Add UX to poll and display link

frontend/staff-dashboard.jsx

@@ -1,24 +1,83 @@
-import React from 'react'
+import React, {useState} from 'react'
 import ReactDOM from 'react-dom'
+import { createRoot } from 'react-dom/client';
 import ErrorBoundary from './components/error-boundary'
 
-import { createRoot } from 'react-dom/client';
+import axios from 'axios'
+
+axios.defaults.xsrfCookieName = 'csrftoken'
+axios.defaults.xsrfHeaderName = 'X-CSRFToken'
+
 
 /* TODO
- * - [ ] intercept clicking on link
- * - [ ] store task id back
- * - [ ] poll result
- * - [ ] display download link when ready
+ * - [ ] Feedback to show result is pending
+ * - [ ] Pending result from backend
 */
 const ExportLinks = props => {
+
+  const [pollingUrl, setPollingUrl] = useState('');
+  const [exportUrl, setExportUrl] = useState('');
+
+  const startPolling = url => {
+    setPollingUrl(url)
+
+    const pollRequest = async backoff => {
+      try {
+        const pollResp = await axios({url, method: 'GET', responseType: 'json'});
+        if (pollResp.status === 200) {
+          console.log(`done polling ${pollingUrl}, ${pollResp}`)
+          const result = pollResp.data
+          if (result.status == 'PENDING'){
+            setTimeout(pollRequest, backoff, backoff*2)
+          } else if (result.status == 'SUCCESS') {
+            setPollingUrl('')
+            setExportUrl(result.result.presigned_url)
+            return
+          }
+        }
+      } catch (e) {
+        // TODO, erm
+        console.log(e)
+      }
+    }
+
+    pollRequest(5000)
+
+  }
+
+  const onClick = e => {
+    e.preventDefault()
+    const url = e.target.href
+    // Post request and start polling
+    axios({url, method: 'GET', responseType: 'json'}).then(res => {
+      if (res.status === 200){
+        console.log(res.data.task_id)
+        console.log('Start polling')
+        startPolling(`/en/export/status/${res.data.task_id}/`)
+      } else {
+        // TODO
+        console.log("error");
+      }
+    }).catch(err => {
+      //TODO 
+      console.log(err);
+    })
+
+  }
+
   return (
+    <>
     <ul className="row list-unstyled">
       { 
         props.exportLinks.map( ({url, text}, index) => 
-          <li key={index} className="col d-flex mb-3"><a className="btn btn-primary w-100" href={url} ><i className="fas fa-download" aria-hidden="true"></i><br/>{text}</a></li>
+          <li key={index} className="col d-flex mb-3">
+            <a className="btn btn-primary w-100" href={url} onClick={onClick} ><i className="fas fa-download" aria-hidden="true"></i><br/>{text}</a>
+          </li>
         )
       }
     </ul>
+      { exportUrl && <a href={exportUrl}>Download your export</a> }
+    </>
   )
 }