using Backend.MarketDataRequest;
using Npgsql;

namespace Backend.DatabaseHandler
{
	public sealed class PostgresHistoricalMarketDataCache : IHistoricalMarketDataCache
	{
		private readonly string _connectionString;

		public PostgresHistoricalMarketDataCache(IConfiguration configuration)
		{
			_connectionString = configuration.GetConnectionString("MarketDataDb")
				?? throw new InvalidOperationException("Missing connection string: MarketDataDb");
		}

		public async Task<List<HistoricalBarRecord>> GetBarsAsync(
			string symbol,
			HistoricalBarSize barSize,
			HistoricalWhatToShow whatToShow,
			bool useRth,
			DateTime startUtc,
			DateTime endUtc,
			CancellationToken cancellationToken = default)
		{
			var results = new List<HistoricalBarRecord>();

			await using var conn = new NpgsqlConnection(_connectionString);
			await conn.OpenAsync(cancellationToken);

			const string sql = """
                SELECT symbol, bar_size, what_to_show, use_rth, timestamp_utc,
                       open, high, low, close, volume
                FROM historical_equity_bars
                WHERE symbol = @symbol
                  AND bar_size = @bar_size
                  AND what_to_show = @what_to_show
                  AND use_rth = @use_rth
                  AND timestamp_utc >= @start_utc
                  AND timestamp_utc <= @end_utc
                ORDER BY timestamp_utc ASC;
                """;

			await using var cmd = new NpgsqlCommand(sql, conn);
			cmd.Parameters.AddWithValue("symbol", symbol);
			cmd.Parameters.AddWithValue("bar_size", barSize.ToIbString());
			cmd.Parameters.AddWithValue("what_to_show", whatToShow.ToIbString());
			cmd.Parameters.AddWithValue("use_rth", useRth);
			cmd.Parameters.AddWithValue("start_utc", startUtc);
			cmd.Parameters.AddWithValue("end_utc", endUtc);

			await using var reader = await cmd.ExecuteReaderAsync(cancellationToken);
			while (await reader.ReadAsync(cancellationToken))
			{
				results.Add(new HistoricalBarRecord
				{
					Symbol = reader.GetString(0),
					BarSize = reader.GetString(1),
					WhatToShow = reader.GetString(2),
					UseRth = reader.GetBoolean(3),
					TimestampUtc = reader.GetDateTime(4),
					Open = reader.GetDouble(5),
					High = reader.GetDouble(6),
					Low = reader.GetDouble(7),
					Close = reader.GetDouble(8),
					Volume = reader.GetInt64(9)
				});
			}

			return results;
		}

		public async Task UpsertBarsAsync(
			IEnumerable<HistoricalBarRecord> bars,
			CancellationToken cancellationToken = default)
		{
			var barList = bars.ToList();
			if (barList.Count == 0)
				return;

			await using var conn = new NpgsqlConnection(_connectionString);
			await conn.OpenAsync(cancellationToken);

			await using var tx = await conn.BeginTransactionAsync(cancellationToken);

			const string sql = """
                INSERT INTO historical_equity_bars
                (
                    symbol, bar_size, what_to_show, use_rth, timestamp_utc,
                    open, high, low, close, volume
                )
                VALUES
                (
                    @symbol, @bar_size, @what_to_show, @use_rth, @timestamp_utc,
                    @open, @high, @low, @close, @volume
                )
                ON CONFLICT (symbol, bar_size, what_to_show, use_rth, timestamp_utc)
                DO UPDATE SET
                    open = EXCLUDED.open,
                    high = EXCLUDED.high,
                    low = EXCLUDED.low,
                    close = EXCLUDED.close,
                    volume = EXCLUDED.volume;
                """;

			foreach (var bar in barList)
			{
				await using var cmd = new NpgsqlCommand(sql, conn, tx);
				cmd.Parameters.AddWithValue("symbol", bar.Symbol);
				cmd.Parameters.AddWithValue("bar_size", bar.BarSize);
				cmd.Parameters.AddWithValue("what_to_show", bar.WhatToShow);
				cmd.Parameters.AddWithValue("use_rth", bar.UseRth);
				cmd.Parameters.AddWithValue("timestamp_utc", bar.TimestampUtc);
				cmd.Parameters.AddWithValue("open", bar.Open);
				cmd.Parameters.AddWithValue("high", bar.High);
				cmd.Parameters.AddWithValue("low", bar.Low);
				cmd.Parameters.AddWithValue("close", bar.Close);
				cmd.Parameters.AddWithValue("volume", bar.Volume);

				await cmd.ExecuteNonQueryAsync(cancellationToken);
			}

			await tx.CommitAsync(cancellationToken);
		}
	}
}