import 'package:drift/drift.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import 'connection/unsupported.dart'
    if (dart.library.ffi) 'connection/native.dart'
    if (dart.library.js_interop) 'connection/web.dart';

part 'app_database.g.dart';

/// Immutable log of GLP-1 injections and scheduled doses.
///
/// [injectionSite] stores the anatomical rotation quadrant as a stable string
/// value (the `InjectionQuadrant.name` identifier of the medication domain
/// enum) so the persistence schema stays decoupled from domain types and the
/// `core` layer never imports feature code.
@DataClassName('MedicationDoseRecord')
class MedicationDosesTable extends Table {
  IntColumn get id => integer().autoIncrement()();

  /// Commercial or compounded name of the GLP-1/GIP agonist (e.g. Tirzepatide).
  TextColumn get compoundName => text().withLength(min: 1, max: 128)();

  /// Total injected quantity in milligrams.
  RealColumn get doseMg => real()();

  /// When the dose was prescribed to be taken (titration schedule anchor).
  DateTimeColumn get scheduledTime => dateTime()();

  /// When the dose was actually administered; `null` while still pending.
  DateTimeColumn get administeredTime => dateTime().nullable()();

  /// Rotation quadrant identifier (e.g. `abdomenLeftLower`).
  TextColumn get injectionSite => text().nullable()();

  TextColumn get notes => text().nullable()();
}

/// Root drift database for the GLP-1 Companion.
///
/// On native platforms the connection is backed by SQLCipher: the 256-bit AES
/// master key provisioned by `CryptoManager` is applied via `PRAGMA key`
/// immediately after the database opens (see `connection/native.dart`). Web
/// builds transparently fall back to a WASM SQLite database, since SQLCipher
/// cannot run inside the browser.
@DriftDatabase(tables: [MedicationDosesTable])
class AppDatabase extends _$AppDatabase {
  /// Opens the platform-appropriate (encrypted on native) database connection.
  AppDatabase() : super(openDatabaseConnection());

  /// Injects a custom executor; used by unit tests with an in-memory database.
  AppDatabase.forTesting(super.executor);

  @override
  int get schemaVersion => 1;

  // ---------------------------------------------------------------------------
  // Injection history CRUD
  // ---------------------------------------------------------------------------
  //
  // These helpers intentionally operate on drift records/companions only:
  // the `core` layer never imports feature domain types, so mapping between
  // `MedicationDoseRecord` and the medication feature's `DoseEntry` entity
  // happens in `features/medication/data/repositories/medication_repository.dart`.

  /// Emits the stored dose history, newest first, and re-emits on every write.
  ///
  /// Ordering uses the administered time (falling back to the scheduled time
  /// for pending rows) so backdated entries sort chronologically.
  Stream<List<MedicationDoseRecord>> watchDoseEntries({int limit = 500}) =>
      (_selectDoseEntries()..limit(limit)).watch();

  /// One-shot snapshot of the dose history, newest first.
  Future<List<MedicationDoseRecord>> getDoseEntries({int limit = 500}) =>
      (_selectDoseEntries()..limit(limit)).get();

  /// Inserts a new row and returns the persisted record including its
  /// auto-incremented primary key.
  Future<MedicationDoseRecord> insertDoseEntry(
    MedicationDosesTableCompanion entry,
  ) async {
    final id = await into(medicationDosesTable).insert(entry);
    return (select(medicationDosesTable)..where((t) => t.id.equals(id)))
        .getSingle();
  }

  /// Partially updates the row identified by [id] (only non-absent companion
  /// columns are written).
  Future<void> updateDoseEntry(
    int id,
    MedicationDosesTableCompanion updates,
  ) =>
      (update(medicationDosesTable)..where((t) => t.id.equals(id))).write(
        updates,
      );

  /// Deletes the row identified by [id]; returns the number of removed rows.
  Future<int> deleteDoseEntry(int id) =>
      (delete(medicationDosesTable)..where((t) => t.id.equals(id))).go();

  /// Most recent row that was actually administered, or `null` when no dose
  /// has been logged yet.
  Future<MedicationDoseRecord?> latestAdministeredDose() =>
      (select(medicationDosesTable)
            ..where((t) => t.administeredTime.isNotNull())
            ..orderBy([
              (t) => OrderingTerm.desc(t.administeredTime),
              (t) => OrderingTerm.desc(t.id),
            ])
            ..limit(1))
          .getSingleOrNull();

  /// Shared newest-first ordering for [watchDoseEntries] and [getDoseEntries].
  SimpleSelectStatement<$MedicationDosesTableTable, MedicationDoseRecord>
      _selectDoseEntries() => select(medicationDosesTable)
        ..orderBy([
          (t) => OrderingTerm.desc(t.administeredTime),
          (t) => OrderingTerm.desc(t.id),
        ]);
}

/// Application-wide database instance; closed when the container is disposed.
final appDatabaseProvider = Provider<AppDatabase>((ref) {
  final database = AppDatabase();
  ref.onDispose(database.close);
  return database;
});