local p = {}
local getArgs = require('Module:Arguments').getArgs
local datePattern = "^(%d+)-(%d+)$"
-- local weatherTemplate = 'Template:Weather box'
local weatherTemplate = 'Template:Climat'
local wrapsTemplate = 'User:Rousseaulambertlp/Weather box'

function p.weatherbox( frame )
    local args = getArgs(frame, { wrappers = wrapsTemplate })
    local dataPage = assert(args.data, 'Missing "data" parameter')
    args.data = nil

    local monthlyHigh, monthlyLow = {}, {}
    local highSum, highCount = {}, {}
    local lowSum, lowCount = {}, {}
    local avgHighSum, avgHighCount = {}, {}
    local avgLowSum, avgLowCount = {}, {}
    local precipSum, precipCount = {}, {}
    local snowfallSum, snowfallCount = {}, {}

	-- There is currently no established way to specify sources, suggestions needed
	-- For now, prepend the link to edit box to the first source
	local source = args['source'] or args['source 1']
	if source then source = '<br>' .. source end
	args['source'] = '[[commons:Data:'.. dataPage ..'|edit data]]' .. source
	args['source 1'] = nil

    for key, row in pairs(mw.ext.data.get(dataPage).data) do
        local date, avgHighTemp, avgLowTemp, extHighTemp, extLowTemp, precipTotalRain, precipTotalSnow, precipTotal, snowGrndLastDay, windDirMaxGust, windSpeedMaxGust = unpack(row)

        local year, month = date:match(datePattern)
        month = tonumber(month)

        if extHighTemp ~= nil and (monthlyHigh[month] == nil or monthlyHigh[month] < extHighTemp) then monthlyHigh[month] = extHighTemp end
        if extLowTemp ~= nil and (monthlyLow[month] == nil or monthlyLow[month] > extLowTemp) then monthlyLow[month] = extLowTemp end
        recordAvg(highSum, highCount, month, extHighTemp)
        recordAvg(lowSum, lowCount, month, extLowTemp)
        recordAvg(avgHighSum, avgHighCount, month, avgHighTemp)
        recordAvg(avgLowSum, avgLowCount, month, avgLowTemp)
        recordAvg(precipSum, precipCount, month, precipTotal)
        recordAvg(snowfallSum, snowfallCount, month, precipTotalSnow)
    end

    local months = {'Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'}
    for i=1, 12 do args[months[i] .. 'tmax-'] = monthlyHigh[i] end
    for i=1, 12 do args[months[i] .. 'tmin-'] = monthlyLow[i] end
--    for i=1, 12 do args[months[i] .. 'avg record high C'] = string.format("%.1f", highSum[i] / highCount[i]) end
--    for i=1, 12 do args[months[i] .. 'avg record low C'] = string.format("%.1f", lowSum[i] / lowCount[i]) end
--    for i=1, 12 do args[months[i] .. 'high C'] = string.format("%.1f", avgHighSum[i] / avgHighCount[i]) end
--    for i=1, 12 do args[months[i] .. 'low C'] = string.format("%.1f", avgLowSum[i] / avgLowCount[i]) end
    for i=1, 12 do args[months[i] .. 'prec-'] = string.format("%.1f", precipSum[i] / precipCount[i]) end
--    for i=1, 12 do args[months[i] .. ' snow mm'] = string.format("%.1f", snowfallSum[i] / snowfallCount[i]) end

    return frame:expandTemplate{ title = weatherTemplate, args = args }
end

function recordAvg(sumTbl, countTbl, month, value)
    if value ~= nil then
        sumTbl[month] = (sumTbl[month] or 0) + value
        countTbl[month] = (countTbl[month] or 0) + 1
    end
end

return p