Module:Date

local date = {}

function date.i2p( dt )

   u = date.i2u(dt)
   dt.args[1] = u
   p = date.u2p(dt)
   return p

end

function date.p2i( dt )

   u = date.p2u(dt)
   dt.args[1] = u
   i = date.u2i(dt)
   return i

end

function date.i2u( dt )

   d      = mw.text.split( dt.args[1], '/')
   day    = tonumber(d[1])
   week   = tonumber(d[2])
   season = tonumber(d[3])
   year   = tonumber(d[4])
   u      = math.floor((year-1)*365.25)+_if(season>1,8*12)+_if(season>2,89)+_if(season>3,89)+(week-1)*8+day+92
   return u

end

function date.p2u( dt )

   d = mw.text.split( dt.args[1], '/')
   day   = tonumber(d[1])
   month = tonumber(d[2])
   year  = tonumber(d[3])
   u = math.floor((year+4495)*365.25)- 241 + day +(month-5)*30 + _if(month>6, 1) + _if(month>9 and year%4==1, 1) - _if(month<5, 1) - _if(month < 4, 1) - _if(month < 2, 1)
   return u

end

function date.u2p( du )

   year      = math.ceil((du.args[1] - 1)/365.25+0.001)-4495
   day_year = du.args[1]%1461-365*math.floor((du.args[1]%1461)/365.25)-_if(year%4==1,1)  
   month    = 1 + _if(day_year>31,1) + _if(day_year>61,1) 
                + _if(day_year>92,1) + _if(day_year>123,1) + _if(day_year>154,1) 
                + _if(day_year>184,1) + _if(day_year>215,1) + _if(day_year>245,1) 
                + _if(day_year>275,1) + _if(day_year>305 + _if((year%4)==1,1),1) + _if(day_year>335 + _if((year%4)==1,1),1)
   day_month = day_year 
                - _if(month>1,31) - _if(month>2,30) - _if(month>3,31)
                - _if(month>4,31) - _if(month>5,31) - _if(month>6,30)
                - _if(month>7,31) - _if(month>8,30) - _if(month>9,30)
                - _if(month>10,30 + _if((year%4)==1,1)) - _if(month>11,30)
   day       = day_month - _if(month==1, 1)-_if(month==3, 1)-_if(month==4, 1)-_if(month==5, 1)-_if(month==7, 1)-_if(month==10 and (year%4==1), 1)
   dt        = tostring(day)..'/'..tostring(month)..'/'..tostring(year)
   return dt

end

function date.u2i( du )

   year       = math.ceil((du.args[1]-92)/365.25)
   day_year   = math.ceil(du.args[1]-(year-1)*365.25-92)
   season     = 1 + _if(day_year > 96,1) + _if(day_year > 96+89,1) + _if(day_year > 96+89+89, 1)
   day_season = day_year - _if(season > 1,96)- _if(season > 2,89) - _if(season > 3,89)
   week       = math.floor((day_season-1)/8)+1
   day_week   = day_season - (week-1)*8
   day        = day_week
   dt         = tostring(day)..'/'..tostring(week)..'/'..tostring(season)..'/'..tostring(year)
   return dt

end

function _if(b, a)

   if b then
       return a
   else
       return 0
   end

end

function date.compare_date( range )

   i = tonumber(range.args[1])
   m = tonumber(range.args[1]) + tonumber(range.args[2])

res = '

' while i < m do i = i +1 f = {} f["args"] = {} f.args[1] = i res = res..''

   end

res = res..'

'..tostring(i)..'

'..tostring(date.u2p(f))..'

'..tostring(date.u2i(f))..'

'

   return res

end

return date