sql-utilities/tests/Strata.SqlTools.LinqToSql.Tests/LinqQueryBreakdownWithClauseTests.cs

using Strata.SqlTools.Breakdowns.LinqToSql;
using Strata.SqlTools.Builders.LinqToSql;
using Strata.SqlTools.SqlBreakdown.Classes;

namespace Strata.SqlTools.SqlBreakdown.Tests.LinqToSql;

[TestFixture]
public class LinqQueryBreakdownWithClauseTests
{
    #region Basic WITH Clause Tests

    [Test]
    public void LinqQueryBreakdown_SupportsWithClause_ViaInheritance()
    {
        // Arrange
        var cte = new LinqQueryBreakdown("id, name", "users", "status = 'active'");
        var mainQuery = new LinqQueryBreakdown("*", "active_users_cte");

        // Act
        mainQuery.AddWithClause("active_users", cte);

        // Assert
        Assert.That(mainQuery.WithClauses, Has.Count.EqualTo(1));
        Assert.That(mainQuery.WithClauses[0].TableName, Is.EqualTo("active_users"));
        Assert.That(mainQuery.WithClauses[0].Query, Is.EqualTo(cte));
    }

    [Test]
    public void LinqQueryBreakdown_GeneratesSql_WithSimpleCTE()
    {
        // Arrange
        var cte = new LinqQueryBreakdown("id, name", "users");
        var mainQuery = new LinqQueryBreakdown("*", "active_users_cte");
        mainQuery.AddWithClause("active_users", cte);

        // Act
        var sql = mainQuery.GetSql();

        // Assert
        Assert.That(sql, Contains.Substring("WITH"));
        Assert.That(sql, Contains.Substring("active_users AS"));
    }

    [Test]
    public void LinqQueryBreakdown_WithMultipleCTEs_GeneratesAllClauses()
    {
        // Arrange
        var cte1 = new LinqQueryBreakdown("id, status", "users", "status = 'active'");
        var cte2 = new LinqQueryBreakdown("user_id, created", "orders", "created >= CURRENT_DATE");

        var mainQuery = new LinqQueryBreakdown("*", "results");
        mainQuery.AddWithClause("active_users", cte1);
        mainQuery.AddWithClause("recent_orders", cte2);

        // Act
        var sql = mainQuery.GetSql();

        // Assert
        Assert.That(sql, Contains.Substring("WITH"));
        Assert.That(sql, Contains.Substring("active_users AS"));
        Assert.That(sql, Contains.Substring("recent_orders AS"));
    }

    #endregion

    #region CTE Parameter Inheritance Tests

    [Test]
    public void LinqQueryBreakdown_CollectsCTEParameters()
    {
        // Arrange
        var cte = new LinqQueryBreakdown("id, name", "users");
        cte.AddParameter("Status", "active");

        var mainQuery = new LinqQueryBreakdown("*", "results");
        mainQuery.AddParameter("Limit", 100);
        mainQuery.AddWithClause("active_users", cte);

        // Act
        var merged = mainQuery.GetMergedParameters();

        // Assert
        var keys = merged.Keys.ToList();
        Assert.That(keys.Any(k => k.Contains("Status")), "Should include CTE parameters");
        Assert.That(keys.Any(k => k.Contains("Limit")), "Should include main query parameters");
    }

    [Test]
    public void LinqQueryBreakdown_MainQueryParamsPrecedence()
    {
        // Arrange
        var cte = new LinqQueryBreakdown("id", "data");
        cte.AddParameter("Value", "cte_value");

        var mainQuery = new LinqQueryBreakdown("*", "results");
        mainQuery.AddParameter("Value", "main_value");
        mainQuery.AddWithClause("data_cte", cte);

        // Act
        var merged = mainQuery.GetMergedParameters();

        // Assert
        var valueKey = merged.Keys.FirstOrDefault(k => k.Contains("Value"));
        Assert.That(valueKey, Is.Not.Null, "Should have a Value parameter");
        Assert.That(merged[valueKey], Is.EqualTo("main_value"), "Main query parameter should take precedence");
    }

    #endregion

    #region Builder Integration Tests

    [Test]
    public void LinqQueryBreakdownBuilder_BuiltQuerySupportsWithClauses()
    {
        // Arrange
        var builder = LinqQueryBreakdownBuilder.CreateForTable("users")
            .SelectAll()
            .Where("id > 0");
        var mainQuery = builder.Build();

        var cte = new LinqQueryBreakdown("id, name", "active_users_data");
        cte.AddParameter("Status", "active");

        // Act
        mainQuery.AddWithClause("active_users", cte);
        var sql = mainQuery.GetSql();

        // Assert
        Assert.That(sql, Contains.Substring("WITH"));
        Assert.That(sql, Contains.Substring("active_users AS"));
    }

    [Test]
    public void LinqQueryBreakdownBuilder_CanAddCTEToBuiltQuery()
    {
        // Arrange
        var builder = LinqQueryBreakdownBuilder.CreateForTable("orders");
        builder.SelectAll().Where("status != 'cancelled'");
        var query = builder.Build();

        var cte1 = new LinqQueryBreakdown("id, order_id", "recent_orders", "created >= CURRENT_DATE");
        cte1.AddParameter("MinDate", DateTime.Today.AddDays(-30));

        var cte2 = new LinqQueryBreakdown("id, name", "users", "active = 1");
        cte2.AddParameter("Status", "active");

        // Act
        query.AddWithClause("recent_orders", cte1);
        query.AddWithClause("active_users", cte2);
        var merged = query.GetMergedParameters();

        // Assert
        Assert.That(query.WithClauses, Has.Count.EqualTo(2));
        var keys = merged.Keys.ToList();
        Assert.That(keys.Any(k => k.Contains("MinDate")));
        Assert.That(keys.Any(k => k.Contains("Status")));
    }

    #endregion

    #region Recursive CTE Tests

    [Test]
    public void LinqQueryBreakdown_SupportsRecursiveCTE_ViaInheritance()
    {
        // Arrange
        var anchorQuery = new LinqQueryBreakdown("id, manager_id, name, 1 as level", "employees", "manager_id IS NULL");
        var recursiveQuery = new LinqQueryBreakdown(
            "e.id, e.manager_id, e.name, h.level + 1",
            "employees e INNER JOIN hierarchy h ON e.manager_id = h.id"
        );

        var mainQuery = new LinqQueryBreakdown("*", "hierarchy");

        var withClause = new WithClause("hierarchy", anchorQuery)
        {
            IsRecursive = true,
            RecursiveQuery = recursiveQuery
        };
        mainQuery.AddWithClause(withClause);

        // Act
        var sql = mainQuery.GetSql();

        // Assert
        Assert.That(sql, Contains.Substring("WITH RECURSIVE"));
        Assert.That(sql, Contains.Substring("hierarchy AS"));
        Assert.That(sql, Contains.Substring("UNION ALL"));
    }

    [Test]
    public void LinqQueryBreakdown_RecursiveCTE_CollectsAllParameters()
    {
        // Arrange
        var anchorQuery = new LinqQueryBreakdown("id, manager_id", "employees");
        anchorQuery.AddParameter("AnchorLevel", 1);

        var recursiveQuery = new LinqQueryBreakdown("e.id, e.manager_id", "employees e INNER JOIN org_hier h ON e.manager_id = h.id");
        recursiveQuery.AddParameter("MaxLevel", 10);

        var mainQuery = new LinqQueryBreakdown("*", "org_hierarchy");
        mainQuery.AddParameter("QueryLimit", 100);

        var withClause = new WithClause("org_hierarchy", anchorQuery)
        {
            IsRecursive = true,
            RecursiveQuery = recursiveQuery
        };
        mainQuery.AddWithClause(withClause);

        // Act
        var merged = mainQuery.GetMergedParameters();

        // Assert
        var keys = merged.Keys.ToList();
        Assert.That(keys.Any(k => k.Contains("AnchorLevel")), "Should include anchor parameters");
        Assert.That(keys.Any(k => k.Contains("MaxLevel")), "Should include recursive parameters");
        Assert.That(keys.Any(k => k.Contains("QueryLimit")), "Should include main query parameters");
    }

    #endregion

    #region SQL Generation Tests

    [Test]
    public void LinqQueryBreakdown_GeneratesProperSqlWithParameters()
    {
        // Arrange
        var cte = new LinqQueryBreakdown("id, name, salary", "employees", "salary > @MinSalary");
        cte.AddParameter("MinSalary", 50000);

        var mainQuery = new LinqQueryBreakdown("user_id, user_name, compensation", "employee_summary");
        mainQuery.AddParameter("DepartmentId", 1);
        mainQuery.AddWithClause("high_earners", cte);

        // Act
        var sql = mainQuery.GetSql();

        // Assert
        Assert.That(sql, Contains.Substring("WITH"));
        Assert.That(sql, Contains.Substring("high_earners AS"));
    }

    [Test]
    public void LinqQueryBreakdown_ToSqlServerSql_WithCTE()
    {
        // Arrange
        var cte = new LinqQueryBreakdown("id, name", "base_data");
        var mainQuery = new LinqQueryBreakdown("*", "cte_data");
        mainQuery.AddWithClause("base", cte);

        // Act
        var sql = mainQuery.GetSql();

        // Assert
        Assert.That(sql, Is.Not.Null);
        // GetSql() should include WITH clause (inherited from QueryBreakdown)
        Assert.That(sql, Contains.Substring("WITH"), "GetSql() should generate WITH clause");
    }

    [Test]
    public void LinqQueryBreakdown_ComplexQuery_WithNestdCTEsAndParameters()
    {
        // Arrange
        var innerCte = new LinqQueryBreakdown("id, dept_id", "employees");
        innerCte.AddParameter("InnerParam", "inner_value");

        var outerCte = new LinqQueryBreakdown("*", "filtered_employees");
        outerCte.AddParameter("OuterParam", "outer_value");
        outerCte.AddWithClause("emp_summary", innerCte);

        var mainQuery = new LinqQueryBreakdown("*", "final_results");
        mainQuery.AddParameter("MainParam", "main_value");
        mainQuery.AddWithClause("emp_data", outerCte);

        // Act
        var merged = mainQuery.GetMergedParameters();
        var sql = mainQuery.GetSql();

        // Assert
        var keys = merged.Keys.ToList();
        Assert.That(keys.Any(k => k.Contains("InnerParam")));
        Assert.That(keys.Any(k => k.Contains("OuterParam")));
        Assert.That(keys.Any(k => k.Contains("MainParam")));
        Assert.That(sql, Contains.Substring("WITH"));
    }

    #endregion
}