add wpm calculation and cute puppygirl animations for the oled

src/wpm.rs

@@ -0,0 +1,55 @@
+use embassy_sync::{blocking_mutex::raw::ThreadModeRawMutex, channel::Channel};
+
+// Channel for sending WPM data
+pub static WPM_CHANNEL: Channel<ThreadModeRawMutex, u64, 32> = Channel::new();
+
+pub struct BucketWpmTracker {
+    buckets: [u8; 15],  // 15 one-second buckets
+    current_second: u64,
+}
+
+impl BucketWpmTracker {
+    pub fn new() -> Self {
+        Self {
+            buckets: [0; 15],
+            current_second: 0,
+        }
+    }
+
+    pub fn add_keypress(&mut self, timestamp_ms: u64) {
+        let second = timestamp_ms / 1000;
+        let bucket_idx = (second % 15) as usize;
+
+        // On new second, clear old buckets
+        if second != self.current_second {
+            let seconds_elapsed = second.saturating_sub(self.current_second).min(15);
+            for i in 0..seconds_elapsed {
+                let idx = ((self.current_second + i + 1) % 15) as usize;
+                self.buckets[idx] = 0;
+            }
+            self.current_second = second;
+        }
+
+        self.buckets[bucket_idx] = self.buckets[bucket_idx].saturating_add(1);
+    }
+
+    pub fn calculate_wpm(&mut self, current_time_ms: u64) -> u64 {
+        let current_second = current_time_ms / 1000;
+
+        // Clear buckets older than 15 seconds
+        if current_second != self.current_second {
+            let seconds_elapsed = current_second.saturating_sub(self.current_second).min(15);
+            for i in 0..seconds_elapsed {
+                let idx = ((self.current_second + i + 1) % 15) as usize;
+                self.buckets[idx] = 0;
+            }
+            self.current_second = current_second;
+        }
+
+        let total_chars: u32 = self.buckets.iter().map(|&x| x as u32).sum();
+
+        // extrapolate 15s of data to 60s
+        // WPM = (chars / 5 chars per word) * (60 seconds / 15 seconds)
+        ((total_chars as f64 * 4f64) / 5f64) as u64
+    }
+}