/**
 * @file config-write.test.js
 * @description Tests for the shared safe-write primitives (atomicWriteFile,
 * createBackup, assertUnder) that cc-mutate.js and the Codex config writer
 * both depend on.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const { describe, it } = require("node:test");
const assert = require("node:assert/strict");
const fs = require("node:fs");
const path = require("node:path");
const os = require("node:os");

const { atomicWriteFile, createBackup, assertUnder } = require("../lib/config-write");

describe("atomicWriteFile", () => {
  it("leaves no temp file behind after a successful write", () => {
    const dir = fs.mkdtempSync(path.join(os.tmpdir(), "cw-"));
    atomicWriteFile(path.join(dir, "a.md"), "body");
    assert.equal(fs.readFileSync(path.join(dir, "a.md"), "utf8"), "body");
    assert.deepEqual(fs.readdirSync(dir), ["a.md"]);
  });
});

describe("createBackup", () => {
  it("backs a directory up as a tree, not a single file", () => {
    const dir = fs.mkdtempSync(path.join(os.tmpdir(), "cw-"));
    fs.mkdirSync(path.join(dir, "src", "sk"), { recursive: true });
    fs.writeFileSync(path.join(dir, "src", "sk", "SKILL.md"), "x");
    const out = createBackup({
      source: path.join(dir, "src", "sk"),
      backupRoot: path.join(dir, "bak"),
      type: "skills",
      name: "sk",
    });
    assert.ok(fs.existsSync(path.join(out, "SKILL.md")));
  });

  it("returns null when the source does not exist", () => {
    const dir = fs.mkdtempSync(path.join(os.tmpdir(), "cw-"));
    const out = createBackup({
      source: path.join(dir, "missing"),
      backupRoot: path.join(dir, "bak"),
      type: "agents",
      name: "missing",
    });
    assert.equal(out, null);
  });
});

describe("assertUnder", () => {
  it("rejects a target outside the root", () => {
    assert.throws(
      () => assertUnder("/a/b", "/a/c/x"),
      (e) => e.code === "EOUTOFROOT"
    );
  });

  it("allows a target under the root", () => {
    assert.doesNotThrow(() => assertUnder("/a/b", "/a/b/c"));
  });
});