From b3166801142648675b40559a2de1ccd85bd1747c Mon Sep 17 00:00:00 2001
From: Nulo <git@nulo.in>
Date: Tue, 29 Aug 2023 20:50:09 -0300
Subject: [PATCH] breadcrumbs

---
 src/lib/breadcrumbs.ts | 48 ++++++++++++++++++++++++++++++++++++++++++
 src/lib/idbValStore.ts | 29 ++++++++++++++++++++++---
 src/lib/router.ts      | 22 ++++++++++---------
 src/views/Page.svelte  | 34 ++++++++++++++++++++++++------
 4 files changed, 113 insertions(+), 20 deletions(-)
 create mode 100644 src/lib/breadcrumbs.ts

diff --git a/src/lib/breadcrumbs.ts b/src/lib/breadcrumbs.ts
new file mode 100644
index 0000000..b4c4b7c
--- /dev/null
+++ b/src/lib/breadcrumbs.ts
@@ -0,0 +1,48 @@
+import { derived } from "svelte/store";
+import IdbValStore from "./idbValStore";
+
+export type PageParams = {
+  worldId: string;
+  pageId: string;
+};
+type WorldId = string;
+type PageId = string;
+
+class BreadcrumbsStore {
+  idb: IdbValStore<Map<WorldId, PageId[]>>;
+  idbLastWorld: IdbValStore<WorldId>;
+  constructor() {
+    this.idb = new IdbValStore("schreiben-breadcrumbs");
+    this.idbLastWorld = new IdbValStore("schreiben-last-world");
+  }
+
+  async newCrumb({ worldId, pageId }: PageParams) {
+    await this.idbLastWorld.set(worldId);
+    await this.idb.update((map) => {
+      if (!map) map = new Map();
+      let crumbs = map.get(worldId) || [];
+      if (crumbs.includes(pageId)) {
+        crumbs = crumbs.slice(0, crumbs.indexOf(pageId) + 1);
+      } else {
+        crumbs.push(pageId);
+      }
+      map.set(worldId, crumbs);
+      return map;
+    });
+  }
+
+  async lastWorldBreadcrumbs() {
+    const map = await this.idb.get();
+    const worldId = await this.idbLastWorld.get();
+    if (!worldId) return;
+    const breadcrumbs = map?.get(worldId);
+    if (!breadcrumbs) return;
+    return { worldId, breadcrumbs };
+  }
+
+  worldStore(worldId: WorldId) {
+    return derived(this.idb, (map) => map?.get(worldId) || []);
+  }
+}
+
+export default new BreadcrumbsStore();
diff --git a/src/lib/idbValStore.ts b/src/lib/idbValStore.ts
index b3ceb2c..e478d4e 100644
--- a/src/lib/idbValStore.ts
+++ b/src/lib/idbValStore.ts
@@ -1,14 +1,37 @@
-import { get, set } from "idb-keyval";
+import { get, set, update } from "idb-keyval";
 
 export default class IdbValStore<T> {
   name: string;
+  subscriptors: ((val: T) => void)[];
   constructor(name: string) {
     this.name = name;
+    this.subscriptors = [];
   }
   get(): Promise<T | undefined> {
     return get<T>(this.name);
   }
-  set(val: T): Promise<void> {
-    return set(this.name, val);
+  async set(val: T): Promise<void> {
+    await set(this.name, val);
+    this.push(val);
+  }
+  async update(updater: (val: T | undefined) => T): Promise<void> {
+    let newVal: T | undefined = undefined;
+    await update(this.name, (val) => (newVal = updater(val)));
+    if (newVal === undefined) throw new Error("what the fuck");
+    this.push(newVal);
+  }
+
+  private push(val: T) {
+    for (const sub of this.subscriptors) sub(val);
+  }
+  subscribe(subscription: (value: T | undefined) => void): () => void {
+    this.subscriptors.push(subscription);
+    (async () => {
+      const val = await this.get();
+      if (this.subscriptors.includes(subscription)) subscription(val);
+    })();
+    return () => {
+      this.subscriptors = this.subscriptors.filter((s) => s !== subscription);
+    };
   }
 }
diff --git a/src/lib/router.ts b/src/lib/router.ts
index 5bfe4e3..783b748 100644
--- a/src/lib/router.ts
+++ b/src/lib/router.ts
@@ -1,6 +1,5 @@
 import navaid from "navaid";
 import { writable } from "svelte/store";
-import { inject } from "regexparam";
 
 import ChooseWorld from "../views/ChooseWorld.svelte";
 import CreateWorld from "../views/CreateWorld.svelte";
@@ -9,9 +8,8 @@ import NotFound from "../views/NotFound.svelte";
 import Page from "../views/Page.svelte";
 import ShareWorld from "../views/ShareWorld.svelte";
 import { routes } from "./routes";
-import IdbValStore from "./idbValStore";
-
-export const lastPageStore = new IdbValStore("schreiben-last-page");
+import breadcrumbs, { type PageParams } from "./breadcrumbs";
+import { inject } from "regexparam";
 
 export const currentRoute = writable<{
   // XXX: in lack of a better type for Svelte components
@@ -34,15 +32,19 @@ router.on(routes.ShareWorld, (params) =>
 router.on(routes.JoinWorld, (params) =>
   currentRoute.set({ component: JoinWorld, params }),
 );
-router.on(routes.Page, (params) =>
-  currentRoute.set({ component: Page, params }),
-);
+router.on(routes.Page, (params) => {
+  currentRoute.set({ component: Page, params });
+  breadcrumbs.newCrumb(params as PageParams);
+});
 
 async function setRouteToLastPage() {
   if (location.pathname === "/") {
-    const lastPage = await lastPageStore.get();
-    if (lastPage) {
-      router.route(inject(routes.Page, lastPage));
+    const lastWorldBreadcrumbs = await breadcrumbs.lastWorldBreadcrumbs();
+    if (lastWorldBreadcrumbs) {
+      const { worldId, breadcrumbs } = lastWorldBreadcrumbs;
+      for (const crumb of breadcrumbs) {
+        router.route(inject(routes.Page, { worldId, pageId: crumb }));
+      }
     }
   }
 }
diff --git a/src/views/Page.svelte b/src/views/Page.svelte
index f28abf7..a8d9e4b 100644
--- a/src/views/Page.svelte
+++ b/src/views/Page.svelte
@@ -1,18 +1,21 @@
 <script lang="ts">
   import type { XmlFragment } from "yjs";
   import { inject } from "regexparam";
+  import ChevronRight from "eva-icons/fill/svg/chevron-right.svg";
   import Editor from "../editor/Editor.svelte";
   import { getWorldPage, getWorldY, type WorldY } from "../lib/doc";
   import { routes } from "../lib/routes";
   import { loadWorlds } from "../lib/worldStorage";
-  import { lastPageStore } from "../lib/router";
+  import breadcrumbs from "../lib/breadcrumbs";
 
   export let worldId: string;
   export let pageId: string;
 
+  $: pageBreadcrumbs = breadcrumbs.worldStore(worldId);
+
   async function loadDoc(
     worldId: string,
-    pageId: string
+    pageId: string,
   ): Promise<{ worldY: WorldY; doc: XmlFragment }> {
     const worlds = await loadWorlds();
     const worldIdentifier = worlds.find((w) => w.room === worldId);
@@ -33,11 +36,6 @@
       })
       .catch((error) => (state = { error }));
   }
-
-  async function saveLastPage() {
-    await lastPageStore.set({ worldId, pageId });
-  }
-  saveLastPage();
 </script>
 
 <nav>
@@ -52,6 +50,28 @@
       </li>
     </ul>
   </details>
+
+  <!-- https://devdojo.com/pines/docs/breadcrumbs -->
+  <div
+    class="flex justify-between rounded-md border border-neutral-200/60 px-3.5 py-1"
+  >
+    <ol
+      class="mb-3 inline-flex items-center space-x-1 text-xs text-neutral-500 sm:mb-0 [&_.active-breadcrumb]:font-medium [&_.active-breadcrumb]:text-neutral-600"
+    >
+      {#each $pageBreadcrumbs as crumb, index}
+        <li>
+          <a
+            href={inject(routes.Page, { worldId, pageId: crumb })}
+            class="inline-flex items-center py-1 font-normal hover:text-neutral-900 focus:outline-none"
+            class:active-breadcrumb={crumb === pageId}>{crumb}</a
+          >
+        </li>
+        {#if index !== $pageBreadcrumbs.length - 1}
+          <ChevronRight class="h-5 w-5 fill-current text-gray-400/70" />
+        {/if}
+      {/each}
+    </ol>
+  </div>
 </nav>
 
 {#if state === "loading"}Cargando...{:else if "doc" in state}