#--
# rbmh/command.rb : rbmhshow 0.4.2
#
# Copyright (C) 2004--2005  Merlin Hughes  <ruby AT merlin DOT org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#++
# Pager commands

# TODO:
# support for repl formatting..

require 'rbmh/ansi'
require 'merlin/each'

module RBMH
  class Command
    def initialize(parameter, context)
      @parameter = parameter
      @context = context
      @color_execute = RBMH::ANSI.color(*(@context.profile['rbmh-color-execute'] or '').split(' '))
      @uncolor = RBMH::ANSI.uncolor
    end

    # throw :abort ignored
    # throw :show repeats show
    def execute(message)
    end

    attr_reader :parameter, :context
  end

  def Command.expand(value)
    value and value.gsub(/\\(.)|\$(\w+)/) { |match|
      escape, variable = $1, $2
      escape or ENV[variable]
    }
  end

  # -- commands below -

  class ExitCommand < Command
    def initialize(parameter, context)
      super(parameter, context)
    end

    def execute(message)
      code = Command.expand(parameter)
      exit(code ? code.to_i : 0)
    end
  end

  class ExecCommand < Command
    def execute(message)
      command = context.prompter.prompt("exec", "", Command.expand(parameter), "RBMH_EXEC")
      return if command.nil?
#       puts "#{@color_execute}#{command}#{@uncolor}"
      exec(command)
    end
  end

  # could handle command failure differently; e.g., prompt user
  class SystemCommand < Command
    def execute(message)
      command = context.prompter.prompt("system", "", Command.expand(parameter), "RBMH_SYSTEM")
      return if command.nil?
#       puts "#{@color_execute}#{command}#{@uncolor}"
#       system(command)
#       raise RBMH::Exception, "command failed - #{command}" if $?.exitstatus != 0
# TODO: add verbose flag? error handling flag?
#       result = `#{command} 3>&2 2>&1 1>&3`
      system(command)
      context.error("#{command} failed") if $?.exitstatus != 0
    end
  end

  class EchoCommand < Command
    def execute(message)
      message = context.prompter.prompt("echo", "", Command.expand(parameter), "RBMH_ECHO")
      return if message.nil?
      puts(message)
    end
  end

  class ShowCommand < Command
    def execute(message)
      show = context.prompter.prompt("show", "", Command.expand(parameter), "RBMH_SHOW")
      return if show.nil?
      msgs = ''
      show.scan(/[^\|]+/).each_with_status { |what, status|
        what.strip!
        begin
          context.show(what)
          throw :show
        rescue RBMH::Exception
          msgs << (status.first? ? '' : status.last? ? ' or ' : ', ') << what
        end
      }
      # TODO: <multiple> if range_str is long (e.g., show `pick all`)
      where = context.range_str ? "sequence #{context.range_str}" : "folder #{context.folder}"
      context.error("no #{msgs} message in #{where}")
      return nil
    end
  end

  class RefileCommand < Command
    def execute(message)
      folder = context.prompter.prompt("refile", "+", Command.expand(parameter), "RBMH_REFILE")
      return if folder.nil?
      # TODO: check whether the folder exists myself
      puts "#{@color_execute}refile +#{folder}#{@uncolor}"
      result = `refile +#{folder} 3>&2 2>&1 1>&3`
      if $?.exitstatus != 0
        context.error(result.empty? ? "refile failed" : result.chop)
      end
    end
  end

  class StoreCommand < Command
    def execute(message)
      @context.shower.toc(message, STDOUT)
      directory = context.prompter.prompt("directory", "", Command.expand(parameter), "RBMH_STORE")
      return if directory.nil?
      parts = context.prompter.prompt("parts", "^", "?", nil)
      return if parts.nil?
      if parts =~ RangesRE
        ranges = parts.scan(RangeRE).collect { |start, finish|
          finish ? (start.to_i .. finish.to_i).to_a : start
        }
        parts = "(#{ranges.join('|')})(\\D|$)"
      end
      begin
        message.store(/^#{parts}/, directory)
      rescue RBMH::Exception
        context.error($!.message)
      end
    end

    RangeRE = /(\d+)(?:\s*-\s*(\d+))?/
    RangesRE = /^\s*#{RangeRE.source}\s*(,\s*#{RangeRE.source})*\s*$/
  end

  class EnvCommand < Command
    def initialize(parameter, context)
      super(parameter, context)
      raise RBMH::Exception, "missing parameter to env" if parameter.nil?
      raise RBMH::Exception, "invalid parameter to env - #{parameter}" unless parameter =~ EnvRE
    end

    def execute(message)
      Command.expand(parameter) =~ EnvRE
      variable, assignment, value = $1, $2, $3
      if ('=' == assignment) || (('^=' == assignment) && (value != ENV[variable]))
        ENV[variable] = value
      else
        ENV.delete(variable)
      end
    end

    EnvRE = /^(\w+)\s*(=|\^=|\/=)\s*(.*)$/
  end

  def Command.lookup(command, parameter, context)
    impl = CommandTable[command]
    if impl.is_a?(Class)
      impl.new(parameter, context)
    elsif impl.is_a?(String)
      raise RBMH::Exception, "unexpected parameter to #{command} - #{parameter}" if parameter
      lookup(impl, command, context)
    else
      raise RBMH::Exception, "unknown command - #{command}"
    end
  end

  CommandTable = {
    "exit" => ExitCommand,
    "exec" => ExecCommand,
    "system" => SystemCommand,
    "echo" => EchoCommand,
    "show" => ShowCommand,
    "refile" => RefileCommand,
    "store" => StoreCommand,
    "env" => EnvCommand,
    "cur" => "show", # show(cur)
    "next" => "show", # show(next)
    "prev" => "show", # show(prev)
    "last" => "show", # show(last)
    "first" => "show", # show(first)
  }
end # module RBMH