require 'columnize'
require 'forwardable'
require_relative 'helper'

module Byebug

  module CommandFunctions
    ##
    # Pad a string with dots at the end to fit :width setting
    #
    def pad_with_dots(string)
      if string.size > Command.settings[:width]
        string[Command.settings[:width]-3 .. -1] = "..."
      end
    end
  end

  # Root dir for byebug
  BYEBUG_DIR = File.expand_path(File.dirname(__FILE__)) unless
    defined?(BYEBUG_DIR)

  class Command

    SubcmdStruct = Struct.new(:name, :min, :short_help, :long_help) unless
      defined?(SubcmdStruct)

    ##
    # Print list of subcmds
    #
    def print_subcmds(subcmds)
      cmd_name = self.class.name[/Byebug::(.*)Command/, 1].downcase
      errmsg "\"#{cmd_name}\" must be followed by the name of a subcommand.\n"
      print "List of \"#{cmd_name}\" subcommands:\n"
      for subcmd in subcmds do
        print "#{cmd_name} #{subcmd.name} -- #{subcmd.short_help}\n"
      end
    end

    include Columnize

    ##
    # Find param in subcmds.
    #
    # @param is downcased and can be abbreviated to the minimum length listed in
    # the subcommands.
    #
    def find(subcmds, param)
      param.downcase!
      for try_subcmd in subcmds do
        if (param.size >= try_subcmd.min) and
            (try_subcmd.name[0..param.size-1] == param)
          return try_subcmd
        end
      end
      return nil
    end

    class << self
      def commands
        @commands ||= []
      end

      DEF_OPTIONS = {
        :allow_in_control     => false,
        :allow_in_post_mortem => false,
        :event                => true ,
        :always_run           => 0    ,
        :unknown              => false,
        :need_context         => false,
      } unless defined?(DEF_OPTIONS)

      def inherited(klass)
        DEF_OPTIONS.each do |o, v|
          klass.options[o] = v if klass.options[o].nil?
        end
        commands << klass
      end

      def load_commands
        Dir[File.join(Byebug.const_get(:BYEBUG_DIR), 'commands', '*')].each {
          |file| require file if file =~ /\.rb$/ }
        Byebug.constants.grep(/Functions$/).map {
          |name| Byebug.const_get(name) }.each { |mod| include mod }
      end

      def method_missing(meth, *args, &block)
        if meth.to_s =~ /^(.+?)=$/
          @options[$1.intern] = args.first
        else
          if @options.has_key?(meth)
            @options[meth]
          else
            super
          end
        end
      end

      def options
        @options ||= {}
      end

      def settings_map
        @@settings_map ||= {}
      end
      private :settings_map

      def settings
        unless defined? @settings and @settings
          @settings = Object.new
          map = settings_map
          c = class << @settings; self end
          if c.respond_to?(:funcall)
            c.funcall(:define_method, :[]) do |name|
              raise "No such setting #{name}" unless map.has_key?(name)
              map[name][:getter].call
            end
          else
            c.send(:define_method, :[]) do |name|
              raise "No such setting #{name}" unless map.has_key?(name)
              map[name][:getter].call
            end
          end
          c = class << @settings; self end
          if c.respond_to?(:funcall)
            c.funcall(:define_method, :[]=) do |name, value|
              raise "No such setting #{name}" unless map.has_key?(name)
              map[name][:setter].call(value)
            end
          else
            c.send(:define_method, :[]=) do |name, value|
              raise "No such setting #{name}" unless map.has_key?(name)
              map[name][:setter].call(value)
            end
          end
        end
        @settings
      end

      def register_setting_var(name, default)
        var_name = "@@#{name}"
        class_variable_set(var_name, default)
        register_setting_get(name) { class_variable_get(var_name) }
        register_setting_set(name) { |value| class_variable_set(var_name, value) }
      end

      def register_setting_get(name, &block)
        settings_map[name] ||= {}
        settings_map[name][:getter] = block
      end

      def register_setting_set(name, &block)
        settings_map[name] ||= {}
        settings_map[name][:setter] = block
      end
    end

    # Register default settings
    register_setting_var(:basename, false)
    register_setting_var(:callstyle, :last)
    register_setting_var(:byebugtesting, false)
    register_setting_var(:force_stepping, false)
    register_setting_var(:full_path, true)
    register_setting_var(:listsize, 10)
    register_setting_var(:stack_trace_on_error, false)
    register_setting_var(:tracing_plus, false)
    register_setting_var(:width,
                         ENV['COLUMNS'].to_i > 10 ? ENV['COLUMNS'].to_i : 80)
    Byebug::ARGV = ARGV.clone unless defined? Byebug::ARGV
    register_setting_var(:argv, Byebug::ARGV)

    def initialize(state)
      @state = state
    end

    def match(input)
      @match = regexp.match(input)
    end

    protected

      extend Forwardable
      def_delegators :@state, :errmsg, :print

      def confirm(msg)
        @state.confirm(msg) == 'y'
      end

      def debug_eval(str, b = get_binding)
        begin
          val = eval(str, b)
        rescue StandardError, ScriptError => e
          if Command.settings[:stack_trace_on_error]
            at = eval("caller(1)", b)
            print "%s:%s\n", at.shift, e.to_s.sub(/\(eval\):1:(in `.*?':)?/, '')
            for i in at
              print "\tfrom %s\n", i
            end
          else
            print "#{e.class} Exception: #{e.message}\n"
          end
          throw :debug_error
        end
      end

      def debug_silent_eval(str)
        begin
          eval(str, get_binding)
        rescue StandardError, ScriptError
          nil
        end
      end

      def get_binding
        @state.context.frame_binding(@state.frame_pos)
      end

      def get_context(thnum)
        Byebug.contexts.find{|c| c.thnum == thnum}
      end
  end

  Command.load_commands

  ##
  # Returns ths settings object.
  # Use Byebug.settings[] and Byebug.settings[]= methods to query and set
  # byebug settings. These settings are available:
  #
  # :autolist                - automatically calls 'list' command on breakpoint
  # :autoeval                - evaluates input in the current binding if it's
  #                            not recognized as a byebug command
  # :autoirb                 - automatically calls 'irb' command on breakpoint
  # :stack_trace_on_error    - shows full stack trace if eval command results in
  #                            an exception
  # :frame_full_path         - displays full paths when showing frame stack
  # :frame_class_names       - displays method's class name when showing frame
  #                            stack
  # :reload_source_on_change - makes 'list' command always display up-to-date
  #                            source code
  # :force_stepping          - stepping command always move to the new line
  #
  def self.settings
    Command.settings
  end
end