Module:Sandbox/Hellknowz/Test

local main = {};

local monthIndices = {
    ['january'] = 1,
    ['february'] = 2,
    ['march'] = 3,
    ['april'] = 4,
    ['may'] = 5,
    ['june'] = 6,
    ['july'] = 7,
    ['august'] = 8,
    ['september'] = 9,
    ['october'] = 10,
    ['november'] = 11,
    ['december'] = 12
}

local monthDays = {
    [1] = 31,
    [2] = 29, -- will check below
    [3] = 31,
    [4] = 30,
    [5] = 31,
    [6] = 30,
    [7] = 31,
    [8] = 31,
    [9] = 30,
    [10] = 31,
    [11] = 30,
    [12] = 31
}

function tryParseDate(input)

    -- First try dMy
    local matchDay, matchMonth, matchYear = input:match('^([0-9][0-9]?) ([A-Za-z]+) ([0-9][0-9][0-9][0-9])$')

    if (matchDay ~= nil) then
        local month = monthIndices[matchMonth:lower()]
        if (month == nil) then return nil end

        return { tonumber(matchDay), month, tonumber(matchYear) }
    end

    return nil

end

function main.hello(frame)

    --[[
    local args = frame.args
    local arg1 = args[1]
    local arg2 = args[2]
    local arg3 = args[3]
    local argNamed = args['named']

    local s = 'Params: '
    if (arg1 ~= nil) then s = s .. '1 = ' .. arg1 end
    if (arg2 ~= nil) then s = s .. '; 2 = ' .. arg2 end
    if (arg3 ~= nil) then s = s .. '; 3 = ' .. arg3 end
    if (argNamed ~= nil) then s = s .. '; named = ' .. argNamed end
    return s
    ]]

    local args = frame.args
    local input = args[1]

    local day, month, year = tryParseDate(input)

    if (day == nil) then
        return input .. ' -> is not a recognized pattern match' end

    if (year < 1760) then
        return input .. ' -> year is too early (calendar discrepancy)' end

    if (year > 2100) then
        return input .. ' -> year is too far into future' end

    if (day == 0) then
        return input .. ' -> day is invalid == 0' end

    if (day > monthDays[month]) then
        return input .. ' -> day is invalid > ' .. monthDays[month] end

    -- February leap year check
    if (month == 2) then
        if (day == 29 and not ((year % 4 == 0) and (year % 100 ~= 0) or (year % 400 == 0))) then
             return input .. ' -> day is invalid > 28'
        end
    end

    return input .. ' -> parsed to ' .. year .. '-' .. month .. '-' .. day; -- won't add 0s

end
 
return main