From 665f5009258adee92643c40f8a65a42b2f23541b Mon Sep 17 00:00:00 2001
From: JustAdumbPrsn <73780892+JustAdumbPrsn@users.noreply.github.com>
Date: Mon, 9 Mar 2026 22:28:03 +0530
Subject: [PATCH] feat: Implement Zen Library data backend (#12701)

---
 src/zen/library/ZenLibrarySections.mjs | 169 +++++++++++++++++++++----
 1 file changed, 142 insertions(+), 27 deletions(-)

diff --git a/src/zen/library/ZenLibrarySections.mjs b/src/zen/library/ZenLibrarySections.mjs
index 2b6b56099..b33336a86 100644
--- a/src/zen/library/ZenLibrarySections.mjs
+++ b/src/zen/library/ZenLibrarySections.mjs
@@ -7,32 +7,38 @@ import { MozLitElement } from "chrome://global/content/lit-utils.mjs";
 
 let lazy = {};
 
+ChromeUtils.defineESModuleGetters(lazy, {
+  Downloads: "resource://gre/modules/Downloads.sys.mjs",
+  DownloadHistory: "resource://gre/modules/DownloadHistory.sys.mjs",
+  DownloadUtils: "resource://gre/modules/DownloadUtils.sys.mjs",
+  PlacesQuery: "resource://gre/modules/PlacesQuery.sys.mjs",
+});
+
 ChromeUtils.defineLazyGetter(lazy, "l10n", function () {
-  return new Localization(
-    ["browser/zen-library.ftl"],
-    true
-  );
+  return new Localization(["browser/zen-library.ftl"], true);
 });
 
 class LibrarySection extends MozLitElement {
   static largeContent = false;
 
   static get id() {
-    throw new Error("Unimplemented");
+    throw new Error("LibrarySection subclass must define a static `id`.");
   }
 
   static get label() {
-    throw new Error("Unimplemented");
+    throw new Error("LibrarySection subclass must define a static `label`.");
   }
 }
 
 class SearchSection extends LibrarySection {
   static properties = {
     searchTerm: { type: String },
+    isEmpty: { type: Boolean },
   };
 
   connectedCallback() {
     this.searchTerm = "";
+    this.isEmpty = false;
     super.connectedCallback();
   }
 
@@ -42,12 +48,15 @@ class SearchSection extends LibrarySection {
   }
 
   renderSearchResults() {
-    return html`${this.searchTerm}`;
+    return html``;
   }
 
   render() {
     return html`
-      <link rel="stylesheet" href="chrome://browser/content/zen-styles/zen-library.css" />
+      <link
+        rel="stylesheet"
+        href="chrome://browser/content/zen-styles/zen-library.css"
+      />
       <hbox class="search-section">
         <image src="chrome://browser/skin/zen-icons/search-glass.svg" />
         <input
@@ -58,30 +67,136 @@ class SearchSection extends LibrarySection {
           .value=${this.searchTerm}
         />
       </hbox>
-      <div class="search-results">
-        ${this.renderSearchResults()}
-      </div>
+      <div class="search-results">${this.renderSearchResults()}</div>
     `;
   }
 }
 
+// History section
+class ZenLibraryHistorySection extends SearchSection {
+  static id = "history";
+  static label = "library-history-section-title";
+
+  #placesQuery = null;
+  #history = null;
+
+  renderSearchResults() {
+    if (this.isEmpty) {
+      return html`<div class="empty-state">
+        ${lazy.l10n.formatValueSync("library-history-empty")}
+      </div>`;
+    }
+    return html`${this.searchTerm}`;
+  }
+
+  async connectedCallback() {
+    super.connectedCallback();
+    try {
+      this.#placesQuery = new lazy.PlacesQuery();
+      this.#history = await this.#placesQuery.getHistory();
+      this.isEmpty = this.#history.size === 0;
+      this.#placesQuery.observeHistory((newHistory) => {
+        this.#history = newHistory;
+        this.isEmpty = this.#history.size === 0;
+        this.requestUpdate();
+      });
+      this.requestUpdate();
+    } catch (ex) {
+      console.error("Zen Library: Failed to initialize history section.", ex);
+    }
+  }
+
+  disconnectedCallback() {
+    super.disconnectedCallback();
+    this.#placesQuery?.close();
+    this.#placesQuery = null;
+    this.#history = null;
+  }
+}
+
+// Downloads section
+class ZenLibraryDownloadsSection extends SearchSection {
+  static id = "downloads";
+  static label = "library-downloads-section-title";
+
+  #downloadList = null;
+  #downloads = [];
+  #downloadsView = null;
+  #batchLoading = false;
+
+  renderSearchResults() {
+    if (this.isEmpty) {
+      return html`<div class="empty-state">
+        ${lazy.l10n.formatValueSync("library-downloads-empty")}
+      </div>`;
+    }
+    return html`${this.searchTerm}`;
+  }
+
+  async connectedCallback() {
+    super.connectedCallback();
+    try {
+      this.#downloadList = await lazy.DownloadHistory.getList({
+        type: lazy.Downloads.PUBLIC,
+      });
+      this.#downloadsView = {
+        onDownloadAdded: (dl) => {
+          // During the initial batch replay addView fires onDownloadAdded for
+          // every existing download oldest-first, so we push to preserve order.
+          // After init, new downloads are unshifted to the front.
+          if (this.#batchLoading) {
+            this.#downloads.push(dl);
+          } else {
+            this.#downloads.unshift(dl);
+            this.isEmpty = false;
+            this.requestUpdate();
+          }
+        },
+        onDownloadBatchEnded: () => {
+          this.#batchLoading = false;
+          this.isEmpty = this.#downloads.length === 0;
+          this.requestUpdate();
+        },
+        onDownloadChanged: (dl) => {
+          this.requestUpdate();
+        },
+        onDownloadRemoved: (dl) => {
+          this.#downloads = this.#downloads.filter((d) => d !== dl);
+          this.isEmpty = this.#downloads.length === 0;
+          this.requestUpdate();
+        },
+      };
+      this.#batchLoading = true;
+      this.#downloadList.addView(this.#downloadsView);
+    } catch (ex) {
+      console.error("Zen Library: Failed to initialize downloads section.", ex);
+    }
+  }
+
+  disconnectedCallback() {
+    super.disconnectedCallback();
+    if (this.#downloadList && this.#downloadsView) {
+      this.#downloadList.removeView(this.#downloadsView);
+    }
+    this.#downloadList = null;
+    this.#downloadsView = null;
+    this.#downloads = [];
+  }
+}
+
+// Spaces section
+class ZenLibrarySpacesSection extends LibrarySection {
+  static largeContent = true;
+  static id = "spaces";
+  static label = "library-spaces-section-title";
+}
+
 export const ZenLibrarySections = {
-  history: class extends SearchSection {
-    static id = "history";
-    static label = "library-history-section-title";
-  },
-  downloads: class extends SearchSection {
-    static id = "downloads";
-    static label = "library-downloads-section-title";
-  },
-  spaces: class extends LibrarySection {
-    static largeContent = true;
-    static id = "spaces";
-    static label = "library-spaces-section-title";
-  },
+  history: ZenLibraryHistorySection,
+  downloads: ZenLibraryDownloadsSection,
+  spaces: ZenLibrarySpacesSection,
 };
 
-for (const section of Object.values(ZenLibrarySections)) {
-  customElements.define(`zen-library-section-${section.id}`, section)
-  ;
+for (const Section of Object.values(ZenLibrarySections)) {
+  customElements.define(`zen-library-section-${Section.id}`, Section);
 }