Finish up weight generation

src/lib/services/calculator/util.ts

@@ -1,4 +1,5 @@
 import { type Metrics } from "$lib/services/calculator/main";
+import avgWeightDataRaw from "$lib/data/avg-weights.json"
 
 // -------------------------------------------------------------------------------------------------
 // DATA MODELS 
@@ -47,8 +48,9 @@ export const minToMs = (min: number) => min * 60000;
 export const secToMs = (sec: number) => sec * 1000;
 export const msToMin = (ms: number) => ms / 60000;
 
-export const feetToCm = (feet: number) => feet * 30.48;
-export const inchesToCm = (inches: number) => inches * 2.54;
+export const ftToCm = (ft: number) => ft * 30.48;
+export const inToCm = (inches: number) => inches * 2.54;
+export const cmToIn = (cm: number) => cm / 2.54;
 
 export const msToTime = (ms: number, includeMs = false): string => {
     const minutes = Math.floor(ms / 60000);
@@ -64,4 +66,65 @@ export const msToTime = (ms: number, includeMs = false): string => {
 
 export const range = (length: number) => Array.from({ length: length }, (_, i) => i + 1);
 
+// export const getAvgWeight = (gender: Gender, age: number) => {
+//     type AvgWeightData = {
+//         metadata: {
+//             unit: StandardUnit
+//         },
+//         weights: Metrics[]
+//     }
+//     let avgWeightData = avgWeightDataRaw as AvgWeightData;
+//
+//     const avgWeights = avgWeightData.weights.filter(a => a.gender === gender);
+//
+//     let lower = avgWeights[0];           // best <= target
+//     let upper = avgWeights[0];           // best >= target
+//     let hasLower = false, hasUpper = false;
+//
+//     for (const avg of avgWeights) {
+//         if (avg.age <= age) {
+//             if (!hasLower || avg.age > lower.age) { lower = avg; hasLower = true; }
+//         }
+//         if (avg.age >= age) {
+//             if (!hasUpper || avg.age < upper.age) { upper = avg; hasUpper = true; }
+//         }
+//     }
+//
+//     // clamp to ends if one side missing
+//     if (!hasLower) lower = avgWeights[0];
+//     if (!hasUpper) upper = avgWeights[avgWeights.length - 1];
+//
+//     // lerp
+//     let ageRatio = upper === lower ? 1 : (age - lower.age) / (upper.age - lower.age);
+//     ageRatio = Math.max(0, Math.min(1, ageRatio));
+//     const interpolatedAvg = lower.weight + (upper.weight - lower.weight) * ageRatio;
+//
+//     return interpolatedAvg;
+// }
 
+export const getAvgWeight = (gender: Gender, age: number) => {
+    type AvgWeightData = {
+        metadata: {
+            unit: StandardUnit
+        },
+        weights: Metrics[]
+    }
+    let avgWeightData = avgWeightDataRaw as AvgWeightData;
+
+    const avgWeights = avgWeightData.weights.filter(a => a.gender === gender);
+    if (!avgWeights.length) throw new Error("No average weights");
+
+    const closest = {
+        diff: Math.abs(avgWeights[0].age - age),
+        avg: avgWeights[0]
+    };
+    for (const avg of avgWeights) {
+        const diff = Math.abs(avg.age - age);
+        if (diff < closest.diff) {
+            closest.diff = diff;
+            closest.avg = avg;
+        }
+    }
+
+    return closest.avg.weight;
+}