# Copyright (C) 2011 Rocky Bernstein <rockyb@rubyforge.net>

module Trepan

  # Command completion methods
  module Complete

    module_function

    # Return an Array of String found from Array of String
    # +complete_ary+ which start out with String +prefix+.
    def complete_token(complete_ary, prefix)
      complete_ary.select { |cmd| cmd.to_s.start_with?(prefix) }.sort
    end
    
    def complete_token_with_next(complete_hash, prefix, cmd_prefix='')
      result = []
      complete_hash.each do |cmd_name, cmd_obj| 
        result << [cmd_name.to_s[cmd_prefix.size..-1], cmd_obj] if 
          cmd_name.to_s.start_with?(cmd_prefix + prefix)
      end
      result.sort{|a, b| a[0] <=> b[0]}
    end
    
    # Find all starting matches in Hash +aliases+ that start with +prefix+,
    # but filter out any matches already in +expanded+.
    def complete_token_filtered(aliases, prefix, expanded)
      complete_ary = aliases.keys
      complete_ary.select { |cmd| 
        cmd.to_s.start_with?(prefix) && ! expanded.member?(aliases[cmd])}.sort
    end

    # Find all starting matches in Hash +aliases+ that start with +prefix+,
    # but filter out any matches already in +expanded+.
    def complete_token_filtered_with_next(aliases, prefix, expanded,
                                          commands)
      complete_ary = aliases.keys
      expanded_ary = expanded.keys
      result = []
      complete_ary.each do |cmd| 
        if cmd.to_s.start_with?(prefix) && 
            !expanded_ary.member?(aliases[cmd])
          result << [cmd, commands[aliases[cmd]]] 
        end
      end
      result
    end

    # Find the next token in str string from start_pos, we return
    # the token and the next blank position after the token or 
    # str.size if this is the last token. Tokens are delimited by
    # white space.
    def next_token(str, start_pos)
      look_at = str[start_pos..-1]
      next_nonblank_pos = start_pos + (look_at =~ /\S/ || 0)
      next_blank_pos = 
        if next_match = str[next_nonblank_pos..-1] =~ /\s/
          next_nonblank_pos + next_match 
        else
          str.size
        end
      return [next_blank_pos, str[next_nonblank_pos...next_blank_pos]]
    end
    
  end
end

if __FILE__ == $0
  include Trepan::Complete
  hash = {'ab' => 1, 'aac' => 2, 'aa' => 3, 'b' => 4}
  p complete_token(hash.keys, 'a')
  p complete_token_with_next(hash, 'a')
  ##   0         1
  ##   0123456789012345678
  x = '  now is  the  time'
  [0, 2, 5, 8, 9, 13, 19].each do |pos|
    p next_token(x, pos)
  end
end