import 'dart:convert';

import 'package:postgres/postgres.dart';

import '../alpaca/alpaca_models.dart';

/// Read-side row for [tradable_assets].
class TradableAssetRow {
  TradableAssetRow({
    required this.symbol,
    required this.assetClass,
    required this.tradable,
    required this.fractionable,
    required this.status,
    required this.refreshedAt,
    this.exchange,
    this.name,
    this.raw,
  });

  final String symbol;
  final String assetClass;
  final String? exchange;
  final String? name;
  final bool tradable;
  final bool fractionable;
  final String status;
  final Map<String, dynamic>? raw;
  final DateTime refreshedAt;
}

/// Postgres access for [tradable_assets] (the daily Alpaca asset universe).
///
/// Writers: only [TradableAssetsSync] (§2.2). Readers: the historical
/// backfill in §3 plus operator/query tooling.
class TradableAssetsDb {
  TradableAssetsDb(this._connection);

  final Connection _connection;

  /// Upserts every entry in [assets] (PK on `symbol`) using [now] as the
  /// shared `refreshed_at`, then marks any rows whose `refreshed_at` is
  /// older than [now] as `status='inactive', tradable=false` — preserving
  /// the historical row but flagging it as no longer in the live universe.
  ///
  /// The two phases run inside a single transaction so a partial failure
  /// can't leave the universe half-updated.
  Future<void> upsertAll(
    List<AlpacaAsset> assets, {
    DateTime? now,
  }) async {
    final DateTime ts = (now ?? DateTime.now()).toUtc();

    await _connection.runTx((TxSession tx) async {
      for (final AlpacaAsset asset in assets) {
        await tx.execute(
          Sql.named(
            '''
            INSERT INTO tradable_assets (
              symbol, asset_class, exchange, name, tradable,
              fractionable, status, raw, refreshed_at
            ) VALUES (
              @symbol, @asset_class, @exchange, @name, @tradable,
              @fractionable, @status, @raw::jsonb, @refreshed_at
            )
            ON CONFLICT (symbol) DO UPDATE SET
              asset_class  = EXCLUDED.asset_class,
              exchange     = EXCLUDED.exchange,
              name         = EXCLUDED.name,
              tradable     = EXCLUDED.tradable,
              fractionable = EXCLUDED.fractionable,
              status       = EXCLUDED.status,
              raw          = EXCLUDED.raw,
              refreshed_at = EXCLUDED.refreshed_at
            ''',
          ),
          parameters: <String, dynamic>{
            'symbol': asset.symbol,
            'asset_class': asset.assetClass,
            'exchange': asset.exchange,
            'name': asset.name,
            'tradable': asset.tradable,
            'fractionable': asset.fractionable,
            'status': asset.status,
            'raw': asset.raw == null ? null : jsonEncode(asset.raw),
            'refreshed_at': ts,
          },
        );
      }

      // Anything not seen in this batch hasn't been refreshed at [ts] yet.
      // Flip it to inactive without bumping refreshed_at, so the audit
      // trail still records "last seen as part of the live universe."
      await tx.execute(
        Sql.named(
          '''
          UPDATE tradable_assets
          SET status = 'inactive', tradable = false
          WHERE refreshed_at < @now
            AND (status <> 'inactive' OR tradable = true)
          ''',
        ),
        parameters: <String, dynamic>{'now': ts},
      );
    });
  }

  /// Symbols currently tradable on the active universe.
  Future<List<String>> listActiveTradableSymbols() async {
    final Result result = await _connection.execute(
      '''
      SELECT symbol
      FROM tradable_assets
      WHERE status = 'active' AND tradable = true
      ORDER BY symbol ASC
      ''',
    );
    return result.map((ResultRow r) => r[0]! as String).toList(growable: false);
  }

  /// Single-row lookup, primarily for tests and admin tooling.
  Future<TradableAssetRow?> getBySymbol(String symbol) async {
    final Result result = await _connection.execute(
      Sql.named(
        '''
        SELECT symbol, asset_class, exchange, name, tradable,
               fractionable, status, raw, refreshed_at
        FROM tradable_assets
        WHERE symbol = @symbol
        ''',
      ),
      parameters: <String, dynamic>{'symbol': symbol},
    );
    if (result.isEmpty) {
      return null;
    }
    return _rowToModel(result.first);
  }

  TradableAssetRow _rowToModel(ResultRow row) {
    final Object? rawValue = row[7];
    Map<String, dynamic>? raw;
    if (rawValue is Map<String, dynamic>) {
      raw = rawValue;
    } else if (rawValue is Map) {
      raw = Map<String, dynamic>.from(rawValue);
    } else if (rawValue != null) {
      raw = jsonDecode(rawValue.toString()) as Map<String, dynamic>;
    }

    return TradableAssetRow(
      symbol: row[0]! as String,
      assetClass: row[1]! as String,
      exchange: row[2] as String?,
      name: row[3] as String?,
      tradable: row[4]! as bool,
      fractionable: row[5]! as bool,
      status: row[6]! as String,
      raw: raw,
      refreshedAt: (row[8]! as DateTime).toUtc(),
    );
  }
}