#!/usr/bin/env ruby

#
# a perl/ack in ruby
# (with less features and less good)
#
# (license is the MIT one)
#


# TODO
# [ ] -i (ignore case)

require 'set'


#
# USAGE

def print_usage
  puts %{

  akr [options] {regex} [start_path]
}
end

#
# COLORS

def color (colcode, s)
  STDOUT.tty? ? "[#{colcode}m#{s}" : s
end
def green (s)
  color(32, s)
end
def red (s)
  color(31, s)
end

def puts_line (l, reg)

  # TODO : what if regex starts with ^ ?

  i = 0
  loop do
    ll = l[i..-1]
    break unless ll
    if m = reg.match(ll)
      print(red(m[0]))
      i = i + m[0].length
    else
      print(l[i, 1])
      i = i + 1
    end
  end
  #puts
end

def scan_file (regex, before, after, path)

  ls = Set.new

  lines = File.readlines(path)

  lines.each_with_index do |line, i|

    if regex.match(line)
      ls << i
      (1..before).to_a.each { |d| ls << (i - d) }
      (1..after).to_a.each { |d| ls << (i + d) }
    end
  end

  return false if ls.size < 1

  puts
  puts(green(path))

  prev = false
  reg = Regexp.compile("^#{regex.to_s}")

  ls.sort.each do |i|

    next if i < 0

    puts '--' if prev && (i - prev > 1)
    prev = (before > 0 || after > 0) ? i : false

    ln = i + 1
    line = lines[i]

    next unless line

    print "#{ln}"
    print regex.match(line) ? ':' : '-'
    print ' '
    print ' ' * (4 - ln.to_s.length)

    puts_line(line, reg)
  end

  true
end

#
# handling params

offset = 0
options = {}

loop do
  a = ARGV[offset]
  break unless a.match(/^-/)
  options[a] = ARGV[offset + 1]
  offset += 2
end

before = options['-B'] || 0
after = options['-A'] || 0

if c = options['-C']
  before = after = c
end

before = before.to_i
after = after.to_i

regex = ARGV[offset]
regex = Regexp.compile(regex)
#regex = Regexp.compile("^(.*)#{regex}(.*)$")

spath = ARGV[offset + 1]

if regex == nil
  print_usage
  exit(1)
end

#
# do it ...

glob = spath ?
  File.join(spath, '**', '*') :
  File.join('**', '*')

exit_code = 1

Dir[glob].each do |path|

  next if File.directory?(path)

  scan_file(regex, before, after, path) && exit_code = 0
end

exit(exit_code)
  # 0 if there was a match, 1 else