api: rewrite python functions in javascript

This fixes an issue with oversized builds which include node_modules inside the python functions despite the folder being excluded by the build process

.gitignore

@@ -122,3 +122,4 @@ dist
 .vscode
 /.env.development.local.example
 /.env
+.vercel

api/supply_info.js

@@ -0,0 +1,81 @@
+const KINT_SUBSCAN_URL = 'https://kintsugi.api.subscan.io/'
+const INTR_SUBSCAN_URL = 'https://interlay.api.subscan.io/'
+
+const KINT_API_KEY = process.env.SUBSCAN_API_KEY
+const INTR_API_KEY = process.env.INTR_SUBSCAN_API_KEY
+
+function fromDecimals (val, decimals) {
+  return val / Math.pow(10, decimals)
+}
+
+async function subscanRequest (url, method = 'GET', json = null) {
+  const headers = {
+    'Content-Type': 'application/json',
+    'X-API-KEY': url.startsWith(INTR_SUBSCAN_URL) ? INTR_API_KEY : KINT_API_KEY
+  }
+
+  const options = { method, headers }
+  if (json) {
+    options.body = JSON.stringify(json)
+  }
+
+  const response = await fetch(url, options)
+  return await response.json()
+}
+
+export default async function (request, response) {
+  if (request.method !== 'GET') {
+    return response.status(400).send('Bad Request')
+  }
+  const path = request.url.split('?')[0]
+  switch (path) {
+    case '/supply/intr-total-supply': {
+      const INTR_SUPPLY = 1_000_000_000
+      return response
+        .status(200)
+        .send(INTR_SUPPLY.toString())
+    }
+    case '/supply/kint-total-supply': {
+      const KINT_SUPPLY = 10_000_000
+      return response
+        .status(200)
+        .send(KINT_SUPPLY.toString())
+    }
+    case '/supply/intr-circ-supply': {
+      const unvestedSupply = fromDecimals(parseInt((await subscanRequest(INTR_SUBSCAN_URL + 'api/scan/token')).data.detail.INTR.available_balance), 10)
+      const systemAccountsSupply = (await subscanRequest(INTR_SUBSCAN_URL + 'api/scan/accounts', 'POST',
+        { filter: 'system', row: 25, page: 0 })).data.list
+        .reduce((acc, curr) => acc + parseFloat(curr.balance), 0)
+      const circulatingSupply = unvestedSupply - systemAccountsSupply
+
+      return response
+        .status(200)
+        .send(circulatingSupply.toString())
+    }
+    case '/supply/kint-circ-supply': {
+      const kintUnvestedSupply = fromDecimals(parseInt((await subscanRequest(KINT_SUBSCAN_URL + 'api/scan/token')).data.detail.KINT.available_balance), 12)
+      const kintSystemAccountsSupply = (await subscanRequest(KINT_SUBSCAN_URL + 'api/scan/accounts', 'POST',
+        { filter: 'system', row: 25, page: 0 })).data.list
+        .reduce((acc, curr) => acc + parseFloat(curr.balance), 0)
+      const kintCirculatingSupply = kintUnvestedSupply - kintSystemAccountsSupply
+
+      return response
+        .status(200)
+        .send(kintCirculatingSupply.toString())
+    }
+    case '/supply/ibtc-supply': {
+      const ibtcSupply = fromDecimals(parseInt((await subscanRequest(INTR_SUBSCAN_URL + 'api/scan/token')).data.detail.IBTC.available_balance), 10)
+      return response
+        .status(200)
+        .send(ibtcSupply.toString())
+    }
+    case '/supply/kbtc-supply': {
+      const kbtcSupply = fromDecimals(parseInt((await subscanRequest(KINT_SUBSCAN_URL + 'api/scan/token')).data.detail.KBTC.available_balance), 8)
+      return response
+        .status(200)
+        .send(kbtcSupply.toString())
+    }
+    default:
+      response.status(404).send('Not Found')
+  }
+};