class PickJaDate

# File lib/pick_ja_date.rb, line 24
def self.date(str)
  p = self.new(str)
  p.parse
  p.time
end

# File lib/pick_ja_date.rb, line 18
def self.extract(str)
  p = self.new(str)
  p.parse
  [p.time, p.str] 
end

# File lib/pick_ja_date.rb, line 30
def initialize(input)
  @input = input
  @now = Time.now
  @time = Time.now
  @str = input
end

# File lib/pick_ja_date.rb, line 156
def add_unit_time(num, unit)
  num = num.to_i
  case unit
  when '分';         @time += num.minute
  when '時間';       @time += num.hour
  when '日';         @time += num.day
  when '週間', '週'; @time += num.week
  when 'ヶ月', '月'; @time += num.month 
  end
end

# File lib/pick_ja_date.rb, line 130
def format(time)
  time.strftime '%Y/%m/%d %H:%M'
end

# File lib/pick_ja_date.rb, line 167
def kanji_to_number(kanji)
  if i = KANJI_NUMBER.chars.index(kanji) 
    i + 1
  else
    kanji
  end
end

# File lib/pick_ja_date.rb, line 122
def match?(regex)
  if @str =~ regex
    yield $~.to_a
  else
    nil
  end
end

# File lib/pick_ja_date.rb, line 149
def next_dow_days(str)
  now = @now.wday
  target = DAYS_OF_WEEK.index(str).to_i
  target += 7 if target <= now
  (target - now)
end

# File lib/pick_ja_date.rb, line 37
def parse
  set_day
  set_time
end

# File lib/pick_ja_date.rb, line 144
def remove_time_word(key)
  @str.sub!(%r{#{key}[のにで]?}, '')
  @str.sub!(%r{^[ 　]|[ 　]$}, '')
end

# File lib/pick_ja_date.rb, line 42
def set_day
  num2 = '([0-9]{1,2})'

  match?(/再来月/){|x| 
    remove_time_word x[0]
    @time = (@time + 2.month)
  }

  match?(/来月/){|x| 
    remove_time_word x[0]
    @time = (@time + 1.month)
  }

  match?(%r{(([0-9]{2,4})[年/-])?#{num2}[月/-]#{num2}日?})do |x|
    all, y_with_suffix, y, m, d = x
    remove_time_word all
    y = @now.year unless y
    @time = @time.change(year: y.to_i, month: m.to_i, day: d.to_i)
    @time += 1.year if @time < @now
    return 
  end

  match?(/月末/){|x| 
    remove_time_word x[0]
    @time = @time.change(day: @now.end_of_month.day)
    return 
  }

  match?(/月初|[1一]日/){|x| 
    remove_time_word x[0]
    @time = (@time + 1.month).change(day: 1)
    return 
  }

  match?(%r{(次の)?(#{DAYS_OF_WEEK.join("|")})曜}) do |x|
    remove, dummy, dow_str = x
    remove_time_word remove
    @time += next_dow_days(dow_str).day
    return 
  end 

  match?(/#{(TODAY + TOMORROW + DAT).join('|')}/) do |x|
    case x.first
    when *TODAY;    add = 0
    when *TOMORROW; add = 1
    when *DAT;      add = 2
    end
    remove_time_word x.first
    @time += add.day
    return 
  end

  # N 日後
  units = '(分|時間|日|週間?|ヶ?月)'
  [
    /([0-9#{KANJI_NUMBER}]{1,2})#{units}後/,
    /あと([0-9]{1,2})#{units}/,
  ].each do |regex|
    match?(regex)do |x|
      str, num, unit = x
      add_unit_time kanji_to_number(num), unit
      remove_time_word str
    end
  end

  match?(%r{#{num2}日}){|x|
    remove_time_word x.first
    @time = @time.change(day: x[1])
  }
end

# File lib/pick_ja_date.rb, line 113
def set_time
  num = '([0-9]{1,2})'
  space = '[ 　]?'
  match?(/#{num}([:：])#{num}/){|x| set_time_result x[0], x[1], x[2]; return}
  match?(/#{num+space}時半/){|x|    set_time_result x[0], x[1], 30;   return}
  match?(/#{num+space}時/){|x|      set_time_result x[0], x[1], 0}
  match?(/#{num+space}分/){|x|      set_time_result x[0], @time.hour, x[1]}
end

# File lib/pick_ja_date.rb, line 134
def set_time_result(remove, hour, min)
  remove_time_word remove
  hour = hour.to_i
  if hour > 24
    @time += (hour.div(24)).day 
    hour = hour % 24
  end
  @time = @time.change(hour: hour, min: min)
end