local util = {}

local FIRST_DATE = os.time({ year = 2020, month = 1, day = 22 })

function util.cachedJSONRequest(url, filename)
  local h, err = http.get(url)

  if not h then
    if not fs.exists(filename) then
      error("Error contacting API: " .. err, 0)
    end

    local cache = fs.open(filename, "r")
    local data = json.decode(cache.readAll())
    cache.close()
    return data
  end

  local rawData = h.readAll()

  local cache = fs.open(filename, "w")
  cache.write(rawData)
  cache.close()

  return json.decode(rawData)
end

function util.formatCommas(number)
  return tostring(number):reverse():gsub("(%d%d%d)", "%1,"):reverse():gsub("^,", "")
end

function util.sortedCloneByKey(tbl, key)
  local out = {}
  for _, v in pairs(tbl) do
    table.insert(out, v)
  end
  table.sort(out, function(a, b) return a[key] > b[key] end)
  return out
end

function util.colourScore(i, val)
  if val == 0 then return nil
  elseif i <= 3 then return colours.red
  elseif i <= 6 then return colours.orange
  else return colours.yellow end
end

function util.recoveredColourScore(i, val)
  if val == 0 then return nil
  elseif i <= 3 then return colours.lime
  else return colours.cyan end -- used as a pastel green
end

function util.scoreData(data)
  table.sort(data, function(a, b) return a.cases > b.cases end)
  for k, v in pairs(data) do
    v.originalIndex = k
  end

  local sortedTodayCases = util.sortedCloneByKey(data, "todayCases")
  local sortedTodayDeaths = util.sortedCloneByKey(data, "todayDeaths")

  for i = 1, 10 do
    local todayCasesDatum = data[sortedTodayCases[i].originalIndex]
    todayCasesDatum.todayCasesColour = util.colourScore(i, todayCasesDatum.todayCases)

    local todayDeathsDatum = data[sortedTodayDeaths[i].originalIndex]
    todayDeathsDatum.todayDeathsColour = util.colourScore(i, todayDeathsDatum.todayDeaths)
  end

  if data[1].recovered ~= nil then
    local sortedRecoveries = util.sortedCloneByKey(data, "recovered")

    for i = 1, 6 do
      local recoveredDatum = data[sortedRecoveries[i].originalIndex]
      recoveredDatum.recoveredColour = util.recoveredColourScore(i, recoveredDatum.recoveredColour)
    end
  end
end

function util.processCumulativeHistoricalData(data)
  local out = {}
  for k, v in pairs(data) do
    local month, day, year = table.unpack(_.map({ k:match("(%d+)/(%d+)/(%d+)") }, tonumber))
    local datum = {
      year = 2000 + year,
      month = month,
      day = day
    }
    datum.time = os.time(datum)
    datum.formatted = os.date("%m/%d", datum.time)
    datum.value = v

    table.insert(out, datum)
  end

  table.sort(out, function(a, b) return a.time < b.time end)

  local lastValue = nil
  for k, datum in pairs(out) do
    local v = datum.value

    if lastValue ~= nil then
      datum.value = v - lastValue
    end

    lastValue = v
  end

  return out
end

function util.handleMonitorArg(...)
  local args = { ... }
  if #args ~= 1 then error("Usage: " .. shell.getRunningProgram() .. "  <monitor>", 0) end

  local mon = peripheral.wrap(args[1])
  if not mon or not mon.setTextScale then error("Monitor not found", 0) end

  mon.setTextScale(0.5)
  return mon, mon.getSize()
end

function util.mainLoop(mainFn, sleepTime)
  while true do
    local ok, err = pcall(mainFn)
    if err == "Terminated" then error(err, 0) end
    if not ok then printError(err) end
    sleep(sleepTime or 900)
  end
end

return util