module Marty::Diagnostic; class Reporter < Request
  class_attribute :reports, :diagnostics, :namespaces

  self.reports     = {}
  self.diagnostics = []
  self.namespaces  = ['Marty']

  def self.run request
    self.request = request

    ops = op.split(/,\s*/).uniq - [unresolve_diagnostic(self)]
    reps = ops.select { |o| reports.key?(o) }

    self.diagnostics = ((ops - reps) + reps.map { |r| reports[r] }.flatten).uniq.
                         map { |d| resolve_diagnostic(d) }

    scope == 'local' ? generate : aggregate
  end

  private

  def self.resolve_diagnostic diag_name
    diag_name = diag_name.camelize
    klass = nil
    namespaces.each do |n|
      klass = (n + '::Diagnostic::' + diag_name).constantize rescue nil
      break if klass
    end
    raise NameError, "#{diag_name} could not be resolved by #{name}" if
      klass.nil?

    klass
  end

  def self.unresolve_diagnostic klass
    klass.name.demodulize.underscore
  end

  def self.generate
    diagnostics.each_with_object({}) do |d, h|
      begin
        h[d.name.demodulize] = d.generate
      rescue StandardError => e
        h.deep_merge!(Fatal.message(e.message, type: d.name.demodulize))
      end
    end
  end

  def self.aggregate
    data = consistency([generate, get_remote_diagnostics].reduce(:deep_merge))
    { 'data' => data, 'errors' => errors(data) }
  end

  def self.consistency data
    data.each_with_object({}) do |(klass, result), h|
      h[klass] = resolve_diagnostic(klass).apply_consistency(result)
    end
  end

  def self.errors data
    data.each_with_object({}) do |(klass, result), new_data|
      new_data[klass] = result.each_with_object({}) do |(node, diagnostic), new_result|
        new_result[node] = diagnostic.each_with_object({}) do |(test, info), new_diagnostic|
          new_diagnostic[test] = info unless
            info['status'] && (scope == 'local' || info['consistent'])
        end
        new_result.delete(node) if new_result[node].empty?
      end
      new_data.delete(klass) if new_data[klass].empty?
    end
  end

  def self.displays result
    result.map { |d, r| resolve_diagnostic(d).display(r) }.sum
  end

  def self.get_remote_diagnostics
    ops = diagnostics.map { |d| unresolve_diagnostic(d) if d.aggregatable }.compact
    return {} if ops.empty?

    nodes = Node.get_nodes - [Node.my_ip]
    remote = nodes.sort.map do |n|
      Thread.new do
        uri = Addressable::URI.new(host: n, port: request.port)
        uri.scheme = ssl? ? 'https' : 'http'
        uri.path = '/marty/diag.json'
        uri.query_values = {
          scope: 'local',
          op: ops.join(','),
        }
        req = Net::HTTP.new(uri.host, uri.port)
        req.use_ssl = ssl?
        req.read_timeout = req.open_timeout = ENV['DIAG_TIMEOUT'] || 10
        req.verify_mode = OpenSSL::SSL::VERIFY_NONE

        begin
          response = req.start { |http| http.get(uri.to_s) }
          next JSON.parse(response.body) if response.code == '200'

          Fatal.message(response.body, type: response.message, node: uri.host)
        rescue StandardError => e
          Fatal.message(e.message, type: e.class, node: uri.host)
        end
      end
    end

    remote.empty? ? {} : remote.map(&:join).map(&:value).reduce(:deep_merge)
  end
end
end