NEXUS_AI.pro/pixel-perfect-pixels-main/src/lib/chat.ts

type Message = { role: "user" | "assistant"; content: string };

const CHAT_URL = `${import.meta.env.VITE_SUPABASE_URL}/functions/v1/chat`;

export type ModelType = "local" | "gemini-flash" | "perplexity-sonar";

export async function streamChat({
  messages,
  model = "gemini-flash",
  onDelta,
  onDone,
  onError,
}: {
  messages: Message[];
  model?: ModelType;
  onDelta: (deltaText: string) => void;
  onDone: () => void;
  onError: (error: string) => void;
}) {
  try {
    const resp = await fetch(CHAT_URL, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Authorization: `Bearer ${import.meta.env.VITE_SUPABASE_PUBLISHABLE_KEY}`,
      },
      body: JSON.stringify({ messages, model }),
    });

    if (!resp.ok) {
      const errorData = await resp.json().catch(() => ({}));
      const errorMessage = errorData.error || `Request failed with status ${resp.status}`;
      if (resp.status === 429) { onError("Rate limit exceeded. Please wait a moment."); return; }
      if (resp.status === 402) { onError("AI credits exhausted. Please add credits."); return; }
      onError(errorMessage);
      return;
    }

    if (!resp.body) { onError("No response body received"); return; }

    const reader = resp.body.getReader();
    const decoder = new TextDecoder();
    let textBuffer = "";
    let streamDone = false;

    while (!streamDone) {
      const { done, value } = await reader.read();
      if (done) break;
      textBuffer += decoder.decode(value, { stream: true });

      let newlineIndex: number;
      while ((newlineIndex = textBuffer.indexOf("\n")) !== -1) {
        let line = textBuffer.slice(0, newlineIndex);
        textBuffer = textBuffer.slice(newlineIndex + 1);
        if (line.endsWith("\r")) line = line.slice(0, -1);
        if (line.startsWith(":") || line.trim() === "") continue;
        if (!line.startsWith("data: ")) continue;
        const jsonStr = line.slice(6).trim();
        if (jsonStr === "[DONE]") { streamDone = true; break; }
        try {
          const parsed = JSON.parse(jsonStr);
          const content = parsed.choices?.[0]?.delta?.content as string | undefined;
          if (content) onDelta(content);
        } catch {
          textBuffer = line + "\n" + textBuffer;
          break;
        }
      }
    }

    if (textBuffer.trim()) {
      for (let raw of textBuffer.split("\n")) {
        if (!raw) continue;
        if (raw.endsWith("\r")) raw = raw.slice(0, -1);
        if (raw.startsWith(":") || raw.trim() === "") continue;
        if (!raw.startsWith("data: ")) continue;
        const jsonStr = raw.slice(6).trim();
        if (jsonStr === "[DONE]") continue;
        try {
          const parsed = JSON.parse(jsonStr);
          const content = parsed.choices?.[0]?.delta?.content as string | undefined;
          if (content) onDelta(content);
        } catch { /* ignore */ }
      }
    }

    onDone();
  } catch (error) {
    console.error("Stream chat error:", error);
    onError(error instanceof Error ? error.message : "An unexpected error occurred");
  }
}