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477import { useState, useCallback, useRef } from 'react';
import type { PipelineViewerResult, StepResult, PIIFinding } from '@/types/pipeline-viewer';
import { apiFetch } from '@/auth/apiFetch';
const MAX_RECONNECT_ATTEMPTS = 10;
const RECONNECT_BASE_DELAY_MS = 2000;
interface ProcessOptions {
imagesScale: number;
doTableStructure: boolean;
}
interface SSEEvent {
type: string;
data: unknown;
id?: number;
}
/**
* Parse an SSE buffer into events + remainder.
* Splits on double-newline boundaries and extracts id: / event: / data: lines.
*/
function parseSSEBuffer(buffer: string): { events: SSEEvent[]; remainder: string } {
const events: SSEEvent[] = [];
const blocks = buffer.split('\n\n');
// Last element may be incomplete — keep as remainder
const remainder = blocks.pop() ?? '';
for (const block of blocks) {
if (!block.trim()) continue;
let eventType = 'message';
let eventId: number | undefined;
let dataLines: string[] = [];
for (const line of block.split('\n')) {
if (line.startsWith('id: ')) {
const parsed = parseInt(line.slice(4).trim(), 10);
if (!isNaN(parsed)) eventId = parsed;
} else if (line.startsWith('event: ')) {
eventType = line.slice(7).trim();
} else if (line.startsWith('data: ')) {
dataLines.push(line.slice(6));
} else if (line.startsWith('data:')) {
dataLines.push(line.slice(5));
}
}
if (dataLines.length > 0) {
try {
const data = JSON.parse(dataLines.join('\n'));
events.push({ type: eventType, data, id: eventId });
} catch {
// Skip malformed JSON
}
}
}
return { events, remainder };
}
export function usePipelineViewer() {
const [result, setResult] = useState<PipelineViewerResult | null>(null);
const [uploading, setUploading] = useState(false);
const [processing, setProcessing] = useState(false);
const [currentStepName, setCurrentStepName] = useState<string | null>(null);
const [statusMessage, setStatusMessage] = useState<string | null>(null);
const [error, setError] = useState<string | null>(null);
const [sessionId, setSessionId] = useState<string | null>(null);
const [piiFindings, setPiiFindings] = useState<PIIFinding[] | null>(null);
const [awaitingPiiDecision, setAwaitingPiiDecision] = useState(false);
const [piiDenied, setPiiDenied] = useState(false);
const abortRef = useRef<AbortController | null>(null);
// Reconnect state — refs to survive across renders without re-triggering effects
const sessionIdRef = useRef<string | null>(null);
const lastEventIdRef = useRef<number>(-1);
/**
* Shared event handler used by both the initial stream and reconnect streams.
* Returns true if the stream should be considered complete (done event received).
*/
function handleSSEEvent(event: SSEEvent): boolean {
// Track event ID for reconnect
if (event.id !== undefined) {
lastEventIdRef.current = event.id;
}
switch (event.type) {
case 'session': {
const { session_id } = event.data as { session_id: string };
sessionIdRef.current = session_id;
setSessionId(session_id);
break;
}
case 'pii_scan': {
const { findings, awaiting_decision, elapsed_ms, error } = event.data as {
findings: PIIFinding[];
finding_count: number;
awaiting_decision: boolean;
elapsed_ms?: number;
error?: string | null;
};
setPiiFindings(findings);
setAwaitingPiiDecision(!!awaiting_decision);
setUploading(false);
setProcessing(true);
// Scan itself is done — clear the "Processing: PII Scan" status so
// the stage tab shows the completed state while we await the decision.
setCurrentStepName(null);
// Synthesize a skeleton result so the pipeline layout (with the
// PII Review stage) renders immediately — otherwise the page falls
// back to the upload form while waiting for docling's init event.
setResult((prev) => {
const piiStep: StepResult = {
name: 'pii_scan',
display_name: 'PII Scan',
version_before: null,
version_after: 'v0',
elapsed_ms: elapsed_ms ?? 0,
changes: [],
metadata: { findings, finding_count: findings.length },
skipped: false,
error: error ?? null,
input_tokens: 0,
output_tokens: 0,
cost_cents: 0,
};
if (prev) {
const withoutPii = prev.steps.filter((s) => s.name !== 'pii_scan');
return { ...prev, steps: [piiStep, ...withoutPii] };
}
return {
filename: '',
total_pages: 0,
versions: {},
page_images: {},
page_markdowns: {},
figures: [],
steps: [piiStep],
stats: {},
warnings: [],
};
});
break;
}
case 'pii_decision': {
const { decision } = event.data as { decision: 'approved' | 'denied'; reason?: string };
setAwaitingPiiDecision(false);
if (decision === 'denied') {
setPiiDenied(true);
} else {
setProcessing(true);
}
break;
}
case 'init': {
const initData = event.data as PipelineViewerResult;
setResult(initData);
setUploading(false);
setProcessing(true);
setStatusMessage(null);
break;
}
case 'page_image': {
const { page, image_base64 } = event.data as { page: string; image_base64: string };
setResult((prev) =>
prev ? { ...prev, page_images: { ...prev.page_images, [page]: image_base64 } } : prev
);
break;
}
case 'figure_image': {
const { ref_id, image_base64 } = event.data as { ref_id: string; image_base64: string };
setResult((prev) => {
if (!prev) return prev;
return {
...prev,
figures: prev.figures.map((f) => (f.ref_id === ref_id ? { ...f, image_base64 } : f)),
};
});
break;
}
case 'status': {
const { message } = event.data as { message: string; type: string };
setStatusMessage(message);
break;
}
case 'processing': {
const { display_name } = event.data as { step_name: string; display_name: string };
setCurrentStepName(display_name);
setStatusMessage(null);
setUploading(false);
setProcessing(true);
// Flip to the pipeline layout immediately so the status bar and
// stage tabs are visible during long-running steps (PII scan,
// docling) that don't emit an init/step event for a while.
setResult((prev) => {
if (prev) return prev;
return {
filename: '',
total_pages: 0,
versions: {},
page_images: {},
page_markdowns: {},
figures: [],
steps: [],
stats: {},
warnings: [],
};
});
break;
}
case 'step': {
const stepData = event.data as {
step: StepResult;
new_versions: Record<string, string>;
new_page_markdowns: Record<string, Record<string, string>>;
};
setResult((prev) => {
if (!prev) return prev;
return {
...prev,
steps: [...prev.steps, stepData.step],
versions: { ...prev.versions, ...stepData.new_versions },
page_markdowns: { ...prev.page_markdowns, ...stepData.new_page_markdowns },
};
});
break;
}
case 'error': {
const { step_name, message } = event.data as { step_name: string; message: string };
console.error(`Pipeline step "${step_name}" failed: ${message}`);
break;
}
case 'done': {
const doneData = event.data as { session_id?: string };
if (doneData.session_id) {
setSessionId(doneData.session_id);
}
setProcessing(false);
setCurrentStepName(null);
return true;
}
}
return false;
}
/**
* Read an SSE stream from a fetch Response and process events with the shared handler.
* Returns true if the stream completed normally (done event), false if interrupted.
*/
async function consumeSSEStream(response: Response, signal: AbortSignal): Promise<boolean> {
const reader = response.body?.getReader();
if (!reader) throw new Error('No response body');
const decoder = new TextDecoder();
let sseBuffer = '';
try {
while (true) {
const { done, value } = await reader.read();
if (done) break;
if (signal.aborted) break;
sseBuffer += decoder.decode(value, { stream: true });
const { events, remainder } = parseSSEBuffer(sseBuffer);
sseBuffer = remainder;
for (const event of events) {
if (handleSSEEvent(event)) return true;
}
}
} catch (err) {
if (!(err instanceof DOMException && err.name === 'AbortError')) {
console.warn('SSE stream interrupted:', err instanceof Error ? err.message : err);
}
}
return false;
}
/**
* Attempt to reconnect to an in-progress session.
*/
async function reconnect(signal: AbortSignal, attempt: number = 0): Promise<void> {
const sid = sessionIdRef.current;
const lastId = lastEventIdRef.current;
if (!sid || signal.aborted) return;
if (attempt >= MAX_RECONNECT_ATTEMPTS) {
console.warn(`SSE reconnect: gave up after ${MAX_RECONNECT_ATTEMPTS} attempts`);
return;
}
// Exponential backoff with jitter, capped at 30s
const baseDelay = Math.min(RECONNECT_BASE_DELAY_MS * Math.pow(2, attempt), 30000);
const delay = baseDelay + Math.random() * 1000;
console.log(`SSE reconnect: attempt ${attempt + 1}/${MAX_RECONNECT_ATTEMPTS} in ${Math.round(delay)}ms (last_event_id=${lastId})`);
await new Promise((r) => setTimeout(r, delay));
if (signal.aborted) return;
try {
const url = `/api/v1/pipeline/sessions/${sid}/stream?last_event_id=${lastId}`;
const response = await apiFetch(url, { signal });
if (!response.ok) {
console.warn(`SSE reconnect: server returned ${response.status}`);
return await reconnect(signal, attempt + 1);
}
const completed = await consumeSSEStream(response, signal);
if (!completed && !signal.aborted) {
// Stream broke again — retry
return await reconnect(signal, attempt + 1);
}
} catch (err) {
if (err instanceof DOMException && err.name === 'AbortError') return;
return await reconnect(signal, attempt + 1);
}
}
const processFile = useCallback(async (file: File, options: ProcessOptions) => {
// Abort any in-flight stream
abortRef.current?.abort();
const controller = new AbortController();
abortRef.current = controller;
// Reset reconnect refs for new upload
sessionIdRef.current = null;
lastEventIdRef.current = -1;
setUploading(true);
setProcessing(false);
setCurrentStepName(null);
setError(null);
setResult(null);
setPiiFindings(null);
setAwaitingPiiDecision(false);
setPiiDenied(false);
try {
const formData = new FormData();
formData.append('file', file);
formData.append('images_scale', String(options.imagesScale));
formData.append('do_table_structure', String(options.doTableStructure));
const response = await apiFetch('/api/v1/pipeline/process/stream', {
method: 'POST',
body: formData,
signal: controller.signal,
});
if (!response.ok) {
const detail = await response.text();
throw new Error(`Processing failed (${response.status}): ${detail}`);
}
const completed = await consumeSSEStream(response, controller.signal);
// If stream didn't complete and we have a session, try to reconnect
if (!completed && sessionIdRef.current && !controller.signal.aborted) {
console.log('SSE stream interrupted, attempting reconnect...');
await reconnect(controller.signal);
}
} catch (err) {
if (err instanceof DOMException && err.name === 'AbortError') {
// User cancelled — not an error
return;
}
// Try reconnect if we have a session
if (sessionIdRef.current && !controller.signal.aborted) {
console.log('SSE stream error, attempting reconnect...');
try {
await reconnect(controller.signal);
return;
} catch {
// Reconnect also failed — fall through to error handling
}
}
// Only set error if we have no results yet.
// Late-stage disconnects are non-fatal when steps have already been received.
setResult((prev) => {
if (!prev) {
setError(err instanceof Error ? err.message : 'Unknown error');
}
return prev;
});
} finally {
setUploading(false);
setProcessing(false);
setCurrentStepName(null);
}
}, []);
const updateVersion = useCallback(
(key: string, markdown: string, pageMarkdowns?: Record<string, string>) => {
setResult((prev) => {
if (!prev) return prev;
const updated = {
...prev,
versions: { ...prev.versions, [key]: markdown },
};
if (pageMarkdowns) {
updated.page_markdowns = { ...prev.page_markdowns, [key]: pageMarkdowns };
}
return updated;
});
},
[],
);
const submitPiiDecision = useCallback(
async (decision: 'approved' | 'denied') => {
const sid = sessionIdRef.current;
if (!sid) return;
try {
await apiFetch(`/api/v1/pipeline/sessions/${sid}/pii-decision`, {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ decision }),
});
// Optimistic UI — the server will also emit pii_decision over SSE.
setAwaitingPiiDecision(false);
if (decision === 'denied') setPiiDenied(true);
} catch (err) {
console.warn('Failed to submit PII decision:', err);
}
},
[],
);
const reset = useCallback(() => {
abortRef.current?.abort();
abortRef.current = null;
sessionIdRef.current = null;
lastEventIdRef.current = -1;
setResult(null);
setError(null);
setProcessing(false);
setCurrentStepName(null);
setStatusMessage(null);
setSessionId(null);
setPiiFindings(null);
setAwaitingPiiDecision(false);
setPiiDenied(false);
}, []);
return {
result,
uploading,
error,
processing,
currentStepName,
statusMessage,
processFile,
reset,
sessionId,
updateVersion,
piiFindings,
awaitingPiiDecision,
piiDenied,
submitPiiDecision,
};
}