/**
 * @file Tests the data-directory resolution in claude-home.js, and the one-time
 * migration that carries an existing `~/.claude/agent-dashboard` (the name the
 * product used before the AgentHub rebrand) over to `~/.claude/agenthub`.
 *
 * The stakes are why this is tested at all: that directory holds the live
 * SQLite database. Resolving to the new path when the data is still under the
 * old one would not lose the data, but it WOULD silently start an empty
 * dashboard, which looks exactly like data loss to whoever opens it.
 *
 * The split matters as much as the migration. `getDataDir()` is a getter that
 * gets asked for the path by tests, doctors and `--help`; if it also moved
 * directories, every one of those would relocate a multi-gigabyte database as a
 * side effect. So it is asserted pure here, and the move lives in its own
 * function that only server startup calls.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const os = require("node:os");
const path = require("node:path");
const fs = require("node:fs");

const { describe, it, beforeEach, after } = require("node:test");
const assert = require("node:assert/strict");

const SUITE_ROOT = fs.mkdtempSync(path.join(os.tmpdir(), "agenthub-datadir-"));
after(() => fs.rmSync(SUITE_ROOT, { recursive: true, force: true }));

// claude-home reads CLAUDE_HOME on every call, so each test can point it
// somewhere fresh without reloading the module.
const {
  getDataDir,
  migrateLegacyDataDir,
  getTranscriptSnapshotDir,
} = require("../lib/claude-home");

let home;
let seq = 0;

beforeEach(() => {
  seq += 1;
  home = path.join(SUITE_ROOT, `home${seq}`, ".claude");
  fs.mkdirSync(home, { recursive: true });
  process.env.CLAUDE_HOME = home;
  delete process.env.DASHBOARD_DATA_DIR;
});

const legacy = () => path.join(home, "agent-dashboard");
const current = () => path.join(home, "agenthub");

/** Put a recognisable database in `dir` so a migration can be proven. */
function seedDataDir(dir, marker) {
  fs.mkdirSync(path.join(dir, "transcripts"), { recursive: true });
  fs.writeFileSync(path.join(dir, "dashboard.db"), marker);
}

describe("getDataDir", () => {
  it("uses the new name on a fresh install", () => {
    assert.equal(getDataDir(), current());
  });

  it("resolves to the legacy directory until it is migrated, and moves nothing", () => {
    seedDataDir(legacy(), "the-real-database");

    assert.equal(getDataDir(), legacy(), "the data is still there, so that is the answer");
    assert.deepEqual(fs.readdirSync(home), ["agent-dashboard"], "resolving must not move anything");
  });

  it("prefers the new directory once both exist", () => {
    seedDataDir(legacy(), "old");
    seedDataDir(current(), "new");

    assert.equal(getDataDir(), current());
  });

  it("lets DASHBOARD_DATA_DIR win", () => {
    seedDataDir(legacy(), "db");
    const pinned = path.join(SUITE_ROOT, `pinned${seq}`);
    process.env.DASHBOARD_DATA_DIR = pinned;

    assert.equal(getDataDir(), pinned);
  });

  it("derives the transcript snapshot dir from the migrated location", () => {
    seedDataDir(legacy(), "db");
    migrateLegacyDataDir();
    assert.equal(getTranscriptSnapshotDir(), path.join(current(), "transcripts"));
  });
});

describe("migrateLegacyDataDir", () => {
  it("moves an existing legacy directory to the new name, keeping its contents", () => {
    seedDataDir(legacy(), "the-real-database");

    assert.equal(migrateLegacyDataDir(), current());
    assert.equal(fs.existsSync(legacy()), false, "the legacy directory should be gone");
    assert.equal(
      fs.readFileSync(path.join(current(), "dashboard.db"), "utf8"),
      "the-real-database"
    );
    assert.ok(fs.existsSync(path.join(current(), "transcripts")), "nested content must survive");
    assert.equal(getDataDir(), current());
  });

  it("does nothing on a fresh install", () => {
    assert.equal(migrateLegacyDataDir(), null);
    assert.deepEqual(fs.readdirSync(home), [], "no directory should be created just by migrating");
  });

  it("migrates once and stays put on later calls", () => {
    seedDataDir(legacy(), "db");
    migrateLegacyDataDir();
    fs.writeFileSync(path.join(current(), "dashboard.db"), "written-after-migration");

    assert.equal(migrateLegacyDataDir(), null);
    assert.equal(
      fs.readFileSync(path.join(current(), "dashboard.db"), "utf8"),
      "written-after-migration",
      "a second call must not re-migrate over newer data"
    );
  });

  it("leaves both alone when the new directory already exists", () => {
    // Nothing sensible to merge here, and picking wrong would hide a database:
    // the new one wins and the legacy one is left untouched for the user.
    seedDataDir(legacy(), "old");
    seedDataDir(current(), "new");

    assert.equal(migrateLegacyDataDir(), null);
    assert.equal(fs.readFileSync(path.join(current(), "dashboard.db"), "utf8"), "new");
    assert.equal(fs.readFileSync(path.join(legacy(), "dashboard.db"), "utf8"), "old");
  });

  it("keeps using the legacy directory when it cannot be moved", () => {
    // A read-only Claude home makes the rename fail. Starting a blank database
    // beside 2 GB of unreachable history is the one outcome worth avoiding.
    seedDataDir(legacy(), "db");
    fs.chmodSync(home, 0o500);
    try {
      assert.equal(migrateLegacyDataDir(), null, "a failed move must not be reported as done");
      assert.equal(getDataDir(), legacy());
    } finally {
      fs.chmodSync(home, 0o700);
    }
  });

  it("never migrates behind an explicit DASHBOARD_DATA_DIR", () => {
    seedDataDir(legacy(), "db");
    process.env.DASHBOARD_DATA_DIR = path.join(SUITE_ROOT, `pinned${seq}`);

    assert.equal(migrateLegacyDataDir(), null);
    assert.ok(fs.existsSync(legacy()), "an explicit data dir must not trigger a migration");
  });
});