From abe6911c7d3a4a739a11c38f475ca1ab8c96238b Mon Sep 17 00:00:00 2001
From: Bryan Kok <bryan.wyern1@gmail.com>
Date: Wed, 24 Feb 2021 18:53:41 +0800
Subject: [PATCH] BabelStone PUA fetcher

---
 etl/babelstone-pua-fetcher.ts | 81 +++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 etl/babelstone-pua-fetcher.ts

diff --git a/etl/babelstone-pua-fetcher.ts b/etl/babelstone-pua-fetcher.ts
new file mode 100644
index 0000000..1280ed6
--- /dev/null
+++ b/etl/babelstone-pua-fetcher.ts
@@ -0,0 +1,81 @@
+import axios from "axios";
+import fs from "fs";
+import moment from "moment";
+import path from "path";
+import {
+  BABELSTONE_PUA_JSON_NAME,
+  BABELSTONE_PUA_JSON_URL,
+  BABELSTONE_SUBDIR_NAME,
+  DATA_CACHE_DIR_NAME,
+} from "./constants";
+
+const BABELSTONE_SUBDIR = path.join(
+  __dirname,
+  DATA_CACHE_DIR_NAME,
+  BABELSTONE_SUBDIR_NAME
+);
+
+const BABELSTONE_PUA_FILE = path.join(
+  BABELSTONE_SUBDIR,
+  BABELSTONE_PUA_JSON_NAME
+);
+
+type PUAEntry = {
+  cp: string;
+  char: string;
+  ids: string;
+  note: string;
+  src: string;
+  src_refs: string;
+  enc_stat: string;
+};
+
+type PUA = {
+  data: PUAEntry[];
+  ts: string;
+};
+
+const isValidBabelPUAFile = (obj: any) => {
+  return "data" in obj && "ts" in obj && moment(obj.ts).isValid();
+};
+
+const fetchBabelData = async () => {
+  if (!fs.existsSync(BABELSTONE_SUBDIR)) {
+    fs.mkdirSync(BABELSTONE_SUBDIR);
+  }
+
+  try {
+    if (!fs.existsSync(BABELSTONE_PUA_FILE)) throw new Error();
+
+    const data = JSON.parse(fs.readFileSync(BABELSTONE_PUA_FILE).toString());
+
+    if (!isValidBabelPUAFile(data)) throw new Error();
+  } catch {
+    console.error("Invalid Babelstone Han PUA file");
+    fs.writeFileSync(
+      BABELSTONE_PUA_FILE,
+      JSON.stringify({
+        data: [],
+        ts: moment(0).toISOString(),
+      })
+    );
+  }
+
+  const data = JSON.parse(
+    fs.readFileSync(BABELSTONE_PUA_FILE).toString()
+  ) as PUA;
+
+  console.log("Connecting …");
+
+  const remoteData = (await axios.get<PUA>(BABELSTONE_PUA_JSON_URL)).data;
+
+  if (moment(remoteData.ts) > moment(data.ts)) {
+    fs.writeFileSync(BABELSTONE_PUA_FILE, JSON.stringify(remoteData));
+  }
+};
+
+export const getPUAData = async (): Promise<PUA> => {
+  await fetchBabelData();
+  const buf = await fs.promises.readFile(BABELSTONE_PUA_FILE);
+  return JSON.parse(buf.toString());
+};