#!/usr/bin/env ruby

require 'tins'
include Tins::GO
require 'term/ansicolor'
include Term::ANSIColor
class String
  include Term::ANSIColor
end
require 'hackmac'
include Hackmac
require 'amatch'
require 'search_ui'
include SearchUI

$opts = go 'c:m:n:jlh', defaults: { ?s => true, ?n => 5 }

def usage
  puts <<~end
  Usage: #{File.basename($0)} [OPTIONS]

    OPTIONS are

      -h          this help
      -l          output GPU performance data as list
      -j          output GPU performance data as json
      -n SECONDS  measure every SECONDS
      -m METRIC   output graph for performance METRIC
      -c COLOR    output graph in this terminal COLOR (between 0 - 255)

  end
  0
end

def ps
  `ioreg -l`.lines.find { |l|
    if l =~ /"PerformanceStatistics" = {([^}]+)}/
      break Hash[
        $1.split(?,).map { |a|
          a = a.split(?=)
          [ a[0][1..-2], (Integer(a[1]) rescue a[1]) ]
        }.sort_by { |name, _| name.downcase }
      ]
    end
  }
end

def list(ps)
  max = ps.keys.max_by(&:size)&.size&.to_i
  include Hackmac::Graph::Formatters
  puts ps.map { |n, v|
    ("%-#{max}s" % n) + " " + ("%s" % send(derive_formatter(n), v)).bold
  }
end

def choose_metric(ps)
  case metric = $opts[?m]
  when nil
    ps_names = ps.keys
    metric = Search.new(
      match: -> answer {
        matcher = Amatch::PairDistance.new(answer.downcase)
        matches = ps_names.map { |n| [ n, -matcher.similar(n.downcase) ] }.
          select { |_, s| s < 0 }.sort_by(&:last).map(&:first)
        matches.empty? and matches = ps_names
        matches.first(Tins::Terminal.lines - 1)
      },
      query: -> _answer, matches, selector {
        matches.each_with_index.
          map { |m, i| i == selector ? m.on_blue : m } * ?\n
      },
      found: -> _answer, matches, selector {
        matches[selector]
      },
      output: STDOUT
    ).start and return metric
  else
    ps.key?(metric) and return metric
  end
  fail "Metric #{metric} not known"
end

def derive_formatter(metric)
  case metric
  when /bytes/i
    :as_bytes
  when /Hz/
    :as_hertz
  when /\(C\)/
    :as_celsius
  when /\(%\)/
    :as_percent
  else
    :as_default
  end
end

def display_graph
  if metric = choose_metric(ps)
    sleep_duration = [ 1, ($opts[?n] || 10).to_i ].max
    format_value = derive_formatter(metric)
    graph = Hackmac::Graph.new(
      title: metric,
      sleep: sleep_duration,
      value: -> _ { ps[metric] },
      color: $opts[?c],
      format_value:
    )
    graph.start
  end
ensure 
  graph&.stop
end

case
when $opts[?h]
  exit usage
when $opts[?l]
  list ps
when $opts[?j]
  jj ps
else
  display_graph
end