Make setting duty cycle interactive, add error handling

Cargo.lock

@@ -36,6 +36,22 @@ version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 
+[[package]]
+name = "eyre"
+version = "0.6.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7cd915d99f24784cdc19fd37ef22b97e3ff0ae756c7e492e9fbfe897d61e2aec"
+dependencies = [
+ "indenter",
+ "once_cell",
+]
+
+[[package]]
+name = "indenter"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "964de6e86d545b246d84badc0fef527924ace5134f30641c203ef52ba83f58d5"
+
 [[package]]
 name = "io-kit-sys"
 version = "0.4.1"
@@ -50,6 +66,7 @@ dependencies = [
 name = "kulifuli-host"
 version = "0.1.0"
 dependencies = [
+ "eyre",
  "serialport",
 ]
 
@@ -99,6 +116,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.21.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.32"

Cargo.toml

@@ -4,4 +4,5 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+eyre = "0.6.12"
 serialport = "4.7.2"

src/main.rs

@@ -1,33 +1,48 @@
+use eyre::{Result, bail, ensure, eyre};
 use serialport::TTYPort;
-use std::io::{Read, Write};
+use std::io::{Read, Write, stdin, stdout};
+use std::str::FromStr;
 use std::time::Duration;
 
-fn main() {
+fn main() -> Result<()> {
     let mut port = serialport::new("/dev/ttyACM0", 9600)
         .timeout(Duration::from_secs(3600))
-        .open_native()
-        .unwrap();
-
-    let duty_cycle = 39;
-    let bytes_written = port
-        .write(&[188, 92, 136, 14, 154, 39, 154, 139, duty_cycle])
-        .unwrap();
-    assert_eq!(bytes_written, 9);
+        .open_native()?;
 
     loop {
-        if let Some(response_byte) = read_byte(&mut port) {
-            println!("Response byte: {}", response_byte);
+        print!("Enter duty cycle: ");
+        stdout().flush()?;
+        let mut requested_dc = String::new();
+        stdin().read_line(&mut requested_dc)?;
+
+        if let Ok(duty_cycle) = u8::from_str(requested_dc.trim())
+            && duty_cycle <= 79
+        {
+            println!("Sending to fan controller...");
+            let bytes_written = port.write(&[188, 92, 136, 14, 154, 39, 154, 139, duty_cycle])?;
+            if bytes_written != 9 {
+                bail!("Could not write enough bytes to serial device");
+            }
+            println!("Awaiting confirmation...");
+
+            let response_byte = read_byte(&mut port)?;
+            if response_byte == duty_cycle {
+                println!("Duty cycle set succesfully");
+            }
+        } else {
+            println!("Invalid duty cycle, should be an integer between 0 and 79");
         }
+        println!();
     }
 }
 
-fn read_byte(port: &mut TTYPort) -> Option<u8> {
+fn read_byte(port: &mut TTYPort) -> Result<u8> {
     let mut response = [0];
     let read_result = port.read(&mut response);
     if let Ok(bytes_read) = read_result {
-        assert_eq!(bytes_read, 1);
-        Some(response[0])
+        ensure!(bytes_read == 1, "Could not read from serial device");
+        Ok(response[0])
     } else {
-        None
+        Err(eyre!("Could not read from serial device"))
     }
 }