git.scottworley.com Git - tattlekey/blob - server/src/main.rs

   1 // tattlekey: A one-key UDP keyboard
   2 // Copyright (C) 2023  Scott Worley <scottworley@scottworley.com>
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
  16
  17 use serde::Serialize;
  18 use std::collections::HashMap;
  19 use std::net::UdpSocket;
  20 use std::time::{Duration, SystemTime, UNIX_EPOCH};
  21
  22 const MESSAGE_SIZE: usize = 12;
  23 const LOGFILENAME: &str = "log.csv";
  24
  25 #[derive(Eq, Debug, Hash, PartialEq, Serialize)]
  26 struct MessageKey {
  27     epoch: u32,
  28     device: u16,
  29     seq: u16,
  30 }
  31
  32 #[derive(Debug)]
  33 struct Message {
  34     key: MessageKey,
  35     t: u64,
  36 }
  37
  38 impl From<&[u8; MESSAGE_SIZE]> for Message {
  39     fn from(value: &[u8; MESSAGE_SIZE]) -> Self {
  40         let ago = u32::from_be_bytes(value[8..=11].try_into().expect("I can't count"));
  41         let press_time = SystemTime::now() - Duration::new(ago.into(), 0);
  42         Self {
  43             key: MessageKey {
  44                 epoch: u32::from_be_bytes(value[0..=3].try_into().expect("I can't count")),
  45                 device: u16::from_be_bytes(value[4..=5].try_into().expect("I can't count")),
  46                 seq: u16::from_be_bytes(value[6..=7].try_into().expect("I can't count")),
  47             },
  48             t: press_time
  49                 .duration_since(UNIX_EPOCH)
  50                 .expect("Bad time?")
  51                 .as_secs(),
  52         }
  53     }
  54 }
  55 impl TryFrom<&[u8]> for Message {
  56     type Error = std::array::TryFromSliceError;
  57     fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
  58         match <[u8; MESSAGE_SIZE]>::try_from(value) {
  59             Ok(correct_size) => Ok(Message::from(&correct_size)),
  60             Err(e) => Err(e),
  61         }
  62     }
  63 }
  64
  65 #[derive(Debug)]
  66 struct Range {
  67     start: u64,
  68     end: u64,
  69 }
  70 impl Range {
  71     fn new(t: &u64) -> Self {
  72         Self { start: *t, end: *t }
  73     }
  74     fn contains(&self, t: &u64) -> bool {
  75         t > &self.start && t < &self.end
  76     }
  77     fn extend(&mut self, t: &u64) {
  78         if t < &self.start {
  79             self.start = *t;
  80         }
  81         if t > &self.end {
  82             self.end = *t;
  83         }
  84     }
  85 }
  86
  87 fn merge_message(presses: &mut HashMap<MessageKey, Range>, message: Message) {
  88     if let Some(r) = presses.get_mut(&message.key) {
  89         if !r.contains(&message.t) {
  90             r.extend(&message.t);
  91         }
  92     } else {
  93         presses.insert(message.key, Range::new(&message.t));
  94     }
  95 }
  96
  97 fn open_log_for_writing() -> csv::Writer<std::fs::File> {
  98     let log_file_exists = std::path::Path::new(LOGFILENAME).exists();
  99     let logfile = std::fs::OpenOptions::new()
 100         .create_new(!log_file_exists)
 101         .append(true)
 102         .open(LOGFILENAME)
 103         .expect("Coudln't open log file");
 104     csv::WriterBuilder::new()
 105         .has_headers(!log_file_exists)
 106         .from_writer(logfile)
 107 }
 108
 109 fn main() {
 110     let socket = UdpSocket::bind("0.0.0.0:29803").expect("couldn't bind to address");
 111     let mut presses = HashMap::<MessageKey, Range>::new();
 112     let mut log = open_log_for_writing();
 113     loop {
 114         let mut buf = [0; MESSAGE_SIZE];
 115         match socket.recv_from(&mut buf) {
 116             Err(e) => eprintln!("Didn't receive data: {e}"),
 117             Ok((number_of_bytes, src_addr)) => {
 118                 let filled_buf = &buf[..number_of_bytes];
 119                 if number_of_bytes != MESSAGE_SIZE {
 120                     eprintln!("Ignoring short message ({number_of_bytes}) from {src_addr}");
 121                     continue;
 122                 }
 123                 let message = Message::try_from(filled_buf).expect("I can't count");
 124                 log.serialize((&message.key, message.t))
 125                     .expect("Couldn't write log");
 126                 log.flush().expect("Couldn't flush log");
 127                 merge_message(&mut presses, message);
 128             }
 129         }
 130     }
 131 }