#!/usr/bin/env ruby

require 'sqlite3'

class App

  DB_FILE='metrics.db'

  class Metric

    def initialize row
      @center_id, @metric,
      @last_zero_time, @last_nonzero_time,
      @low1, @high1, @low3, @high3, @low24,
      @since_low1, @since_high1, @since_low3,
      @since_high3, @since_low24 = row
      @values = []
      @v1 = @v3 = @v24 = 0
    end

    attr_reader :metric, :low24

    def tdif sym, a, b
      d = (b-a)/3600.0
      if d > 36 then
        sprintf("%s %ud", sym, (d/24.0).round)
      else
        sprintf("%s %uh", sym, d.round)
      end
    end

    def alerting?
      [@since_low1, @since_low3, @since_high1, @since_high3, @since_low24].any?
    end

    def alert lastts
      buf=[]
      buf << tdif('low1', @since_low1, lastts) if @since_low1
      buf << tdif('low3', @since_low3, lastts) if @since_low3
      buf << tdif('high1', @since_high1, lastts) if @since_high1
      buf << tdif('high3', @since_high3, lastts) if @since_high3
      buf << tdif('low24', @since_low24, lastts) if @since_low24
      if buf.empty? then
        nil
      else
        "#{metric} #{buf.join(',')}"
      end
    end

    def addval v
      return if @values.size >= 24
      @values.push v
      @v24 += v
      return if @values.size > 3
      @v3 += v
      return if @values.size > 1
      @v1 = v
    end

    def gt a, b
      if a > b then ">"
      else " "
      end
    end

    def numtab
      sprintf("%14s|%5u%s%5u%s%5u|%5u%s%5u%s%5u|%5u%s%5u",
        @metric,
        @low1.round, gt(@low1,@v1), @v1.round, gt(@v1,@high1), @high1.round,
        @low3.round, gt(@low3,@v3), @v3.round, gt(@v3,@high3), @high3.round,
        @low24.round, gt(@low24,@v24), @v24.round)
    end

    def self.numtab
      s=sprintf("%14s|%5s %5s %5s|%5s %5s %5s|%5s %5s",
              'metric', 'low', '1hr', 'high', 'low', '3hr', 'high', 'low', '24hr')
      s.gsub(/ /,'_')
    end

    def dump
      sprintf("%s=%s;", @metric, @values.reverse.join(' '))
    end

  end

  class Center

    def initialize center_id
      @center_id = center_id
      @mdb=Hash.new
    end

    def register_metric mobj
      @mdb[mobj.metric]=mobj
    end

    def addval row
      c,m,ts,v = row
      return unless @mdb[m]
      @mdb[m].addval(v)
    end

    def alert lastts
      buf = @mdb.values.map{|mobj| mobj.alert(lastts)}.compact
      if buf.empty?
        then nil
      else
        "ALERT(#{buf.join('/')})"
      end
    end

    def alerting?
      @mdb.values.map{|mobj| mobj.alerting?}.any?
    end

    def all_silent?
      @mdb.values.map{|mobj| mobj.low24 == 0}.all?
    end

    def summary lastts
      r = []
      amsg = alert(lastts)
      r << amsg if amsg
      if all_silent? then
        r << "(silent centre)"
      else
        r << Metric::numtab
        r << @mdb['files_received'].numtab
        r << @mdb['errors'].numtab if @mdb['errors'].low24 > 0
        r << @mdb['invalid'].numtab if @mdb['invalid'].low24 > 0
        r << @mdb['bulletins'].numtab if @mdb['bulletins']
        r << @mdb['stored'].numtab if @mdb['stored'].alerting?
        r << @mdb['not_stored'].numtab if @mdb['not_stored'].alerting?
        r << '' if self.alerting?
        %w(files_received errors invalid stored not_stored bulletins).each{|mn|
          r << @mdb[mn].dump if @mdb[mn] and @mdb[mn].alerting?
        }
      end
      r.join("\n")
    end

  end

  def initialize
    @cdb=Hash.new
    @db=SQLite3::Database.new(DB_FILE)
    @lastts=nil
  end

  def input
    #lasttime = @db.execute(<<~ENDSQL).first.first
    #  SELECT MAX(ts) FROM metrics;
    #ENDSQL
    sel1 = @db.execute(<<~ENDSQL)
      SELECT
        center_id, metric,
        last_zero_time, last_nonzero_time,
        low1, high1, low3, high3, low24,
        since_low1, since_high1, since_low3, since_high3, since_low24
      FROM last_state
      LEFT JOIN thresholds USING(center_id, metric)
      LEFT JOIN alert_state USING(center_id, metric);
    ENDSQL
    sel1.each do |row|
        center_id = row.first
        @cdb[center_id]=Center.new(center_id) unless @cdb[center_id]
        @cdb[center_id].register_metric(Metric.new(row))
    end
    sel1=nil
    sel2 = @db.execute(<<~ENDSQL)
      SELECT MAX(ts) FROM metrics;
    ENDSQL
    @lastts = sel2.first.first
    sel3 = @db.execute(<<~ENDSQL, @lastts-86400.0)
      SELECT center_id, metric, ts, value
      FROM metrics
      WHERE ts > ?
      ORDER BY center_id, metric, ts DESC;
    ENDSQL
    sel3.each {|row|
      center_id=row.first
      @cdb[center_id].addval(row)
    }
  end

  def output
    @cdb.keys.each do |center_id|
      next unless @cdb[center_id].alerting?
      puts "=== #{center_id.upcase} ==="
      puts @cdb[center_id].summary(@lastts)
      puts ""
    end
    @cdb.keys.each do |center_id|
      next if @cdb[center_id].alerting?
      puts "=== #{center_id.upcase} ==="
      puts @cdb[center_id].summary(@lastts)
      puts ""
    end
  end

  def run
    input
    output
  end

end

App.new.run