import test from "node:test";
import assert from "node:assert/strict";
import {createStreamRenderer} from "../public/js/streamRenderer.js";
import {createTextStreamEvents} from "../src/services/streamEvents.js";

test("streaming sends linear-sized deltas, applies replacements and batches rendering", () => {
    const events = [], frames = new Map(), rendered = [];
    let nextId = 0;
    const renderer = createStreamRenderer({
        onReply: text => rendered.push(["reply", text]), onThinking: text => rendered.push(["thinking", text]),
        schedule: callback => { frames.set(++nextId, callback); return nextId; }, cancel: id => frames.delete(id)
    });
    const emit = createTextStreamEvents((type, data) => {
        events.push({type, data});
        renderer[{chunk: "onChunk", thinking: "onThinking", replace: "onReplace"}[type]](data);
    });
    for (let i = 0; i < 1000; i++) emit.onChunk("a", "a".repeat(i + 1));
    assert.equal(JSON.stringify(events).length < 45000, true);
    assert.equal(frames.size, 1);
    assert.equal(rendered.length, 0);
    renderer.flush();
    assert.deepEqual(rendered, [["reply", "a".repeat(1000)]]);
    emit.onThinking("provisional", "provisional");
    emit.onThinking("", ""); emit.onChunk("", "");
    emit.onChunk("Corrected", "Corrected");
    renderer.flush();
    assert.deepEqual(rendered.slice(1), [["thinking", ""], ["reply", "Corrected"]]);
    assert.ok(events.some(event => event.type === "replace" && event.data.target === "reply"));
    renderer.onChunk({chunk: " stale"});
    renderer.dispose();
    assert.equal(frames.size, 0);
    renderer.flush();
    assert.equal(rendered.at(-1)[1], "Corrected");
    renderer.onChunk({chunk: "", fullReply: ""});
    renderer.onChunk({chunk: "Legacy", fullReply: "Legacy"});
    renderer.flush();
    assert.equal(rendered.at(-1)[1], "Legacy");
});