require 'java'
require 'fileutils'
Dir["lib/jars/*"].each {|file| require file }

class Geoff
  class Error                  < StandardError ; end
  class MissingIndexedProperty < Geoff::Error  ; end
  class InvalidRules           < Geoff::Error  ; end

  def self.import *args
    Importer.import *args
  end

  class Importer
    Subgraph = org.neo4j.geoff.Subgraph

    class << self
      def import_files(*files, options)
        concatenated = files.map{|f|File.read f}.join "\n"

        import concatenated, options
      end

      def import_file(file, options = {})
        rules = File.read(file)
        import(rules, options)
      end

      def import(geoff, options = {})
        geoff = geoff.to_geoff unless geoff.is_a? String

        geoff = geoff.split "\n" if geoff.is_a? String

        new(geoff, options).go
      end
    end

    def initialize(rules, options)
      @rules = rules
      @options = options
      log @options.inspect
    end

    def go
      raise Geoff::InvalidRules.new('Invalid rules') unless validate_rules(@rules)
      delete_database if drop?

      log 'importing the database'

      import_geoff_rules @rules
      rebuild_indexes

      true
    end

    private

    def delete_database
      if testmode?
        Neo4j::Transaction.run do
          Neo4j.db.each_node do |n|
            n.del unless n.neo_id == 0
          end
        end
      else
        Neo4j.db.shutdown
        FileUtils.rm_rf Neo4j::Config[:storage_path]
        log "restarting the database #{Neo4j::Config[:storage_path]}"
        Neo4j.db.start
      end
    end

    def import_geoff_rules(rules)
      sub_graph = Subgraph.new(rules)
      node_map = build_node_map
      org.neo4j.geoff.Geoff.mergeIntoNeo4j(sub_graph, Neo4j.db.graph, node_map );
    end

    def build_node_map
      root_node.rels(:outgoing).inject({}) do |h, r|
        h[r.rel_type.to_s] = r.end_node
        h
      end.merge("ROOT" => root_node)
    end

    def rebuild_indexes
      log 're-building indexes'
      types = root_node.relationships.map { |r| Kernel.const_get(r.get_type.to_s) }

      Neo4j::Transaction.run do
        types.each do |type|
          re_index(type)
        end
      end
    end

    def re_index(type)
      log "-> re-indexing #{type}"
      props = type.instance_variable_get(:@_decl_props)
      indexed_props = props.find_all { |_, p| p.has_key?(:index) }

      indexed_props.each do |index|
        all = type.all

        all.each do |node|
          @current_node = node
          @current_index = index.first
          node.add_index index.first
        end
      end

    rescue NativeException => e
      log "-" * 80
      message = "#{type} missing indexed attribute #{@current_index}, on node: #{@current_node.attributes}"
      log message
      log "-" * 80
      log e.message
      log "-" * 80
      raise Geoff::MissingIndexedProperty, message
    end

    def tx
      Neo4j::Transaction.run { yield if block_given? }
    end

    def root_node
      Neo4j.ref_node
    end

    def log(message)
      $stdout.puts message unless silent?
    end

    def drop?
      option_value?(:drop, false)
    end

    def silent?
      option_value? :silent
    end

    def testmode?
      option_value? :test
    end

    def option_value?(key, default = false)
      @options[key].nil? ? default : @options[key]
    end

    def validate_rules(rules)
      @invalid = Array(rules).map do |r|
        validate_rule(r)
      end.compact

      @invalid.each { |r, message| log "Rule '#{r}' is invalid: #{message}" }
      @invalid.empty?
    end

    def validate_rule(rule)
      Subgraph.new(Array(rule))
      nil
    rescue Exception => e
      return [rule, e.message]
    end

  end

end