Prefetch timeline tasks and harden concurrent task loading

Execution tasks were previously seeded from the
executions embedded in the transfer details payload.
That payload no longer carries them, so tasks are
now fetched from the dedicated per-execution
endpoint instead.

Signed-off-by: Mihaela Balutoiu <mbalutoiu@cloudbasesolutions.com>

src/stores/TransferStore.ts

@@ -130,6 +130,7 @@ class TransferStore {
         this.executionsHasOlderPage = hasOlderPage;
         this.executionsLoading = false;
       });
+      this.prefetchExecutionsTasks(raw);
     } catch (err) {
       runInAction(() => {
         this.executionsLoading = false;
@@ -171,6 +172,7 @@ class TransferStore {
         this.executionsHasOlderPage = hasOlderPage;
         this.executionsPaginationLoading = false;
       });
+      this.prefetchExecutionsTasks(raw);
     } catch (err) {
       runInAction(() => {
         this.executionsHasOlderPage = false;
@@ -365,55 +367,100 @@ class TransferStore {
 
   currentlyLoadingExecution = "";
 
+  private loadingExecutionTaskIds: Set<string> = new Set();
+
   @action async getExecutionTasks(options: {
     transferId: string;
     executionId?: string;
     polling?: boolean;
   }) {
     const { transferId: transferId, executionId, polling } = options;
-
-    if (!polling && this.currentlyLoadingExecution === executionId) {
-      return;
-    }
-    this.currentlyLoadingExecution = polling
+    const targetId = polling
       ? this.currentlyLoadingExecution
       : executionId || "";
-    if (!this.currentlyLoadingExecution) {
-      return;
-    }
-
-    if (
-      !polling &&
-      this.executionsTasks.find(e => e.id === this.currentlyLoadingExecution)
-    ) {
+    if (!targetId) {
       return;
     }
 
     if (!polling) {
+      this.currentlyLoadingExecution = targetId;
+      if (this.executionsTasks.find(e => e.id === targetId)) {
+        this.executionsTasksLoading = false;
+        return;
+      }
+      if (this.loadingExecutionTaskIds.has(targetId)) {
+        this.executionsTasksLoading = true;
+        return;
+      }
+      this.loadingExecutionTaskIds.add(targetId);
       this.executionsTasksLoading = true;
     }
 
     try {
       const executionTasks = await TransferSource.getExecutionTasks({
         transferId: transferId,
-        executionId: this.currentlyLoadingExecution,
+        executionId: targetId,
         polling,
       });
       runInAction(() => {
         this.executionsTasks = [
-          ...this.executionsTasks.filter(
-            e => e.id !== this.currentlyLoadingExecution,
-          ),
+          ...this.executionsTasks.filter(e => e.id !== targetId),
           executionTasks,
         ];
       });
     } catch (err) {
       console.error(err);
     } finally {
-      runInAction(() => {
-        this.executionsTasksLoading = false;
-      });
+      if (!polling) {
+        runInAction(() => {
+          this.loadingExecutionTaskIds.delete(targetId);
+          if (this.currentlyLoadingExecution === targetId) {
+            this.executionsTasksLoading = false;
+          }
+        });
+      }
+    }
+  }
+
+  @action async prefetchExecutionsTasks(
+    executions: Execution[],
+  ): Promise<void> {
+    const transferId = this.transferDetails?.id;
+    if (!transferId) {
+      return;
     }
+    await Promise.all(
+      executions.map(async execution => {
+        if (
+          this.executionsTasks.find(e => e.id === execution.id) ||
+          this.loadingExecutionTaskIds.has(execution.id)
+        ) {
+          return;
+        }
+        this.loadingExecutionTaskIds.add(execution.id);
+        try {
+          const executionTasks = await TransferSource.getExecutionTasks({
+            transferId,
+            executionId: execution.id,
+            polling: true,
+          });
+          runInAction(() => {
+            if (!this.executionsTasks.find(e => e.id === execution.id)) {
+              this.executionsTasks = [...this.executionsTasks, executionTasks];
+            }
+            if (this.currentlyLoadingExecution === execution.id) {
+              this.executionsTasksLoading = false;
+            }
+          });
+        } catch (err) {
+          console.error(err);
+        } finally {
+          runInAction(() => {
+            this.loadingExecutionTaskIds.delete(execution.id);
+          });
+        }
+      }),
+    );
   }
 
   @action async execute(transferId: string, fields?: Field[]): Promise<void> {