Ditch `Commands` namespace for base command.

Reading `Rails::Commands::Command` feels excessive. Especially if users can subclass command
to write their own commands — which I'd like to aim for.

Switch to `Rails::Command` before we get too far into things.

1 files changed, 70 insertions, 0 deletions

diff --git a/railties/lib/rails/command.rb b/railties/lib/rails/command.rb
new file mode 100644
index 0000000000..6587984b53
--- /dev/null
+++ b/railties/lib/rails/command.rb
@@ -0,0 +1,70 @@
+require 'rails/commands/commands_tasks'
+
+module Rails
+  class Command
+    attr_reader :argv
+
+    def initialize(argv = [])
+      @argv = argv
+
+      @option_parser = build_option_parser
+      @options = {}
+    end
+
+    def self.run(task_name, argv)
+      command_name = command_name_for(task_name)
+
+      if command = command_for(command_name)
+        command.new(argv).run(command_name)
+      else
+        Rails::CommandsTasks.new(argv).run_command!(task_name)
+      end
+    end
+
+    def run(command_name)
+      parse_options_for(command_name)
+      @option_parser.parse! @argv
+
+      public_send(command_name)
+    end
+
+    def self.options_for(command_name, &options_to_parse)
+      @@command_options[command_name] = options_to_parse
+    end
+
+    def self.set_banner(command_name, banner)
+      options_for(command_name) { |opts, _| opts.banner = banner }
+    end
+
+    private
+      @@commands = []
+      @@command_options = {}
+
+      def parse_options_for(command_name)
+        @@command_options.fetch(command_name, proc {}).call(@option_parser, @options)
+      end
+
+      def build_option_parser
+        OptionParser.new do |opts|
+          opts.on('-h', '--help', 'Show this help.') do
+            puts opts
+            exit
+          end
+        end
+      end
+
+      def self.inherited(command)
+        @@commands << command
+      end
+
+      def self.command_name_for(task_name)
+        task_name.gsub(':', '_').to_sym
+      end
+
+      def self.command_for(command_name)
+        @@commands.find do |command|
+          command.public_instance_methods.include?(command_name)
+        end
+      end
+  end
+end