require 'benchmark'

SOURCE_DATA = [
  {:name => 'host', :id => 1},
  {:name => 'problem', :id => 3},
  {:name => 'host_outage', :id => 4},
  {:name => 'host', :id => 5},
  {:name => 'host', :id => 2},
  {:name => 'host_outage', :id => 2},
  {:name => 'host', :id => 7},
  {:name => 'problem', :id => 4},
  {:name => 'host_outage', :id => 7}
]

def working_base
  names = SOURCE_DATA.collect{ |a| a[:name] }
  names.uniq.collect do |n|
    {:name => n, :count => names.grep(n).size}
  end
end

def first_attempt
  counts = {}
  SOURCE_DATA.each do |a|
    counts[a[:name]] ||= 0
    counts[a[:name]] += 1
  end
  counts
end

def first_attempt_with_format
  counts = {}
  SOURCE_DATA.each do |a|
    counts[a[:name]] ||= 0
    counts[a[:name]] += 1
  end

  names = []
  counts.each_pair do |k,v|
    names << { :name => k, :count => v }
  end
  names
end

def second_attempt
  counts = []
  SOURCE_DATA.each do |a|
    c = counts.find { |c| c[:name] == a[:name] }
    c.nil? ? counts << { :name => a[:name], :count => 1 } : counts[counts.index(c)][:count] += 1
  end
  counts
end

def hendrik_1
  result = {}
  SOURCE_DATA.each do |a|
    if result[a[:name]].nil?
      result[a[:name]] = 1
    else
      result[a[:name]] = result[a[:name]] + 1
    end
  end
  result
end

RUNS = 10_000

Benchmark.benchmark do |dm|
  puts ""

  dm.report { RUNS.times { working_base } }
  puts working_base.inspect
  puts ""

  dm.report { RUNS.times { first_attempt } }
  puts first_attempt.inspect
  puts ""

  dm.report { RUNS.times { first_attempt_with_format } }
  puts first_attempt_with_format.inspect
  puts ""

  dm.report { RUNS.times { second_attempt } }
  puts second_attempt.inspect
  puts ""

  dm.report { RUNS.times { hendrik_1 } }
  puts hendrik_1.inspect
  puts ""
end