Spec::Rake::SpecTask.new('rcov') do |t|
  t.spec_files  = FileList['spec/**/*.rb']
  t.rcov        = true
  t.rcov_opts   = ['--exclude', 'lib', '--exclude', 'gems']
  t.libs        << Dir["lib/**/*"]
end
 
 
RCov::VerifyTask.new(:verify_rcov) do |t|
  t.threshold   = 10.00                     # to get started
  t.index_html  = 'coverage/index.html'     # the path to html report
end

 
# the `log' file in `yaml' format
#
COVERAGE_YML   = 'coverage.yml'
 
# read the last 'threshold' from the .yml file
# and return `10.0' as value if the file isn't existant
#
def read_yaml_threshold
 
    threshold = 10.0
 
    return threshold unless File.exist? COVERAGE_YML
 
    yaml  = read_yaml_file COVERAGE_YML
 
    threshold = yaml["THRESHOLD"].to_s
 
    threshold.to_f
end
 
 
# write the given `value' in `yaml' format
# back into `log' file.
#
def write_yaml_threshold value
    File.open(COVERAGE_YML, 'w') do |f|
        f.write({"THRESHOLD" => value}.to_yaml)
    end
end

 
# read the previous threshold once and
# reuse it in tasks to reduce file-access
# 
@old_threshold = read_yaml_threshold
 
 
# the SpecTask from above
#
desc "Run all rspec tests with RCOV"
Spec::Rake::SpecTask.new('rcov') do |t|
  t.spec_files  = FileList['spec/**/*.rb']
  t.rcov        = true
  t.rcov_opts   = ['--exclude', 'lib', '--exclude', 'gems']
  t.libs        << Dir["lib/**/*"]
end
 
 
# the "verify" task which is still executable 
# because the`threshold' property contains the
# current `threhold' value from `coverage.yml'
#
desc "Check code-coverage of project"
RCov::VerifyTask.new(:verify_rcov) do |t|
 
  threshold   = @old_threshold
 
  Rake::Task['rcov'].execute
 
  t.threshold   = threshold
  t.index_html  = 'coverage/index.html'
end
 
 
# the actual 'capture and update' task which retrieves the 'previous' 
# threshold and executes the `VerifyTask' and captures the 'new' threshold 
# and finally compares them. if `new' threshold has increased the 
# `coverage.yml' is updated.
#
task :run_verify do |t|
 
    old_threshold = @old_threshold
 
    log = `rake verify_rcov -f #{__FILE__}` # | tee coverage_log.txt`
 
    new_threshold = threshold_from log
 
    if new_threshold.to_f > old_threshold.to_f
 
        begin
            write_yaml_threshold new_threshold
        rescue => e
            puts "ERROR #{e.message} "
        end
 
        puts "Finished ...\n "
 
    else
        if new_threshold.to_f >= old_threshold.to_f
            puts "Finished with `coverage' of #{new_threshold}% ..."
        else
            puts "Failed to finish with `coverage' of #{old_threshold}% => #{new_threshold}% ..."
        end
    end
end