markdownify-usage

#!/usr/bin/env ruby
# vim:fileencoding=utf-8

require 'digest/sha2'

def mangle(text)
  text.gsub(/\t/, '    ')
    .gsub(/^(NAME|USAGE|COMMANDS|GLOBAL OPTIONS|OPTIONS|DESCRIPTION):/, '### \1')
    .gsub(/^   ([a-z]+, [a-z])  /, '* `\1`')
    .gsub(/^\s+/, '')
    .gsub(/^(--[-a-z]+, -[a-zA-Z])/, '* `\1`')
    .gsub(/^(--[-a-z]+)/, '* `\1`')
    .gsub(/(\$[A-Z_]{2,})/, '`\1`')
    .gsub(/^### `([A-Z `]+)`$/, '### \1')
    .gsub(/\[([-a-z_ ])\]/, '[`\1`]')
    .gsub(/^(command upload.*|artifacts \[global.*)/, '`\1`')
    .gsub(/\s+$/, '')
    .gsub(/^### /, "\n### ")
end

generated_warning = ':boom: ' \
  '**Warning: file generated from [USAGE.in.md](./USAGE.in.md) ** ' \
  ":boom:\n"

exe = "#{ENV['GOPATH'].split(':').first}/bin/artifacts"
usage = `#{exe} help 2>&1`.chomp.split("\n").reject do |line|
  line =~ /^VERSION|\s+v\d\.\d\.\d/
end.join("\n")

output = $stdin.read.sub(/___GENERATED_WARNING___/, generated_warning)
  .sub(/___USAGE___/, mangle(usage))
  .sub(/___UPLOAD_USAGE___/, mangle(`#{exe} help upload 2>&1`.chomp))
output = output.gsub(/___CHECKSUM___/, Digest::SHA256.base64digest(output))
$stdout.puts(output)