import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import { splitWithDimensions } from "../gridSplitter";
import { uploadBlobToGatewayMedia } from "@/utils/gatewayMediaUpload";

vi.mock("@/utils/gatewayMediaUpload", () => ({
  uploadBlobToGatewayMedia: vi.fn(async () => ({ url: "https://media.example/split.png" })),
}));

class MockImage {
  width = 100;
  height = 100;
  onload: (() => void) | null = null;
  onerror: (() => void) | null = null;

  set src(_value: string) {
    queueMicrotask(() => this.onload?.());
  }
}

function mockCanvas() {
  return {
    width: 0,
    height: 0,
    getContext: vi.fn(() => ({
      drawImage: vi.fn(),
    })),
    toBlob: vi.fn((callback: (blob: Blob | null) => void) => {
      callback(new Blob(["split"], { type: "image/png" }));
    }),
  } as unknown as HTMLCanvasElement;
}

describe("gridSplitter", () => {
  const originalCreateElement = document.createElement.bind(document);

  beforeEach(() => {
    vi.clearAllMocks();
    vi.stubGlobal("Image", MockImage);
    vi.stubGlobal("fetch", vi.fn(async () => ({
      ok: true,
      blob: async () => new Blob(["source"], { type: "image/png" }),
    })));
    vi.stubGlobal("URL", {
      ...URL,
      createObjectURL: vi.fn(() => "blob:canvas-safe-source"),
      revokeObjectURL: vi.fn(),
    });
    vi.spyOn(document, "createElement").mockImplementation((tagName: string) => {
      if (tagName === "canvas") return mockCanvas();
      return originalCreateElement(tagName);
    });
  });

  afterEach(() => {
    vi.unstubAllGlobals();
    vi.restoreAllMocks();
  });

  it("loads remote images through the media proxy before canvas splitting", async () => {
    const result = await splitWithDimensions("https://remote.example/grid.png", 1, 1);

    expect(fetch).toHaveBeenCalledWith(
      `/api/proxy-media?url=${encodeURIComponent("https://remote.example/grid.png")}`
    );
    expect(URL.createObjectURL).toHaveBeenCalled();
    expect(URL.revokeObjectURL).toHaveBeenCalledWith("blob:canvas-safe-source");
    expect(uploadBlobToGatewayMedia).toHaveBeenCalledWith(
      expect.any(Blob),
      expect.stringMatching(/^grid-cell-\d+-1\.png$/),
      "image/png",
      "image"
    );
    expect(result.images).toEqual(["https://media.example/split.png"]);
  });
});