#!/usr/bin/env ruby

require 'date'
TODAY = Date.today

class Entry < Struct.new(:depth, :state, :desc, :force, :children)
end

def parse(io, filename=nil)
  todos = [Entry.new(-1, "/", "", nil, [])]

  while line = io.gets
    if line =~ /\A(?:\s*(?:#|\/\/)\s)?(\s*)([-xX?*])\s+(.*)/
      force = nil

      i, state, desc = $1.size, $2, $3
      while i <= todos.last.depth
        todos.pop
      end

      force = "-"  if $always

# - support Rnn/P for limited repetitions?
      if desc =~ %r{\[(\d\d\d\d-\d\d-\d\d)(?: \d\d:\d\d)?\](.*)(R/P(\d+Y)?(\d+M)?(\d+W)?(\d+D)?)}
        date = Date.parse($1)

        before, mid, after = $`, $2, $'
        spec = $3

        while date <= TODAY
          date = date.next_year($4.to_i)  if $4
          date = date.next_month($5.to_i)  if $5
          date = date.next_day(7 * $6.to_i)  if $6
          date = date.next_day($7.to_i)  if $7

          force = "-"
          desc = before + date.iso8601 + mid + spec + after
        end
      else
        todos.reverse_each { |t|
          if t.force
            state = t.force
            break
          end
        }
      end

      state = "-"  if $always

      e = Entry.new(i, state, desc, force, [])
      todos.last.children << e
      todos << e

      print " "*e.depth, state, " ", desc, "\n"
    else
      puts line
    end
  end

  todos.first
end

$always = false
if ARGV[0] == "-a"
  $always = true
end

parse STDIN