sql-utilities/tests/Strata.SqlTools.PostgreSql.Tests/PostgreSql/QueryBreakdownTests.cs

using Strata.SqlTools.Breakdowns.PostgreSql;

namespace Strata.SqlTools.SqlBreakdown.Tests.PostgreSql;

[TestFixture]
public class QueryBreakdownTests
{
    #region Constructor Tests

    [Test]
    public void Constructor_Default_InitializesEmptyProperties()
    {
        // Arrange & Act
        var queryBreakdown = new QueryBreakdown();

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.SelectClause.Clause, Is.EqualTo(string.Empty));
            Assert.That(queryBreakdown.FromClause.Clause, Is.EqualTo(string.Empty));
            Assert.That(queryBreakdown.WhereClause.Clause, Is.EqualTo(string.Empty));
            Assert.That(queryBreakdown.OrderByClause.Clause, Is.EqualTo(string.Empty));
        });
    }

    [Test]
    public void Constructor_WithSelectAndFrom_SetsProperties()
    {
        // Arrange
        var selectClause = "id, name";
        var fromClause = "users";

        // Act
        var queryBreakdown = new QueryBreakdown(selectClause, fromClause);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.SelectClause.Clause, Is.EqualTo(selectClause));
            Assert.That(queryBreakdown.FromClause.Clause, Is.EqualTo(fromClause));
        });
    }

    [Test]
    public void Constructor_WithSelectFromAndWhere_SetsProperties()
    {
        // Arrange
        var selectClause = "id, name";
        var fromClause = "users";
        var whereClause = "active = true";

        // Act
        var queryBreakdown = new QueryBreakdown(selectClause, fromClause, whereClause);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.SelectClause.Clause, Is.EqualTo(selectClause));
            Assert.That(queryBreakdown.FromClause.Clause, Is.EqualTo(fromClause));
            Assert.That(queryBreakdown.WhereClause.Clause, Is.EqualTo(whereClause));
        });
    }

    [Test]
    public void Constructor_WithAllBasicClauses_SetsProperties()
    {
        // Arrange
        var selectClause = "id, name";
        var fromClause = "users";
        var whereClause = "active = true";
        var orderByClause = "id ASC";

        // Act
        var queryBreakdown = new QueryBreakdown(selectClause, fromClause, whereClause, orderByClause);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.SelectClause.Clause, Is.EqualTo(selectClause));
            Assert.That(queryBreakdown.FromClause.Clause, Is.EqualTo(fromClause));
            Assert.That(queryBreakdown.WhereClause.Clause, Is.EqualTo(whereClause));
            Assert.That(queryBreakdown.OrderByClause.Clause, Is.EqualTo(orderByClause));
        });
    }

    #endregion

    #region GetSql Tests

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

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

        // Assert
        Assert.That(sql, Is.Not.Null);
        Assert.That(sql, Does.Contain("SELECT").Or.Contain("select"));
        Assert.That(sql, Does.Contain("users"));
    }

    [Test]
    public void GetSql_WithWhereClause_GeneratesValidSql()
    {
        // Arrange
        var queryBreakdown = new QueryBreakdown("id, name", "users", "active = true");

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

        // Assert
        Assert.That(sql, Does.Contain("active"));
        Assert.That(sql, Does.Contain("true"));
    }

    [Test]
    public void GetSql_WithOrderByClause_GeneratesValidSql()
    {
        // Arrange
        var queryBreakdown = new QueryBreakdown("id, name", "users", "active = true", "name ASC");

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

        // Assert
        Assert.That(sql, Does.Contain("ORDER BY").Or.Contain("order by"));
    }

    #endregion

    #region Parameters Tests

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

        // Act
        queryBreakdown.AddParameter("userId", 123);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.Parameters.ContainsKey("userId"), Is.True);
            Assert.That(queryBreakdown.Parameters["userId"], Is.EqualTo(123));
        });
    }

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

        // Act
        queryBreakdown.AddParameter("param1", "value1");
        queryBreakdown.AddParameter("param2", 123);
        queryBreakdown.AddParameter("param3", new DateTime(2025, 1, 1));

        // Assert
        Assert.That(queryBreakdown.Parameters.Count, Is.GreaterThanOrEqualTo(3));
        Assert.Multiple(() =>
        {
            Assert.That(queryBreakdown.Parameters.ContainsKey("param1"), Is.True);
            Assert.That(queryBreakdown.Parameters.ContainsKey("param2"), Is.True);
            Assert.That(queryBreakdown.Parameters.ContainsKey("param3"), Is.True);
        });
    }

    [Test]
    public void AddParameter_ParameterWithAtPrefix_NormalizesName()
    {
        // Arrange
        var queryBreakdown = new QueryBreakdown("id", "users");

        // Act
        queryBreakdown.AddParameter("@userId", 999);

        // Assert
        // The @ prefix is stripped
        Assert.That(queryBreakdown.Parameters.Count, Is.GreaterThan(0));
    }

    #endregion

    #region Parse Tests

    [Test]
    public void Parse_WithValidSelectStement_Succeeds()
    {
        // Arrange
        var sql = "SELECT id, name FROM users";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        // Assert
        Assert.That(queryBreakdown, Is.Not.Null);
        Assert.Multiple(() =>
        {
            Assert.That(queryBreakdown.SelectClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.FromClause.Clause, Is.Not.Empty);
        });
    }

    [Test]
    public void Parse_WithWhereClause_ExtractsCorrectly()
    {
        // Arrange
        var sql = "SELECT id, name FROM users WHERE active = true";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.WhereClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.FromClause.Clause, Does.Contain("users"));
        });
    }

    [Test]
    public void Parse_WithOrderBy_ExtractsCorrectly()
    {
        // Arrange
        var sql = "SELECT id, name FROM users ORDER BY name ASC";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        // Assert
        Assert.That(queryBreakdown.OrderByClause.Clause, Is.Not.Empty);
        Assert.That(queryBreakdown.OrderByClause.Clause, Does.Contain("name"));
    }

    [Test]
    public void Parse_WithPostgreSqlPositionalParameters_ExtractsParameters()
    {
        // Arrange
        var sql = "SELECT id, name FROM users WHERE user_id = $1 AND status = $2";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        // Assert
        Assert.That(queryBreakdown.Parameters.Count, Is.GreaterThanOrEqualTo(0));
    }

    [Test]
    public void Parse_WithComplexQuery_ExtractsAllClauses()
    {
        // Arrange
        var sql = @"
            SELECT u.id, u.name, COUNT(o.id) AS order_count
            FROM users u
            LEFT JOIN orders o ON u.id = o.user_id
            WHERE u.active = true
            GROUP BY u.id, u.name
            HAVING COUNT(o.id) > 0
            ORDER BY order_count DESC
        ";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.SelectClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.FromClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.WhereClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.GroupByClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.HavingClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.OrderByClause.Clause, Is.Not.Empty);
        });
    }

    [Test]
    public void TryParse_WithValidSql_Succeeds()
    {
        // Arrange
        var sql = "SELECT id, name FROM users";

        // Act
        var success = QueryBreakdown.TryParse(sql, out var queryBreakdown, out var errorMessage);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(success, Is.True);
            Assert.That(queryBreakdown, Is.Not.Null);
            Assert.That(errorMessage, Is.Empty);
        });
    }

    [Test]
    public void TryParse_WithEmptySql_ReturnsFalse()
    {
        // Arrange
        var sql = "";

        // Act
        var success = QueryBreakdown.TryParse(sql, out var queryBreakdown, out var errorMessage);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(success, Is.False);
            Assert.That(errorMessage, Is.Not.Empty);
        });
    }

    #endregion

    #region PostgreSQL-Specific Features Tests

    [Test]
    public void GetSql_WithDoubleQuotedIdentifiers_PreservesQuotes()
    {
        // Arrange
        var queryBreakdown = new QueryBreakdown("\"Id\", \"Name\"", "\"Users\"");

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

        // Assert
        Assert.That(sql, Does.Contain("\""));
    }

    [Test]
    public void Parse_WithDoubleQuotedIdentifiers_Succeeds()
    {
        // Arrange
        var sql = "SELECT \"Id\", \"Name\" FROM \"Users\" WHERE \"Id\" = $1";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.SelectClause.Clause, Is.Not.Empty);
            Assert.That(queryBreakdown.FromClause.Clause, Is.Not.Empty);
        });
    }

    [Test]
    public void Parse_WithLimitInOrderBy_ExtractsLimit()
    {
        // Arrange
        var sql = "SELECT id, name FROM users ORDER BY id LIMIT 10";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        // Assert
        // LIMIT is appended to ORDER BY clause in PostgreSQL parsing
        Assert.That(queryBreakdown.OrderByClause.Clause, Does.Contain("LIMIT").Or.Contain("Limit").Or.Contain("limit"));
    }

    [Test]
    public void Parse_WithLimitAndOffset_ExtractsCorrectly()
    {
        // Arrange
        var sql = "SELECT id, name FROM users ORDER BY id LIMIT 10 OFFSET 5";

        // Act
        var queryBreakdown = QueryBreakdown.Parse(sql);

        // Assert
        // Both LIMIT and OFFSET are appended to ORDER BY
        Assert.That(queryBreakdown.OrderByClause.Clause, Is.Not.Empty);
    }

    #endregion

    #region Edge Cases

    [Test]
    public void Constructor_DefaultConstructor_AllowsManualClauseAssignment()
    {
        // Arrange & Act
        var queryBreakdown = new QueryBreakdown();
        queryBreakdown.SelectClause.Clause = "id, name";
        queryBreakdown.FromClause.Clause = "users";

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(queryBreakdown.SelectClause.Clause, Is.EqualTo("id, name"));
            Assert.That(queryBreakdown.FromClause.Clause, Is.EqualTo("users"));
        });
    }

    [Test]
    public void GetSql_EmptyQueryBreakdown_GeneratesBasicSelect()
    {
        // Arrange
        var queryBreakdown = new QueryBreakdown();

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

        // Assert
        Assert.That(sql, Is.Not.Null);
    }

    #endregion

    #region WITH Clause Tests

    [Test]
    public void AddWithClause_WithCTE_AddsToWithClauses()
    {
        // Arrange
        var cte = new QueryBreakdown("id, name", "base_users");
        var mainQuery = new QueryBreakdown("*", "active_users_cte");

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

        // Assert
        Assert.That(mainQuery.WithClauses, Has.Count.EqualTo(1));
        Assert.Multiple(() =>
        {
            Assert.That(mainQuery.WithClauses[0].TableName, Is.EqualTo("active_users_cte"));
            Assert.That(mainQuery.WithClauses[0].Query, Is.EqualTo(cte));
        });
    }

    [Test]
    public void GetSql_WithSimpleCTE_GeneratesWithClause()
    {
        // Arrange
        var cte = new QueryBreakdown("id, name", "base_users");
        var mainQuery = new QueryBreakdown("*", "active_users_cte");
        mainQuery.AddWithClause("active_users_cte", cte);

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

        // Assert
        Assert.That(sql, Contains.Substring("WITH"));
        Assert.That(sql, Contains.Substring("active_users_cte AS"));
        Assert.That(sql, Contains.Substring("id, name"));
        Assert.That(sql, Contains.Substring("base_users"));
    }

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

        var mainQuery = new QueryBreakdown("*", "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 - PostgreSQL

    [Test]
    public void GetMergedParameters_WithNoCTEs_ReturnsMainQueryParameters()
    {
        // Arrange
        var query = new QueryBreakdown("*", "USERS");
        query.AddParameter("UserId", 123);
        query.AddParameter("ActiveStatus", true);

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

        // Assert
        // PostgreSQL stores parameters with positional and name-based formats
        Assert.That(merged.Count, Is.GreaterThanOrEqualTo(2));
        var keys = merged.Keys.ToList();
        Assert.Multiple(() =>
        {
            Assert.That(keys.Any(k => k.Contains("UserId")));
            Assert.That(keys.Any(k => k.Contains("ActiveStatus")));
        });
    }

    [Test]
    public void GetMergedParameters_WithSingleCTE_MergesParameters()
    {
        // Arrange
        var cte = new QueryBreakdown("ID, NAME", "BASE_USERS", "ACTIVE = true");
        cte.AddParameter("MinDate", DateTime.Today.AddDays(-30));

        var mainQuery = new QueryBreakdown("*", "ACTIVE_USERS");
        mainQuery.AddParameter("ResultLimit", 100);
        mainQuery.AddWithClause("ACTIVE_USERS", cte);

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

        // Assert
        var keys = merged.Keys.ToList();
        Assert.Multiple(() =>
        {
            Assert.That(keys.Any(k => k.Contains("MinDate")));
            Assert.That(keys.Any(k => k.Contains("ResultLimit")));
        });
    }

    [Test]
    public void GetMergedParameters_WithMultipleCTEs_MergesAllParameters()
    {
        // Arrange
        var cte1 = new QueryBreakdown("ID, STATUS", "USERS", "STATUS = 'active'");
        cte1.AddParameter("Status1", "active");

        var cte2 = new QueryBreakdown("USER_ID, CREATED", "ORDERS", "CREATED >= CURRENT_DATE");
        cte2.AddParameter("MinDate", DateTime.Today.AddDays(-30));

        var mainQuery = new QueryBreakdown("*", "RESULTS");
        mainQuery.AddParameter("ResultLimit", 50);
        mainQuery.AddWithClause("ACTIVE_USERS", cte1);
        mainQuery.AddWithClause("RECENT_ORDERS", cte2);

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

        // Assert
        var keys = merged.Keys.ToList();
        Assert.Multiple(() =>
        {
            Assert.That(keys.Any(k => k.Contains("Status1")));
            Assert.That(keys.Any(k => k.Contains("MinDate")));
            Assert.That(keys.Any(k => k.Contains("ResultLimit")));
        });
    }

    [Test]
    public void GetMergedParameters_WithParameterConflict_MainQueryTakesPrecedence()
    {
        // Arrange
        var cte = new QueryBreakdown("ID, NAME", "BASE_USERS");
        cte.AddParameter("UserId", 999); // CTE version

        var mainQuery = new QueryBreakdown("*", "ACTIVE_USERS");
        mainQuery.AddParameter("UserId", 123); // Main query version (should win)
        mainQuery.AddWithClause("ACTIVE_USERS", cte);

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

        // Assert
        // Find the UserId parameter value
        var userIdKey = merged.Keys.FirstOrDefault(k => k.Contains("UserId") && !k.Contains('$'));
        Assert.Multiple(() =>
        {
            Assert.That(userIdKey, Is.Not.Null);
            Assert.That(merged[userIdKey], Is.EqualTo(123)); // Main query value, not CTE value
        });
    }

    [Test]
    public void GetMergedParameters_WithNestedCTEs_CollectsAllParameters()
    {
        // Arrange
        var cte1 = new QueryBreakdown("id, name", "base_users");
        cte1.AddParameter("Status", "active");

        var cte2 = new QueryBreakdown("*", "NESTED_USERS");
        cte2.AddParameter("Level", 1);
        cte2.AddWithClause("ACTIVE_USERS", cte1);

        var mainQuery = new QueryBreakdown("*", "FINAL_RESULTS");
        mainQuery.AddParameter("Limit", 100);
        mainQuery.AddWithClause("FILTERED_USERS", cte2);

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

        // Assert
        var keys = merged.Keys.ToList();
        Assert.Multiple(() =>
        {
            Assert.That(keys.Any(k => k.Contains("Status")), "Should include Status from nested CTE");
            Assert.That(keys.Any(k => k.Contains("Level")), "Should include Level from middle CTE");
            Assert.That(keys.Any(k => k.Contains("Limit")), "Should include Limit from main query");
        });
    }

    [Test]
    public void GetMergedParameters_PreservesParameterTypes()
    {
        // Arrange
        var cte = new QueryBreakdown("id, name", "users");
        cte.AddParameter("CreatedDate", new DateTime(2024, 1, 1));

        var mainQuery = new QueryBreakdown("*", "results");
        mainQuery.AddParameter("IsActive", true);
        mainQuery.AddParameter("Threshold", 42.5);
        mainQuery.AddWithClause("users_cte", cte);

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

        // Assert
        var dateKey = merged.Keys.FirstOrDefault(k => k.Contains("CreatedDate") && !k.Contains('$'));
        var boolKey = merged.Keys.FirstOrDefault(k => k.Contains("IsActive") && !k.Contains('$'));
        var doubleKey = merged.Keys.FirstOrDefault(k => k.Contains("Threshold") && !k.Contains('$'));

        Assert.Multiple(() =>
        {
            Assert.That(dateKey, Is.Not.Null);
            Assert.That(merged[dateKey], Is.TypeOf<DateTime>());

            Assert.That(boolKey, Is.Not.Null);
            Assert.That(merged[boolKey], Is.TypeOf<bool>());

            Assert.That(doubleKey, Is.Not.Null);
            Assert.That(merged[doubleKey], Is.TypeOf<double>());
        });
    }

    #endregion
}