From eb0720c5921688a8c784046f0c0e804129004918 Mon Sep 17 00:00:00 2001
From: Raihan Ariq <202310715297@mhs.ubharajaya.ac.id>
Date: Thu, 6 Nov 2025 22:05:44 +0700
Subject: [PATCH] Kalkulasi BMI pada Fungsi calculateBMI()

---
 .../com/example/bmicalculator/MainActivity.kt | 37 +++++++++++++------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/app/src/main/java/com/example/bmicalculator/MainActivity.kt b/app/src/main/java/com/example/bmicalculator/MainActivity.kt
index 46b4ef4..c3872e0 100644
--- a/app/src/main/java/com/example/bmicalculator/MainActivity.kt
+++ b/app/src/main/java/com/example/bmicalculator/MainActivity.kt
@@ -63,7 +63,9 @@ import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import com.example.bmicalculator.ui.theme.BMICalculatorTheme
+import java.text.DecimalFormat
 import java.text.NumberFormat
+import kotlin.math.pow
 
 class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -86,12 +88,12 @@ class MainActivity : ComponentActivity() {
 fun BMICalculatorLayout() {
     var heightInput by remember { mutableStateOf("") }
     var weightInput by remember { mutableStateOf("") }
-    var unitUSC by remember { mutableStateOf(false) }
+    var unitUSC     by remember { mutableStateOf(false) }
 
-    val BmiHeight = heightInput.toDoubleOrNull() ?: 0.0
-    val BmiWeight = weightInput.toDoubleOrNull() ?: 0.0
-    val bmi = calculateBMI(BmiHeight, BmiWeight, unitUSC)
-    val category = calculateBMICategory(BmiHeight, BmiWeight, unitUSC)
+    val BmiHeight   = heightInput.toDoubleOrNull() ?: 0.0
+    val BmiWeight   = weightInput.toDoubleOrNull() ?: 0.0
+    val bmi         = calculateBMI(BmiHeight, BmiWeight, unitUSC)
+    val category    = calculateBMICategory(BmiHeight, BmiWeight, unitUSC)
 
     Column(
         modifier = Modifier
@@ -192,15 +194,28 @@ fun UnitUSCFormulaRow(
 
 /**
  * Calculates the BMI
+ * dengan Rumus SI Metrics Unit (Default)
+ * dan
+ * dengan Rumus USC Units
  *
  * Catatan: tambahkan unit test untuk kalkulasi BMI ini
  */
-private fun calculateBMI(BmiHeight: Double, BmiWeight: Double = 15.0, unitUSC: Boolean): String {
-    var bmi = BmiWeight / 100 * BmiHeight
-    if (unitUSC) {
-        bmi = kotlin.math.ceil(bmi)
+private fun calculateBMI(BmiHeight: Double, BmiWeight: Double, unitUSC: Boolean): String {
+    if (BmiHeight <= 0 || BmiWeight <= 0){
+        return "0"
     }
-    return NumberFormat.getNumberInstance().format(bmi)
+
+    val heightInMeter   = BmiHeight/100 // konversi centimeter ke meter
+    val heightInInch    = BmiHeight * 0.3937 // konversi centimeter ke inci
+    val weightInPound   = BmiWeight * 2.2046 // konversi berat badan ke pound (lbs)
+
+    var bmi = BmiWeight / heightInMeter.pow(2)
+    if (unitUSC) {
+        bmi = 703 * (weightInPound / heightInInch.pow(2))
+    }
+    
+    val df = DecimalFormat("#.#")
+    return df.format(bmi)
 }
 /**
  * Calculates the BMI Category
@@ -221,4 +236,4 @@ fun TipTimeLayoutPreview() {
     BMICalculatorTheme {
         BMICalculatorLayout()
     }
-}
\ No newline at end of file
+}