added cors support and started chat client

packages/chat-client/src/api/orchestration.js

@@ -0,0 +1,80 @@
+const BASE_URL = import.meta.env.VITE_ORCHESTRATION_URL ?? '';
+
+// ── Sessions ────────────────────────────────────────────────
+
+export async function fetchSessions(limit = 20, offset = 0) {
+  const res = await fetch(`${BASE_URL}/sessions?limit=${limit}&offset=${offset}`);
+  if (!res.ok) throw new Error(`Failed to fetch sessions: ${res.status}`);
+  return res.json();
+}
+
+export async function fetchSessionHistory(sessionId, limit = 50, offset = 0) {
+  const res = await fetch(`${BASE_URL}/sessions/${sessionId}/history?limit=${limit}&offset=${offset}`);
+  if (!res.ok) throw new Error(`Failed to fetch history: ${res.status}`);
+  return res.json();
+}
+
+// ── Chat ────────────────────────────────────────────────────
+
+export async function sendMessage(sessionId, message, model) {
+  const res = await fetch(`${BASE_URL}/chat`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ sessionId, message, model }),
+  });
+  if (!res.ok) throw new Error(`Chat request failed: ${res.status}`);
+  return res.json();
+}
+
+// onChunk(text) called for each token
+// onDone({ model, tokenCount }) called when stream closes
+// returns an abort function — call it to cancel mid-stream
+export function streamMessage(sessionId, message, model, { onChunk, onDone, onError }) {
+  const controller = new AbortController();
+
+  (async () => {
+    try {
+      const res = await fetch(`${BASE_URL}/chat/stream`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ sessionId, message, model }),
+        signal: controller.signal,
+      });
+
+      if (!res.ok) throw new Error(`Stream request failed: ${res.status}`);
+
+      const reader = res.body.getReader();
+      const decoder = new TextDecoder();
+      let buffer = '';
+
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+
+        // Append to buffer and split on double newline (SSE event delimiter)
+        buffer += decoder.decode(value, { stream: true });
+        const events = buffer.split('\n\n');
+        buffer = events.pop(); // last item may be incomplete — keep in buffer
+
+        for (const event of events) {
+          const line = event.trim();
+          if (!line.startsWith('data: ')) continue;
+
+          const raw = line.slice(6);
+          try {
+            const data = JSON.parse(raw);
+            if (data.text) onChunk(data.text);
+            if (data.done) onDone({ model, tokenCount: data.tokenCount ?? 0 });
+            if (data.error) onError(new Error(data.error));
+          } catch {
+            // malformed JSON — skip
+          }
+        }
+      }
+    } catch (err) {
+      if (err.name !== 'AbortError') onError(err);
+    }
+  })();
+
+  return () => controller.abort();
+}