Implemented catching panics and displaying them on the display. Also implemented a deep-sleep based loop

src/main.rs

@@ -1,11 +1,11 @@
+use core::panic;
 use std::borrow::Cow;
 use std::str::FromStr;
 
 use chrono::{format::Fixed, DateTime, Datelike, Days, FixedOffset, NaiveTime};
 use embedded_graphics::{
-    mono_font::{MonoTextStyle, MonoTextStyleBuilder},
     prelude::{Dimensions, Point},
-    text::{Baseline, Text, TextStyleBuilder},
+    text::{Text},
     Drawable,
 };
 use epd_waveshare::{color::Color, epd7in5_v2::Epd7in5, prelude::WaveshareDisplay};
@@ -22,13 +22,20 @@ use esp_idf_svc::{
     nvs::EspDefaultNvsPartition,
     wifi::Configuration,
 };
+use esp_idf_sys::esp_deep_sleep;
 use u8g2_fonts::U8g2TextStyle;
 use untis::{Date, Lesson};
-use embedded_layout::{layout::linear::{spacing::DistributeFill, ElementSpacing, FixedMargin, LinearLayout}, prelude::*};
+use embedded_layout::{layout::linear::{spacing::DistributeFill, FixedMargin, LinearLayout}, prelude::*};
 
 type Timetable = [[Option<Lesson>;8]; 5];
 
 
+#[link_section = ".rtc.data"]
+static mut WAKEUP_COUNTER: u64 = 0;
+
+#[link_section = ".rtc.data"]
+static mut ERROR_MSG: Option<[u8; 2048]> = None;
+
 fn main() -> anyhow::Result<()> {
     // It is necessary to call this function once. Otherwise some patches to the runtime
     // implemented by esp-idf-sys might not link properly. See https://github.com/esp-rs/esp-idf-template/issues/71
@@ -49,6 +56,32 @@ fn main() -> anyhow::Result<()> {
 
     let dc = PinDriver::output(miso).unwrap();
 
+
+    std::panic::set_hook(Box::new(|panic|{
+        let msg: String = format!("{}", panic);/* if let Some(s) = panic.payload().downcast_ref::<&str>() {
+            format!("{s:?}")
+        } else if let Some(s) = panic.payload().downcast_ref::<String>() {
+            format!("{s:?}")
+        } else {
+            format!("Failed to downcast panic msg")
+        }; */
+        let msg_bytes = msg.into_bytes();
+
+        // Copy the string buffer into the array
+        let mut buffer = [0u8; 2048];
+        for i in 0..(buffer.len().min(msg_bytes.len())){
+            buffer[i] = msg_bytes[i];
+        }
+
+        unsafe{
+            ERROR_MSG = Some(buffer);
+
+            // Sleep for a second
+            esp_deep_sleep(1_000_000)
+        }
+    }));
+
+
     log::info!("Initialized pins");
 
     let config = config::Config::new();
@@ -66,13 +99,46 @@ fn main() -> anyhow::Result<()> {
 
     log::info!("Initialized spi interface");
 
+    // Initialize the draw buffer
     // Allocating on the stack makes the chip crash. We gotta put it on the heap
     let mut display = Box::new(epd_waveshare::epd7in5_v2::Display7in5::default());
     display.set_rotation(epd_waveshare::prelude::DisplayRotation::Rotate0);
 
+    unsafe {
+        WAKEUP_COUNTER += 1;
+    }
+
     let mut delay = Ets;
 
+    unsafe{
+        if let Some(error) = ERROR_MSG{
+
+            // Draw to the display
+            let text_style = U8g2TextStyle::new(u8g2_fonts::fonts::u8g2_font_7x14_mr, Color::White);
+
+            let error_label = Text::new("An error occured:", Point::zero(), &text_style);
+
+            let error_message = String::from_utf8_lossy(&error);
+            let error_message = match &error_message{
+                Cow::Borrowed(c) => *c,
+                Cow::Owned(c) => &c
+            } ;
+
+
+            let error_message_label = Text::new(error_message, Point::zero(), &text_style);
+            let mut vg = [error_label, error_message_label];
+            LinearLayout::vertical(Views::new(&mut vg))
+            .arrange()
+            .draw(&mut *display).unwrap();
+
             let mut epd7in5 = Epd7in5::new(&mut spi, busy, dc, rst, &mut delay, None).unwrap();
+            epd7in5.update_and_display_frame(&mut spi, &*display.buffer(), &mut delay)?;
+            epd7in5.sleep(&mut spi, &mut delay)?;
+
+            // Sleep for 12 hours
+            esp_deep_sleep(12*60*60*60*1000_000)
+        }
+    }
 
     // Create a file called wifi-creds.txt and write SSID and password into it separated by a line break
     let mut creds = include_str!("../wifi-creds.txt").split('\n');
@@ -115,13 +181,26 @@ fn main() -> anyhow::Result<()> {
 
     let (tt, now) = fetch_timetable(httpconnection);
 
+
+    // Render the layout
     draw_layout(&mut display, &tt, now);
-    //draw_text(&mut display, &tt[3][5].clone().unwrap().subjects.first().as_ref().unwrap().name, 5, 5);
+
+    // Actually push changes to the display
+    let mut epd7in5 = Epd7in5::new(&mut spi, busy, dc, rst, &mut delay, None).unwrap();
     epd7in5.update_and_display_frame(&mut spi, &*display.buffer(), &mut delay)?;
     epd7in5.sleep(&mut spi, &mut delay)?;
     log::info!("Completed");
 
-   Ok(())
+    wifi.disconnect().unwrap();
+    wifi.stop().unwrap();
+
+    drop(epd7in5);
+    drop(wifi);
+    drop(spi);
+
+    unsafe{
+        esp_deep_sleep(10 * 60 * 1000_000);
+    }
 }
 
 fn draw_layout(display: &mut epd_waveshare::epd7in5_v2::Display7in5, timetable: &Timetable, now: DateTime<FixedOffset>){
@@ -166,7 +245,8 @@ fn draw_layout(display: &mut epd_waveshare::epd7in5_v2::Display7in5, timetable:
 
     let columns = Views::new(&mut columns);
 
-    let time_str = format!("{}", now.format("%Y-%m-%d %H:%M"));
+    // Unsafe is needed to access static mutable variable
+    let time_str = format!("{} ({})", now.format("%Y-%m-%d %H:%M"), unsafe {WAKEUP_COUNTER});
     let time_text = Text::new(&time_str, Point::zero(), &text_style_small);
 
     let time_table_grid = LinearLayout::horizontal(columns)