Reorganization of library structure to better match Arduino spec (#20)

Note, this will also require to you "uninstall and reinstall" the Arduino library due to the library file location changes.

Reviewed-on: https://git.pinkduck.xyz/awonak/libGravity/pulls/20

src/analog_input.h

@@ -0,0 +1,88 @@
+/**
+ * @file analog_input.h
+ * @author Adam Wonak (https://github.com/awonak)
+ * @brief Class for interacting with analog inputs.
+ * @version 0.1
+ * @date 2025-05-23
+ *
+ * @copyright MIT - (c) 2025 - Adam Wonak - adam.wonak@gmail.com
+ *
+ */
+#ifndef ANALOG_INPUT_H
+#define ANALOG_INPUT_H
+
+const int MAX_INPUT = (1 << 10) - 1;  // Max 10 bit analog read resolution.
+
+// estimated default calibration value
+const int CALIBRATED_LOW = -566;
+const int CALIBRATED_HIGH = 512;
+
+class AnalogInput {
+   public:
+    AnalogInput() {}
+    ~AnalogInput() {}
+
+    /**
+     * Initializes a analog input object.
+     *
+     * @param pin gpio pin for the analog input.
+     */
+    void Init(uint8_t pin) {
+        pinMode(pin, INPUT);
+        pin_ = pin;
+    }
+
+    /**
+     * Read the value of the analog input and set instance state.
+     *
+     */
+    void Process() {
+        old_read_ = read_;
+        int raw = analogRead(pin_);
+        read_ = map(raw, 0, MAX_INPUT, low_, high_);
+        read_ = constrain(read_ - offset_, -512, 512);
+        if (inverted_) read_ = -read_;
+    }
+
+    // Set calibration values.
+
+    void AdjustCalibrationLow(int amount) { low_ += amount; }
+
+    void AdjustCalibrationHigh(int amount) { high_ += amount; }
+
+    void SetOffset(float percent) { offset_ = -(percent)*512; }
+
+    void SetAttenuation(float percent) {
+        low_ = abs(percent) * CALIBRATED_LOW;
+        high_ = abs(percent) * CALIBRATED_HIGH;
+        inverted_ = percent < 0;
+    }
+
+    /**
+     * Get the current value of the analog input within a range of +/-512.
+     *
+     * @return read value within a range of +/-512.
+     *
+     */
+    inline int16_t Read() { return read_; }
+
+    /**
+     * Return the analog read value as voltage.
+     *
+     * @return A float representing the voltage (-5.0 to +5.0).
+     *
+     */
+    inline float Voltage() { return ((read_ / 512.0) * 5.0); }
+
+   private:
+    uint8_t pin_;
+    int16_t read_;
+    uint16_t old_read_;
+    // calibration values.
+    int offset_ = 0;
+    int low_ = CALIBRATED_LOW;
+    int high_ = CALIBRATED_HIGH;
+    bool inverted_ = false;
+};
+
+#endif