namespace NeonSprawl.Server.Game.Factions;

/// <summary>PostgreSQL-backed faction standing keyed by normalized player id + faction id (NEO-135).</summary>
public sealed class PostgresFactionStandingStore(
    Npgsql.NpgsqlDataSource dataSource,
    IFactionDefinitionRegistry factionRegistry) : IFactionStandingStore
{
    /// <inheritdoc />
    public bool CanWritePlayer(string playerId)
    {
        var player = FactionStandingIds.NormalizePlayerId(playerId);
        if (player.Length == 0)
        {
            return false;
        }

        PostgresPlayerFactionStandingBootstrap.EnsureSchema(dataSource);
        using var conn = dataSource.OpenConnection();
        return PlayerExists(conn, player);
    }

    /// <inheritdoc />
    public FactionStandingReadOutcome TryGetStanding(string playerId, string factionId)
    {
        var player = FactionStandingIds.NormalizePlayerId(playerId);
        var faction = FactionStandingIds.NormalizeFactionId(factionId);
        if (player.Length == 0 || faction.Length == 0)
        {
            return DenyRead(FactionStandingReasonCodes.PlayerNotWritable);
        }

        if (!factionRegistry.TryGetDefinition(faction, out var definition) || definition is null)
        {
            return DenyRead(FactionStandingReasonCodes.UnknownFaction);
        }

        PostgresPlayerFactionStandingBootstrap.EnsureSchema(dataSource);
        using var conn = dataSource.OpenConnection();
        if (!PlayerExists(conn, player))
        {
            return DenyRead(FactionStandingReasonCodes.PlayerNotWritable);
        }

        using var cmd = new Npgsql.NpgsqlCommand(
            """
            SELECT standing
            FROM player_faction_standing
            WHERE player_id = @pid AND faction_id = @fid
            LIMIT 1;
            """,
            conn);
        cmd.Parameters.AddWithValue("pid", player);
        cmd.Parameters.AddWithValue("fid", faction);
        var scalar = cmd.ExecuteScalar();
        var raw = scalar is null or DBNull
            ? 0
            : scalar is int xi
                ? xi
                : Convert.ToInt32(scalar, System.Globalization.CultureInfo.InvariantCulture);
        return new FactionStandingReadOutcome(true, null, FactionStandingIds.ClampStanding(raw, definition));
    }

    /// <inheritdoc />
    public FactionStandingMutationOutcome TryApplyStandingDelta(string playerId, string factionId, int deltaAmount)
    {
        var player = FactionStandingIds.NormalizePlayerId(playerId);
        var faction = FactionStandingIds.NormalizeFactionId(factionId);
        if (player.Length == 0 || faction.Length == 0)
        {
            return DenyMutation(FactionStandingReasonCodes.PlayerNotWritable);
        }

        if (!factionRegistry.TryGetDefinition(faction, out var definition) || definition is null)
        {
            return DenyMutation(FactionStandingReasonCodes.UnknownFaction);
        }

        PostgresPlayerFactionStandingBootstrap.EnsureSchema(dataSource);
        using var conn = dataSource.OpenConnection();
        using var tx = conn.BeginTransaction();
        if (!PlayerExists(conn, player, tx))
        {
            tx.Rollback();
            return DenyMutation(FactionStandingReasonCodes.PlayerNotWritable);
        }

        var raw = 0;
        using (var sel = new Npgsql.NpgsqlCommand(
                   """
                   SELECT standing
                   FROM player_faction_standing
                   WHERE player_id = @pid AND faction_id = @fid
                   LIMIT 1
                   FOR UPDATE;
                   """,
                   conn,
                   tx))
        {
            sel.Parameters.AddWithValue("pid", player);
            sel.Parameters.AddWithValue("fid", faction);
            var scalar = sel.ExecuteScalar();
            raw = scalar is null or DBNull
                ? 0
                : scalar is int xi
                    ? xi
                    : Convert.ToInt32(scalar, System.Globalization.CultureInfo.InvariantCulture);
        }

        var previousStanding = FactionStandingIds.ClampStanding(raw, definition);
        var newStanding = FactionStandingIds.ClampStanding(raw + deltaAmount, definition);

        using var upsert = new Npgsql.NpgsqlCommand(
            """
            INSERT INTO player_faction_standing (player_id, faction_id, standing, updated_at)
            VALUES (@pid, @fid, @standing, now())
            ON CONFLICT (player_id, faction_id)
            DO UPDATE SET standing = EXCLUDED.standing, updated_at = now();
            """,
            conn,
            tx);
        upsert.Parameters.AddWithValue("pid", player);
        upsert.Parameters.AddWithValue("fid", faction);
        upsert.Parameters.AddWithValue("standing", newStanding);
        upsert.ExecuteNonQuery();
        tx.Commit();
        return new FactionStandingMutationOutcome(true, null, previousStanding, newStanding);
    }

    private static bool PlayerExists(Npgsql.NpgsqlConnection conn, string playerIdNormalized, Npgsql.NpgsqlTransaction? tx = null)
    {
        using var cmd = new Npgsql.NpgsqlCommand(
            "SELECT 1 FROM player_position WHERE player_id = @pid LIMIT 1;",
            conn,
            tx);
        cmd.Parameters.AddWithValue("pid", playerIdNormalized);
        return cmd.ExecuteScalar() is not null;
    }

    private static FactionStandingReadOutcome DenyRead(string reasonCode) =>
        new(false, reasonCode, 0);

    private static FactionStandingMutationOutcome DenyMutation(string reasonCode) =>
        new(false, reasonCode, 0, 0);
}