icps

notes

Days

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# encoding: utf-8
# .rvmrc rvm use 2.5.1
require 'date'
require '/data/ruby/debug/debug.rb'

def cheack_date_true(year, month, day)
    not leap_year(year) and month == 2 and day == 29
end

def leap_year_days(y)
    leap_year(y) ? 366 : 365
end

def leap_year(y)
    y % 4 == 0 && y % 100 != 0 || y % 400 == 0
end

def md(y)
    if leap_year(y)
        [0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    else
        [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    end
end

def days(date)
    year, month, day = date.split("/").map(&:to_i)
    return false if cheack_date_true(year, month, day)
    y = year - 1
    years  = y * 365 + (y / 4 - y / 100 + y / 400)
    months = md(year)[1..(month - 1)].sum
    years + months + day
end

def add_date(date, num)
    return Date.parse(date) if num == 0
    year, month, day = date.split("/").map(&:to_i)
    return false if cheack_date_true(year, month, day)
    left_year = md(year)[month..13].sum - day
    if num > left_year
        month = day = 0
        num -= left_year
        until num < leap_year_days(year + 1)
            num -= leap_year_days(year + 1)
            year += 1
        end
        year += 1
    elsif num == left_year
        return "#{year}/12/31"
    end
    num += day
    md(year).each_with_index do |d, idx|
        next if idx < month
        if num <= d
            return "#{year}/#{idx}/#{num}"
        else
            num -= d
        end
    end
end

def between(sdate, edate)
    s = days(sdate)
    e = days(edate)
    s and e ? (days(edate) - days(sdate)).abs : false
end

#i = Time.now.to_i
#t = Time.at(i)

adate = '1950/1/1'
bdate = '1981/2/29'
cdate = '2000/2/29'
p days(adate)
p days(bdate)
p between(adate, bdate)
p between(adate, cdate)
p add_date(cdate, 1000)