From 6d19fdb66e782b2a18edfb94541e08dd5ce6158f Mon Sep 17 00:00:00 2001
From: Derrick Hammer <derrick@derrickhammer.com>
Date: Fri, 17 Nov 2023 04:57:15 -0500
Subject: [PATCH] feat: add StorageLocationProvider

---
 src/storage.ts | 138 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)

diff --git a/src/storage.ts b/src/storage.ts
index 1b6c31a..a8835f9 100644
--- a/src/storage.ts
+++ b/src/storage.ts
@@ -1,3 +1,7 @@
+import { S5Node } from "#node.js";
+import { Multihash } from "#multihash.js";
+import NodeId from "#nodeId.js";
+
 export default class StorageLocation {
   type: number;
   parts: string[];
@@ -29,3 +33,137 @@ export default class StorageLocation {
     }, expiry: ${expiryDate.toISOString()})`;
   }
 }
+
+class StorageLocationProvider {
+  private node: S5Node;
+  private hash: Multihash;
+  private types: number[];
+
+  private static readonly storageLocationTypeFull: number = 0; // Example value, adjust as necessary
+  private readonly timeoutDuration: number = 60000; // Duration in milliseconds
+
+  private availableNodes: NodeId[] = [];
+  private uris: Map<NodeId, StorageLocation> = new Map<
+    NodeId,
+    StorageLocation
+  >();
+
+  private timeout?: Date;
+  private isTimedOut: boolean = false;
+
+  constructor(
+    node: S5Node,
+    hash: Multihash,
+    types: number[] = [StorageLocationProvider.storageLocationTypeFull],
+  ) {
+    this.node = node;
+    this.hash = hash;
+    this.types = types;
+  }
+
+  async start(): Promise<void> {
+    this.uris = new Map(
+      await this.node.getCachedStorageLocations(this.hash, this.types),
+    );
+
+    this.availableNodes = Array.from(this.uris.keys());
+    this.node.services.p2p.sortNodesByScore(this.availableNodes);
+
+    this.timeout = new Date(Date.now() + this.timeoutDuration);
+
+    let requestSent = false;
+
+    while (true) {
+      const newUris = new Map(
+        await this.node.getCachedStorageLocations(this.hash, this.types),
+      );
+
+      if (
+        this.availableNodes.length === 0 &&
+        newUris.size < 2 &&
+        !requestSent
+      ) {
+        this.node.services.p2p.sendHashRequest(this.hash, this.types);
+        requestSent = true;
+      }
+
+      let hasNewNode = false;
+
+      for (const [key, value] of newUris) {
+        if (!this.uris.has(key) || this.uris.get(key) !== value) {
+          this.uris.set(key, value);
+          if (!this.availableNodes.includes(key)) {
+            this.availableNodes.push(key);
+            hasNewNode = true;
+          }
+        }
+      }
+
+      if (hasNewNode) {
+        this.node.services.p2p.sortNodesByScore(this.availableNodes);
+      }
+
+      await new Promise((resolve) => setTimeout(resolve, 10));
+
+      if (new Date() > this.timeout) {
+        this.isTimedOut = true;
+        return;
+      }
+
+      while (this.availableNodes.length > 0 || !this.isWaitingForUri) {
+        await new Promise((resolve) => setTimeout(resolve, 10));
+        if (new Date() > this.timeout) {
+          this.isTimedOut = true;
+          return;
+        }
+      }
+    }
+  }
+
+  private isWaitingForUri: boolean = false;
+
+  async next(): Promise<SignedStorageLocation> {
+    this.timeout = new Date(Date.now() + this.timeoutDuration);
+
+    while (true) {
+      if (this.availableNodes.length > 0) {
+        this.isWaitingForUri = false;
+        const nodeId = this.availableNodes.shift()!;
+
+        return new SignedStorageLocation(nodeId, this.uris.get(nodeId)!);
+      }
+
+      this.isWaitingForUri = true;
+
+      if (this.isTimedOut) {
+        throw new Error(
+          `Could not download raw file: Timed out after ${this.timeoutDuration}ms ${this.hash}`,
+        );
+      }
+
+      await new Promise((resolve) => setTimeout(resolve, 10));
+    }
+  }
+
+  upvote(uri: SignedStorageLocation): void {
+    this.node.services.p2p.upvote(uri.nodeId);
+  }
+
+  downvote(uri: SignedStorageLocation): void {
+    this.node.services.p2p.downvote(uri.nodeId);
+  }
+}
+
+class SignedStorageLocation {
+  nodeId: NodeId;
+  location: StorageLocation;
+
+  constructor(nodeId: NodeId, location: StorageLocation) {
+    this.nodeId = nodeId;
+    this.location = location;
+  }
+
+  toString(): string {
+    return `SignedStorageLocation(${this.location}, ${this.nodeId})`;
+  }
+}