From 48658d5a552a3615eece481f01ad52ffb670ff8b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sybren=20A=2E=20St=C3=BCvel?= <sybren@stuvel.eu>
Date: Sun, 19 Mar 2023 20:08:51 +0100
Subject: [PATCH] Add a simple 'skip_initial' filter (#4582)
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* Add a simple 'skip' filter

This filter simply skips the first `send_first_at` values, then passes
everything as-is. This is quite useful when you know the first few sensor
readings should be ignored.

Example YAML:

```yaml
sensor:
  - platform: sgp30
    id: mysensor_sgp30
    eco2:
      id: mysensor_sgp30_co2
      name: "eCO₂"
      accuracy_decimals: 0
      filters:
        - skip:
            send_first_at: 41
```

* Rename the filter to `skip_initial` and simplify the schema

New usage:

```yaml
      filters:
        - skip_initial: 41
```

* Apply clang-format
---
 esphome/components/sensor/__init__.py |  6 ++++++
 esphome/components/sensor/filter.cpp  | 13 +++++++++++++
 esphome/components/sensor/filter.h    | 18 ++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/esphome/components/sensor/__init__.py b/esphome/components/sensor/__init__.py
index 821e0afac0..b63e157efb 100644
--- a/esphome/components/sensor/__init__.py
+++ b/esphome/components/sensor/__init__.py
@@ -194,6 +194,7 @@ SensorPublishAction = sensor_ns.class_("SensorPublishAction", automation.Action)
 Filter = sensor_ns.class_("Filter")
 QuantileFilter = sensor_ns.class_("QuantileFilter", Filter)
 MedianFilter = sensor_ns.class_("MedianFilter", Filter)
+SkipInitialFilter = sensor_ns.class_("SkipInitialFilter", Filter)
 MinFilter = sensor_ns.class_("MinFilter", Filter)
 MaxFilter = sensor_ns.class_("MaxFilter", Filter)
 SlidingWindowMovingAverageFilter = sensor_ns.class_(
@@ -365,6 +366,11 @@ MIN_SCHEMA = cv.All(
 )
 
 
+@FILTER_REGISTRY.register("skip_initial", SkipInitialFilter, cv.positive_not_null_int)
+async def skip_initial_filter_to_code(config, filter_id):
+    return cg.new_Pvariable(filter_id, config)
+
+
 @FILTER_REGISTRY.register("min", MinFilter, MIN_SCHEMA)
 async def min_filter_to_code(config, filter_id):
     return cg.new_Pvariable(
diff --git a/esphome/components/sensor/filter.cpp b/esphome/components/sensor/filter.cpp
index bf65ac590f..472649ebdc 100644
--- a/esphome/components/sensor/filter.cpp
+++ b/esphome/components/sensor/filter.cpp
@@ -74,6 +74,19 @@ optional<float> MedianFilter::new_value(float value) {
   return {};
 }
 
+// SkipInitialFilter
+SkipInitialFilter::SkipInitialFilter(size_t num_to_ignore) : num_to_ignore_(num_to_ignore) {}
+optional<float> SkipInitialFilter::new_value(float value) {
+  if (num_to_ignore_ > 0) {
+    num_to_ignore_--;
+    ESP_LOGV(TAG, "SkipInitialFilter(%p)::new_value(%f) SKIPPING, %u left", this, value, num_to_ignore_);
+    return {};
+  }
+
+  ESP_LOGV(TAG, "SkipInitialFilter(%p)::new_value(%f) SENDING", this, value);
+  return value;
+}
+
 // QuantileFilter
 QuantileFilter::QuantileFilter(size_t window_size, size_t send_every, size_t send_first_at, float quantile)
     : send_every_(send_every), send_at_(send_every - send_first_at), window_size_(window_size), quantile_(quantile) {}
diff --git a/esphome/components/sensor/filter.h b/esphome/components/sensor/filter.h
index b560545b76..05934a26e8 100644
--- a/esphome/components/sensor/filter.h
+++ b/esphome/components/sensor/filter.h
@@ -102,6 +102,24 @@ class MedianFilter : public Filter {
   size_t window_size_;
 };
 
+/** Simple skip filter.
+ *
+ * Skips the first N values, then passes everything else.
+ */
+class SkipInitialFilter : public Filter {
+ public:
+  /** Construct a SkipInitialFilter.
+   *
+   * @param num_to_ignore How many values to ignore before the filter becomes a no-op.
+   */
+  explicit SkipInitialFilter(size_t num_to_ignore);
+
+  optional<float> new_value(float value) override;
+
+ protected:
+  size_t num_to_ignore_;
+};
+
 /** Simple min filter.
  *
  * Takes the min of the last <send_every> values and pushes it out every <send_every>.