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::{Deserialize, 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)]
  26 struct MessageKey {
  27     epoch: u32,
  28     device: u16,
  29     seq: u16,
  30 }
  31
  32 #[derive(Debug, Deserialize, Serialize)]
  33 struct Message {
  34     epoch: u32,
  35     device: u16,
  36     seq: u16,
  37     t: u64,
  38 }
  39 impl Message {
  40     fn key(&self) -> MessageKey {
  41         MessageKey {
  42             epoch: self.epoch,
  43             device: self.device,
  44             seq: self.seq,
  45         }
  46     }
  47 }
  48
  49 impl From<&[u8; MESSAGE_SIZE]> for Message {
  50     fn from(value: &[u8; MESSAGE_SIZE]) -> Self {
  51         let ago = u32::from_be_bytes(value[8..=11].try_into().expect("I can't count"));
  52         let press_time = SystemTime::now() - Duration::new(ago.into(), 0);
  53         Self {
  54             epoch: u32::from_be_bytes(value[0..=3].try_into().expect("I can't count")),
  55             device: u16::from_be_bytes(value[4..=5].try_into().expect("I can't count")),
  56             seq: u16::from_be_bytes(value[6..=7].try_into().expect("I can't count")),
  57             t: press_time
  58                 .duration_since(UNIX_EPOCH)
  59                 .expect("Bad time?")
  60                 .as_secs(),
  61         }
  62     }
  63 }
  64 impl TryFrom<&[u8]> for Message {
  65     type Error = std::array::TryFromSliceError;
  66     fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
  67         match <[u8; MESSAGE_SIZE]>::try_from(value) {
  68             Ok(correct_size) => Ok(Message::from(&correct_size)),
  69             Err(e) => Err(e),
  70         }
  71     }
  72 }
  73
  74 #[derive(Debug)]
  75 struct Range {
  76     start: u64,
  77     end: u64,
  78 }
  79 impl Range {
  80     fn new(t: &u64) -> Self {
  81         Self { start: *t, end: *t }
  82     }
  83     fn contains(&self, t: &u64) -> bool {
  84         t > &self.start && t < &self.end
  85     }
  86     fn extend(&mut self, t: &u64) {
  87         if t < &self.start {
  88             self.start = *t;
  89         }
  90         if t > &self.end {
  91             self.end = *t;
  92         }
  93     }
  94 }
  95
  96 fn merge_message(presses: &mut HashMap<MessageKey, Range>, message: Message) {
  97     let key = message.key();
  98     if let Some(r) = presses.get_mut(&key) {
  99         if !r.contains(&message.t) {
 100             r.extend(&message.t);
 101         }
 102     } else {
 103         presses.insert(key, Range::new(&message.t));
 104     }
 105 }
 106
 107 fn replay_log() -> HashMap<MessageKey, Range> {
 108     let mut presses = HashMap::new();
 109     if std::path::Path::new(LOGFILENAME).exists() {
 110         let mut log = csv::Reader::from_path(LOGFILENAME).expect("Couldn't open log for replay");
 111         for message in log.deserialize() {
 112             merge_message(
 113                 &mut presses,
 114                 message.expect("Error reading log during replay"),
 115             );
 116         }
 117     }
 118     presses
 119 }
 120
 121 fn open_log_for_writing() -> csv::Writer<std::fs::File> {
 122     let log_file_exists = std::path::Path::new(LOGFILENAME).exists();
 123     let logfile = std::fs::OpenOptions::new()
 124         .create_new(!log_file_exists)
 125         .append(true)
 126         .open(LOGFILENAME)
 127         .expect("Coudln't open log file");
 128     csv::WriterBuilder::new()
 129         .has_headers(!log_file_exists)
 130         .from_writer(logfile)
 131 }
 132
 133 fn main() {
 134     let socket = UdpSocket::bind("0.0.0.0:29803").expect("couldn't bind to address");
 135     let mut presses = replay_log();
 136     let mut log = open_log_for_writing();
 137     loop {
 138         let mut buf = [0; MESSAGE_SIZE];
 139         match socket.recv_from(&mut buf) {
 140             Err(e) => eprintln!("Didn't receive data: {e}"),
 141             Ok((number_of_bytes, src_addr)) => {
 142                 let filled_buf = &buf[..number_of_bytes];
 143                 if number_of_bytes != MESSAGE_SIZE {
 144                     eprintln!("Ignoring short message ({number_of_bytes}) from {src_addr}");
 145                     continue;
 146                 }
 147                 let message = Message::try_from(filled_buf).expect("I can't count");
 148                 log.serialize(&message).expect("Couldn't write log");
 149                 log.flush().expect("Couldn't flush log");
 150                 merge_message(&mut presses, message);
 151             }
 152         }
 153     }
 154 }