Improve `bin/secpick` script and add more options

This adds additional options that make it easier to use this script:

1. It adds `--dry-run` option that only displays Git commands that are
going to be executed.
2. It adds `--remote` option that makes it possible to override Git
remote name.

bin/secpick

@@ -8,7 +8,7 @@ require 'rainbow/refinement'
 using Rainbow
 
 BRANCH_PREFIX = 'security'.freeze
-REMOTE = 'dev'.freeze
+DEFAULT_REMOTE = 'dev'.freeze
 NEW_MR_URL = 'https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/new'.freeze
 
 options = { version: nil, branch: nil, sha: nil }
@@ -27,6 +27,14 @@ parser = OptionParser.new do |opts|
     options[:sha] = sha
   end
 
+  opts.on('-r', '--remote abcd', 'Git remote name of dev.gitlab.org (optional, default to `dev`)') do |remote|
+    options[:remote] = remote
+  end
+
+  opts.on('-d', '--dry-run', 'Show resulting Git commands without calling them') do |remote|
+    options[:try] = true
+  end
+
   opts.on('-h', '--help', 'Displays Help') do
     puts opts
 
@@ -37,39 +45,82 @@ end
 parser.parse!
 
 options[:branch] ||= `git rev-parse --abbrev-ref HEAD`
+options[:remote] ||= DEFAULT_REMOTE
 
 abort("Missing options. Use #{$0} --help to see the list of options available".red) if options.values.include?(nil)
 abort("Wrong version format #{options[:version].bold}".red) unless options[:version] =~ /\A\d*\-\d*\Z/
 
-ee = File.exist?('./CHANGELOG-EE.md')
-original_branch = options[:branch].strip
-branch = "#{original_branch}-#{options[:version]}"
-branch.prepend("#{BRANCH_PREFIX}-") unless branch.start_with?("#{BRANCH_PREFIX}-")
-branch = branch.freeze
-stable_branch = "#{BRANCH_PREFIX}-#{options[:version]}".tap do |name|
-  name << "-ee" if ee
-end.freeze
+class SecurityFix
+  def initialize(options)
+    @options = options
+  end
 
-command = "git fetch #{REMOTE} #{stable_branch} && git checkout #{stable_branch} && git pull #{REMOTE} #{stable_branch} && git checkout -B #{branch} && git cherry-pick #{options[:sha]} && git push #{REMOTE} #{branch} && git checkout #{original_branch}"
+  def ee?
+    File.exist?('./CHANGELOG-EE.md')
+  end
 
-stdin, stdout, stderr, wait_thr = Open3.popen3(command)
+  def dry_run?
+    @options[:try] == true
+  end
 
-puts stdout.read&.green
-puts stderr.read&.red
+  def original_branch
+    @options[:branch].strip
+  end
 
-if wait_thr.value.success?
-  params = {
+  def source_branch
+    branch = "#{original_branch}-#{@options[:version]}"
+    branch.prepend("#{BRANCH_PREFIX}-") unless branch.start_with?("#{BRANCH_PREFIX}-")
+    branch = branch.freeze
+  end
+
+  def security_branch
+    "#{BRANCH_PREFIX}-#{@options[:version]}".tap do |name|
+      name << "-ee" if ee?
+    end.freeze
+  end
+
+  def git_commands
+    ["git fetch #{@options[:remote]} #{security_branch}",
+     "git checkout #{security_branch}",
+     "git pull #{@options[:remote]} #{security_branch}",
+     "git checkout -B #{source_branch}",
+     "git cherry-pick #{@options[:sha]}",
+     "git push #{@options[:remote]} #{source_branch}",
+     "git checkout #{original_branch}"]
+  end
+
+  def gitlab_params
+    {
       merge_request: {
-      source_branch: branch,
-      target_branch: stable_branch,
-      title: "WIP: [#{options[:version].tr('-', '.')}] ",
+        source_branch: source_branch,
+        target_branch: security_branch,
+        title: "WIP: [#{@options[:version].tr('-', '.')}] ",
         description: '/label ~security'
       }
     }
+  end
+
+  def create!
+    if dry_run?
+      puts git_commands.join("\n").green
+      puts "\nMerge request params: ".blue
+      pp gitlab_params
+    else
+      cmd = git_commands.join(' && ')
+      stdin, stdout, stderr, wait_thr = Open3.popen3(cmd)
 
-  puts "#{NEW_MR_URL}?#{params.to_query}".blue
+      puts stdout.read&.green
+      puts stderr.read&.red
+
+      if wait_thr.value.success?
+        puts "#{NEW_MR_URL}?#{gitlab_params.to_query}".blue
+      end
+
+      stdin.close
+      stdout.close
+      stderr.close
+    end
+  end
 end
 
-stdin.close
-stdout.close
-stderr.close
+SecurityFix.new(options).create!