From ee4e8cfdcf5a15ddb15792252bb4324813ef1402 Mon Sep 17 00:00:00 2001
From: Onne Gorter <onne@framer.com>
Date: Sun, 30 Jun 2024 16:52:16 +0200
Subject: [PATCH] Fixes last point of graphs.

Especially for items that don't often change state, the last state could
be essentially be ignored for quite a while, using the average of the
last series of entries instead.

Also for detailed graphs, the initial values could be off, because the
initial last value would be computed on bad data, resulting in NaN.

And no longer adds a double entry at end if graph has only one point.
---
 .../lovelace/common/graph/coordinates.ts       | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/panels/lovelace/common/graph/coordinates.ts b/src/panels/lovelace/common/graph/coordinates.ts
index 56f525196502..d075835410cf 100644
--- a/src/panels/lovelace/common/graph/coordinates.ts
+++ b/src/panels/lovelace/common/graph/coordinates.ts
@@ -22,9 +22,16 @@ const calcPoints = (
   let xRatio = width / (hours - (detail === 1 ? 1 : 0));
   xRatio = isFinite(xRatio) ? xRatio : width;
 
-  const first = history.filter(Boolean)[0];
+  let first = history.filter(Boolean)[0];
+  if (detail > 1) {
+    first = first.filter(Boolean)[0];
+  }
   let last = [average(first), lastValue(first)];
 
+  const getY = (value: number): number => {
+    return height + strokeWidth / 2 - (value - min) / yRatio;
+  };
+
   const getCoords = (item: any[], i: number, offset = 0, depth = 1) => {
     if (depth > 1 && item) {
       return item.forEach((subItem, index) =>
@@ -37,8 +44,7 @@ const calcPoints = (
     if (item) {
       last = [average(item), lastValue(item)];
     }
-    const y =
-      height + strokeWidth / 2 - ((item ? last[0] : last[1]) - min) / yRatio;
+    const y = getY(item ? last[0] : last[1]);
     return coords.push([x, y]);
   };
 
@@ -46,11 +52,7 @@ const calcPoints = (
     getCoords(history[i], i, 0, detail);
   }
 
-  if (coords.length === 1) {
-    coords[1] = [width, coords[0][1]];
-  }
-
-  coords.push([width, coords[coords.length - 1][1]]);
+  coords.push([width, getY(last[1])]);
   return coords;
 };