sql-utilities/tests/Strata.SqlTools.SqlBreakdown.Tests/Exceptions/ExceptionHandlingTests.cs

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

namespace Strata.SqlTools.SqlBreakdown.Tests.Exceptions;

[TestFixture]
public class ExceptionHandlingTests
{
    #region SqlParseException Tests

    [Test]
    public void SqlParseException_StoresProperties()
    {
        // Arrange
        var message = "Unexpected token";
        var sql = "SELECT * FRM users";
        var position = 10;

        // Act
        var exception = new SqlParseException(message, sql, position);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(exception.Message, Does.Contain(message));
            Assert.That(exception.Sql, Is.EqualTo(sql));
            Assert.That(exception.Position, Is.EqualTo(position));
            Assert.That(exception.NearText, Is.Not.Empty);
        });
    }

    [Test]
    public void SqlParseException_FormatsMessageWithContext()
    {
        // Arrange
        var message = "Invalid syntax";
        var sql = "SELECT id, name FROM users WHERE active = INVALID";
        var position = 40;

        // Act
        var exception = new SqlParseException(message, sql, position);

        // Assert
        Assert.That(exception.Message, Does.Contain("Invalid syntax"));
        Assert.That(exception.Message, Does.Contain("Position: 40"));
        Assert.That(exception.Message, Does.Contain("Near:"));
    }

    [Test]
    public void SqlParseException_HandlesNullSql()
    {
        // Arrange
        var message = "SQL is null";
        string? sql = null;
        var position = 0;

        // Act
        var exception = new SqlParseException(message, sql!, position);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(exception.Message, Does.Contain("SQL is null"));
            Assert.That(exception.Sql, Is.EqualTo(string.Empty));
            Assert.That(exception.NearText, Is.EqualTo(string.Empty));
        });
    }

    [Test]
    public void SqlParseException_TruncatesLongSql()
    {
        // Arrange
        var message = "Parse error";
        var sql = new string('A', 250) + " FROM users";
        var position = 100;

        // Act
        var exception = new SqlParseException(message, sql, position);

        // Assert
        Assert.That(exception.Message, Does.Contain("truncated"));
    }

    [Test]
    public void SqlParseException_WithInnerException()
    {
        // Arrange
        var message = "Parse failed";
        var sql = "SELECT * FROM users";
        var position = 5;
        var innerException = new InvalidOperationException("Original error");

        // Act
        var exception = new SqlParseException(message, sql, position, innerException);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(exception.InnerException, Is.EqualTo(innerException));
            Assert.That(exception.Message, Does.Contain("Parse failed"));
        });
    }

    #endregion

    #region CteValidationException Tests

    [Test]
    public void CteValidationException_StoresProperties()
    {
        // Arrange
        var message = "CTE name required";
        var cteName = "my_cte";
        var validationRule = "TableNameRequired";

        // Act
        var exception = new CteValidationException(message, cteName, validationRule);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(exception.Message, Does.Contain(message));
            Assert.That(exception.CteName, Is.EqualTo(cteName));
            Assert.That(exception.ValidationRule, Is.EqualTo(validationRule));
        });
    }

    [Test]
    public void CteValidationException_IncludesHintForKnownRules()
    {
        // Arrange
        var message = "Table name is required";
        var validationRule = "TableNameRequired";

        // Act
        var exception = new CteValidationException(message, null, validationRule);

        // Assert
        Assert.That(exception.Message, Does.Contain("Hint:"));
        Assert.That(exception.Message, Does.Contain("non-empty table name"));
    }

    [Test]
    public void CteValidationException_HandlesUnknownRule()
    {
        // Arrange
        var message = "Validation failed";
        var validationRule = "UnknownRule123";

        // Act
        var exception = new CteValidationException(message, "my_cte", validationRule);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(exception.ValidationRule, Is.EqualTo(validationRule));
            Assert.That(exception.Message, Does.Contain("Validation failed"));
        });
    }

    [Test]
    public void CteValidationException_WithInnerException()
    {
        // Arrange
        var message = "Validation error";
        var cteName = "test_cte";
        var validationRule = "DuplicateCteName";
        var innerException = new ArgumentException("Duplicate");

        // Act
        var exception = new CteValidationException(message, cteName, validationRule, innerException);

        // Assert
        Assert.That(exception.InnerException, Is.EqualTo(innerException));
    }

    #endregion

    #region QueryBreakdown.Parse Exception Tests

    [Test]
    public void Parse_WithNullSql_ThrowsArgumentNullException()
    {
        // Arrange
        string? sql = null;

        // Act & Assert
        Assert.Throws<ArgumentNullException>(() => QueryBreakdown.Parse(sql!));
    }

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

        // Act & Assert
        Assert.Throws<ArgumentNullException>(() => QueryBreakdown.Parse(sql));
    }

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

        // Act & Assert
        Assert.Throws<ArgumentNullException>(() => QueryBreakdown.Parse(sql));
    }

    [Test]
    public void Parse_WithInvalidSql_ThrowsSqlParseException()
    {
        // Arrange
        var sql = "INVALID SQL STATEMENT";

        // Act & Assert
        var exception = Assert.Throws<SqlParseException>(() => QueryBreakdown.Parse(sql));
        Assert.Multiple(() =>
        {
            Assert.That(exception!.Sql, Is.EqualTo(sql));
            Assert.That(exception.Message, Does.Contain("Failed to parse"));
        });
    }

    [Test]
    public void Parse_WithMalformedSql_ProvidesSqlParseExceptionWithContext()
    {
        // Arrange - Use SQL that will definitely fail parsing
        var sql = "SELECT WHERE FROM";

        // Act
        var exception = Assert.Throws<SqlParseException>(() => QueryBreakdown.Parse(sql));

        // Assert
        Assert.That(exception, Is.Not.Null);
        Assert.That(exception!.Sql, Is.EqualTo(sql));
    }

    #endregion

    #region AddWithClause Validation Tests

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

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause(null!, cteQuery));
        Assert.That(exception!.ValidationRule, Is.EqualTo("TableNameRequired"));
    }

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

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause("", cteQuery));
        Assert.That(exception!.ValidationRule, Is.EqualTo("TableNameRequired"));
    }

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

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause("   ", cteQuery));
        Assert.That(exception!.ValidationRule, Is.EqualTo("TableNameRequired"));
    }

    [Test]
    public void AddWithClause_WithNullQuery_ThrowsCteValidationException()
    {
        // Arrange
        var query = new QueryBreakdown();

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause("test_cte", (QueryBreakdown)null!));
        Assert.Multiple(() =>
        {
            Assert.That(exception!.ValidationRule, Is.EqualTo("QueryRequired"));
            Assert.That(exception.CteName, Is.EqualTo("test_cte"));
        });
    }

    [Test]
    public void AddWithClause_WithDuplicateName_ThrowsCteValidationException()
    {
        // Arrange
        var query = new QueryBreakdown();
        var cte1 = new QueryBreakdown("id", "users");
        var cte2 = new QueryBreakdown("name", "products");

        query.AddWithClause("my_cte", cte1);

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause("my_cte", cte2));
        Assert.Multiple(() =>
        {
            Assert.That(exception!.ValidationRule, Is.EqualTo("DuplicateCteName"));
            Assert.That(exception.Message, Does.Contain("already exists"));
        });
    }

    [Test]
    public void AddWithClause_WithDuplicateName_CaseInsensitive_ThrowsCteValidationException()
    {
        // Arrange
        var query = new QueryBreakdown();
        var cte1 = new QueryBreakdown("id", "users");
        var cte2 = new QueryBreakdown("name", "products");

        query.AddWithClause("MY_CTE", cte1);

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause("my_cte", cte2));
        Assert.That(exception!.ValidationRule, Is.EqualTo("DuplicateCteName"));
    }

    [Test]
    public void AddWithClause_WithSql_NullTableName_ThrowsCteValidationException()
    {
        // Arrange
        var query = new QueryBreakdown();

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause(null!, "SELECT * FROM users"));
        Assert.That(exception!.ValidationRule, Is.EqualTo("TableNameRequired"));
    }

    [Test]
    public void AddWithClause_WithSql_NullSql_ThrowsCteValidationException()
    {
        // Arrange
        var query = new QueryBreakdown();

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause("my_cte", (string)null!));
        Assert.That(exception!.ValidationRule, Is.EqualTo("QueryRequired"));
    }

    [Test]
    public void AddWithClause_WithSql_InvalidSql_ThrowsSqlParseException()
    {
        // Arrange
        var query = new QueryBreakdown();

        // Act & Assert
        var exception = Assert.Throws<SqlParseException>(() =>
            query.AddWithClause("my_cte", "INVALID SQL"));
        Assert.Multiple(() =>
        {
            Assert.That(exception!.Message, Does.Contain("my_cte"));
            Assert.That(exception.Sql, Is.EqualTo("INVALID SQL"));
        });
    }

    [Test]
    public void AddWithClause_WithIWithClause_NullClause_ThrowsCteValidationException()
    {
        // Arrange
        var query = new QueryBreakdown();

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause((WithClause)null!));
        Assert.That(exception!.ValidationRule, Is.EqualTo("QueryRequired"));
    }

    [Test]
    public void AddWithClause_WithIWithClause_NoQueryOrSql_ThrowsCteValidationException()
    {
        // Arrange
        var query = new QueryBreakdown();
        var withClause = new WithClause
        {
            TableName = "test_cte"
            // Query and Sql are both null
        };

        // Act & Assert
        var exception = Assert.Throws<CteValidationException>(() =>
            query.AddWithClause(withClause));
        Assert.Multiple(() =>
        {
            Assert.That(exception!.ValidationRule, Is.EqualTo("QueryRequired"));
            Assert.That(exception.Message, Does.Contain("Query or Sql"));
        });
    }

    [Test]
    public void AddWithClause_ValidCte_Succeeds()
    {
        // Arrange
        var query = new QueryBreakdown();
        var cteQuery = new QueryBreakdown("id, name", "users", "active = 1");

        // Act
        query.AddWithClause("active_users", cteQuery);

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

    #endregion

    #region Exception Message Quality Tests

    [Test]
    public void CteValidationException_TableNameRequired_HasHelpfulMessage()
    {
        // Act
        var exception = new CteValidationException(
            "CTE table name cannot be null",
            null,
            "TableNameRequired");

        // Assert
        Assert.That(exception.Message, Does.Contain("non-empty table name"));
        Assert.That(exception.Message, Does.Contain("Hint:"));
    }

    [Test]
    public void CteValidationException_DuplicateCteName_HasHelpfulMessage()
    {
        // Act
        var exception = new CteValidationException(
            "Duplicate CTE name",
            "my_cte",
            "DuplicateCteName");

        // Assert
        Assert.That(exception.Message, Does.Contain("unique"));
        Assert.That(exception.Message, Does.Contain("Hint:"));
    }

    [Test]
    public void SqlParseException_ShowsNearText()
    {
        // Arrange
        var sql = "SELECT id, name FROM users WHERE active = 1 AND status = 'INVALID'";
        var position = 50;

        // Act
        var exception = new SqlParseException("Syntax error", sql, position);

        Assert.Multiple(() =>
        {
            // Assert
            Assert.That(exception.NearText, Does.Contain("status"));
            Assert.That(exception.Message, Does.Contain("Near:"));
        });
    }

    #endregion
}