Implement barometric pressure trend monitoring and visualization

1 files changed, 108 insertions, 0 deletions

diff --git a/android-app/app/src/main/temp/HeadingDataProcessor.kt b/android-app/app/src/main/temp/HeadingDataProcessor.kt
new file mode 100755
index 0000000..7625f90
--- /dev/null
+++ b/android-app/app/src/main/temp/HeadingDataProcessor.kt
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+package org.terst.nav.temp // Temporarily placing in 'temp' due to permissions
+
+import android.hardware.GeomagneticField
+import android.location.Location
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.update
+import java.util.Date
+
+/**
+ * Data class representing processed heading information.
+ * @param trueHeading The heading relative to true North (0-359.9 degrees).
+ * @param magneticHeading The heading relative to magnetic North (0-359.9 degrees).
+ * @param magneticVariation The difference between true and magnetic North at the current location (+E, -W).
+ * @param cog Course Over Ground (0-359.9 degrees).
+ */
+data class HeadingInfo(
+    val trueHeading: Float,
+    val magneticHeading: Float,
+    val magneticVariation: Float,
+    val cog: Float
+)
+
+/**
+ * Processor for handling heading data, including magnetic variation calculations
+ * using the Android GeomagneticField.
+ */
+class HeadingDataProcessor {
+
+    private val _headingInfoFlow = MutableStateFlow(HeadingInfo(0f, 0f, 0f, 0f))
+    val headingInfoFlow: StateFlow<HeadingInfo> = _headingInfoFlow.asStateFlow()
+
+    private var currentLatitude: Double = 0.0
+    private var currentLongitude: Double = 0.0
+    private var currentAltitude: Double = 0.0
+
+    /**
+     * Updates the current geographic location for magnetic variation calculations.
+     */
+    fun updateLocation(latitude: Double, longitude: Double, altitude: Double) {
+        currentLatitude = latitude
+        currentLongitude = longitude
+        currentAltitude = altitude
+        // Recalculate magnetic variation if location changes
+        updateHeadingInfo(_headingInfoFlow.value.trueHeading, _headingInfoFlow.value.cog, true)
+    }
+
+    /**
+     * Processes a new true heading and Course Over Ground (COG) value.
+     * @param newTrueHeading The new true heading in degrees.
+     * @param newCog The new COG in degrees.
+     */
+    fun updateTrueHeadingAndCog(newTrueHeading: Float, newCog: Float) {
+        updateHeadingInfo(newTrueHeading, newCog, true)
+    }
+
+    /**
+     * Processes a new magnetic heading and Course Over Ground (COG) value.
+     * @param newMagneticHeading The new magnetic heading in degrees.
+     * @param newCog The new COG in degrees.
+     */
+    fun updateMagneticHeadingAndCog(newMagneticHeading: Float, newCog: Float) {
+        updateHeadingInfo(newMagneticHeading, newCog, false)
+    }
+
+    private fun updateHeadingInfo(heading: Float, cog: Float, isTrueHeadingInput: Boolean) {
+        val magneticVariation = calculateMagneticVariation()
+        val (finalTrueHeading, finalMagneticHeading) = if (isTrueHeadingInput) {
+            Pair(heading, (heading - magneticVariation + 360) % 360)
+        } else {
+            Pair((heading + magneticVariation + 360) % 360, heading)
+        }
+
+        _headingInfoFlow.update {
+            it.copy(
+                trueHeading = finalTrueHeading,
+                magneticHeading = finalMagneticHeading,
+                magneticVariation = magneticVariation,
+                cog = cog
+            )
+        }
+    }
+
+    /**
+     * Calculates the magnetic variation (declination) for the current location.
+     * @return Magnetic variation in degrees (+E, -W).
+     */
+    private fun calculateMagneticVariation(): Float {
+        // GeomagneticField requires current time in milliseconds
+        val currentTimeMillis = System.currentTimeMillis()
+
+        // Create a dummy Location object to get altitude if only lat/lon are updated
+        // GeomagneticField needs altitude, using 0 if not provided
+        val geoField = GeomagneticField(
+            currentLatitude.toFloat(),
+            currentLongitude.toFloat(),
+            currentAltitude.toFloat(), // Altitude in meters
+            currentTimeMillis
+        )
+        return geoField.declination // Declination is the magnetic variation
+    }
+
+    // Helper function to normalize angles (0-359.9) - though modulo handles this for positive floats
+    private fun normalizeAngle(angle: Float): Float {
+        return (angle % 360 + 360) % 360
+    }
+}