--[[
this module is meant for language-dependant time calculations.
ATM it exports a single function: sumHMS, which accepts unnamed (aka "order based")
arguments in the form ssss (any number of digits) or "mm:ss" or "hh:mm:ss:,
converts them all to seconds, sums them up, and returns the output string 
describing the total duration, using mw.getContentLanguage():formatDuration()
an optional paramter, "units" tells the formatting function which units to use:
e.g. ((invoke:Duration | sumHMS | 7211 | units = minutes, seconds)) will return "120 minutes and 11 seconds".
((invoke:Duration|sumHMS| 1:0:11 | 1:00:00 | units= seconds)) will return "7211 seconds"
]]


local function sumHMS( args )
    local total = 0
    local units, kunits
    
    local function oneMore( st )
        if type( st ) ~= 'string' then return end
        local t, ar = 0, { st:match( "^%s*(%d*):?(%d*):?(%d*)%s*$" ) }
        for _, v in ipairs( ar ) do
            local n = tonumber( v )
            if n then t = t * 60 + n end
        end
        total = total + t
    end

    local function beenthereDoneit( factor, unit, pad, first, last )
        if kunits and not kunits[unit] then return '' end
        local res = math.floor( total / factor )
        if first and res == 0 and not last then return '' end
        total = total % factor
        return string.format( '%0' .. ( first and '1' or pad ) .. 'd' .. ( not last and ':' or '' ), res )
    end

    for _, v in ipairs( args ) do oneMore( v ) end
    if args.units or args['יחידות'] then 
        units = {}; kunits = {}
        for unit in mw.ustring.gmatch( args.units or args['יחידות'] , "%w+" ) do 
            table.insert( units, unit )
            kunits[unit] = 1
        end
    end
    if args['פלט'] == 'נא' then
        local h = beenthereDoneit( 3600, 'hours', 1, true, false )
        local m = beenthereDoneit( 60, 'minutes', 2, h == '', false )
        local s = beenthereDoneit( 1, 'seconds', 2, h == '' and m == '', true )
        return h .. m .. s  
    end
    return mw.language.getContentLanguage():formatDuration( total, units )
end

return {
    sumHMS = function( frame ) return sumHMS( frame.args ) end,
}