# frozen_string_literal: true

module GoodJob
  class ScheduledByQueueChart
    def initialize(filter)
      @filter = filter
    end

    def data
      end_time = Time.current
      start_time = end_time - 1.day
      table_name = GoodJob::ActiveJobJob.table_name

      count_query = Arel.sql(GoodJob::Execution.pg_or_jdbc_query(<<~SQL.squish))
        SELECT *
        FROM generate_series(
          date_trunc('hour', $1::timestamp),
          date_trunc('hour', $2::timestamp),
          '1 hour'
        ) timestamp
        LEFT JOIN (
          SELECT
              date_trunc('hour', scheduled_at) AS scheduled_at,
              queue_name,
              count(*) AS count
            FROM (
              #{@filter.filtered_query.except(:select, :order).select('queue_name', "COALESCE(#{table_name}.scheduled_at, #{table_name}.created_at)::timestamp AS scheduled_at").to_sql}
            ) sources
            GROUP BY date_trunc('hour', scheduled_at), queue_name
        ) sources ON sources.scheduled_at = timestamp
        ORDER BY timestamp ASC
      SQL

      binds = [
        ActiveRecord::Relation::QueryAttribute.new('start_time', start_time, ActiveRecord::Type::DateTime.new),
        ActiveRecord::Relation::QueryAttribute.new('end_time', end_time, ActiveRecord::Type::DateTime.new),
      ]
      executions_data = GoodJob::Execution.connection.exec_query(GoodJob::Execution.pg_or_jdbc_query(count_query), "GoodJob Dashboard Chart", binds)

      queue_names = executions_data.reject { |d| d['count'].nil? }.map { |d| d['queue_name'] || BaseFilter::EMPTY }.uniq
      labels = []
      queues_data = executions_data.to_a.group_by { |d| d['timestamp'] }.each_with_object({}) do |(timestamp, values), hash|
        labels << timestamp.in_time_zone.strftime('%H:%M')
        queue_names.each do |queue_name|
          (hash[queue_name] ||= []) << values.find { |d| d['queue_name'] == queue_name }&.[]('count')
        end
      end

      {
        labels: labels,
        datasets: queues_data.map do |queue, data|
          label = queue || '(none)'
          {
            label: label,
            data: data,
            backgroundColor: string_to_hsl(label),
            borderColor: string_to_hsl(label),
          }
        end,
      }
    end

    def string_to_hsl(string)
      hash_value = string.sum

      hue = hash_value % 360
      saturation = (hash_value % 50) + 50
      lightness = '50'

      "hsl(#{hue}, #{saturation}%, #{lightness}%)"
    end
  end
end