# general class to handle comparing and pushing data to the remote end
class UpdateAgent

  MAX_HASHES_AT_A_TIME = 100
  MAX_TO_BATCH_AT_A_TIME = 10
  SLEEP_PERIOD = 3

  DEBUG = false

  def initialize(data=nil, options={})
    @options = options
    @attributes = []
    @data = []
    @create = []
    @update = []
    if data
      if data.is_a?(Array)
        @data = data
        @attributes = data.first.keys.sort
      else
        read_from_file(data)
      end
    end
    check_for_invalid_columns
  end
  
  def check_for_invalid_columns
    if invalid = @data.detect { |row| row['id'] }
      puts "Error: one or more records contain an 'id' column."
      puts "You must utilize 'legacy_id' rather than 'id' so that"
      puts "identity and foreign keys are maintained from your"
      puts "existing membership management database."
      exit
    end
  end
  
  # load data from csv file and do some type conversion for bools and dates
  # first row must be attribute names
  def read_from_file(filename)
    csv = FasterCSV.open(filename, 'r')
    @attributes = csv.shift
    record_count = 0
    @data = csv.map do |row|
      hash = {}
      row.each_with_index do |value, index|
        key = @attributes[index]
        next if IGNORE_ATTRIBUTES.include?(key)
        if DATETIME_ATTRIBUTES.include?(key)
          if value.blank?
            value = nil
          else
            begin
              value = DateTime.parse(value)
            rescue ArgumentError
              puts "Invalid date in #{filename} record #{index} (#{key}) - #{value}"
              exit(1)
            end
          end
        elsif BOOLEAN_ATTRIBUTES.include?(key)
          if value == '' or value == nil
            value = nil
          elsif %w(no false 0).include?(value.downcase)
            value = false
          else
            value = true
          end
        elsif INTEGER_ATTRIBUTES.include?(key)
          value = value.to_s != '' ? value.scan(/\d/).join.to_i : nil
        end
        hash[key] = value
      end
      record_count += 1
      print "reading record #{record_count}\r"
      hash['deleted'] = false
      hash
    end
    puts
    @attributes << 'deleted'
    @attributes.reject! { |a| IGNORE_ATTRIBUTES.include?(a) }
  end
  
  def ids
    @data.map { |r| r['id'] }.compact
  end
  
  def legacy_ids
    @data.map { |r| r['legacy_id'] }.compact
  end

  def compare(force=false)
    compare_hashes(legacy_ids, force)
  end
  
  def has_work?
    (@create + @update).any?
  end

  def present
    puts "The following #{resource.name.downcase} records will be pushed..."
    puts 'legacy id  name'
    puts '---------- -------------------------------------'
    @create.each { |r| present_record(r, true) }
    @update.each { |r| present_record(r) }
    puts
  end
  
  def present_record(row, new=false)
    puts "#{row['legacy_id'].to_s.ljust(10)} #{name_for(row).to_s.ljust(40)} #{new ? '(new)' : '     '}"
    if DEBUG
      puts row.values_hash(@attributes)
      puts row['remote_hash']
    end
  end
  
  def confirm
    agree('Do you want to continue, pushing these records to OneBody? ')
  end
  
  # use ActiveResource to create/update records on remote end
  def push
    @errors = []
    puts 'Updating remote end...'
    index = 0
    print "#{resource.name} 0/0\r"; STDOUT.flush
    (@create + @update).each_slice(MAX_TO_BATCH_AT_A_TIME) do |records|
      response = resource.post(:batch, {}, records.to_xml)
      statuses = Hash.from_xml(response.body)['records']
      statuses.each do |status|
        record = data_by_id[status['legacy_id']]
        record['id'] = status['id']
        if status['status'] == 'error'
          puts "#{status['legacy_id']}: #{status['error']}"
          @errors << {:record => record, :error => status['error']}
          record['error_messages'] = status['error']
        end
      end
      index += records.length
      print "#{resource.name} #{index}/#{@create.length + @update.length}\r"; STDOUT.flush
      sleep SLEEP_PERIOD
    end
    puts
  end
  
  def errors
    (@create + @update).select { |r| r['error_messages'] }
  end
  
  def send_notification
    if n = @options['notifications']
      puts 'Sending notification...'
      if @errors and @errors.any?
        subject = 'OneBody UpdateAgent Errors'
        body = "There were #{@errors.length} error(s) running UpdateAgent.\n\nPlease visit #{ONEBODY_SITE}/admin/syncs for details."
      else
        subject = 'OneBody UpdateAgent Success'
        body = "OneBody UpdateAgent completed without any errors.\n"
      end
      Net::SMTP.start(n['host'], n['port'].to_i) do |smtp|
        smtp.send_message(
          "From: #{n['from_email']}\nTo: #{n['to_email']}\nSubject: #{subject}\n\n#{body}",
          n['from_email'],
          n['to_email']
        )
      end
    end
  end
  
  def start_sync
    @sync = Sync.create(:complete => false)
  end
  
  def finish_sync(create_items=true, mark_complete=true)
    if create_items
      @sync.post(
        :create_items,
        {},
        (
          @create.map { |r| to_sync_item(r, 'create') } +
          @update.map { |r| to_sync_item(r, 'update') }
        ).to_xml
      )
    end
    if mark_complete
      @sync.complete = true
      @sync.error_count = errors.length
      @sync.success_count = (@create + @update).length - errors.length
      @sync.save
    end
  end
  
  def to_sync_item(record, operation)
    h = {
      :syncable_type  => self.resource.name,
      :syncable_id    => record['id'],
      :name           => name_for(record),
      :legacy_id      => record['legacy_id'],
      :operation      => operation,
      :status         => record['error_messages'] ? 'error' : 'success'
    }
    if record['error_messages']
      h[:error_messages] = record['error_messages'].split('; ')
    end
    return h    
  end

  def data_by_id
    @data_by_id ||= begin
      by_id = {}
      @data.each { |r| by_id[r['legacy_id'].to_i] = r }
      by_id
    end
  end

  attr_accessor :attributes, :data, :sync
  attr_reader :update, :create
  
  class << self; attr_accessor :resource; end
  def resource; self.class.resource; end
  
  protected
  
  # ask remote end for value hashe for each record (50 at a time) 
  # mark records to create or update based on response
  def compare_hashes(ids, force=false)
    ids.each_slice(MAX_HASHES_AT_A_TIME) do |some_ids|
      print '.'; STDOUT.flush
      options = {:attrs => @attributes.join(','), :legacy_id => some_ids.join(',')}
      options.merge!(:debug => true) if DEBUG
      response = resource.post(:hashify, {}, options.to_xml)
      hashes = Hash.from_xml(response.body)['records'].to_a
      hashes.each do |record|
        row = data_by_id[record['legacy_id'].to_i]
        if DEBUG
          row['remote_hash'] = record['hash']
          @update << row if force or row.values_for_hash(@attributes).join != record['hash'] or (resource.name == 'Person' and record['family_id'].nil?)
        else
          @update << row if force or row.values_hash(@attributes) != record['hash'] or (resource.name == 'Person' and record['family_id'].nil?)
        end
      end
      @create += some_ids.reject { |id| hashes.map { |h| h['legacy_id'].to_i }.include?(id.to_i) }.map { |id| data_by_id[id.to_i] }
      sleep SLEEP_PERIOD
    end
    puts
  end
end