made more functional'n shit

src/main.rs

@@ -1,4 +1,7 @@
 use serial::SerialPort;
+use std::io::BufRead;
+use std::io::BufReader;
+use std::io::Result as IoResult;
 
 use walkdir::WalkDir;
 fn main() {
@@ -39,8 +42,10 @@ fn main() {
         match entry {
             Err(e) => eprintln!("error when reading music dir, continuing: {:?}", e),
             Ok(entry) => {
-                if entry.file_type().is_file() && entry.path().extension() != Some(std::ffi::OsStr::new("jpg")){
-                    music.push(entry.path().to_owned());
+                if entry.file_type().is_file()
+                    && entry.path().extension() != Some(std::ffi::OsStr::new("jpg"))
+                {
+                    music.push(Some(entry.path().to_owned()));
                 }
             }
         }
@@ -52,27 +57,6 @@ fn main() {
     music.shuffle(&mut rng);
     println!("loaded {} \"songs\"", music.len());
 
-    /*
-    for i in (0..music.len()).rev() {
-        enum Err{
-            Empty,
-            File,
-        }
-        let c = || -> Result<(), Err> {
-            // we might run out of music cause we are deliting inline, this is fine.
-            let choice = &music.get(i).ok_or(Err::Empty)?;
-
-        let f = std::fs::File::open(&choice).map_err(|_| Err::File)?;
-        let rdr = BufReader::new(f);
-        let _d = rodio::Decoder::new(rdr).map_err(|_| Err::File)?;
-        Ok(())
-        };
-        match (c)() {
-            Err(Err::File) => {dbg!(music.remove(i));},
-            _ => (),
-        }
-    }
-    */
     println!("checked all songs");
     println!("opening audio output");
     let (_stream, stream_handle) = rodio::OutputStream::try_default()
@@ -80,67 +64,168 @@ fn main() {
     let mut sink = rodio::Sink::try_new(&stream_handle).expect("could not create sink");
     println!("audio output opened");
 
-    use std::io::BufRead;
-    use std::io::BufReader;
-    let mut port = BufReader::new(port);
+    #[derive(Clone, Copy)]
+    struct Hyst {
+        max: usize,
+        prechoice: usize,
+        /// value when the choice was last changed
+        prechoice_val: usize,
+        /// value of last read
+        preval: usize,
+        /// number of times the same (but changed) value has been read
+        stability: usize,
+    }
 
-    // wage has valid range 0-5000
-    let mut max: usize = 5000;
-    let mut preval = 0;
-    let mut prechoice = 0;
-    let mut readbuf = String::new();
-    let mut n_changed = 0;
+    let equality_range = 1;
+    let stability_tresh = 7;
 
-    use std::io::Write;
-    port.get_mut().write(b"r").unwrap();
+    let hyst = Hyst {
+        // wage has valid range 0-5000
+        max: 5000,
+        prechoice: 0,
+        prechoice_val: 0,
+        preval: 0,
+        stability: 0,
+    };
 
-    loop {
-        readbuf.clear();
-        port.read_line(&mut readbuf).unwrap();
-        //println!("got line: {}", readbuf);
-        let err = "got invalid message from wage";
-        let w: usize = readbuf.trim().parse().expect(err);
-        if w == 8888 || w == 69_69_69_69 {
-            // special values: 8888 and 69696969
-            // are turned off and EEEE
-        } else {
-            max = max.max(w);
-            let choice = (w * (music.len() - 1)) / max;
-            let absdiff = w.max(preval) - w.min(preval);
-            if absdiff > 1 && choice != prechoice {
-                n_changed += 1;
-            } else {
-                n_changed = 0;
-            }
-            if n_changed >= 7 {
-                let choicef = &music[(music.len() - 1) - choice];
-                println!("changing song to {:?}", choicef);
-                let mut c = || -> Result<(), ()> {
-                    let f = std::fs::File::open(choicef).map_err(|_| ())?;
-                    let rdr = BufReader::new(f);
-                    let d = rodio::Decoder::new(rdr).map_err(|_| ())?;
-                    //let s = rodio::source::SineWave::new(440);
-                    let newsink =
-                        rodio::Sink::try_new(&stream_handle).expect("could not create sink");
-                    newsink.append(d);
+    let musiclen = music.len();
 
-                    sink.stop();
-                    sink = newsink;
-                    Ok(())
-                };
-                if let Err(_error) = (c)() {
-                    println!("music was not music");
-                    let r = music.remove((music.len() - 1) - choice);
-                    println!("removed {:?}", r);
+    let read_delay = std::time::Duration::from_millis(100);
+    // first remove noise
+    let iter = PortIter::new(port, read_delay)
+        .unwrap()
+        .map(|e| e.unwrap())
+        .scan(hyst, |hyst, el| {
+            hyst.max = hyst.max.max(el);
+            let absdiff = el.max(hyst.prechoice_val) - el.min(hyst.prechoice_val);
+            if absdiff > equality_range {
+                if hyst.preval == el {
+                    hyst.stability += 1;
                 } else {
-                    preval = w;
-                    prechoice = choice;
-                    n_changed = 0;
+                    hyst.stability = 0;
+                }
+                if hyst.stability > stability_tresh {
+                    let choice = (el * (musiclen - 1)) / hyst.max;
+                    if choice != hyst.prechoice {
+                        hyst.prechoice = choice;
+                        hyst.stability = 0;
+                        hyst.preval = el;
+                        return Some(Some((el, hyst.max)));
+                    }
+                }
+            }
+            Some(None)
+        });
+    // next: turn de-noised into a decoder
+    let iter = iter
+        // skip thing the denoiser denoised
+        .flatten()
+        .map(|(e, max)| {
+        let decoder;
+        // re-run until we hit actually valid music files
+        loop {
+            let base = (e * (music.len() - 1)) / max;
+            let mut delta: isize = 0;
+            let choicef;
+            let choice;
+            // search for non-deleted paths in a cyclic pattern around base choice
+            // (0, -1, 1, -2, 2...)
+            loop {
+                let modchoice = if delta > 0 {
+                    let c = base + (delta as usize);
+                    delta = -delta;
+                    c
+                } else {
+                    let c = base - (delta as usize);
+                    delta = (-delta) + 1;
+                    c
+                };
+                if let Some(Some(c)) = music.get(modchoice) {
+                    choicef = c;
+                    choice = modchoice;
+                    break;
+                }
+            }
+            // try to decode
+            let c = || -> Result<rodio::Decoder<_>, ()> {
+                let f = std::fs::File::open(choicef).map_err(|_| ())?;
+                let rdr = BufReader::new(f);
+                rodio::Decoder::new(rdr).map_err(|_| ())
+            };
+            match (c)() {
+                Ok(d) => {
+                    decoder = d;
+                    break;
+                }
+                Err(()) => {
+                    eprintln!("{:?} was not actually music", choicef);
+                    music[choice] = None;
                 }
             }
         }
+        decoder
+    });
+    // now just play the decoder
+    for decoder in iter {
+        let newsink = rodio::Sink::try_new(&stream_handle).expect("could not create sink");
+        newsink.append(decoder);
 
-        std::thread::sleep(std::time::Duration::from_millis(100));
-        port.get_mut().write(b"r").unwrap();
+        sink.stop();
+        sink = newsink;
+    }
+}
+
+#[derive(Debug)]
+enum PortIterErr {
+    Io(std::io::Error),
+    Parse(std::num::ParseIntError),
+}
+
+impl From<std::io::Error> for PortIterErr {
+    fn from(e: std::io::Error) -> Self {
+        Self::Io(e)
+    }
+}
+impl From<std::num::ParseIntError> for PortIterErr {
+    fn from(e: std::num::ParseIntError) -> Self {
+        Self::Parse(e)
+    }
+}
+
+struct PortIter<S: SerialPort> {
+    port: BufReader<S>,
+    delay: std::time::Duration,
+}
+impl<S: SerialPort> PortIter<S> {
+    fn new(mut p: S, delay: std::time::Duration) -> IoResult<Self> {
+        p.write_all(b"r")?;
+        Ok(Self {
+            port: BufReader::new(p),
+            delay,
+        })
+    }
+}
+impl<S: SerialPort> Iterator for PortIter<S> {
+    type Item = Result<usize, PortIterErr>;
+    fn next(&mut self) -> Option<Result<usize, PortIterErr>> {
+        let mut buf = String::new();
+        let r = self.port.read_line(&mut buf);
+        match r {
+            Ok(0) => return None,
+            Err(e) => return Some(Result::Err(e.into())),
+            Ok(_) => (),
+        };
+
+        let num = match buf.parse::<usize>() {
+            Err(e) => return Some(Result::Err(e.into())),
+            Ok(num) => num,
+        };
+        match self.port.get_mut().write_all(b"r") {
+            Ok(_) => (),
+            Err(e) => return Some(Result::Err(e.into())),
+        }
+
+        std::thread::sleep(self.delay);
+        Some(Result::Ok(num))
     }
 }