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batalert/src/main.rs
2020-12-27 15:59:17 +01:00

121 lines
4 KiB
Rust

use clap::{App, Arg};
use crossbeam_channel::{select, tick};
use notify_rust::{Notification, Urgency};
use std::fs;
use std::time::Duration;
fn main() {
// parse CLI options
let matches = App::new("batalert")
.version("0.2.0")
.author("Felix Ortmann <flx.ortmann@gmail.com>")
.about("Sends D-Bus notification when battery runs low.")
.arg(
Arg::with_name("uevent")
.short("u")
.long("uevent")
.default_value("/sys/class/power_supply/BAT0/uevent")
.help("Read the battery capacity from this uevent file."),
)
.arg(
Arg::with_name("alert")
.short("a")
.long("alert")
.default_value("15")
.help("Send the first notification when battery falls below this threshold"),
)
.arg(
Arg::with_name("notification-step")
.short("n")
.long("notification-step")
.default_value("3")
.help("Repeat notifications for every n percent the battery discharges"),
)
.arg(
Arg::with_name("timeout")
.short("t")
.long("timeout")
.default_value("15")
.help("Hide the notification after t seconds"),
)
.arg(
Arg::with_name("icon")
.short("i")
.long("icon")
.default_value("/usr/share/icons/Adwaita/256x256/legacy/battery-caution.png")
.help("Use this icon (PNG) when displaying notifications"),
)
.get_matches();
let uevt_file = matches.value_of("uevent").unwrap();
let icon = matches.value_of("icon").unwrap();
let threshold = matches.value_of("alert").unwrap().parse::<i8>().unwrap();
let step = matches
.value_of("notification-step")
.unwrap()
.parse::<i8>()
.unwrap();
let timeout = matches.value_of("timeout").unwrap().parse::<i32>().unwrap();
// periodic task to compare battery level with configuration
let notify = |cap| send_notification(cap, icon, timeout * 1000);
watch(&uevt_file, threshold, step, notify);
}
// Puts a notification to the D-Bus
fn send_notification(cap: i8, icon: &str, timeout: i32) {
Notification::new()
.summary(&format!("Battery {}%", cap))
.body("Charge your battery soon to avoid shutdown")
.icon(icon)
.urgency(Urgency::Critical)
.timeout(timeout)
.show()
.unwrap();
}
// Checks the current battery percentage. Calls the notification function
// periodically in the configured `step` interval if the battery discharges and
// is below the configured threshold
fn watch<F: Fn(i8)>(uevt_file: &str, threshold: i8, step: i8, notify: F) {
let ticker = tick(Duration::from_millis(5000));
let mut alert_threshold = threshold;
loop {
select! {
recv(ticker) -> _ => {
let (cap, status) = extract_status(&uevt_file);
if status.to_lowercase() == "discharging" && cap <= alert_threshold {
notify(cap);
alert_threshold = cap - step;
}
else if status.to_lowercase() == "charging" {
alert_threshold = threshold;
}
}
}
}
}
// Extracts the battery capacity (percentage) and charging status
fn extract_status(uevt_file: &str) -> (i8, String) {
let contents = fs::read_to_string(uevt_file).expect("Something went wrong reading the file");
let cap = contents
.lines()
.find(|s| s.contains("POWER_SUPPLY_CAPACITY"))
.unwrap()
.split("=")
.nth(1)
.unwrap()
.parse::<i8>()
.unwrap();
let status = contents
.lines()
.find(|s| s.contains("POWER_SUPPLY_STATUS"))
.unwrap()
.split("=")
.nth(1)
.unwrap()
.to_string();
return (cap, status);
}