require 'digest'

require 'norikra/typedef'
require 'norikra/error'

module Norikra
  class TypedefManager
    attr_reader :typedefs

    def initialize(opts={})
      @typedefs = {} # {target => Typedef}
      @mutex = Mutex.new
    end

    def field_list(target)
      @typedefs[target].dump.map{|key,hash_value| hash_value}
      # @typedefs[target].fields.values.sort{|a,b| a.name <=> b.name}.map(&:to_hash)
    end

    def add_target(target, fields)
      # fields nil || [] => lazy
      # fields {'fieldname' => 'type'}
      @mutex.synchronize do
        raise Norikra::ArgumentError, "target '#{target}' already exists" if @typedefs[target]
        @typedefs[target] = Typedef.new(fields)
      end
    end

    def remove_target(target)
      @mutex.synchronize do
        raise Norikra::ArgumentError, "target '#{target}' doesn't exists" unless @typedefs[target]
        @typedefs.delete(target)
      end
    end

    def lazy?(target)
      @typedefs[target].lazy?
    end

    def activate(target, fieldset)
      fieldset.bind(target, :base)
      @typedefs[target].activate(fieldset)
    end

    def reserve(target, field, type)
      @typedefs[target].reserve(field, type)
    end

    def ready?(query)
      query.targets.all?{|t| @typedefs[t] && ! @typedefs[t].lazy? && @typedefs[t].field_defined?(query.fields(t))} &&
        query.fields(nil).all?{|f| query.targets.any?{|t| @typedefs[t].field_defined?([f])}}
    end

    def register_waiting_fields(query)
      query.targets.each do |t|
        next if t.nil?

        typedef = @typedefs[t]
        fields = typedef.fields

        query.fields(t).each do |fieldname|
          if !fields.has_key?(fieldname) && !typedef.waiting_fields.include?(fieldname)
            typedef.waiting_fields.push(fieldname)
          end
        end
      end
    end

    def generate_fieldset_mapping(query)
      fields_set = {}

      query.targets.each do |target|
        fields_set[target] = query.fields(target)
      end
      query.fields(nil).each do |field|
        assumed = query.targets.select{|t| @typedefs[t].field_defined?([field])}
        if assumed.size != 1
          raise Norikra::ClientError, "cannot determine target for field '#{field}' in this query"
        end
        fields_set[assumed.first].push(field)
      end

      mapping = {}
      fields_set.each do |target,fields|
        mapping[target] = generate_query_fieldset(target, fields.sort.uniq)
      end
      mapping
    end

    def bind_fieldset(target, level, fieldset)
      fieldset.bind(target, level)
      @typedefs[target].push(level, fieldset)
    end

    def unbind_fieldset(target, level, fieldset)
      @typedefs[target].pop(level, fieldset)
    end

    def replace_fieldset(target, old_fieldset, new_fieldset)
      @typedefs[target].replace(:data, old_fieldset, new_fieldset)
    end

    def generate_base_fieldset(target, event)
      guessed = @typedefs[target].simple_guess(event, false, false) # all fields are non-optional
      guessed.update(@typedefs[target].fields, false)
      guessed
    end

    def generate_query_fieldset(target, field_name_list)
      # all fields of field_name_list should exists in definitions of typedef fields
      # for this premise, call 'bind_fieldset' for data fieldset before this method.
      required_fields = {}
      @mutex.synchronize do
        @typedefs[target].fields.each do |fieldname, field|
          if field_name_list.include?(fieldname) || !(field.optional?)
            required_fields[fieldname] = {:type => field.type, :optional => field.optional}
          end
        end
      end
      Norikra::FieldSet.new(required_fields)
    end

    def base_fieldset(target)
      @typedefs[target].baseset
    end

    def subsets(target, fieldset) # for data fieldset
      sets = []
      @mutex.synchronize do
        @typedefs[target].queryfieldsets.each do |set|
          sets.push(set) if set.subset?(fieldset)
        end
        sets.push(@typedefs[target].baseset)
      end
      sets
    end

    def supersets(target, fieldset) # for query fieldset
      sets = []
      @mutex.synchronize do
        @typedefs[target].datafieldsets.each do |set|
          sets.push(set) if fieldset.subset?(set)
        end
      end
      sets
    end

    def refer(target_name, event, strict=false)
      @typedefs[target_name].refer(event, strict)
    end

    def dump_target(name)
      @typedefs[name].dump_all
    end
  end
end