wldash/src/backlight.rs

use crate::module::{ModuleImpl, Input};
use crate::buffer::Buffer;
use crate::color::Color;
use crate::draw::{draw_text, ROBOTO_REGULAR};

use std::fs::OpenOptions;
use std::path::{Path, PathBuf};
use std::io::{Read, Write};
use std::io::{Error, ErrorKind};
use chrono::{DateTime, Local};

pub struct Backlight {
    device_path: PathBuf,
    cur_brightness: u64,
    max_brightness: u64,
    dirty: bool,
}

fn read_file_as_u64(path: &Path) -> Result<u64, Error> {
    let mut file = OpenOptions::new()
            .read(true)
            .open(path)?;
    let mut str = String::new();
    file.read_to_string(&mut str)?;
    str.pop();
    str.parse::<u64>().map_err(|_e| {Error::new(ErrorKind::Other, "unable to parse value")})
}

fn write_file_as_u64(path: &Path, value: u64) -> Result<(), Error> {
    let mut file = OpenOptions::new()
            .write(true)
            .open(path)?;
    file.write_fmt(format_args!("{}", value))
}

impl Backlight {
    pub fn update(&mut self) -> Result<(), Error> {
        self.cur_brightness = read_file_as_u64(self.device_path.join("brightness").as_path())?;
        self.max_brightness = read_file_as_u64(self.device_path.join("max_brightness").as_path())?;
        self.dirty = true;
        Ok(())
    }

    pub fn sync(&mut self) -> Result<(), Error> {
        write_file_as_u64(self.device_path.join("brightness").as_path(), self.cur_brightness)?;
        self.update()?;
        Ok(())
    }

    pub fn brightness(&self) -> f32 {
        if self.cur_brightness > self.max_brightness {
            // what.
            return 100.0;
        }

        (self.cur_brightness as f32 / self.max_brightness as f32) * 100.0
    }

    pub fn add(&mut self, diff: f32) -> Result<(), Error> {
        let inc = ((self.max_brightness as f32) / 100.0 * diff) as i64;

        self.cur_brightness = if self.cur_brightness as i64 + inc < 1 {
            1
        } else if self.cur_brightness as i64 + inc > self.max_brightness as i64 {
            self.max_brightness
        } else {
            (self.cur_brightness as i64 + inc) as u64
        };

        Ok(())
    }

    pub fn default() -> Result<Self, Error> {
        let devices = Path::new("/sys/class/backlight")
                           .read_dir()?;

        let first_device = devices.take(1).next().unwrap().unwrap();
        let mut dev = Backlight{
            device_path: first_device.path(),
            cur_brightness: 0,
            max_brightness: 0,
            dirty: true,
        };

        dev.update()?;

        Ok(dev)
    }
}

impl ModuleImpl for Backlight {
    fn draw(&self, buf: &mut Buffer, bg: &Color, _time: &DateTime<Local>) -> Result<Vec<(i32, i32, i32, i32)>, Error> {
        buf.memset(bg);
        draw_text(
            ROBOTO_REGULAR,
            &mut buf.subdimensions((0, 0, 256, 24)),
            bg,
            &Color::new(1.0, 1.0, 1.0, 1.0),
            24.0,
            &format!("backlight: {:}%", self.brightness() as u8),
        )?;
        Ok(vec![buf.get_signed_bounds()])
    }

    fn update(&mut self, _time: &DateTime<Local>, force: bool) -> Result<bool, ::std::io::Error>{
        if self.dirty || force {
            self.dirty = false;
            Ok(true)
        } else {
            Ok(false)
        }
    }

    fn input(&mut self, input: Input) {
        match input {
            Input::Scroll{pos: _pos, x: _x, y} => {
                self.add((y * -1.0) as f32 / 8.0).unwrap();
                self.sync().unwrap();
            },
            Input::Click{pos: _pos, button} => {
                match button {
                    273 => { // Right click
                        self.cur_brightness = if self.cur_brightness == 1 {
                            self.max_brightness
                        } else {
                            1
                        };
                        self.sync().unwrap();
                    },
                    _ => {}
                }
            },
        }
    }
}