import { test, expect } from "@playwright/test";
import { CanvasRevisionConflict, VideoCanvasSaveQueue } from "@/lib/video-canvas/save-queue";

test("coalesces edits made during a save and uses the returned revision", async () => {
  let release!: (value: string) => void;
  const calls: string[][] = [];
  const queue = new VideoCanvasSaveQueue("initial", "r0", async (value, revision) => {
    calls.push([value, revision]);
    return calls.length === 1 ? new Promise<string>(resolve => { release = resolve; }) : "r2";
  }, () => {});
  queue.update("first");
  const pending = queue.flush();
  queue.update("second");
  queue.update("latest");
  expect(queue.flush()).toBe(pending);
  release("r1");
  await pending;
  expect(calls).toEqual([["first", "r0"], ["latest", "r1"]]);
  expect(queue.dirty).toBe(false);
});

test("failed save retains edits and retries only the latest snapshot", async () => {
  const calls: string[][] = [];
  const queue = new VideoCanvasSaveQueue("initial", "r0", async (value, revision) => {
    calls.push([value, revision]);
    if (calls.length === 1) throw new Error("offline");
    return "r1";
  }, () => {});
  queue.update("first");
  await queue.flush();
  expect(queue.dirty).toBe(true);
  expect(queue.failed).toBe(true);
  queue.update("latest");
  await queue.flush();
  expect(calls).toEqual([["first", "r0"], ["latest", "r0"]]);
  expect(queue.dirty).toBe(false);
});

test("revision conflict cannot be retried as an overwrite", async () => {
  let calls = 0;
  const queue = new VideoCanvasSaveQueue("initial", "r0", async () => {
    calls++;
    throw new CanvasRevisionConflict("changed elsewhere");
  }, () => {});
  queue.update("first");
  await queue.flush();
  queue.update("latest");
  await queue.flush();
  expect(calls).toBe(1);
  expect(queue.dirty).toBe(true);
});

test("unchanged canvas does not write", async () => {
  let calls = 0;
  const queue = new VideoCanvasSaveQueue("initial", "r0", async () => { calls++; return "r1"; }, () => {});
  queue.update("initial");
  await queue.flush();
  expect(calls).toBe(0);
});