use-debate-stream.ts
4,079 bytes
| 1 | 'use client'; |
|---|---|
| 2 | |
| 3 | import { useCallback, useRef, useState } from 'react'; |
| 4 | import type { DebateEvent } from '@/core/events'; |
| 5 | import type { DebateConfigInput } from '@/core/schemas'; |
| 6 | import { applyEvent, initialDebateView, type DebateView } from '@/lib/debate-view'; |
| 7 | |
| 8 | export type StreamPhase = 'idle' | 'connecting' | 'streaming' | 'done' | 'error'; |
| 9 | |
| 10 | /** |
| 11 | * Drives a live debate: POSTs the config, reads the SSE body, and folds every |
| 12 | * frame through the shared reducer. The debate continues server-side even if |
| 13 | * this component unmounts (see debate-runner) - the returned `debateId` can be |
| 14 | * used to reload state on reconnect. |
| 15 | */ |
| 16 | export function useDebateStream() { |
| 17 | const [view, setView] = useState<DebateView>(() => initialDebateView()); |
| 18 | const [phase, setPhase] = useState<StreamPhase>('idle'); |
| 19 | const [errorMsg, setErrorMsg] = useState<string | null>(null); |
| 20 | /** Machine-readable error code from the API (e.g. 'NO_KEY'), when present. */ |
| 21 | const [errorCode, setErrorCode] = useState<string | null>(null); |
| 22 | const abortRef = useRef<AbortController | null>(null); |
| 23 | |
| 24 | const handleFrame = useCallback((frame: string) => { |
| 25 | let eventName = ''; |
| 26 | let dataLine = ''; |
| 27 | for (const line of frame.split('\n')) { |
| 28 | if (line.startsWith('event:')) eventName = line.slice(6).trim(); |
| 29 | else if (line.startsWith('data:')) dataLine += line.slice(5).trim(); |
| 30 | } |
| 31 | if (!dataLine) return; |
| 32 | |
| 33 | if (eventName === 'ready') { |
| 34 | try { |
| 35 | const d = JSON.parse(dataLine) as { debateId: string }; |
| 36 | setView((v) => ({ ...v, debateId: d.debateId })); |
| 37 | } catch { |
| 38 | /* ignore */ |
| 39 | } |
| 40 | return; |
| 41 | } |
| 42 | if (eventName === 'error') { |
| 43 | try { |
| 44 | setErrorMsg((JSON.parse(dataLine) as { message?: string }).message ?? 'Debate failed'); |
| 45 | } catch { |
| 46 | setErrorMsg('Debate failed'); |
| 47 | } |
| 48 | setPhase('error'); |
| 49 | return; |
| 50 | } |
| 51 | try { |
| 52 | const ev = JSON.parse(dataLine) as DebateEvent; |
| 53 | setView((v) => applyEvent(v, ev)); |
| 54 | } catch { |
| 55 | /* skip malformed frame */ |
| 56 | } |
| 57 | }, []); |
| 58 | |
| 59 | const start = useCallback( |
| 60 | async (config: DebateConfigInput) => { |
| 61 | abortRef.current?.abort(); |
| 62 | const controller = new AbortController(); |
| 63 | abortRef.current = controller; |
| 64 | setView(initialDebateView(config.question)); |
| 65 | setErrorMsg(null); |
| 66 | setErrorCode(null); |
| 67 | setPhase('connecting'); |
| 68 | |
| 69 | try { |
| 70 | const res = await fetch('/api/debates/run', { |
| 71 | method: 'POST', |
| 72 | headers: { 'Content-Type': 'application/json' }, |
| 73 | body: JSON.stringify(config), |
| 74 | signal: controller.signal, |
| 75 | }); |
| 76 | |
| 77 | if (!res.ok || !res.body) { |
| 78 | const err = (await res.json().catch(() => null)) as { error?: string; code?: string } | null; |
| 79 | setErrorMsg(err?.error ?? `Request failed (${res.status})`); |
| 80 | setErrorCode(err?.code ?? null); |
| 81 | setPhase('error'); |
| 82 | return; |
| 83 | } |
| 84 | |
| 85 | setPhase('streaming'); |
| 86 | const reader = res.body.getReader(); |
| 87 | const decoder = new TextDecoder(); |
| 88 | let buffer = ''; |
| 89 | for (;;) { |
| 90 | const { done, value } = await reader.read(); |
| 91 | if (done) break; |
| 92 | buffer += decoder.decode(value, { stream: true }); |
| 93 | const frames = buffer.split('\n\n'); |
| 94 | buffer = frames.pop() ?? ''; |
| 95 | for (const frame of frames) if (frame.trim() && !frame.startsWith(':')) handleFrame(frame); |
| 96 | } |
| 97 | setPhase((p) => (p === 'error' ? p : 'done')); |
| 98 | } catch (err) { |
| 99 | if ((err as Error).name === 'AbortError') return; |
| 100 | setErrorMsg((err as Error).message); |
| 101 | setPhase('error'); |
| 102 | } |
| 103 | }, |
| 104 | [handleFrame], |
| 105 | ); |
| 106 | |
| 107 | const cancel = useCallback(() => { |
| 108 | abortRef.current?.abort(); |
| 109 | setPhase((p) => (p === 'streaming' || p === 'connecting' ? 'idle' : p)); |
| 110 | }, []); |
| 111 | |
| 112 | const reset = useCallback(() => { |
| 113 | abortRef.current?.abort(); |
| 114 | setView(initialDebateView()); |
| 115 | setErrorMsg(null); |
| 116 | setErrorCode(null); |
| 117 | setPhase('idle'); |
| 118 | }, []); |
| 119 | |
| 120 | return { view, phase, errorMsg, errorCode, start, cancel, reset }; |
| 121 | } |
| 122 | |