Add endpoints for Dexscreener support #422

src/typescript/frontend/src/app/dexscreener/README.md

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+# DEX Screener Adapter Specs
+
+<!-- markdownlint-disable -->
+
+<b>Taken from https://dexscreener.notion.site/DEX-Screener-Adapter-Specs-cc1223cdf6e74a7799599106b65dcd0e </b>
+
+<!-- markdownlint-enable -->
+
+v1.1 / Dec 2023
+
+The DEX Screener Adapter is a set of HTTP endpoints that allows DEX Screener to
+track historical and real-time data for any Partner Decentralized Exchange.
+Adapters are responsible for supplying accurate and up-to-date data, whereas DEX
+Screener handles all data ingestion, processing and serving.
+
+## Overview
+
+- The DEX Screener Indexer queries Adapter endpoints to continuously index
+  events as they become available, in chunks of one or many blocks at a time.
+  Each block is only queried once, so caution must be taken to ensure that all
+  returned data is accurate at the time of indexing.
+- Adapters are to be deployed, served and maintained by the Partner
+- If adapter endpoints become unreachable indexing will halt and automatically
+  resume once they become available again
+- The Indexer allows for customizable rate limits and block chunk size to ensure
+  Adapter endpoints are not overloaded
+
+## Endpoints
+
+- An in-depth explanation of the schemas expected for each endpoint is described
+  on the `Schemas` section below
+
+- Numbers for amounts and price can be both `number` and `string`. Strings are
+  more suitable when dealing with extremely small or extremely large numbers
+  that can't be accurately serialized into JSON numbers.
+
+- Indexing will halt if schemas are invalid or contain unexpected values
+  (i.e.: `swapEvent.priceNative=0` or `pair.name=""`)

src/typescript/frontend/src/app/dexscreener/asset.ts

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+/***
+ Request: GET /asset?id=:string
+
+ Response Schema:
+ // interface AssetResponse {
+ //  asset: Asset;
+ // }
+
+ Example Response:
+ // {
+ //   "asset": {
+ //     "id": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
+ //     "name": "Wrapped Ether",
+ //     "symbol": "WETH",
+ //     "totalSupply": 10000000,
+ //     "circulatingSupply": 900000,
+ //     "coinGeckoId": "ether",
+ //     "coinMarketCapId": "ether"
+ //   }
+ // }
+ **/
+
+import { type NextRequest, NextResponse } from "next/server";
+import { toMarketEmojiData } from "@sdk/emoji_data";
+import { EMOJICOIN_SUPPLY } from "@sdk/const";
+import { calculateCirculatingSupply } from "@sdk/markets";
+import { symbolEmojiStringToArray } from "./util";
+import { fetchMarketState } from "@/queries/market";
+
+/**
+ * - In most cases, asset ids will correspond to contract addresses. Ids are case-sensitive.
+ * - All `Asset` props aside from `id` may be mutable. The Indexer will periodically query assets for their most
+ * up-to-date info
+ * - `totalSupply` is optional but DEX Screener cannot calculate FDV/Market Cap if not available
+ * - `circulatingSupply` is optional but DEX Screener may not be able to show accurate market cap if not available
+ * - `coinGeckoId` and `coinMarketCapId` are optional but may be used for displaying additional token information such
+ * as image, description and self-reported/off-chain circulating supply
+ * - `metadata` includes any optional auxiliary info not covered in the default schema and not required in most cases
+ */
+export interface Asset {
+  id: string;
+  name: string;
+  symbol: string;
+  totalSupply: number | string;
+  circulatingSupply?: number | string;
+  coinGeckoId?: string;
+  coinMarketCapId?: string;
+  metadata?: Record<string, string>;
+}
+
+export interface AssetResponse {
+  asset: Asset;
+}
+
+/**
+ * Fetches an asset by a string of the emojis that represent the asset
+ * @param assetId
+ */
+export async function getAsset(assetId: string): Promise<Asset> {
+  const marketEmojiData = toMarketEmojiData(assetId);
+  const symbolEmojis = symbolEmojiStringToArray(assetId);
+  const marketState = await fetchMarketState({ searchEmojis: symbolEmojis });
+
+  const circulatingSupply: { circulatingSupply?: number | string } = {};
+  if (marketState && marketState.state) {
+    circulatingSupply.circulatingSupply = calculateCirculatingSupply(marketState.state).toString();
+  }
+
+  return {
+    id: assetId,
+    name: marketEmojiData.symbolData.name,
+    symbol: marketEmojiData.symbolData.symbol,
+    totalSupply: Number(EMOJICOIN_SUPPLY),
+    ...circulatingSupply,
+    // coinGeckoId: assetId,
+    // coinMarketCapId: assetId,
+  };
+}
+
+// NextJS JSON response handler
+export async function GET(request: NextRequest): Promise<NextResponse<AssetResponse>> {
+  const searchParams = request.nextUrl.searchParams;
+  const assetId = searchParams.get("id");
+  if (!assetId) {
+    // This is a required field, and is an error otherwise
+    return new NextResponse("id is a parameter", { status: 400 });
+  }
+  const asset = await getAsset(assetId);
+  return NextResponse.json({ asset });
+}