require 'shellwords'
require 'optparse'

require 'rake/task_manager'
require 'rake/file_list'
require 'rake/thread_pool'
require 'rake/thread_history_display'
require 'rake/trace_output'
require 'rake/win32'

module Rake

  CommandLineOptionError = Class.new(StandardError)

  ######################################################################
  # Rake main application object.  When invoking +rake+ from the
  # command line, a Rake::Application object is created and run.
  #
  class Application
    include TaskManager
    include TraceOutput

    # The name of the application (typically 'rake')
    attr_reader :name

    # The original directory where rake was invoked.
    attr_reader :original_dir

    # Name of the actual rakefile used.
    attr_reader :rakefile

    # Number of columns on the terminal
    attr_accessor :terminal_columns

    # List of the top level task names (task names from the command line).
    attr_reader :top_level_tasks

    DEFAULT_RAKEFILES = [
      'rakefile',
      'Rakefile',
      'rakefile.rb',
      'Rakefile.rb'
    ].freeze

    # Initialize a Rake::Application object.
    def initialize
      super
      @name = 'rake'
      @rakefiles = DEFAULT_RAKEFILES.dup
      @rakefile = nil
      @pending_imports = []
      @imported = []
      @loaders = {}
      @default_loader = Rake::DefaultLoader.new
      @original_dir = Dir.pwd
      @top_level_tasks = []
      add_loader('rb', DefaultLoader.new)
      add_loader('rf', DefaultLoader.new)
      add_loader('rake', DefaultLoader.new)
      @tty_output = STDOUT.tty?
      @terminal_columns = ENV['RAKE_COLUMNS'].to_i
    end

    # Run the Rake application.  The run method performs the following
    # three steps:
    #
    # * Initialize the command line options (+init+).
    # * Define the tasks (+load_rakefile+).
    # * Run the top level tasks (+top_level+).
    #
    # If you wish to build a custom rake command, you should call
    # +init+ on your application.  Then define any tasks.  Finally,
    # call +top_level+ to run your top level tasks.
    def run
      standard_exception_handling do
        init
        load_rakefile
        top_level
      end
    end

    # Initialize the command line parameters and app name.
    def init(app_name='rake')
      standard_exception_handling do
        @name = app_name
        handle_options
        collect_tasks
      end
    end

    # Find the rakefile and then load it and any pending imports.
    def load_rakefile
      standard_exception_handling do
        raw_load_rakefile
      end
    end

    # Run the top level tasks of a Rake application.
    def top_level
      run_with_threads do
        if options.show_tasks
          display_tasks_and_comments
        elsif options.show_prereqs
          display_prerequisites
        else
          top_level_tasks.each { |task_name| invoke_task(task_name) }
        end
      end
    end

    # Run the given block with the thread startup and shutdown.
    def run_with_threads
      thread_pool.gather_history if options.job_stats == :history

      yield

      thread_pool.join
      if options.job_stats
        stats = thread_pool.statistics
        puts "Maximum active threads: #{stats[:max_active_threads]}"
        puts "Total threads in play:  #{stats[:total_threads_in_play]}"
      end
      ThreadHistoryDisplay.new(thread_pool.history).show if
        options.job_stats == :history
    end

    # Add a loader to handle imported files ending in the extension
    # +ext+.
    def add_loader(ext, loader)
      ext = ".#{ext}" unless ext =~ /^\./
      @loaders[ext] = loader
    end

    # Application options from the command line
    def options
      @options ||= OpenStruct.new
    end

    # Return the thread pool used for multithreaded processing.
    def thread_pool             # :nodoc:
      @thread_pool ||= ThreadPool.new(options.thread_pool_size || FIXNUM_MAX)
    end

    # private ----------------------------------------------------------------

    def invoke_task(task_string)
      name, args = parse_task_string(task_string)
      t = self[name]
      t.invoke(*args)
    end

    def parse_task_string(string)
      if string =~ /^([^\[]+)(\[(.*)\])$/
        name = $1
        args = $3.split(/\s*,\s*/)
      else
        name = string
        args = []
      end
      [name, args]
    end

    # Provide standard exception handling for the given block.
    def standard_exception_handling
      yield
    rescue SystemExit
      # Exit silently with current status
      raise
    rescue OptionParser::InvalidOption => ex
      $stderr.puts ex.message
      exit(false)
    rescue Exception => ex
      # Exit with error message
      display_error_message(ex)
      exit_because_of_exception(ex)
    end

    # Exit the program because of an unhandle exception.
    # (may be overridden by subclasses)
    def exit_because_of_exception(ex)
      exit(false)
    end

    # Display the error message that caused the exception.
    def display_error_message(ex)
      trace "#{name} aborted!"
      trace ex.message
      if options.backtrace
        trace ex.backtrace.join("\n")
      else
        trace Backtrace.collapse(ex.backtrace).join("\n")
      end
      trace "Tasks: #{ex.chain}" if has_chain?(ex)
      trace "(See full trace by running task with --trace)" unless
        options.backtrace
    end

    # Warn about deprecated usage.
    #
    # Example:
    #    Rake.application.deprecate("import", "Rake.import", caller.first)
    #
    def deprecate(old_usage, new_usage, call_site)
      unless options.ignore_deprecate
        $stderr.puts "WARNING: '#{old_usage}' is deprecated.  " +
          "Please use '#{new_usage}' instead.\n" +
          "    at #{call_site}"
      end
    end

    # Does the exception have a task invocation chain?
    def has_chain?(exception)
      exception.respond_to?(:chain) && exception.chain
    end
    private :has_chain?

    # True if one of the files in RAKEFILES is in the current directory.
    # If a match is found, it is copied into @rakefile.
    def have_rakefile
      @rakefiles.each do |fn|
        if File.exist?(fn)
          others = FileList.glob(fn, File::FNM_CASEFOLD)
          return others.size == 1 ? others.first : fn
        elsif fn == ''
          return fn
        end
      end
      return nil
    end

    # True if we are outputting to TTY, false otherwise
    def tty_output?
      @tty_output
    end

    # Override the detected TTY output state (mostly for testing)
    def tty_output=(tty_output_state)
      @tty_output = tty_output_state
    end

    # We will truncate output if we are outputting to a TTY or if we've been
    # given an explicit column width to honor
    def truncate_output?
      tty_output? || @terminal_columns.nonzero?
    end

    # Display the tasks and comments.
    def display_tasks_and_comments
      displayable_tasks = tasks.select { |t|
        (options.show_all_tasks || t.comment) &&
          t.name =~ options.show_task_pattern
      }
      case options.show_tasks
      when :tasks
        width = displayable_tasks.map { |t| t.name_with_args.length }.max || 10
        if truncate_output?
          max_column = terminal_width - name.size - width - 7
        else
          max_column = nil
        end

        displayable_tasks.each do |t|
          printf("#{name} %-#{width}s  # %s\n",
            t.name_with_args,
            max_column ? truncate(t.comment, max_column) : t.comment)
        end
      when :describe
        displayable_tasks.each do |t|
          puts "#{name} #{t.name_with_args}"
          comment = t.full_comment || ""
          comment.split("\n").each do |line|
            puts "    #{line}"
          end
          puts
        end
      when :lines
        displayable_tasks.each do |t|
          t.locations.each do |loc|
            printf "#{name} %-30s %s\n", t.name_with_args, loc
          end
        end
      else
        fail "Unknown show task mode: '#{options.show_tasks}'"
      end
    end

    def terminal_width
      if @terminal_columns.nonzero?
        result = @terminal_columns
      else
        result = unix? ? dynamic_width : 80
      end
      (result < 10) ? 80 : result
    rescue
      80
    end

    # Calculate the dynamic width of the
    def dynamic_width
      @dynamic_width ||= (dynamic_width_stty.nonzero? || dynamic_width_tput)
    end

    def dynamic_width_stty
      %x{stty size 2>/dev/null}.split[1].to_i
    end

    def dynamic_width_tput
      %x{tput cols 2>/dev/null}.to_i
    end

    def unix?
      RbConfig::CONFIG['host_os'] =~
        /(aix|darwin|linux|(net|free|open)bsd|cygwin|solaris|irix|hpux)/i
    end

    def windows?
      Win32.windows?
    end

    def truncate(string, width)
      if string.nil?
        ""
      elsif string.length <= width
        string
      else
        (string[0, width - 3] || "") + "..."
      end
    end

    # Display the tasks and prerequisites
    def display_prerequisites
      tasks.each do |t|
        puts "#{name} #{t.name}"
        t.prerequisites.each { |pre| puts "    #{pre}" }
      end
    end

    def trace(*strings)
      options.trace_output ||= $stderr
      trace_on(options.trace_output, *strings)
    end

    def sort_options(options)
      options.sort_by { |opt|
        opt.select { |o| o =~ /^-/ }.map { |o| o.downcase }.sort.reverse