From 01037462d6ce220563034dd084d68c1a1f69de6d Mon Sep 17 00:00:00 2001
From: Pavel <Pavel.Murygin@gmail.com>
Date: Tue, 22 Jun 2021 13:28:17 +0300
Subject: [PATCH] Passing environment via a separate json file (#15)

---
 env/env.json      |  4 +++
 index.html        |  1 +
 src/index.js      | 86 +++++++++++++++++++++++++++++++++++++++++++----
 webpack.config.js |  3 ++
 4 files changed, 87 insertions(+), 7 deletions(-)
 create mode 100644 env/env.json

diff --git a/env/env.json b/env/env.json
new file mode 100644
index 0000000..c3af7be
--- /dev/null
+++ b/env/env.json
@@ -0,0 +1,4 @@
+{
+    "nodes": [],
+    "logLevel": "error"
+}
diff --git a/index.html b/index.html
index 3b2efd7..ac0dd34 100644
--- a/index.html
+++ b/index.html
@@ -24,6 +24,7 @@
   gtag('js', new Date());
   gtag('config', 'G-6ZTQKE1D4L');
 </script>
+<script id="env" type="application/json" src="env/env.json"></script>
 <div id="root"></div>
 </body>
 </html>
diff --git a/src/index.js b/src/index.js
index add6312..caa1f20 100644
--- a/src/index.js
+++ b/src/index.js
@@ -19,6 +19,7 @@ import 'css-spinners/dist/all.min.css';
 import './main.css';
 // eslint-disable-next-line import/no-extraneous-dependencies
 import log from 'loglevel';
+import Multiaddr from 'multiaddr';
 import { dev, krasnodar } from '@fluencelabs/fluence-network-environment';
 import {
     createClient,
@@ -33,12 +34,83 @@ import * as serviceWorker from './serviceWorker';
 import { eventType } from './types';
 import { getAll } from './_aqua/app';
 
-const relayIdx = 3;
+const defaultNetworkName = 'krasnodar';
 
-const relays = krasnodar;
-// const relays = dev;
+const defaultEnv = {
+    relays: krasnodar,
+    relayIdx: 3,
+    logLevel: 'error',
+};
 
-function genFlags(peerId) {
+async function loadScript(script) {
+    return new Promise((resolve, reject) => {
+        var xhr = new XMLHttpRequest();
+        xhr.open('GET', script.src);
+        xhr.onreadystatechange = function () {
+            if (xhr.readyState === XMLHttpRequest.DONE && xhr.status === 200) {
+                resolve(xhr.responseText);
+            }
+        };
+        xhr.onerror = reject;
+        xhr.onabort = reject;
+        xhr.send();
+    });
+}
+
+function isMultiaddr(multiaddr) {
+    try {
+        Multiaddr(multiaddr);
+        return true;
+    } catch (error) {
+        return false;
+    }
+}
+
+async function initEnvironment() {
+    try {
+        const script = document.getElementById('env');
+        if (!script) {
+            console.log("Couldn't load environment, falling back to default (${defaultNetworkName})");
+            return defaultEnv;
+        }
+
+        const scriptContent = await loadScript(script);
+        const envWrapper = JSON.parse(scriptContent);
+
+        const res = { ...defaultEnv };
+
+        const data = envWrapper ? envWrapper.nodes : [];
+        if (data.length === 0) {
+            console.log(`Environment is empty, falling back to default (${defaultNetworkName})`);
+        } else {
+            data.forEach((element) => {
+                if (!element.multiaddr) {
+                    console.error('multiaddr field is missing for ', element);
+                }
+                if (!element.peerId) {
+                    console.error('peerId field is missing for ', element);
+                }
+                if (!isMultiaddr(element.multiaddr)) {
+                    console.error(`Value ${element.multiaddr} is not a correct multiaddr`);
+                }
+            });
+            res.relays = data;
+            res.relayIdx = 0;
+        }
+
+        if (envWrapper.logLevel !== undefined) {
+            res.logLevel = envWrapper.logLevel;
+        }
+
+        return res;
+    } catch (error) {
+        console.error("Couldn't parse environment, error: ", error);
+    }
+
+    return defaultEnv;
+}
+
+function genFlags(peerId, relays, relayIdx) {
     return {
         peerId,
         relayId: relays[relayIdx].peerId,
@@ -69,10 +141,10 @@ function event(name, peer, peers, identify, services, modules, blueprints) {
 /* eslint-enable */
 
 (async () => {
-    setLogLevel('INFO');
-
+    const { relays, relayIdx, logLevel } = await initEnvironment();
+    setLogLevel(logLevel);
     const pid = await generatePeerId();
-    const flags = genFlags(pid.toB58String());
+    const flags = genFlags(pid.toB58String(), relays, relayIdx);
     console.log(`connect with client: ${pid.toB58String()}`);
 
     // If the relay is ever changed, an event shall be sent to elm
diff --git a/webpack.config.js b/webpack.config.js
index a7f0676..b6ab174 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -40,6 +40,9 @@ var common = {
                 {
                     from: 'favicon.ico',
                 },
+                {
+                    from: './env/*.*',
+                },
             ],
         }),
     ],