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

namespace SQLLinter.Infrastructure.Rules;

public class SchemaQualifyRule : BaseRuleVisitor, IRule
{
    private readonly List<string> tableAliases = new()
    {
        "INSERTED",
        "UPDATED",
        "DELETED"
    };

    public override string Text => "Имя объекта без схемы: {0}";

    public override void Visit(TSqlStatement node)
    {
        var childAliasVisitor = new ChildAliasVisitor();
        node.AcceptChildren(childAliasVisitor);
        tableAliases.AddRange(childAliasVisitor.TableAliases);
    }

    public override void Visit(NamedTableReference node) => VisitTableName(node.SchemaObject, true);

    public override void Visit(CreateTableStatement node) => VisitTableName(node.SchemaObjectName, false);

    public override void Visit(AlterTableStatement node) => VisitTableName(node.SchemaObjectName, false);

    public override void Visit(TruncateTableStatement node) => VisitTableName(node.TableName, false);

    public override void Visit(DropTableStatement node)
    {
        foreach (var schemaObjectName in node.Objects)
        {
            VisitTableName(schemaObjectName, false);
        }
    }

    private void VisitTableName(SchemaObjectName node, bool canHaveTableAliases)
    {
        if (node.SchemaIdentifier != null)
        {
            return;
        }

        // не проверять схему во временных таблицах
        if (node.BaseIdentifier.Value.Contains('#'))
        {
            return;
        }

        // не проверять схему псевдонимов таблиц
        if (canHaveTableAliases && tableAliases.Exists(x => x.Equals(node.BaseIdentifier.Value, StringComparison.OrdinalIgnoreCase)))
        {
            return;
        }

        AddViolation(node, SQLHelpers.ObjectGetFullName(node));
    }

    public class ChildAliasVisitor : TSqlFragmentVisitor
    {
        public List<string> TableAliases { get; } = new();

        public override void Visit(TableReferenceWithAlias node)
        {
            if (node.Alias != null)
            {
                TableAliases.Add(node.Alias.Value);
            }
        }

        public override void Visit(CommonTableExpression node)
        {
            TableAliases.Add(node.ExpressionName.Value);
        }
    }
}