import { mkdir, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { afterAll, beforeAll, describe, expect, it } from "vitest";
import { readFileTool } from "../src/tools/read-file.js";

const testDir = join(tmpdir(), `read-file-test-${Date.now()}`);
const ctx = { cwd: testDir, storageRoot: testDir };

beforeAll(async () => {
  await mkdir(testDir, { recursive: true });
  await writeFile(join(testDir, "hello.txt"), "hello world", "utf8");
});

afterAll(async () => {
  await rm(testDir, { recursive: true, force: true });
});

describe("readFileTool", () => {
  it("reads a file successfully", async () => {
    const result = await readFileTool.execute({ path: "hello.txt" }, ctx);
    expect(result).toBe("hello world");
  });

  it("returns error for non-existent file", async () => {
    const result = await readFileTool.execute({ path: "nope.txt" }, ctx);
    expect(result).toMatch(/^Error:/);
  });

  it("returns error for directory", async () => {
    const result = await readFileTool.execute({ path: "." }, ctx);
    expect(result).toBe("Error: not a file");
  });

  it("returns error when path is not a string", async () => {
    const result = await readFileTool.execute({ path: 123 }, ctx);
    expect(result).toBe("Error: path must be a string");
  });

  it("returns error when args is null", async () => {
    const result = await readFileTool.execute(null, ctx);
    expect(result).toBe("Error: path must be a string");
  });

  it("returns error for file exceeding 512KB limit", async () => {
    const bigFile = join(testDir, "big.txt");
    await writeFile(bigFile, Buffer.alloc(512 * 1024 + 1, 65));
    const result = await readFileTool.execute({ path: "big.txt" }, ctx);
    expect(result).toMatch(/Error:.*limit/);
  });
});