From 1c1f9a6a898bb7f38ea4a7905fafa7421f89d60a Mon Sep 17 00:00:00 2001
From: Zack Arnett <arnett.zackary@gmail.com>
Date: Wed, 22 Apr 2020 05:33:49 -0400
Subject: [PATCH] Graph Footer: Cache State History (#5499)

* Cache State History for entity

* State history reset on config change

* Fetching

* reviews

* Merge fixes

* Remove file again ?
---
 .../common/graph/get-history-coordinates.ts   | 28 ---------
 .../header-footer/hui-graph-header-footer.ts  | 60 +++++++++++++++++--
 2 files changed, 54 insertions(+), 34 deletions(-)
 delete mode 100644 src/panels/lovelace/common/graph/get-history-coordinates.ts

diff --git a/src/panels/lovelace/common/graph/get-history-coordinates.ts b/src/panels/lovelace/common/graph/get-history-coordinates.ts
deleted file mode 100644
index a8d08cf4ca..0000000000
--- a/src/panels/lovelace/common/graph/get-history-coordinates.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import { fetchRecent } from "../../../../data/history";
-import { HomeAssistant } from "../../../../types";
-import { coordinates } from "./coordinates";
-
-export const getHistoryCoordinates = async (
-  hass: HomeAssistant,
-  entity: string,
-  hours: number,
-  detail: number
-): Promise<number[][]> => {
-  const endTime = new Date();
-  const startTime = new Date();
-  startTime.setHours(endTime.getHours() - hours);
-
-  const stateHistory = await fetchRecent(hass, entity, startTime, endTime);
-
-  if (stateHistory.length < 1 || stateHistory[0].length < 1) {
-    return [];
-  }
-
-  const coords = coordinates(stateHistory[0], hours, 500, detail);
-
-  if (!coords) {
-    return [];
-  }
-
-  return coords;
-};
diff --git a/src/panels/lovelace/header-footer/hui-graph-header-footer.ts b/src/panels/lovelace/header-footer/hui-graph-header-footer.ts
index b82616ba61..05f311fd83 100644
--- a/src/panels/lovelace/header-footer/hui-graph-header-footer.ts
+++ b/src/panels/lovelace/header-footer/hui-graph-header-footer.ts
@@ -9,14 +9,18 @@ import {
   TemplateResult,
 } from "lit-element";
 import { HomeAssistant } from "../../../types";
-import { getHistoryCoordinates } from "../common/graph/get-history-coordinates";
+import { HassEntity } from "home-assistant-js-websocket";
 
 import "@polymer/paper-spinner/paper-spinner";
 import "../components/hui-graph-base";
 import { LovelaceHeaderFooter } from "../types";
 import { GraphHeaderFooterConfig } from "./types";
+import { hasConfigOrEntityChanged } from "../common/has-changed";
+import { fetchRecent } from "../../../data/history";
+import { coordinates } from "../common/graph/coordinates";
 
 const MINUTE = 60000;
+const DAY = 86400000;
 
 @customElement("hui-graph-header-footer")
 export class HuiGraphHeaderFooter extends LitElement
@@ -33,6 +37,10 @@ export class HuiGraphHeaderFooter extends LitElement
 
   private _date?: Date;
 
+  private _stateHistory?: HassEntity[];
+
+  private _fetching = false;
+
   public setConfig(config: GraphHeaderFooterConfig): void {
     if (!config?.entity || config.entity.split(".")[0] !== "sensor") {
       throw new Error(
@@ -83,16 +91,25 @@ export class HuiGraphHeaderFooter extends LitElement
     `;
   }
 
-  protected firstUpdated(): void {
-    this._date = new Date();
+  protected shouldUpdate(changedProps: PropertyValues): boolean {
+    return hasConfigOrEntityChanged(this, changedProps);
   }
 
   protected updated(changedProps: PropertyValues) {
-    if (!this._config || !this.hass) {
+    if (
+      !this._config ||
+      !this.hass ||
+      (this._fetching && !changedProps.has("_config"))
+    ) {
       return;
     }
 
     if (changedProps.has("_config")) {
+      const oldConfig = changedProps.get("_config") as GraphHeaderFooterConfig;
+      if (!oldConfig || oldConfig.entity !== this._config.entity) {
+        this._stateHistory = [];
+      }
+
       this._getCoordinates();
     } else if (Date.now() - this._date!.getTime() >= MINUTE) {
       this._getCoordinates();
@@ -100,14 +117,45 @@ export class HuiGraphHeaderFooter extends LitElement
   }
 
   private async _getCoordinates(): Promise<void> {
-    this._coordinates = await getHistoryCoordinates(
+    this._fetching = true;
+    const endTime = new Date();
+    const startTime =
+      !this._date || !this._stateHistory?.length
+        ? new Date(
+            new Date().setHours(
+              endTime.getHours() - this._config!.hours_to_show!
+            )
+          )
+        : this._date;
+
+    if (this._stateHistory!.length) {
+      this._stateHistory = this._stateHistory!.filter(
+        (entity) =>
+          endTime.getTime() - new Date(entity.last_changed).getTime() <= DAY
+      );
+    }
+
+    const stateHistory = await fetchRecent(
       this.hass!,
       this._config!.entity,
+      startTime,
+      endTime,
+      Boolean(this._stateHistory!.length)
+    );
+
+    if (stateHistory.length && stateHistory[0].length) {
+      this._stateHistory!.push(...stateHistory[0]);
+    }
+
+    this._coordinates = coordinates(
+      this._stateHistory,
       this._config!.hours_to_show!,
+      500,
       this._config!.detail!
     );
 
-    this._date = new Date();
+    this._date = endTime;
+    this._fetching = false;
   }
 
   static get styles(): CSSResult {