using NUnit.Framework;
using Strata.SqlTools.Breakdowns.SqlServer;
using Strata.SqlTools.SqlBreakdown.Classes;

namespace Strata.SqlTools.SqlBreakdown.Tests.SqlServer.Performance;

[TestFixture]
public class GetClausesCachingTests
{
    [Test]
    public void GetClauses_CalledMultipleTimes_ReturnsSameInstance()
    {
        // Arrange
        var query = new QueryBreakdown("id, name", "users");

        // Act
        var clauses1 = query.GetClauses();
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.SameAs(clauses1), "GetClauses should return the same cached instance when clauses haven't changed");
    }

    [Test]
    public void GetClauses_AfterSelectClauseChange_ReturnsNewInstance()
    {
        // Arrange
        var query = new QueryBreakdown("id", "users");
        var clauses1 = query.GetClauses();

        // Act - Replace entire clause object to trigger property setter
        query.SelectClause = new SqlExpressionClause { Clause = "id, name, email" };
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance after SelectClause changes");
        Assert.That(clauses2.SelectClause?.Clause, Is.EqualTo("id, name, email"));
    }

    [Test]
    public void GetClauses_AfterFromClauseChange_ReturnsNewInstance()
    {
        // Arrange
        var query = new QueryBreakdown("id", "users");
        var clauses1 = query.GetClauses();

        // Act - Replace entire clause object to trigger property setter
        query.FromClause = new SqlClause { Clause = "customers" };
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance after FromClause changes");
        Assert.That(clauses2.FromClause?.Clause, Is.EqualTo("customers"));
    }

    [Test]
    public void GetClauses_AfterWhereClauseChange_ReturnsNewInstance()
    {
        // Arrange
        var query = new QueryBreakdown("id", "users", "active = 1");
        var clauses1 = query.GetClauses();

        // Act - Replace entire clause object to trigger property setter
        query.WhereClause = new SqlExpressionClause { Clause = "active = 1 AND deleted = 0" };
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance after WhereClause changes");
        Assert.That(clauses2.WhereClause?.Clause, Is.EqualTo("active = 1 AND deleted = 0"));
    }

    [Test]
    public void GetClauses_AfterGroupByClauseChange_ReturnsNewInstance()
    {
        // Arrange
        var query = new QueryBreakdown("COUNT(*) AS total", "users");
        query.GroupByClause = new SqlExpressionClause { Clause = "status" };
        var clauses1 = query.GetClauses();

        // Act - Replace entire clause object to trigger property setter
        query.GroupByClause = new SqlExpressionClause { Clause = "status, type" };
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance after GroupByClause changes");
        Assert.That(clauses2.GroupByClause?.Clause, Is.EqualTo("status, type"));
    }

    [Test]
    public void GetClauses_AfterHavingClauseChange_ReturnsNewInstance()
    {
        // Arrange
        var query = new QueryBreakdown("COUNT(*) AS total", "users");
        query.HavingClause = new SqlExpressionClause { Clause = "COUNT(*) > 10" };
        var clauses1 = query.GetClauses();

        // Act - Replace entire clause object to trigger property setter
        query.HavingClause = new SqlExpressionClause { Clause = "COUNT(*) > 100" };
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance after HavingClause changes");
        Assert.That(clauses2.HavingClause?.Clause, Is.EqualTo("COUNT(*) > 100"));
    }

    [Test]
    public void GetClauses_AfterOrderByClauseChange_ReturnsNewInstance()
    {
        // Arrange
        var query = new QueryBreakdown("id, name", "users");
        query.OrderByClause = new SqlExpressionClause { Clause = "id ASC" };
        var clauses1 = query.GetClauses();

        // Act - Replace entire clause object to trigger property setter
        query.OrderByClause = new SqlExpressionClause { Clause = "name DESC" };
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance after OrderByClause changes");
        Assert.That(clauses2.OrderByClause?.Clause, Is.EqualTo("name DESC"));
    }

    [Test]
    public void GetClauses_AfterMultipleChanges_CacheInvalidatedEachTime()
    {
        // Arrange
        var query = new QueryBreakdown("id", "users");
        var clauses1 = query.GetClauses();

        // Act & Assert - Change 1
        query.SelectClause = new SqlExpressionClause { Clause = "id, name" };
        var clauses2 = query.GetClauses();
        Assert.That(clauses2, Is.Not.SameAs(clauses1));

        // Get again without changes - should return cached
        var clauses2b = query.GetClauses();
        Assert.That(clauses2b, Is.SameAs(clauses2));

        // Act & Assert - Change 2
        query.WhereClause = new SqlExpressionClause { Clause = "active = 1" };
        var clauses3 = query.GetClauses();
        Assert.That(clauses3, Is.Not.SameAs(clauses2));

        // Get again without changes - should return cached
        var clauses3b = query.GetClauses();
        Assert.That(clauses3b, Is.SameAs(clauses3));
    }

    [Test]
    public void GetClauses_ReplacingEntireClauseObject_ReturnsNewInstance()
    {
        // Arrange
        var query = new QueryBreakdown("id", "users");
        var clauses1 = query.GetClauses();

        // Act - Replace entire clause object
        query.SelectClause = new SqlExpressionClause { Clause = "id, name, email" };
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance when clause object is replaced");
        Assert.That(clauses2.SelectClause?.Clause, Is.EqualTo("id, name, email"));
    }

    [Test]
    public void GetClauses_ApplyClauses_InvalidatesCache()
    {
        // Arrange
        var query = new QueryBreakdown("id", "users");
        var clauses1 = query.GetClauses();

        var newClauses = new SqlClauses
        {
            SelectClause = new SqlExpressionClause { Clause = "id, name" },
            FromClause = new SqlClause { Clause = "customers" }
        };

        // Act
        query.ApplyClauses(newClauses);
        var clauses2 = query.GetClauses();

        // Assert
        Assert.That(clauses2, Is.Not.SameAs(clauses1), "GetClauses should return a new instance after ApplyClauses");
        Assert.That(clauses2.SelectClause?.Clause, Is.EqualTo("id, name"));
        Assert.That(clauses2.FromClause?.Clause, Is.EqualTo("customers"));
    }

    [Test]
    public void GetClauses_InitialCall_ReturnsPopulatedObject()
    {
        // Arrange
        var query = new QueryBreakdown("id, name", "users", "active = 1");
        query.OrderByClause.Clause = "name ASC";

        // Act
        var clauses = query.GetClauses();

        // Assert
        Assert.That(clauses, Is.Not.Null);
        Assert.That(clauses.SelectClause?.Clause, Is.EqualTo("id, name"));
        Assert.That(clauses.FromClause?.Clause, Is.EqualTo("users"));
        Assert.That(clauses.WhereClause?.Clause, Is.EqualTo("active = 1"));
        Assert.That(clauses.OrderByClause?.Clause, Is.EqualTo("name ASC"));
    }

    [Test]
    public void GetClauses_AfterNoChanges_ReturnsSameCachedInstance()
    {
        // Arrange
        var query = new QueryBreakdown("id, name", "users");

        // Act - Call GetClauses multiple times without any modifications
        var clauses1 = query.GetClauses();
        var clauses2 = query.GetClauses();
        var clauses3 = query.GetClauses();

        // Assert - All should be the same instance
        Assert.That(clauses2, Is.SameAs(clauses1));
        Assert.That(clauses3, Is.SameAs(clauses1));
    }
}