blazer/lib/blazer/result.rb

module Blazer
  class Result
    attr_reader :data_source, :columns, :rows, :error, :cached_at, :just_cached

    def initialize(data_source, columns, rows, error, cached_at, just_cached)
      @data_source = data_source
      @columns = columns
      @rows = rows
      @error = error
      @cached_at = cached_at
      @just_cached = just_cached
    end

    def timed_out?
      error == Blazer::TIMEOUT_MESSAGE
    end

    def cached?
      cached_at.present?
    end

    def boom
      @boom ||= begin
        boom = {}
        columns.each_with_index do |key, i|
          query = data_source.smart_columns[key]
          if query
            values = rows.map { |r| r[i] }.compact.uniq
            result = data_source.run_statement(ActiveRecord::Base.send(:sanitize_sql_array, [query.sub("{value}", "(?)"), values]))
            boom[key] = Hash[result.rows.map { |k, v| [k.to_s, v] }]
          end
        end
        boom
      end
    end

    def column_types
      @column_types ||= begin
        columns.each_with_index.map do |k, i|
          v = (rows.find { |r| r[i] } || {})[i]
          if boom[k]
            "string"
          elsif v.is_a?(Numeric)
            "numeric"
          elsif v.is_a?(Time) || v.is_a?(Date)
            "time"
          elsif v.nil?
            nil
          else
            "string"
          end
        end
      end
    end

    def chart_type
      @chart_type ||= begin
        if column_types.compact.size >= 2 && column_types.compact == ["time"] + (column_types.compact.size - 1).times.map { "numeric" }
          "line"
        elsif column_types == ["time", "string", "numeric"]
          "line2"
        elsif column_types.compact.size >= 2 && column_types == ["string"] + (column_types.compact.size - 1).times.map { "numeric" }
          "bar"
        elsif column_types == ["string", "string", "numeric"]
          "bar2"
        end
      end
    end

    def detect_anomaly
      anomaly = nil
      message = nil

      if rows.empty?
        message = "No data"
      else
        if chart_type == "line" || chart_type == "line2"
          series = []

          if chart_type == "line"
            columns[1..-1].each_with_index.each do |k, i|
              series << {name: k, data: rows.map{ |r| [r[0], r[i + 1]] }}
            end
          else
            rows.group_by { |r| v = r[1]; (boom[columns[1]] || {})[v.to_s] || v }.each_with_index.map do |(name, v), i|
              series << {name: name, data: v.map { |v2| [v2[0], v2[2]] }}
            end
          end

          current_series = nil
          begin
            anomalies = []
            series.each do |s|
              current_series = s[:name]
              anomalies << s[:name] if anomaly?(s[:data])
            end
            anomaly = anomalies.any?
            if anomaly
              if anomalies.size == 1
                message = "Anomaly detected in #{anomalies.first}"
              else
                message = "Anomalies detected in #{anomalies.to_sentence}"
              end
            else
              message = "No anomalies detected"
            end
          rescue => e
            message = "#{current_series}: #{e.message}"
            raise e if Rails.env.development?
          end
        else
          message = "Bad format"
        end
      end

      [anomaly, message]
    end

    def anomaly?(series)
      series = series.reject { |v| v[0].nil? }.sort_by { |v| v[0] }

      csv_str =
        CSV.generate do |csv|
          csv << ["timestamp", "count"]
          series.each do |row|
            csv << row
          end
        end

      r_script = %x[which Rscript].chomp
      type = series.any? && series.last.first.to_time - series.first.first.to_time >= 2.weeks ? "ts" : "vec"
      args = [type, csv_str]
      raise "R not found" if r_script.empty?
      command = "#{r_script} --vanilla #{File.expand_path("../detect_anomalies.R", __FILE__)} #{args.map { |a| Shellwords.escape(a) }.join(" ")}"
      output = %x[#{command}]
      if output.empty?
        raise "Unknown R error"
      end

      rows = CSV.parse(output, headers: true)
      error = rows.first && rows.first["x"]
      raise error if error

      timestamps = []
      if type == "ts"
        rows.each do |row|
          timestamps << Time.parse(row["timestamp"])
        end
        timestamps.include?(series.last[0].to_time)
      else
        rows.each do |row|
          timestamps << row["index"].to_i
        end
        timestamps.include?(series.length)
      end
    end
  end
end