using Microsoft.SqlServer.TransactSql.ScriptDom;
using SQLLinter.Common;
using SQLLinter.Common.Helpers;

namespace SQLLinter.Infrastructure.Rules;

public class ColumnNullabilityRule : BaseRuleVisitor
{
    public override string Text => "При объявлении таблицы необходимо указывать для столбцов NULL/NOT NULL: таблица {0} - столбец [{1}]";

    private string? _currentTable;

    public override void Visit(CreateTableStatement node)
    {
        _currentTable = SQLHelpers.ObjectGetFullName(node.SchemaObjectName);


        foreach (var element in node.Definition.ColumnDefinitions)
        {
            CheckColumn(element);
        }

        _currentTable = null;
    }

    public override void Visit(AlterTableAddTableElementStatement node)
    {
        _currentTable = SQLHelpers.ObjectGetFullName(node.SchemaObjectName);

        foreach (var element in node.Definition.ColumnDefinitions)
        {
            CheckColumn(element);
        }

        _currentTable = null;
    }

    public override void Visit(AlterTableAlterColumnStatement node)
    {
        _currentTable = SQLHelpers.ObjectGetFullName(node.SchemaObjectName);

        bool hasNullabilityConstraint = node.Options
            .OfType<NullableConstraintDefinition>()
            .Any();

        if (!hasNullabilityConstraint)
        {
            AddViolation(node,
                _currentTable ?? "<unknown>",
                node.ColumnIdentifier?.Value ?? "<unknown>");
        }

        _currentTable = null;

    }

    public override void Visit(DeclareTableVariableStatement node)
    {
        _currentTable = node.Body.VariableName.Value;

        foreach (var column in node.Body.Definition.ColumnDefinitions)
        {
            CheckColumn(column);
        }
    }

    private void CheckColumn(ColumnDefinition node)
    {
        bool hasNullabilityConstraint = node.Constraints
            .OfType<NullableConstraintDefinition>()
            .Any();

        if (!hasNullabilityConstraint)
        {
            AddViolation(node,
                _currentTable ?? "<unknown>",
                node.ColumnIdentifier?.Value ?? "<unknown>");
        }
    }
}