require_dependency 'topic_subtype'

class Report
  # Change this line each time report format change
  # and you want to ensure cache is reset
  SCHEMA_VERSION = 3

  attr_accessor :type, :data, :total, :prev30Days, :start_date,
                :end_date, :category_id, :group_id, :filter,
                :labels, :async, :prev_period, :facets, :limit, :processing, :average, :percent,
                :higher_is_better, :icon, :modes, :category_filtering,
                :group_filtering, :prev_data, :prev_start_date, :prev_end_date,
                :dates_filtering, :error, :primary_color, :secondary_color, :filter_options

  def self.default_days
    30
  end

  def initialize(type)
    @type = type
    @start_date ||= Report.default_days.days.ago.utc.beginning_of_day
    @end_date ||= Time.now.utc.end_of_day
    @prev_end_date = @start_date
    @average = false
    @percent = false
    @higher_is_better = true
    @category_filtering = false
    @group_filtering = false
    @modes = [:table, :chart]
    @prev_data = nil
    @dates_filtering = true
    @filter_options = nil
    @filter = nil

    tertiary = ColorScheme.hex_for_name('tertiary') || '0088cc'
    @primary_color = rgba_color(tertiary)
    @secondary_color = rgba_color(tertiary, 0.1)
  end

  def self.cache_key(report)
    (+"reports:") <<
    [
      report.type,
      report.category_id,
      report.start_date.to_date.strftime("%Y%m%d"),
      report.end_date.to_date.strftime("%Y%m%d"),
      report.group_id,
      report.filter,
      report.facets,
      report.limit,
      SCHEMA_VERSION,
    ].compact.map(&:to_s).join(':')
  end

  def self.clear_cache(type = nil)
    pattern = type ? "reports:#{type}:*" : "reports:*"

    Discourse.cache.keys(pattern).each do |key|
      Discourse.cache.redis.del(key)
    end
  end

  def self.wrap_slow_query(timeout = 20000)
    ActiveRecord::Base.connection.transaction do
      # Set a statement timeout so we can't tie up the server
      DB.exec "SET LOCAL statement_timeout = #{timeout}"
      yield
    end
  end

  def prev_start_date
    self.start_date - (self.end_date - self.start_date)
  end

  def prev_end_date
    self.start_date
  end

  def filter_values
    if self.filter.present?
      return self.filter.delete_prefix("[").delete_suffix("]").split("&").map { |param| param.split("=") }.to_h
    end
    {}
  end

  def as_json(options = nil)
    description = I18n.t("reports.#{type}.description", default: "")
    {
      type: type,
      title: I18n.t("reports.#{type}.title", default: nil),
      xaxis: I18n.t("reports.#{type}.xaxis", default: nil),
      yaxis: I18n.t("reports.#{type}.yaxis", default: nil),
      description: description.presence ? description : nil,
      data: data,
      start_date: start_date&.iso8601,
      end_date: end_date&.iso8601,
      prev_data: self.prev_data,
      prev_start_date: prev_start_date&.iso8601,
      prev_end_date: prev_end_date&.iso8601,
      category_id: category_id,
      group_id: group_id,
      filter: self.filter,
      prev30Days: self.prev30Days,
      dates_filtering: self.dates_filtering,
      report_key: Report.cache_key(self),
      primary_color: self.primary_color,
      secondary_color: self.secondary_color,
      labels: labels || [
        {
          type: :date,
          property: :x,
          title: I18n.t("reports.default.labels.day")
        },
        {
          type: :number,
          property: :y,
          title: I18n.t("reports.default.labels.count")
        },
      ],
      processing: self.processing,
      average: self.average,
      percent: self.percent,
      higher_is_better: self.higher_is_better,
      category_filtering: self.category_filtering,
      group_filtering: self.group_filtering,
      filter_options: self.filter_options,
      modes: self.modes,
    }.tap do |json|
      json[:icon] = self.icon if self.icon
      json[:error] = self.error if self.error
      json[:total] = self.total if self.total
      json[:prev_period] = self.prev_period if self.prev_period
      json[:prev30Days] = self.prev30Days if self.prev30Days
      json[:limit] = self.limit if self.limit

      if type == 'page_view_crawler_reqs'
        json[:related_report] = Report.find('web_crawlers', start_date: start_date, end_date: end_date)&.as_json
      end
    end
  end

  def Report.add_report(name, &block)
    singleton_class.instance_eval { define_method("report_#{name}", &block) }
  end

  def self._get(type, opts = nil)
    opts ||= {}

    # Load the report
    report = Report.new(type)
    report.start_date = opts[:start_date] if opts[:start_date]
    report.end_date = opts[:end_date] if opts[:end_date]
    report.category_id = opts[:category_id] if opts[:category_id]
    report.group_id = opts[:group_id] if opts[:group_id]
    report.filter = opts[:filter] if opts[:filter]
    report.facets = opts[:facets] || [:total, :prev30Days]
    report.limit = opts[:limit] if opts[:limit]
    report.processing = false
    report.average = opts[:average] if opts[:average]
    report.percent = opts[:percent] if opts[:percent]
    report.higher_is_better = opts[:higher_is_better] if opts[:higher_is_better]
    report
  end

  def self.find_cached(type, opts = nil)
    report = _get(type, opts)
    Discourse.cache.read(cache_key(report))
  end

  def self.cache(report, duration)
    Discourse.cache.write(cache_key(report), report.as_json, force: true, expires_in: duration)
  end

  def self.find(type, opts = nil)
    opts ||= {}

    begin
      report = _get(type, opts)
      report_method = :"report_#{type}"

      begin
        wrap_slow_query do
          if respond_to?(report_method)
            send(report_method, report)
          elsif type =~ /_reqs$/
            req_report(report, type.split(/_reqs$/)[0].to_sym)
          else
            return nil
          end
        end
      rescue ActiveRecord::QueryCanceled, PG::QueryCanceled => e
        report.error = :timeout
      end
    rescue Exception => e

      # In test mode, don't swallow exceptions by default to help debug errors.
      raise if Rails.env.test? && !opts[:wrap_exceptions_in_test]

      # ensures that if anything unexpected prevents us from
      # creating a report object we fail elegantly and log an error
      if !report
        Rails.logger.error("Couldn’t create report `#{type}`: <#{e.class} #{e.message}>")
        return nil
      end

      report.error = :exception

      # given reports can be added by plugins we don’t want dashboard failures
      # on report computation, however we do want to log which report is provoking
      # an error
      Rails.logger.error("Error while computing report `#{report.type}`: #{e.message}\n#{e.backtrace.join("\n")}")
    end

    report
  end

  def self.req_report(report, filter = nil)
    data =
      if filter == :page_view_total
        ApplicationRequest.where(req_type: [
          ApplicationRequest.req_types.reject { |k, v| k =~ /mobile/ }.map { |k, v| v if k =~ /page_view/ }.compact
        ].flatten)
      else
        ApplicationRequest.where(req_type: ApplicationRequest.req_types[filter])
      end

    if filter == :page_view_total
      report.icon = 'file'
    end

    report.data = []
    data.where('date >= ? AND date <= ?', report.start_date, report.end_date)
      .order(date: :asc)
      .group(:date)
      .sum(:count)
      .each do |date, count|
      report.data << { x: date, y: count }
    end

    report.total = data.sum(:count)

    report.prev30Days = data.where(
        'date >= ? AND date < ?',
        (report.start_date - 31.days), report.start_date
      ).sum(:count)
  end

  def self.report_about(report, subject_class, report_method = :count_per_day)
    basic_report_about report, subject_class, report_method, report.start_date, report.end_date
    add_counts report, subject_class
  end

  def self.basic_report_about(report, subject_class, report_method, *args)
    report.data = []

    subject_class.send(report_method, *args).each do |date, count|
      report.data << { x: date, y: count }
    end
  end

  def self.add_prev_data(report, subject_class, report_method, *args)
    if report.modes.include?(:chart) && report.facets.include?(:prev_period)
      prev_data = subject_class.send(report_method, *args)
      report.prev_data = prev_data.map { |k, v| { x: k, y: v } }
    end
  end

  def self.add_counts(report, subject_class, query_column = 'created_at')
    if report.facets.include?(:prev_period)
      prev_data = subject_class
        .where("#{query_column} >= ? and #{query_column} < ?",
          report.prev_start_date,
          report.prev_end_date)

      report.prev_period = prev_data.count
    end

    if report.facets.include?(:total)
      report.total = subject_class.count
    end

    if report.facets.include?(:prev30Days)
      report.prev30Days = subject_class
        .where("#{query_column} >= ? and #{query_column} < ?",
          report.start_date - 30.days,
          report.start_date).count
    end
  end

  def self.post_action_report(report, post_action_type)
    report.data = []
    PostAction.count_per_day_for_type(post_action_type, category_id: report.category_id, start_date: report.start_date, end_date: report.end_date).each do |date, count|
      report.data << { x: date, y: count }
    end
    countable = PostAction.unscoped.where(post_action_type_id: post_action_type)
    countable = countable.joins(post: :topic).merge(Topic.in_category_and_subcategories(report.category_id)) if report.category_id
    add_counts report, countable, 'post_actions.created_at'
  end

  def self.private_messages_report(report, topic_subtype)
    report.icon = 'envelope'
    subject = Topic.where('topics.user_id > 0')
    basic_report_about report, subject, :private_message_topics_count_per_day, report.start_date, report.end_date, topic_subtype
    subject = Topic.private_messages.where('topics.user_id > 0').with_subtype(topic_subtype)
    add_counts report, subject, 'topics.created_at'
  end

  DiscourseEvent.on(:site_setting_saved) do |site_setting|
    if ["backup_location", "s3_backup_bucket"].include?(site_setting.name.to_s)
      clear_cache(:storage_stats)
    end
  end

  def rgba_color(hex, opacity = 1)
    if hex.size == 3
      chars = hex.scan(/\w/)
      hex = chars.zip(chars).flatten.join
    end

    if hex.size < 3
      hex = hex.ljust(6, hex.last)
    end

    rgbs = hex_to_rgbs(hex)

    "rgba(#{rgbs.join(',')},#{opacity})"
  end

  private

  def hex_to_rgbs(hex_color)
    hex_color = hex_color.gsub('#', '')
    rgbs = hex_color.scan(/../)
    rgbs
      .map! { |color| color.hex }
      .map! { |rgb| rgb.to_i }
  end
end

require_relative "reports/visits"
require_relative "reports/visits_mobile"
require_relative "reports/consolidated_page_views"
require_relative "reports/top_ignored_users"
require_relative "reports/top_uploads"
require_relative "reports/moderators_activity"
require_relative "reports/signups"
require_relative "reports/storage_stats"
require_relative "reports/suspicious_logins"
require_relative "reports/new_contributors"
require_relative "reports/users_by_trust_level"
require_relative "reports/staff_logins"
require_relative "reports/users_by_type"
require_relative "reports/user_flagging_ratio"
require_relative "reports/post_edits"
require_relative "reports/daily_engaged_users"
require_relative "reports/flags_status"
require_relative "reports/trending_search"
require_relative "reports/top_referrers"
require_relative "reports/top_traffic_sources"
require_relative "reports/top_referred_topics"
require_relative "reports/notify_user_private_messages"
require_relative "reports/user_to_user_private_messages"
require_relative "reports/user_to_user_private_messages_with_replies"
require_relative "reports/system_private_messages"
require_relative "reports/moderator_warning_private_messages"
require_relative "reports/notify_moderators_private_messages"
require_relative "reports/flags"
require_relative "reports/likes"
require_relative "reports/bookmarks"
require_relative "reports/dau_by_mau"
require_relative "reports/profile_views"
require_relative "reports/topics"
require_relative "reports/posts"
require_relative "reports/time_to_first_response"
require_relative "reports/topics_with_no_response"
require_relative "reports/emails"