require 'semantic_logger'

class Thor
  class Command < Struct.new( :name,
                              :description,
                              :long_description,
                              :usage,
                              :options,
                              :ancestor_name )
    include SemanticLogger::Loggable
    
    FILE_REGEXP = /^#{Regexp.escape(File.dirname(__FILE__))}/

    def initialize(name, description, long_description, usage, options = nil)
      super(name.to_s, description, long_description, usage, options || {})
    end

    def initialize_copy(other) #:nodoc:
      super(other)
      self.options = other.options.dup if other.options
    end

    def hidden?
      false
    end

    # By default, a command invokes a method in the thor class. You can change
    # this implementation to create custom commands.
    def run(instance, args = [])
      logger.trace "Command#run",
        self: self,
        instance: instance,
        args: args
      
      arity = nil

      if private_method?(instance)
        instance.class.handle_no_command_error(name)
      elsif public_method?(instance)
        arity = instance.method(name).arity
        instance.__send__(name, *args)
      elsif local_method?(instance, :method_missing)
        instance.__send__(:method_missing, name.to_sym, *args)
      else
        instance.class.handle_no_command_error(name)
      end
    rescue ArgumentError => e
      if handle_argument_error?(instance, e, caller)
        instance.class.handle_argument_error(self, e, args, arity)
      else
        raise e
      end
    rescue NoMethodError => e
      if handle_no_method_error?(instance, e, caller)
        instance.class.handle_no_command_error(name)
      else
        raise e
      end
    rescue Exception => error
      # NOTE  Need to use `#__send__` because the instance may define a
      #       command (method) `#send` - and one of the test fixtures **does**:
      #       
      #       //spec/fixtures/script.thor:100
      #       
      #       That's why the Thor code above uses `#__send__`, and we need to
      #       too.
      #       
      instance.__send__ :on_run_error, error, self, args
      
      # We should not get here!!!
      # {Thor::Base#on_run_error} should exit or re-raise :(
      logger.error "#on_run_error failed to exit or re-raise", error: error
      
      # If you want something done right...
      raise error
    end

    # Returns the formatted usage by injecting given required arguments
    # and required options into the given usage.
    def formatted_usage(klass, namespace = true, subcommand = false)
      logger.trace "Formatting usage",
        self: self,
        klass: klass,
        namespace: namespace,
        subcommand: subcommand,
        ancestor_name: ancestor_name
      
      if ancestor_name
        formatted = "#{ancestor_name} ".dup # add space
      elsif namespace
        namespace = klass.namespace
        formatted = "#{namespace.gsub(/^(default)/, '')}:".dup
      end
      formatted ||= "#{klass.namespace.split(':').last} ".dup if subcommand

      formatted ||= "".dup

      # Add usage with required arguments
      formatted << if klass && !klass.arguments.empty?
                     usage.to_s.gsub(/^#{name}/) do |match|
                       match  << " " \
                              << klass.arguments.map(&:usage).compact.join(" ")
                     end
                   else
                     usage.to_s
                   end

      # Add required options
      formatted << " #{required_options}"

      # Strip and go!
      formatted.strip
    end

  protected

    def not_debugging?(instance)
      !(instance.class.respond_to?(:debugging) && instance.class.debugging)
    end

    def required_options
      @required_options ||= options.
        map { |_, o| o.usage if o.required? }.
        compact.
        sort.
        join(" ")
    end

    # Given a target, checks if this class name is a public method.
    def public_method?(instance) #:nodoc:
      !(instance.public_methods & [name.to_s, name.to_sym]).empty?
    end

    def private_method?(instance)
      !(instance.private_methods & [name.to_s, name.to_sym]).empty?
    end

    def local_method?(instance, name)
      methods = instance.public_methods(false) +
                instance.private_methods(false) +
                instance.protected_methods(false)
      !(methods & [name.to_s, name.to_sym]).empty?
    end

    def sans_backtrace(backtrace, caller) #:nodoc:
      saned = backtrace.reject { |frame|
        (frame =~ FILE_REGEXP) ||
        (frame =~ /\.java:/ && RUBY_PLATFORM =~ /java/) ||
        (frame =~ %r{^kernel/} && RUBY_ENGINE =~ /rbx/)
      }
      saned - caller
    end

    def handle_argument_error?(instance, error, caller)
      not_debugging?(instance) \
      && (  error.message =~ /wrong number of arguments/ \
            || error.message =~ /given \d*, expected \d*/ ) \
      && begin
        saned = sans_backtrace(error.backtrace, caller)
        # Ruby 1.9 always include the called method in the backtrace
        saned.empty? || (saned.size == 1 && RUBY_VERSION >= "1.9")
      end
    end

    def handle_no_method_error?(instance, error, caller)
      not_debugging?(instance) &&
        error.message =~ \
          /^undefined method `#{name}' for #{Regexp.escape(instance.to_s)}$/
    end
  end
  Task = Command

  # A command that is hidden in help messages but still invocable.
  class HiddenCommand < Command
    def hidden?
      true
    end
  end
  HiddenTask = HiddenCommand

  # A dynamic command that handles method missing scenarios.
  class DynamicCommand < Command
    def initialize(name, options = nil)
      super(  name.to_s,
              "A dynamically-generated command",
              name.to_s,
              name.to_s,
              options )
    end

    def run(instance, args = [])
      if (instance.methods & [name.to_s, name.to_sym]).empty?
        super
      else
        instance.class.handle_no_command_error(name)
      end
    end
  end
  DynamicTask = DynamicCommand
end