79 lines
2.9 KiB
Nix
79 lines
2.9 KiB
Nix
{
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lib,
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pkgs,
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config,
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...
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}: let
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battery-watch = pkgs.writeHaskellScript
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{
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name = "battery-watch";
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bins = [pkgs.acpi];
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imports = [
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"DBus.Notify"
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"Control.Concurrent"
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"Text.Megaparsec"
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"Text.Megaparsec.Char"
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"Text.Megaparsec.Char.Lexer"
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"Replace.Megaparsec"
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"Data.Maybe"
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];
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} ''
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moderateLevel = 50 -- percent
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lowLevel = 20 -- percent
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criticalLevel = 8 -- percent
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minute = 60 * 1000 * 1000 -- threadDelay takes microseconds
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main = do
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client <- connectSession
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let loop = \lastState handleMay -> do
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newState <- getState
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let noteMay = chooseAction lastState newState
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handle <- if | Just note <- noteMay -> Just <$> maybe (notify client note) (flip (replace client) note) handleMay
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| otherwise -> pure handleMay
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threadDelay $ minute `div` 4
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loop newState handle
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loop (BatState True 100) Nothing
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data BatState = BatState { charging :: Bool, level :: Int }
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getState = do
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batteryStateText <- decodeUtf8 <$> (acpi "-a" |> captureTrim)
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batteryLevelText <- decodeUtf8 <$> (acpi "-b" |> captureTrim)
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chargerOnline <- maybe (fail "Couldn‘t get charging state") pure $ parseMaybe onlineParser batteryStateText
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batteryLevel <- maybe (fail "Couldn‘t get battery level") pure $ parseMaybe levelParser batteryLevelText
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pure $ BatState chargerOnline batteryLevel
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type Parser = Parsec Text LText
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onlineParser :: Parser Bool
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onlineParser = not . null . rights <$> sepCap (string "on-line")
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levelParser :: Parser Int
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levelParser = (maybe (fail "No Number found") pure . listToMaybe . rights) =<< sepCap (decimal <* "%")
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chooseAction :: BatState -> BatState -> Maybe Note
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chooseAction (BatState wasCharging lastLevel) (BatState isCharging currentLevel)
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| wasCharging && isCharging = Nothing
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| wasCharging && not isCharging = Just $ myNote{summary = "Charger disconnected." }
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| not wasCharging && isCharging = Just $ myNote{summary = "Charger connected.", expiry = Milliseconds 5000 }
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| currentLevel <= criticalLevel = Just $ myNote{summary = "Battery is very low!" }
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| currentLevel <= lowLevel && currentLevel < lastLevel = Just $ myNote{summary = "Battery is low!"}
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| ((currentLevel `mod` 5 == 0 && currentLevel <= moderateLevel) || (currentLevel `mod` 10 == 0)) && currentLevel < lastLevel = Just $ myNote{summary = "Battery is discharging."}
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| otherwise = Nothing
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where
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myNote = blankNote { body = Just $ Text [i|#{currentLevel}% remaining.|]}
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'';
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in {
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systemd.user = {
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services.battery = {
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Unit.Description = "Watch battery state and warn user";
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Service = {
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ExecStart = "${battery-watch}/bin/battery-watch";
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Restart = "always";
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RestartSec = 60;
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};
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Install.WantedBy = ["default.target"];
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};
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};
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}
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