import type { SpawnSyncReturns } from "child_process";
import { beforeEach, describe, expect, test, vi } from "vitest";

const mocks = vi.hoisted(() => {
  return {
    spawnSync:
      vi.fn<
        (
          command: string,
          args: string[],
          options: unknown,
        ) => SpawnSyncReturns<Buffer>
      >(),
    clipboard: {
      hasImage: vi.fn<() => boolean>(),
      getImageBinary: vi.fn<() => Promise<Uint8Array | null>>(),
    },
  };
});

vi.mock("child_process", () => {
  return {
    spawnSync: mocks.spawnSync,
  };
});

vi.mock("../src/utils/clipboard-native.js", () => {
  return {
    clipboard: mocks.clipboard,
  };
});

function spawnOk(stdout: Buffer): SpawnSyncReturns<Buffer> {
  return {
    pid: 123,
    output: [Buffer.alloc(0), stdout, Buffer.alloc(0)],
    stdout,
    stderr: Buffer.alloc(0),
    status: 0,
    signal: null,
  };
}

function spawnError(error: Error): SpawnSyncReturns<Buffer> {
  return {
    pid: 123,
    output: [Buffer.alloc(0), Buffer.alloc(0), Buffer.alloc(0)],
    stdout: Buffer.alloc(0),
    stderr: Buffer.alloc(0),
    status: null,
    signal: null,
    error,
  };
}

describe("readClipboardImage", () => {
  beforeEach(() => {
    vi.resetModules();
    mocks.spawnSync.mockReset();
    mocks.clipboard.hasImage.mockReset();
    mocks.clipboard.getImageBinary.mockReset();
  });

  test("Wayland: uses wl-paste and never calls clipboard", async () => {
    mocks.clipboard.hasImage.mockImplementation(() => {
      throw new Error("clipboard.hasImage should not be called on Wayland");
    });

    mocks.spawnSync.mockImplementation((command, args, _options) => {
      if (command === "wl-paste" && args[0] === "--list-types") {
        return spawnOk(Buffer.from("text/plain\nimage/png\n", "utf-8"));
      }
      if (command === "wl-paste" && args[0] === "--type") {
        return spawnOk(Buffer.from([1, 2, 3]));
      }
      throw new Error(
        `Unexpected spawnSync call: ${command} ${args.join(" ")}`,
      );
    });

    const { readClipboardImage } =
      await import("../src/utils/clipboard-image.js");
    const result = await readClipboardImage({
      platform: "linux",
      env: { WAYLAND_DISPLAY: "1" },
    });
    expect(result).not.toBeNull();
    expect(result?.mimeType).toBe("image/png");
    expect(Array.from(result?.bytes ?? [])).toEqual([1, 2, 3]);
  });

  test("Wayland: falls back to xclip when wl-paste is missing", async () => {
    mocks.clipboard.hasImage.mockImplementation(() => {
      throw new Error("clipboard.hasImage should not be called on Wayland");
    });

    const enoent = new Error("spawn ENOENT");
    (enoent as { code?: string }).code = "ENOENT";

    mocks.spawnSync.mockImplementation((command, args, _options) => {
      if (command === "wl-paste") {
        return spawnError(enoent);
      }

      if (command === "xclip" && args.includes("TARGETS")) {
        return spawnOk(Buffer.from("image/png\n", "utf-8"));
      }

      if (command === "xclip" && args.includes("image/png")) {
        return spawnOk(Buffer.from([9, 8]));
      }

      return spawnOk(Buffer.alloc(0));
    });

    const { readClipboardImage } =
      await import("../src/utils/clipboard-image.js");
    const result = await readClipboardImage({
      platform: "linux",
      env: { XDG_SESSION_TYPE: "wayland" },
    });
    expect(result).not.toBeNull();
    expect(result?.mimeType).toBe("image/png");
    expect(Array.from(result?.bytes ?? [])).toEqual([9, 8]);
  });

  test("Non-Wayland: uses clipboard", async () => {
    mocks.spawnSync.mockImplementation(() => {
      throw new Error(
        "spawnSync should not be called for non-Wayland sessions",
      );
    });

    mocks.clipboard.hasImage.mockReturnValue(true);
    mocks.clipboard.getImageBinary.mockResolvedValue(new Uint8Array([7]));

    const { readClipboardImage } =
      await import("../src/utils/clipboard-image.js");
    const result = await readClipboardImage({ platform: "linux", env: {} });
    expect(result).not.toBeNull();
    expect(result?.mimeType).toBe("image/png");
    expect(Array.from(result?.bytes ?? [])).toEqual([7]);
  });

  test("Non-Wayland: returns null when clipboard has no image", async () => {
    mocks.spawnSync.mockImplementation(() => {
      throw new Error(
        "spawnSync should not be called for non-Wayland sessions",
      );
    });

    mocks.clipboard.hasImage.mockReturnValue(false);

    const { readClipboardImage } =
      await import("../src/utils/clipboard-image.js");
    const result = await readClipboardImage({ platform: "linux", env: {} });
    expect(result).toBeNull();
  });
});