import { getCurrentDocumentFile, DOCX_CONTENT_TYPE } from "./fileService";

interface FileMockState {
  getFileCalls: number;
  requestedSlices: number[];
  closeCalls: number;
}

/** mock Office.context.document.getFileAsync + File.getSliceAsync/closeAsync */
function installOfficeFileMock(
  slices: Uint8Array[],
  options: { failSliceIndex?: number; failClose?: boolean; sliceDataForm?: "buffer" | "view" } = {}
): FileMockState {
  const state: FileMockState = { getFileCalls: 0, requestedSlices: [], closeCalls: 0 };

  const file = {
    sliceCount: slices.length,
    getSliceAsync: (index: number, callback: (result: unknown) => void) => {
      state.requestedSlices.push(index);
      if (options.failSliceIndex === index) {
        callback({ status: "failed", error: { message: `อ่าน slice ${index} พัง (mock)` } });
      } else {
        // host จริงอาจส่งมาเป็น ArrayBuffer หรือ view — ทดสอบทั้งคู่
        const data = options.sliceDataForm === "view" ? slices[index] : slices[index].buffer;
        callback({ status: "succeeded", value: { index, data, size: slices[index].byteLength } });
      }
    },
    closeAsync: (callback?: (result: unknown) => void) => {
      state.closeCalls++;
      callback?.({ status: options.failClose ? "failed" : "succeeded" });
    },
  };

  (globalThis as unknown as Record<string, unknown>).Office = {
    FileType: { Compressed: "compressed", Text: "text" },
    AsyncResultStatus: { Succeeded: "succeeded", Failed: "failed" },
    context: {
      document: {
        getFileAsync: (
          _fileType: unknown,
          _options: unknown,
          callback: (result: unknown) => void
        ) => {
          state.getFileCalls++;
          callback({ status: "succeeded", value: file });
        },
      },
    },
  };

  return state;
}

function bytes(...values: number[]): Uint8Array {
  return new Uint8Array(values);
}

describe("getCurrentDocumentFile", () => {
  it("ประกอบ slice หลากขนาดเป็น Blob เดียว อ่านครบทุก slice ตามลำดับ และ closeAsync หนึ่งครั้ง", async () => {
    const state = installOfficeFileMock([
      bytes(1, 2, 3),
      bytes(4, 5),
      new Uint8Array(2048).fill(9),
    ]);

    const blob = await getCurrentDocumentFile();

    expect(blob.type).toBe(DOCX_CONTENT_TYPE);
    expect(blob.size).toBe(3 + 2 + 2048);
    expect(state.requestedSlices).toEqual([0, 1, 2]);
    expect(state.getFileCalls).toBe(1);
    expect(state.closeCalls).toBe(1);
  });

  it("slice มาเป็น typed array view (ไม่ใช่ ArrayBuffer) ก็ประกอบได้", async () => {
    const state = installOfficeFileMock([bytes(10, 20), bytes(30)], { sliceDataForm: "view" });

    const blob = await getCurrentDocumentFile();

    expect(blob.size).toBe(3);
    expect(state.closeCalls).toBe(1);
  });

  it("อ่าน slice กลางที่พัง → reject พร้อม error แต่ยังเรียก closeAsync เสมอ", async () => {
    const state = installOfficeFileMock([bytes(1), bytes(2), bytes(3)], { failSliceIndex: 1 });

    await expect(getCurrentDocumentFile()).rejects.toThrow("อ่าน slice 1 พัง (mock)");
    expect(state.closeCalls).toBe(1);
    expect(state.requestedSlices).toEqual([0, 1]);
  });

  it("closeAsync fail เอง → ไม่ทำ flow พัง (blob ยังคืนมา)", async () => {
    installOfficeFileMock([bytes(7, 8, 9)], { failClose: true });

    const blob = await getCurrentDocumentFile();
    expect(blob.size).toBe(3);
  });
});