MAESTRO: implement analysis hook

frontend/src/hooks/useAnalysis.ts

@@ -0,0 +1,160 @@
+import { useCallback, useEffect, useRef, useState } from "react";
+import { flushSync } from "react-dom";
+
+import { apiClient, type SseEvent } from "../lib/api-client";
+import type { AnalysisConfig, AnalysisProgress, AnalysisReport } from "../types/analysis";
+
+export type AnalysisStatus =
+  | "idle"
+  | "submitting"
+  | "analysing"
+  | "complete"
+  | "error"
+  | "timeout";
+
+export interface AnalysisRequest {
+  headers: string;
+  config: AnalysisConfig;
+}
+
+export interface UseAnalysisState {
+  status: AnalysisStatus;
+  progress: AnalysisProgress | null;
+  result: AnalysisReport | null;
+  error: string | null;
+  submit: (request: AnalysisRequest) => Promise<void>;
+  cancel: () => void;
+}
+
+const scheduleTask = (handler: () => void): void => {
+  setTimeout(handler, 0);
+};
+
+const useAnalysis = (): UseAnalysisState => {
+  const [status, setStatus] = useState<AnalysisStatus>("idle");
+  const [progress, setProgress] = useState<AnalysisProgress | null>(null);
+  const [result, setResult] = useState<AnalysisReport | null>(null);
+  const [error, setError] = useState<string | null>(null);
+
+  const abortRef = useRef<AbortController | null>(null);
+  const requestIdRef = useRef(0);
+  const inFlightRef = useRef(false);
+  const mountedRef = useRef(true);
+  const hasProgressRef = useRef(false);
+
+  useEffect(() => {
+    return () => {
+      mountedRef.current = false;
+      abortRef.current?.abort();
+    };
+  }, []);
+
+  const resetState = useCallback(() => {
+    setProgress(null);
+    setResult(null);
+    setError(null);
+  }, []);
+
+  const handleEvent = useCallback(
+    (
+      event: SseEvent<AnalysisProgress | AnalysisReport>,
+      requestId: number,
+      signal: AbortSignal,
+    ) => {
+      scheduleTask(() => {
+        if (!mountedRef.current) {
+          return;
+        }
+        if (!inFlightRef.current || requestIdRef.current !== requestId) {
+          return;
+        }
+        if (signal.aborted) {
+          return;
+        }
+
+        if (event.event === "progress") {
+          const payload = event.data as AnalysisProgress;
+          if (!hasProgressRef.current) {
+            hasProgressRef.current = true;
+            flushSync(() => {
+              setProgress(payload);
+              setStatus("analysing");
+            });
+            return;
+          }
+          setProgress(payload);
+          return;
+        }
+
+        if (event.event === "result") {
+          const report = event.data as AnalysisReport;
+          setResult(report);
+          inFlightRef.current = false;
+          setStatus(report.metadata.timedOut ? "timeout" : "complete");
+        }
+      });
+    },
+    [],
+  );
+
+  const submit = useCallback(
+    async (request: AnalysisRequest): Promise<void> => {
+      requestIdRef.current += 1;
+      const requestId = requestIdRef.current;
+
+      abortRef.current?.abort();
+      const controller = new AbortController();
+      abortRef.current = controller;
+      inFlightRef.current = true;
+
+      setStatus("submitting");
+      resetState();
+      hasProgressRef.current = false;
+
+      try {
+        await apiClient.stream<AnalysisRequest, AnalysisProgress | AnalysisReport>(
+          "/api/analyse",
+          {
+            body: request,
+            signal: controller.signal,
+            onEvent: (event) => handleEvent(event, requestId, controller.signal),
+          },
+        );
+      } catch (err) {
+        if (!mountedRef.current || controller.signal.aborted) {
+          return;
+        }
+        if (requestIdRef.current !== requestId) {
+          return;
+        }
+
+        inFlightRef.current = false;
+        const message = err instanceof Error ? err.message : "Unknown error";
+        setError(message);
+        setStatus("error");
+      }
+    },
+    [handleEvent, resetState],
+  );
+
+  const cancel = useCallback(() => {
+    if (abortRef.current) {
+      abortRef.current.abort();
+    }
+    inFlightRef.current = false;
+    setStatus("idle");
+    resetState();
+    hasProgressRef.current = false;
+  }, [resetState]);
+
+  return {
+    status,
+    progress,
+    result,
+    error,
+    submit,
+    cancel,
+  };
+};
+
+export default useAnalysis;