/**
 * @file Ersetzt eine Antwort während der Neugenerierung in ihrer Nachrichtenkarte und stellt sie bei Fehlern wieder her.
 */
import {stream} from "./api.js";
import {updateReasoning, finishReasoning} from "./reasoning.js";
import {appendSources} from "./webSearch.js";

// Keep the original nodes (including action handlers) until a committed answer arrives.
export async function regenerateInline({card, scroller, endpoint, payload, renderContent, complete}) {
    const original = [...card.childNodes];
    const status = document.createElement("div");
    status.className = "loading-shell";
    status.setAttribute("role", "status");
    status.textContent = "Generating...";
    const body = document.createElement("div");
    body.className = "msg-content streaming-content";
    let committed = false;
    const update = operation => {
        const bottom = card.getBoundingClientRect().bottom;
        const viewport = scroller.getBoundingClientRect();
        const follow = bottom >= viewport.top && Math.abs(bottom - viewport.bottom) < 100;
        operation();
        if (follow) scroller.scrollTop += card.getBoundingClientRect().bottom - bottom;
    };
    // Anchor to this response, including when a long old answer collapses.
    update(() => card.replaceChildren(original[0].cloneNode(true), status, body));
    card.setAttribute("aria-busy", "true");
    try {
        await stream(endpoint, payload, {
            onStatus: data => update(() => {
                status.textContent = data.status === "searching" ? "Searching the web..."
                    : data.status === "analyzing" ? "Analyzing attachments..." : "Generating...";
                if ("sources" in data) {
                    card.querySelector(".msg-sources")?.remove();
                    appendSources(card, data.sources);
                }
            }),
            onThinking: ({fullThinking}) => update(() => updateReasoning(card, fullThinking, true)),
            onChunk: ({fullReply}) => update(() => {
                status.hidden = Boolean(fullReply);
                if (fullReply) finishReasoning(card);
                renderContent(body, fullReply);
            }),
            onError: ({error}) => { throw new Error(error || "Unable to regenerate message."); },
            onDone: ({message}) => {
                if (!message) throw new Error("Missing regenerated response.");
                update(() => complete(message));
                committed = true;
            }
        });
    } finally {
        // Bei Fehler oder Abbruch die ursprünglichen Knoten samt Ereignishandlern wieder einsetzen.
        if (!committed) update(() => card.replaceChildren(...original));
        card.removeAttribute("aria-busy");
    }
}