server: extract open_log_for_writing()

[tattlekey] / server / src / main.rs

diff --git a/server/src/main.rs b/server/src/main.rs
index e7a11a969c037e00a796aafeff6258501ec15e9a..5edadbb9bc3b671244e46f6d24dcb1f471958ab0 100644 (file)
--- a/server/src/main.rs
+++ b/server/src/main.rs
@@ -1,3 +1,123 @@
+// tattlekey: A one-key UDP keyboard
+// Copyright (C) 2023  Scott Worley <scottworley@scottworley.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use serde::Serialize;
+use std::collections::HashMap;
+use std::net::UdpSocket;
+use std::time::{Duration, SystemTime};
+
+const MESSAGE_SIZE: usize = 12;
+const LOGFILENAME: &str = "log.csv";
+
+#[derive(Eq, Debug, Hash, PartialEq, Serialize)]
+struct MessageKey {
+    epoch: u32,
+    device: u16,
+    seq: u16,
+}
+
+#[derive(Debug)]
+struct Message {
+    key: MessageKey,
+    t: SystemTime,
+}
+
+impl From<&[u8; MESSAGE_SIZE]> for Message {
+    fn from(value: &[u8; MESSAGE_SIZE]) -> Self {
+        let ago = u32::from_be_bytes(value[8..=11].try_into().expect("I can't count"));
+        Self {
+            key: MessageKey {
+                epoch: u32::from_be_bytes(value[0..=3].try_into().expect("I can't count")),
+                device: u16::from_be_bytes(value[4..=5].try_into().expect("I can't count")),
+                seq: u16::from_be_bytes(value[6..=7].try_into().expect("I can't count")),
+            },
+            t: SystemTime::now() - Duration::new(ago.into(), 0),
+        }
+    }
+}
+impl TryFrom<&[u8]> for Message {
+    type Error = std::array::TryFromSliceError;
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        match <[u8; MESSAGE_SIZE]>::try_from(value) {
+            Ok(correct_size) => Ok(Message::from(&correct_size)),
+            Err(e) => Err(e),
+        }
+    }
+}
+
+#[derive(Debug)]
+struct Range {
+    start: SystemTime,
+    end: SystemTime,
+}
+impl Range {
+    fn new(t: &SystemTime) -> Self {
+        Self { start: *t, end: *t }
+    }
+    fn contains(&self, t: &SystemTime) -> bool {
+        t > &self.start && t < &self.end
+    }
+    fn extend(&mut self, t: &SystemTime) {
+        if t < &self.start {
+            self.start = *t;
+        }
+        if t > &self.end {
+            self.end = *t;
+        }
+    }
+}
+
+fn open_log_for_writing() -> csv::Writer<std::fs::File> {
+    let log_file_exists = std::path::Path::new(LOGFILENAME).exists();
+    let logfile = std::fs::OpenOptions::new()
+        .create_new(!log_file_exists)
+        .append(true)
+        .open(LOGFILENAME)
+        .expect("Coudln't open log file");
+    csv::WriterBuilder::new()
+        .has_headers(!log_file_exists)
+        .from_writer(logfile)
+}
+
 fn main() {
-    println!("Hello, world!");
+    let mut log = open_log_for_writing();
+    let mut presses = HashMap::<MessageKey, Range>::new();
+    let socket = UdpSocket::bind("0.0.0.0:29803").expect("couldn't bind to address");
+    loop {
+        let mut buf = [0; MESSAGE_SIZE];
+        match socket.recv_from(&mut buf) {
+            Err(e) => eprintln!("Didn't receive data: {e}"),
+            Ok((number_of_bytes, src_addr)) => {
+                let filled_buf = &buf[..number_of_bytes];
+                if number_of_bytes != MESSAGE_SIZE {
+                    eprintln!("Ignoring short message ({number_of_bytes}) from {src_addr}");
+                    continue;
+                }
+                let message = Message::try_from(filled_buf).expect("I can't count");
+                log.serialize((&message.key, message.t))
+                    .expect("Couldn't write log");
+                log.flush().expect("Couldn't flush log");
+                if let Some(r) = presses.get_mut(&message.key) {
+                    if !r.contains(&message.t) {
+                        r.extend(&message.t);
+                    }
+                } else {
+                    presses.insert(message.key, Range::new(&message.t));
+                }
+            }
+        }
+    }
 }