src/utils/beam.ts

import {Settings} from "@/contexts/settings";
import {LogAction} from "@/contexts/log";

export async function* streamAPI(
    prompt: string,
    settings: Settings,
    log: LogAction,
): AsyncGenerator<string> {
    log(`Fetching ${settings.postCount} posts from Beam API…`);
    const response = await fetch(new URL(settings.apiURL), {
        method: "POST",
        headers: {
            "Content-Type": "application/json",
            "Accept": "text/event-stream",
            "Authorization": `Bearer ${settings.apiKey}`
        },
        body: JSON.stringify({
            "prompt": prompt,
            "posts_count": settings.postCount,
            "temperature": settings.temperature,
        }),
    });

    if (!response.ok) {
        const message = `Failed to fetch API (${response.status} ${response.statusText}): ${await response.text()}`;
        log(message);
        throw new Error(message);
    }

    log("Reading HTTP stream…");
    try {
        const decoder = new TextDecoder();
        for await (const chunk of response.body) {
            const text = decoder.decode(chunk, { stream: true });
            yield text;
        }
        log("Stream reading completed.");
    } catch(e) {
        log("Error while reading the HTTP stream.")
    }
}