.find(:first, :conditions => [ 'param_name_id = ?', pn])) ? pv.value : nil
    end
  end

  def ref(dummy_argument=:work_arround_for_ruby_GC_bug)
    "#{self[:restype].split("::").collect { |s| s.capitalize }.join("::")}[#{self.title}]"
  end

  # Returns a hash of parameter names and values, no ActiveRecord instances.
  def to_hash
    Puppet::Rails::ParamValue.find_all_params_from_resource(self).inject({}) do |hash, value|
      hash[value['name']] ||= []
      hash[value['name']] << value.value
      hash
    end
  end

  # Convert our object to a resource.  Do not retain whether the object
  # is exported, though, since that would cause it to get stripped
  # from the configuration.
  def to_resource(scope)
    hash = self.attributes
    hash["type"] = hash["restype"]
    hash.delete("restype")

    # FIXME At some point, we're going to want to retain this information
    # for logging and auditing.
    hash.delete("host_id")
    hash.delete("updated_at")
    hash.delete("source_file_id")
    hash.delete("created_at")
    hash.delete("id")
    hash.each do |p, v|
      hash.delete(p) if v.nil?
    end
    hash[:scope] = scope
    hash[:source] = scope.source
    hash[:parameters] = []
    names = []
    self.param_names.each do |pname|
      # We can get the same name multiple times because of how the
      # db layout works.
      next if names.include?(pname.name)
      names << pname.name
      hash[:parameters] << pname.to_resourceparam(self, scope.source)
    end
    obj = Puppet::Parser::Resource.new(hash.delete("type"), hash.delete("title"), hash)

    # Store the ID, so we can check if we're re-collecting the same resource.
    obj.collector_id = self.id

    obj
  end
end