import fs from 'fs/promises';
import os from 'os';
import path from 'path';
import { afterEach, describe, expect, it } from 'vitest';
import {
  ANALYZE_FORCE_STORAGE_REQUIREMENTS,
  ANALYZE_STORAGE_REQUIREMENTS,
  INDEX_FORCE_STORAGE_REQUIREMENTS,
  InvalidStoragePathError,
  STORAGE_PATH_ENV,
  STORAGE_ROOT_ENV,
  requireDeletableStoragePath,
  requireStoragePath,
  StorageDeletionError,
  StorageRequirementError,
  defaultStoragePath,
  ensureStoragePathWritable,
  getIndexStorageRequirements,
  inspectStoragePath,
  resolveStoragePath,
  storagePathFromRoot,
  storageSlotName,
  validateConfiguredStoragePath,
} from '../../src/storage/storage-resolver.js';

const temporaryPaths: string[] = [];
const savedStoragePath = process.env[STORAGE_PATH_ENV];
const savedStorageRoot = process.env[STORAGE_ROOT_ENV];
const savedHome = process.env.GITNEXUS_HOME;

const makeTempDir = async (prefix: string): Promise<string> => {
  const dir = await fs.mkdtemp(path.join(os.tmpdir(), prefix));
  temporaryPaths.push(dir);
  return dir;
};

afterEach(async () => {
  if (savedStoragePath === undefined) delete process.env[STORAGE_PATH_ENV];
  else process.env[STORAGE_PATH_ENV] = savedStoragePath;
  if (savedStorageRoot === undefined) delete process.env[STORAGE_ROOT_ENV];
  else process.env[STORAGE_ROOT_ENV] = savedStorageRoot;
  if (savedHome === undefined) delete process.env.GITNEXUS_HOME;
  else process.env.GITNEXUS_HOME = savedHome;
  await Promise.all(
    temporaryPaths.splice(0).map((dir) => fs.rm(dir, { recursive: true, force: true })),
  );
});

describe('storage resolver', () => {
  it('keeps the repository-local default when no override or registration exists', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-repo-');
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];
    process.env.GITNEXUS_HOME = await makeTempDir('gitnexus-storage-resolver-home-');

    expect(resolveStoragePath(repo)).toBe(defaultStoragePath(repo));
  });

  it('uses an explicit complete storage path before a root or registered slot', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-repo-');
    const home = await makeTempDir('gitnexus-storage-resolver-home-');
    const registered = path.join(home, 'registered-index');
    const explicit = path.join(home, 'explicit-index');
    const root = path.join(home, 'external-root');
    process.env.GITNEXUS_HOME = home;
    await fs.writeFile(
      path.join(home, 'registry.json'),
      JSON.stringify([{ path: repo, storagePath: registered }]),
    );
    process.env[STORAGE_PATH_ENV] = explicit;
    process.env[STORAGE_ROOT_ENV] = root;

    expect(resolveStoragePath(repo)).toBe(explicit);
  });

  it('derives an isolated slot beneath an explicit storage root before the registered slot', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-repo-');
    const home = await makeTempDir('gitnexus-storage-resolver-home-');
    const registered = path.join(home, 'registered-index');
    const root = path.join(home, 'external-root');
    process.env.GITNEXUS_HOME = home;
    await fs.writeFile(
      path.join(home, 'registry.json'),
      JSON.stringify([{ path: repo, storagePath: registered }]),
    );
    delete process.env[STORAGE_PATH_ENV];
    process.env[STORAGE_ROOT_ENV] = root;

    expect(resolveStoragePath(repo)).toBe(storagePathFromRoot(root, repo));
  });

  it('uses a registered external slot after the explicit override is absent', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-repo-');
    const home = await makeTempDir('gitnexus-storage-resolver-home-');
    const registered = path.join(home, 'registered-index');
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];
    process.env.GITNEXUS_HOME = home;
    await fs.writeFile(
      path.join(home, 'registry.json'),
      JSON.stringify([{ path: repo, storagePath: registered }]),
    );

    expect(resolveStoragePath(repo)).toBe(registered);
  });

  it('uses a registered external slot when the repository is reached through a symlink', async () => {
    const root = await makeTempDir('gitnexus-storage-resolver-symlink-');
    const repo = path.join(root, 'repo');
    const linkedRepo = path.join(root, 'repo-link');
    const home = await makeTempDir('gitnexus-storage-resolver-home-');
    const registered = path.join(home, 'registered-index');
    await fs.mkdir(repo);
    await fs.symlink(repo, linkedRepo, process.platform === 'win32' ? 'junction' : 'dir');
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];
    process.env.GITNEXUS_HOME = home;
    await fs.writeFile(
      path.join(home, 'registry.json'),
      JSON.stringify([{ path: repo, storagePath: registered }]),
    );

    expect(resolveStoragePath(linkedRepo)).toBe(registered);
  });

  it.skipIf(process.platform !== 'win32')(
    'matches a registered missing repository through a Windows extended-length path',
    async () => {
      const home = await makeTempDir('gitnexus-storage-resolver-home-');
      const repo = path.join(home, 'removed-repository');
      const registered = path.join(home, 'registered-index');
      delete process.env[STORAGE_PATH_ENV];
      delete process.env[STORAGE_ROOT_ENV];
      process.env.GITNEXUS_HOME = home;
      await fs.writeFile(
        path.join(home, 'registry.json'),
        JSON.stringify([{ path: repo, storagePath: registered }]),
      );

      expect(resolveStoragePath(`\\\\?\\${repo}`)).toBe(registered);
    },
  );

  it('uses the repository-local default for a legacy registry row without storagePath', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-legacy-');
    const home = await makeTempDir('gitnexus-storage-resolver-home-');
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];
    process.env.GITNEXUS_HOME = home;
    await fs.writeFile(path.join(home, 'registry.json'), JSON.stringify([{ path: repo }]));

    expect(resolveStoragePath(repo)).toBe(defaultStoragePath(repo));
  });

  it('rejects a malformed matching registry row', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-repo-');
    const home = await makeTempDir('gitnexus-storage-resolver-home-');
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];
    process.env.GITNEXUS_HOME = home;
    await fs.writeFile(
      path.join(home, 'registry.json'),
      JSON.stringify([null, 1, [], { path: repo, storagePath: 1 }]),
    );

    expect(() => resolveStoragePath(repo)).toThrow(InvalidStoragePathError);
  });

  it.each(['', 'relative/index', `bad\0index`, path.parse(process.cwd()).root])(
    'rejects invalid configured storage path %j',
    (value) => {
      expect(() => validateConfiguredStoragePath(value)).toThrow(InvalidStoragePathError);
    },
  );

  it('strips trailing dots and spaces from a storage slot basename without a regex', () => {
    const slot = storageSlotName(path.join(path.sep, 'tmp', 'My Repo. . '));
    expect(slot.startsWith('My Repo-')).toBe(true);
    expect(slot).toMatch(/-[0-9a-f]{12}$/);
  });

  it('maps a Windows-reserved basename into a safe slot prefix', () => {
    const slot = storageSlotName(path.join(path.sep, 'tmp', 'CON'));
    expect(slot.startsWith('repository-CON-')).toBe(true);
  });

  it('trims an adversarial run of trailing spaces in linear time', () => {
    const slot = storageSlotName(path.join(path.sep, 'tmp', `keep${' '.repeat(10_000)}`));
    expect(slot.startsWith('keep-')).toBe(true);
  });

  it('rejects inspecting a filesystem-root storage path', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-root-repo-');
    const inspection = await inspectStoragePath(path.parse(process.cwd()).root, repo);
    expect(inspection.state).toBe('invalid_param');
  });

  it('creates independent external slots and verifies they are writable', async () => {
    const root = await makeTempDir('gitnexus-storage-resolver-slots-');
    const first = path.join(root, 'first');
    const second = path.join(root, 'second');

    await Promise.all([ensureStoragePathWritable(first), ensureStoragePathWritable(second)]);

    expect((await fs.stat(first)).isDirectory()).toBe(true);
    expect((await fs.stat(second)).isDirectory()).toBe(true);
  });

  it('fails before analysis when the target names a file instead of a writable directory', async () => {
    const root = await makeTempDir('gitnexus-storage-resolver-file-');
    const target = path.join(root, 'not-a-directory');
    await fs.writeFile(target, 'not a directory');

    await expect(ensureStoragePathWritable(target)).rejects.toThrow();
  });

  it('allows deletion of a missing or empty repository-local slot', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-delete-repo-');
    const storagePath = defaultStoragePath(repo);
    await fs.mkdir(storagePath, { recursive: true });

    await expect(requireDeletableStoragePath({ path: repo, storagePath })).resolves.toBe(
      storagePath,
    );
  });

  it('allows deletion of a repository-local slot whose metadata belongs to another repository', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-delete-repo-');
    const storagePath = defaultStoragePath(repo);
    await fs.mkdir(storagePath, { recursive: true });
    await fs.writeFile(
      path.join(storagePath, 'gitnexus.json'),
      JSON.stringify({ repoPath: path.join(path.dirname(repo), 'other-repo') }),
    );

    await expect(requireDeletableStoragePath({ path: repo, storagePath })).resolves.toBe(
      storagePath,
    );
  });

  it('rejects a foreign external slot even when force requirements allow foreign', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-foreign-repo-');
    const storagePath = await makeTempDir('gitnexus-storage-resolver-foreign-storage-');
    await fs.mkdir(path.join(storagePath, 'lbug'), { recursive: true });
    await fs.writeFile(
      path.join(storagePath, 'gitnexus.json'),
      JSON.stringify({
        repoPath: path.join(path.dirname(repo), 'other-repo'),
        storagePath,
      }),
    );
    delete process.env[STORAGE_ROOT_ENV];
    process.env[STORAGE_PATH_ENV] = storagePath;

    await expect(
      requireStoragePath(repo, ANALYZE_FORCE_STORAGE_REQUIREMENTS),
    ).rejects.toBeInstanceOf(StorageRequirementError);
    await expect(requireStoragePath(repo, INDEX_FORCE_STORAGE_REQUIREMENTS)).rejects.toBeInstanceOf(
      StorageRequirementError,
    );
    await expect(requireDeletableStoragePath({ path: repo, storagePath })).rejects.toBeInstanceOf(
      StorageDeletionError,
    );
  });

  it('treats a lock-only storage directory as empty so non-force analyze can proceed', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-lock-repo-');
    const storagePath = defaultStoragePath(repo);
    await fs.mkdir(storagePath, { recursive: true });
    await fs.writeFile(path.join(storagePath, 'analyze.lock'), 'pid');
    await fs.writeFile(path.join(storagePath, 'analyze.lock.guard'), 'guard');
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];

    await expect(requireStoragePath(repo, ANALYZE_STORAGE_REQUIREMENTS)).resolves.toBe(storagePath);
  });

  it('lets --force adopt a foreign repository-local slot, not the non-force analyze set', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-adopt-repo-');
    const storagePath = defaultStoragePath(repo);
    await fs.mkdir(path.join(storagePath, 'lbug'), { recursive: true });
    await fs.writeFile(
      path.join(storagePath, 'gitnexus.json'),
      JSON.stringify({
        repoPath: path.join(path.dirname(repo), 'other-repo'),
        storagePath,
      }),
    );
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];

    expect(ANALYZE_FORCE_STORAGE_REQUIREMENTS.allowedStates).toEqual([
      'missing',
      'empty',
      'owned',
      'unowned',
      'foreign',
    ]);
    expect(INDEX_FORCE_STORAGE_REQUIREMENTS.allowedStates).toEqual(['owned', 'unowned', 'foreign']);
    expect(INDEX_FORCE_STORAGE_REQUIREMENTS.requireCodeIndexDB).toBe(true);
    expect(getIndexStorageRequirements(true)).toBe(INDEX_FORCE_STORAGE_REQUIREMENTS);

    await expect(requireStoragePath(repo, ANALYZE_STORAGE_REQUIREMENTS)).rejects.toBeInstanceOf(
      StorageRequirementError,
    );
    await expect(requireStoragePath(repo, ANALYZE_FORCE_STORAGE_REQUIREMENTS)).resolves.toBe(
      storagePath,
    );
    await expect(requireStoragePath(repo, INDEX_FORCE_STORAGE_REQUIREMENTS)).resolves.toBe(
      storagePath,
    );
  });

  it('lets --force adopt a foreign repository-local slot reached through a symlink', async () => {
    const root = await makeTempDir('gitnexus-storage-resolver-force-symlink-');
    const repo = path.join(root, 'repo');
    const linkedRepo = path.join(root, 'repo-link');
    await fs.mkdir(repo);
    await fs.symlink(repo, linkedRepo, process.platform === 'win32' ? 'junction' : 'dir');
    const storagePath = defaultStoragePath(linkedRepo);
    await fs.mkdir(path.join(storagePath, 'lbug'), { recursive: true });
    await fs.writeFile(
      path.join(storagePath, 'gitnexus.json'),
      JSON.stringify({
        repoPath: path.join(path.dirname(repo), 'other-repo'),
        storagePath,
      }),
    );
    delete process.env[STORAGE_PATH_ENV];
    delete process.env[STORAGE_ROOT_ENV];

    await expect(
      requireStoragePath(linkedRepo, ANALYZE_FORCE_STORAGE_REQUIREMENTS),
    ).resolves.toMatch(/[\\/]\.gitnexus$/);
  });

  it('requires matching metadata before deleting an external slot', async () => {
    const repo = await makeTempDir('gitnexus-storage-resolver-delete-repo-');
    const storagePath = await makeTempDir('gitnexus-storage-resolver-delete-storage-');
    await fs.writeFile(
      path.join(storagePath, 'gitnexus.json'),
      JSON.stringify({ repoPath: repo, storagePath }),
    );

    await expect(requireDeletableStoragePath({ path: repo, storagePath })).resolves.toBe(
      storagePath,
    );

    await fs.rm(path.join(storagePath, 'gitnexus.json'));
    await expect(requireDeletableStoragePath({ path: repo, storagePath })).rejects.toBeInstanceOf(
      StorageDeletionError,
    );
  });

  it('rejects a storage path that is the repository after symlink resolution', async () => {
    const root = await makeTempDir('gitnexus-storage-resolver-delete-symlink-');
    const repo = path.join(root, 'repo');
    const linkParent = path.join(root, 'link');
    await fs.mkdir(repo);
    await fs.symlink(root, linkParent, process.platform === 'win32' ? 'junction' : 'dir');
    const aliasedRepo = path.join(linkParent, 'repo');

    await expect(
      requireDeletableStoragePath({ path: repo, storagePath: aliasedRepo }),
    ).rejects.toBeInstanceOf(StorageDeletionError);
  });
});