From 1b4a9c006da91c7f61923002415d0ea2461981af Mon Sep 17 00:00:00 2001
From: "guillem.cordoba" <guillem.cordoba@gmail.com>
Date: Tue, 15 Oct 2024 13:41:41 +0200
Subject: [PATCH] queryLiveEntriesSignal

---
 packages/signals/package.json     |  81 +++++++++++------------
 packages/signals/src/holochain.ts | 105 ++++++++++++++++++++++++++++++
 2 files changed, 144 insertions(+), 42 deletions(-)

diff --git a/packages/signals/package.json b/packages/signals/package.json
index 066126b..740405e 100644
--- a/packages/signals/package.json
+++ b/packages/signals/package.json
@@ -1,43 +1,40 @@
 {
-  "name": "@holochain-open-dev/signals",
-  "version": "0.300.7",
-  "description": "Holochain async-signals to build reusable holochain-open-dev modules",
-  "author": "guillem.cordoba@gmail.com",
-  "main": "dist/index.js",
-  "module": "dist/index.js",
-  "types": "dist/index.d.ts",
-  "files": [
-    "dist",
-    "src"
-  ],
-  "exports": {
-    ".": "./dist/index.js",
-    "./dist/*": "./dist/*"
-  },
-  "scripts": {
-    "start": "vite --open",
-    "build": "npm run lint && tsc",
-    "lint": "eslint src",
-    "test": "vitest run",
-    "prepublish": "npm run build"
-  },
-  "dependencies": {
-    "@holochain-open-dev/utils": "^0.300.2",
-    "@holochain/client": "^0.17.1",
-    "@shoelace-style/shoelace": "^2.11.2",
-    "async-signals": "^0.1.10",
-    "lit-signal-watcher": "^0.1.1",
-    "signal-polyfill": "^0.1.1"
-  },
-  "devDependencies": {
-    "@types/lodash-es": "^4.17.6",
-    "js-base64": "^3.7.7",
-    "typescript": "^5.4.0",
-    "vite": "^4.1.1",
-    "vitest": "^1.5.0"
-  },
-  "publishConfig": {
-    "access": "public"
-  },
-  "type": "module"
-}
\ No newline at end of file
+	"name": "@holochain-open-dev/signals",
+	"version": "0.300.8",
+	"description": "Holochain async-signals to build reusable holochain-open-dev modules",
+	"author": "guillem.cordoba@gmail.com",
+	"main": "dist/index.js",
+	"module": "dist/index.js",
+	"types": "dist/index.d.ts",
+	"files": ["dist", "src"],
+	"exports": {
+		".": "./dist/index.js",
+		"./dist/*": "./dist/*"
+	},
+	"scripts": {
+		"start": "vite --open",
+		"build": "npm run lint && tsc",
+		"lint": "eslint src",
+		"test": "vitest run",
+		"prepublish": "npm run build"
+	},
+	"dependencies": {
+		"@holochain-open-dev/utils": "^0.300.2",
+		"@holochain/client": "^0.17.1",
+		"@shoelace-style/shoelace": "^2.11.2",
+		"async-signals": "^0.1.10",
+		"lit-signal-watcher": "^0.1.1",
+		"signal-polyfill": "^0.1.1"
+	},
+	"devDependencies": {
+		"@types/lodash-es": "^4.17.6",
+		"js-base64": "^3.7.7",
+		"typescript": "^5.4.0",
+		"vite": "^4.1.1",
+		"vitest": "^1.5.0"
+	},
+	"publishConfig": {
+		"access": "public"
+	},
+	"type": "module"
+}
diff --git a/packages/signals/src/holochain.ts b/packages/signals/src/holochain.ts
index eba97e7..a3405c0 100644
--- a/packages/signals/src/holochain.ts
+++ b/packages/signals/src/holochain.ts
@@ -837,3 +837,108 @@ export function deletedLinksSignal<
 
 	return signal;
 }
+
+// Keeps an up to date list of the entries in the agent's source chain for the given entry type
+export function queryLiveEntriesSignal<
+	T,
+	S extends ActionCommittedSignal<any, any> & any,
+>(
+	client: ZomeClient<S>,
+	queryEntries: () => Promise<Array<EntryRecord<T>>>,
+	entry_type: string,
+	pollIntervalMs: number = 20_000,
+): AsyncSignal<Array<EntryRecord<T>>> {
+	let active = false;
+	let unsubs: () => void | undefined;
+	let queriedEntries: Array<EntryRecord<T>> | undefined;
+	const signal = new Signal.State<AsyncResult<Array<EntryRecord<T>>>>(
+		{ status: 'pending' },
+		{
+			[Signal.subtle.watched]: () => {
+				active = true;
+				const fetch = async () => {
+					if (!active) return;
+
+					const nQueriedEntries = await queryEntries().finally(() => {
+						if (active) {
+							setTimeout(() => fetch(), pollIntervalMs);
+						}
+					});
+					if (
+						queriedEntries === undefined ||
+						!areArrayHashesEqual(
+							queriedEntries.map(r => r.actionHash),
+							nQueriedEntries.map(r => r.actionHash),
+						)
+					) {
+						queriedEntries = nQueriedEntries;
+						signal.set({
+							status: 'completed',
+							value: queriedEntries,
+						});
+					}
+				};
+				fetch().catch(error => {
+					signal.set({
+						status: 'error',
+						error,
+					});
+				});
+				unsubs = client.onSignal(async originalSignal => {
+					if (!active) return;
+					if (!(originalSignal as ActionCommittedSignal<any, any>).type) return;
+					const hcSignal = originalSignal as ActionCommittedSignal<any, any>;
+
+					if (
+						hcSignal.type === 'EntryCreated' &&
+						hcSignal.app_entry.type === entry_type
+					) {
+						const newEntry = new EntryRecord<T>({
+							entry: {
+								Present: {
+									entry_type: 'App',
+									entry: encode(hcSignal.app_entry),
+								},
+							},
+							signed_action: hcSignal.action,
+						});
+						if (!queriedEntries) queriedEntries = [];
+						queriedEntries.push(newEntry);
+						signal.set({
+							status: 'completed',
+							value: queriedEntries,
+						});
+					} else if (hcSignal.type === 'EntryDeleted') {
+						if (
+							queriedEntries?.find(
+								e =>
+									e.actionHash.toString() ===
+									hcSignal.action.hashed.content.deletes_address.toString(),
+							)
+						) {
+							queriedEntries = queriedEntries.filter(
+								e =>
+									e.actionHash.toString() !==
+									hcSignal.action.hashed.content.deletes_address.toString(),
+							);
+							signal.set({
+								status: 'completed',
+								value: queriedEntries,
+							});
+						}
+					}
+				});
+			},
+			[Signal.subtle.unwatched]: () => {
+				signal.set({
+					status: 'pending',
+				});
+				active = false;
+				queriedEntries = undefined;
+				unsubs();
+			},
+		},
+	);
+
+	return signal;
+}