import 'dart:convert';
import 'dart:typed_data';

import 'package:crypto/crypto.dart';
import 'package:halkyon_base_server/base.dart';
import 'package:serverpod/protocol.dart' show CloudStorageEntry;
import 'package:serverpod/serverpod.dart';
import 'package:test/test.dart';

import '../support/fixtures.dart';
import '../test_tools/serverpod_test_tools.dart';

/// A host's row naming a file: the space it is in, the file's hash, and who
/// may read it (its space's members).
typedef _Row = ({UuidValue space, String sha256, Set<UuidValue> readers});

void main() {
  withServerpod('Files (ADR 0043)', (sessionBuilder, endpoints) {
    late Session session;
    late UuidValue alice;
    late UuidValue bob;

    /// The host's live rows, by their ID.
    late Map<UuidValue, _Row> rows;
    final image = utf8.encode('an image');
    final imageHash = sha256.convert(image).toString();

    /// The file store a host gives, over [rows], taking what [accepts] does.
    FileStore store({AcceptsFile accepts = FileStore.acceptsAny}) => FileStore(
      fileOfRow: (session, rowId) async {
        final row = rows[rowId];
        final caller = UuidValue.withValidation(
          session.authenticated!.userIdentifier,
        );
        return row == null || !row.readers.contains(caller)
            ? null
            : (space: row.space, sha256: row.sha256);
      },
      liveHashes: (session, space, hashes) async => {
        for (final row in rows.values)
          if (row.space == space && (hashes?.contains(row.sha256) ?? true))
            row.sha256,
      },
      maxBytes: 64,
      accepts: accepts,
    );

    setUp(() {
      useBase(sessionBuilder, files: store());
      session = sessionBuilder.build();
      alice = const Uuid().v7obj();
      bob = const Uuid().v7obj();
      rows = {};
    });

    tearDown(() async {
      fileLimits = null;
      await FileAllowance.db.deleteWhere(
        session,
        where: (t) => t.authUserId.inSet({alice, bob}),
      );
      await session.db.unsafeExecute(
        'DELETE FROM "serverpod_cloud_storage" WHERE "path" LIKE \'spaces/%\'',
      );
    });

    /// [person]'s session, `identified`.
    TestSessionBuilder signedIn(UuidValue person) => sessionBuilder.copyWith(
      authentication: AuthenticationOverride.authenticationInfo(person.uuid, {
        identified,
      }),
    );

    /// Adds [bytes] as [person], as an app does.
    Future<bool> add(
      UuidValue person,
      List<int> bytes, {
      String? as,
      bool? encrypted,
    }) async {
      final hash = as ?? sha256.convert(bytes).toString();
      final description = await endpoints.files.startUpload(
        signedIn(person),
        hash,
        bytes.length,
        encrypted: encrypted,
      );
      if (description != null) {
        await _upload(session, description, bytes);
      }
      return await endpoints.files.finishUpload(
        signedIn(person),
        hash,
        encrypted: encrypted,
      );
    }

    /// A row of [space] naming [hash], which [readers] may read.
    UuidValue row(UuidValue space, String hash, Set<UuidValue> readers) {
      final id = const Uuid().v7obj();
      rows[id] = (space: space, sha256: hash, readers: readers);
      return id;
    }

    test('refuses callers who are not signed in', () async {
      final nobody = sessionBuilder.copyWith(
        authentication: AuthenticationOverride.unauthenticated(),
      );
      await expectLater(
        endpoints.files.startUpload(nobody, imageHash, image.length),
        throwsA(isA<ServerpodUnauthenticatedException>()),
      );
      await expectLater(
        endpoints.files.download(nobody, const Uuid().v7obj()),
        throwsA(isA<ServerpodUnauthenticatedException>()),
      );
    });

    test('a host without a file store keeps no files', () async {
      useBase(sessionBuilder);
      await expectLater(
        endpoints.files.startUpload(signedIn(alice), imageHash, image.length),
        throwsA(isA<StateError>()),
      );
      await expectLater(
        endpoints.files.usage(signedIn(alice)),
        throwsA(isA<StateError>()),
      );
    });

    test("stores a file in the caller's space once, and serves it by a row "
        'its reader may read', () async {
      expect(await add(alice, image), isTrue);
      expect(
        await endpoints.files.startUpload(
          signedIn(alice),
          imageHash,
          image.length,
        ),
        isNull,
        reason: 'it is there',
      );
      final id = row(alice, imageHash, {alice, bob});

      expect(
        Uint8List.sublistView(
          await endpoints.files.download(signedIn(bob), id),
        ),
        image,
      );
    });

    test("serves nothing of a row the caller can't read, an unknown row, or "
        'a file not uploaded, alike', () async {
      await add(alice, image);
      final hers = row(alice, imageHash, {alice});
      final missing = row(alice, sha256.convert([1]).toString(), {alice});

      for (final (person, id) in [
        (bob, hers),
        (alice, const Uuid().v7obj()),
        (alice, missing),
      ]) {
        await expectLater(
          endpoints.files.download(signedIn(person), id),
          throwsA(isA<StoredFileNotFoundException>()),
        );
      }
    });

    test('keeps no file whose content has another hash', () async {
      expect(
        await add(alice, image, as: sha256.convert([7]).toString()),
        false,
      );
      expect(await _stored(session), isEmpty);
    });

    test('refuses what is no SHA-256, and sizes out of range', () async {
      for (final (hash, size) in [
        ('not a hash', 1),
        (imageHash.toUpperCase(), 1),
        (imageHash, 0),
        (imageHash, 65),
      ]) {
        await expectLater(
          endpoints.files.startUpload(signedIn(alice), hash, size),
          throwsA(isA<ArgumentError>()),
          reason: '$hash $size',
        );
      }
      // Sealed, it may be larger by what sealing adds.
      expect(
        await endpoints.files.startUpload(
          signedIn(alice),
          imageHash,
          65,
          encrypted: true,
        ),
        isNotNull,
      );
    });

    test('keeps a file said to be sealed only when it starts as one; the '
        "host's own rule decides the rest", () async {
      expect(await add(alice, image, encrypted: true), isFalse);
      final sealed = [...ascii.encode('HLKF'), 1, 9, 9];
      expect(await add(alice, sealed, encrypted: true), isTrue);

      useBase(
        sessionBuilder,
        files: store(accepts: FileStore.acceptsSealedOnly),
      );
      expect(await add(bob, image), isFalse);
      expect(await add(bob, sealed, encrypted: true), isTrue);
    });

    group('room', () {
      test('a person keeps no more than their room; an allowance gives one '
          'person more', () async {
        fileLimits = const FileLimits(identifiedBytes: 10, instanceBytes: null);
        await expectLater(
          endpoints.files.startUpload(signedIn(alice), imageHash, 11),
          throwsA(isA<FileLimitExceededException>()),
        );

        await FileAllowance.db.insertRow(
          session,
          FileAllowance(authUserId: alice, maxBytes: 64),
        );
        expect(
          await endpoints.files.startUpload(signedIn(alice), imageHash, 11),
          isNotNull,
        );
        await expectLater(
          endpoints.files.startUpload(signedIn(bob), imageHash, 11),
          throwsA(isA<FileLimitExceededException>()),
        );
      });

      test("counts the files the space's live rows name, and those claimed "
          'lately', () async {
        await add(alice, image);
        row(alice, imageHash, {alice});
        final usage = await endpoints.files.usage(signedIn(alice));
        expect(usage.usedBytes, image.length);

        rows.clear();
        await _claimed(
          session,
          alice,
          imageHash,
          DateTime.now().toUtc().subtract(const Duration(days: 8)),
        );
        expect(
          (await endpoints.files.usage(signedIn(alice))).usedBytes,
          0,
          reason: 'no live row names it, and it was claimed long ago',
        );
      });

      test("the operator's allowance goes with the person", () async {
        await FileAllowance.db.insertRow(
          session,
          FileAllowance(authUserId: alice, maxBytes: 64),
        );
        await deletePerson(session, alice);
        expect(
          await FileAllowance.db.find(
            session,
            where: (t) => t.authUserId.equals(alice),
          ),
          isEmpty,
        );
      });
    });

    group('pruning', () {
      final longAgo = DateTime.now().toUtc().subtract(const Duration(days: 8));

      test('deletes files no live row names, claimed long ago; keeps the '
          'rest', () async {
        final other = utf8.encode('another');
        final otherHash = sha256.convert(other).toString();
        await add(alice, image);
        await add(alice, other);
        row(alice, imageHash, {alice});
        await _claimed(session, alice, imageHash, longAgo);
        await _claimed(session, alice, otherHash, longAgo);

        expect(await pruneUnreferencedFiles(session, now: DateTime.now()), 1);
        expect(await _stored(session), {storedFilePath(alice, imageHash)});
      });

      test('keeps a file claimed lately, named or not', () async {
        await add(alice, image);
        expect(await pruneUnreferencedFiles(session, now: DateTime.now()), 0);
      });
    });
  });
}

/// Uploads [bytes] as the upload [description] says, standing in for the
/// app's HTTP upload, as in Halkyon Learn's tests.
Future<void> _upload(
  Session session,
  String description,
  List<int> bytes,
) async {
  final url = Uri.parse(
    (jsonDecode(description) as Map<String, Object?>)['url']! as String,
  );
  final storage =
      Serverpod.instance.storage[url.queryParameters['storage']!]!
          as DatabaseCloudStorage;
  await storage.storeUnverifiedFile(
    session: session,
    path: url.queryParameters['path']!,
    byteData: ByteData.sublistView(Uint8List.fromList(bytes)),
  );
}

/// The stored files' paths.
Future<Set<String>> _stored(Session session) async => {
  for (final [path as String] in await session.db.unsafeQuery(
    'SELECT "path" FROM "serverpod_cloud_storage" WHERE "path" LIKE '
    "'spaces/%'",
  ))
    path,
};

/// Makes the stored file with [hash] of [space] last claimed [at].
Future<void> _claimed(
  Session session,
  UuidValue space,
  String hash,
  DateTime at,
) => CloudStorageEntry.db.updateWhere(
  session,
  columnValues: (t) => [t.addedTime(at)],
  where: (t) =>
      t.storageId.equals(fileStorage) &
      t.path.equals(storedFilePath(space, hash)),
);