Use cached consumption value

central_backend/src/energy/consumption_cache.rs

@@ -0,0 +1,85 @@
+use crate::constants;
+use crate::energy::consumption::EnergyConsumption;
+use log::log;
+
+pub struct ConsumptionCache {
+    nb_vals: usize,
+    values: Vec<EnergyConsumption>,
+}
+
+impl ConsumptionCache {
+    pub fn new(nb_vals: usize) -> Self {
+        Self {
+            nb_vals,
+            values: vec![],
+        }
+    }
+
+    pub fn add_value(&mut self, value: EnergyConsumption) {
+        if self.values.len() >= self.nb_vals {
+            self.values.remove(0);
+        }
+
+        self.values.push(value);
+    }
+
+    pub fn median_value(&self) -> EnergyConsumption {
+        if self.values.is_empty() {
+            return constants::FALLBACK_PRODUCTION_VALUE;
+        }
+
+        let mut clone = self.values.clone();
+        clone.sort();
+        let median = clone[clone.len() / 2];
+
+        log::info!("Cached consumption: {:?} / Median: {}", self.values, median);
+
+        median
+    }
+}
+
+#[cfg(test)]
+pub mod test {
+    use crate::constants;
+    use crate::energy::consumption_cache::ConsumptionCache;
+
+    #[test]
+    fn empty_vec() {
+        let cache = ConsumptionCache::new(10);
+        assert_eq!(cache.median_value(), constants::FALLBACK_PRODUCTION_VALUE);
+    }
+
+    #[test]
+    fn single_value() {
+        let mut cache = ConsumptionCache::new(10);
+        cache.add_value(-10);
+        assert_eq!(cache.median_value(), -10);
+    }
+
+    #[test]
+    fn four_values() {
+        let mut cache = ConsumptionCache::new(10);
+        cache.add_value(50);
+        cache.add_value(-10);
+        cache.add_value(-10);
+        cache.add_value(-10000);
+        assert_eq!(cache.median_value(), -10);
+    }
+
+    #[test]
+    fn many_values() {
+        let mut cache = ConsumptionCache::new(6);
+
+        for i in 0..1000 {
+            cache.add_value(-i);
+        }
+
+        cache.add_value(10);
+        cache.add_value(50);
+        cache.add_value(-10);
+        cache.add_value(-10);
+        cache.add_value(-30);
+        cache.add_value(-10000);
+        assert_eq!(cache.median_value(), -10);
+    }
+}