import { describe, it, expect, vi, beforeEach, Mock } from "vitest";
// Mock modules with inline factories to avoid vitest hoisting issues.
vi.mock("electron", () => {
  const dialogMocks = {
    showOpenDialog: vi.fn(),
    showSaveDialog: vi.fn(),
  };
  return { dialog: dialogMocks };
});

vi.mock("node:fs", () => {
  const fsMocks = {
    existsSync: vi.fn(),
    readFileSync: vi.fn(),
    writeFileSync: vi.fn(),
    createReadStream: vi.fn(),
    mkdirSync: vi.fn(),
  };
  return {
    default: fsMocks,
    existsSync: fsMocks.existsSync,
    readFileSync: fsMocks.readFileSync,
    writeFileSync: fsMocks.writeFileSync,
    createReadStream: fsMocks.createReadStream,
    mkdirSync: fsMocks.mkdirSync,
  };
});

vi.mock("fs/promises", () => ({
  readFile: vi.fn(),
  writeFile: vi.fn(),
  stat: vi.fn(),
  rm: vi.fn(),
}));

import { dialog } from "electron";
import fs from "node:fs";
import * as fsp from "fs/promises";
import path from "node:path";

describe("File Operations and Utilities", () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  describe("select-file IPC handler", () => {
    it("should handle successful file selection", async () => {
      const mockResult = {
        canceled: false,
        filePaths: ["/path/to/file1.txt", "/path/to/file2.pdf"],
      };

      (dialog.showOpenDialog as Mock).mockResolvedValue(mockResult);

      const result = await dialog.showOpenDialog({} as any, {
        properties: ["openFile", "multiSelections"],
      });

      expect(result.canceled).toBe(false);
      expect(result.filePaths).toHaveLength(2);
      expect(result.filePaths[0]).toContain(".txt");
      expect(result.filePaths[1]).toContain(".pdf");
    });

    it("should handle cancelled file selection", async () => {
      const mockResult = {
        canceled: true,
        filePaths: [],
      };

      (dialog.showOpenDialog as Mock).mockResolvedValue(mockResult);

      const result = await dialog.showOpenDialog({} as any, {
        properties: ["openFile", "multiSelections"],
      });

      expect(result.canceled).toBe(true);
      expect(result.filePaths).toHaveLength(0);
    });

    it("should handle file selection with filters", async () => {
      const options = {
        properties: ["openFile"] as const,
        filters: [
          { name: "Text Files", extensions: ["txt", "md"] },
          { name: "PDF Files", extensions: ["pdf"] },
          { name: "All Files", extensions: ["*"] },
        ],
      };

      expect(options.filters).toHaveLength(3);
      expect(options.filters[0].extensions).toContain("txt");
      expect(options.filters[1].extensions).toContain("pdf");
    });

    it("should process successful file selection result", () => {
      const result = {
        canceled: false,
        filePaths: ["/path/to/selected/file.txt"],
      };

      if (!result.canceled && result.filePaths.length > 0) {
        const firstFile = result.filePaths[0];
        const fileName = path.basename(firstFile);
        const fileExt = path.extname(firstFile);

        expect(fileName).toBe("file.txt");
        expect(fileExt).toBe(".txt");
      }
    });
  });

  describe("read-file IPC handler", () => {
    it("should successfully read file content", async () => {
      const mockContent = "This is the file content\nWith multiple lines";
      (fsp.readFile as Mock).mockResolvedValue(mockContent);

      const content = await fsp.readFile("/path/to/file.txt", "utf-8");

      expect(content).toBe(mockContent);
      expect(content).toContain("multiple lines");
    });

    it("should handle file read errors", async () => {
      const error = new Error("ENOENT: no such file or directory");
      (fsp.readFile as Mock).mockRejectedValue(error);

      try {
        await fsp.readFile("/nonexistent/file.txt", "utf-8");
      } catch (e) {
        expect(e).toBeInstanceOf(Error);
        expect((e as Error).message).toContain("no such file or directory");
      }
    });

    it("should handle different file encodings", async () => {
      const mockContent = Buffer.from("Binary content");
      (fsp.readFile as Mock).mockResolvedValue(mockContent);

      const content = await fsp.readFile("/path/to/binary.bin");

      expect(Buffer.isBuffer(content)).toBe(true);
    });

    it("should validate file path", () => {
      const filePath = path.normalize("/path/to/file.txt");
      const isAbsolute = path.isAbsolute(filePath);
      const normalizedPath = path.normalize(filePath);

      expect(isAbsolute).toBe(true);
      expect(normalizedPath).toBe(filePath);
    });
  });

  describe("reveal-in-folder IPC handler", () => {
    it("should handle valid file path", () => {
      const filePath = "/Users/test/Documents/file.txt";
      const isValid = path.isAbsolute(filePath) && filePath.length > 0;

      expect(isValid).toBe(true);
    });

    it("should handle invalid file path", () => {
      const filePath = "";
      const isValid = path.isAbsolute(filePath) && filePath.length > 0;

      expect(isValid).toBe(false);
    });

    it("should normalize file path", () => {
      const filePath = "/Users/test/../test/Documents/./file.txt";
      const normalized = path.normalize(filePath);

      expect(normalized).toBe(path.normalize("/Users/test/Documents/file.txt"));
    });

    it("should extract directory from file path", () => {
      const filePath = "/Users/test/Documents/file.txt";
      const directory = path.dirname(filePath);

      expect(path.normalize(directory)).toBe(
        path.normalize("/Users/test/Documents")
      );
    });
  });

  describe("File System Utilities", () => {
    it("should check file existence", () => {
      (fs.existsSync as Mock).mockReturnValue(true);

      const exists = fs.existsSync("/path/to/file.txt");
      expect(exists).toBe(true);
    });

    it("should handle non-existent files", () => {
      (fs.existsSync as Mock).mockReturnValue(false);

      const exists = fs.existsSync("/path/to/nonexistent.txt");
      expect(exists).toBe(false);
    });

    it("should create directory path", () => {
      const dirPath = "/path/to/new/directory";
      const mockMkdirSync = vi.fn();
      vi.mocked(fs).mkdirSync = mockMkdirSync;

      fs.mkdirSync(dirPath, { recursive: true });

      expect(mockMkdirSync).toHaveBeenCalledWith(dirPath, { recursive: true });
    });

    it("should handle path operations", () => {
      const filePath = "/Users/test/Documents/file.txt";

      const basename = path.basename(filePath);
      const dirname = path.dirname(filePath);
      const extname = path.extname(filePath);
      const parsed = path.parse(filePath);

      expect(basename).toBe("file.txt");
      expect(path.normalize(dirname)).toBe(
        path.normalize("/Users/test/Documents")
      );
      expect(extname).toBe(".txt");
      expect(parsed.name).toBe("file");
      expect(parsed.ext).toBe(".txt");
    });
  });

  describe("File Validation", () => {
    it("should validate file extension", () => {
      const allowedExtensions = [".txt", ".md", ".json", ".pdf"];
      const filePath = "/path/to/document.pdf";
      const fileExt = path.extname(filePath);

      const isAllowed = allowedExtensions.includes(fileExt);
      expect(isAllowed).toBe(true);
    });

    it("should reject invalid file extension", () => {
      const allowedExtensions = [".txt", ".md", ".json"];
      const filePath = "/path/to/executable.exe";
      const fileExt = path.extname(filePath);

      const isAllowed = allowedExtensions.includes(fileExt);
      expect(isAllowed).toBe(false);
    });

    it("should validate file size", () => {
      const maxSize = 10 * 1024 * 1024; // 10MB
      const mockStats = { size: 5 * 1024 * 1024 }; // 5MB

      const isValidSize = mockStats.size <= maxSize;
      expect(isValidSize).toBe(true);
    });

    it("should reject files that are too large", () => {
      const maxSize = 10 * 1024 * 1024; // 10MB
      const mockStats = { size: 20 * 1024 * 1024 }; // 20MB

      const isValidSize = mockStats.size <= maxSize;
      expect(isValidSize).toBe(false);
    });
  });

  describe("File Content Processing", () => {
    it("should process text file content", () => {
      const content = "Line 1\nLine 2\nLine 3";
      const lines = content.split("\n");

      expect(lines).toHaveLength(3);
      expect(lines[0]).toBe("Line 1");
      expect(lines[2]).toBe("Line 3");
    });

    it("should handle empty file content", () => {
      const content = "";
      const lines = content.split("\n");

      expect(lines).toHaveLength(1);
      expect(lines[0]).toBe("");
    });

    it("should process CSV-like content", () => {
      const content =
        "name,age,email\nJohn,30,john@example.com\nJane,25,jane@example.com";
      const lines = content.split("\n");
      const headers = lines[0].split(",");

      expect(headers).toEqual(["name", "age", "email"]);
      expect(lines).toHaveLength(3);
    });

    it("should handle binary file detection", () => {
      const textContent = "This is regular text content";
      const binaryContent = Buffer.from([0x00, 0x01, 0x02, 0xff]);

      const isText = typeof textContent === "string";
      const isBinary = Buffer.isBuffer(binaryContent);

      expect(isText).toBe(true);
      expect(isBinary).toBe(true);
    });
  });

  describe("File Stream Operations", () => {
    it("should create readable stream", () => {
      const mockCreateReadStream = vi.fn().mockReturnValue({
        pipe: vi.fn(),
        on: vi.fn(),
        destroy: vi.fn(),
      });

      vi.mocked(fs).createReadStream = mockCreateReadStream;

      const stream = fs.createReadStream("/path/to/file.txt");

      expect(mockCreateReadStream).toHaveBeenCalledWith("/path/to/file.txt");
      expect(stream.pipe).toBeDefined();
      expect(stream.on).toBeDefined();
    });

    it("should handle stream errors", () => {
      const mockStream = {
        on: vi.fn((event, callback) => {
          if (event === "error") {
            setTimeout(() => callback(new Error("Stream error")), 0);
          }
        }),
        destroy: vi.fn(),
      };

      let errorReceived = false;
      mockStream.on("error", (error) => {
        errorReceived = true;
        expect(error.message).toBe("Stream error");
      });

      setTimeout(() => {
        expect(errorReceived).toBe(true);
      }, 10);
    });

    it("should cleanup stream resources", () => {
      const mockStream = {
        destroy: vi.fn(),
        on: vi.fn(),
      };

      // Simulate cleanup
      if (mockStream && typeof mockStream.destroy === "function") {
        mockStream.destroy();
      }

      expect(mockStream.destroy).toHaveBeenCalled();
    });
  });
});