using Strata.SqlTools.Breakdowns.Snowflake;
using Strata.SqlTools.Markdown.Snowflake;

namespace Strata.SqlTools.Markdown.Tests.Snowflake;

[TestFixture]
public class SqlStatementGeneratorTests
{
    private SqlStatementGenerator _generator = null!;

    [SetUp]
    public void Setup()
    {
        _generator = new SqlStatementGenerator();
    }

    [Test]
    public void GenerateSequenceDiagram_SnowflakeQuery_GeneratesValidDiagram()
    {
        // Arrange
        var query = QueryBreakdown.Parse(@"
            SELECT USER_ID, USER_NAME, EMAIL
            FROM USERS
            WHERE STATUS = 'ACTIVE'
        ", isMicrosoftSql: false);

        // Act
        var result = _generator.GenerateSequenceDiagram(query, "User Query Flow");

        // Assert
        Assert.That(result, Does.Contain("```mermaid"));
        Assert.That(result, Does.Contain("sequenceDiagram"));
        Assert.That(result, Does.Contain("### User Query Flow"));
        Assert.That(result, Does.Contain("```"));
    }

    [Test]
    public void GenerateSequenceDiagram_WithSnowflakeCTE_ShowsMainStatement()
    {
        // Arrange
        var query = QueryBreakdown.Parse(@"
            WITH ACTIVE_CUSTOMERS AS (
                SELECT CUSTOMER_ID, CUSTOMER_NAME
                FROM CUSTOMERS
                WHERE STATUS = 'ACTIVE'
            )
            SELECT C.CUSTOMER_ID, C.CUSTOMER_NAME, COUNT(O.ORDER_ID) AS ORDER_COUNT
            FROM ACTIVE_CUSTOMERS C
            LEFT JOIN ORDERS O ON C.CUSTOMER_ID = O.CUSTOMER_ID
            GROUP BY C.CUSTOMER_ID, C.CUSTOMER_NAME
        ", isMicrosoftSql: false);

        // Act
        var result = _generator.GenerateSequenceDiagram(query);

        // Assert
        Assert.That(result, Does.Contain("Execute Main Statement"));
        Assert.That(result, Does.Contain("activate DB"));
        Assert.That(result, Does.Contain("deactivate DB"));
    }

    [Test]
    public void GenerateSequenceDiagram_ComplexSnowflakeQuery_GeneratesSequenceDiagram()
    {
        // Arrange
        var query = QueryBreakdown.Parse(@"
            SELECT REGION, PRODUCT, SUM(SALES) AS TOTAL_SALES
            FROM SALES_DATA
            WHERE SALE_DATE >= :startDate
            GROUP BY REGION, PRODUCT
            HAVING SUM(SALES) > 1000
            ORDER BY TOTAL_SALES DESC
        ", isMicrosoftSql: false);

        // Act
        var result = _generator.GenerateSequenceDiagram(query, "Sales Analysis");

        // Assert
        Assert.That(result, Does.Contain("### Sales Analysis"));
        Assert.That(result, Does.Contain("sequenceDiagram"));
        Assert.That(result, Does.Contain("Execute Main Statement"));
        Assert.That(result, Does.Contain("activate DB"));
        Assert.That(result, Does.Contain("Return Results"));
    }

    [Test]
    public void GenerateEntityRelationshipDiagram_SnowflakeTables_GeneratesERDiagram()
    {
        // Arrange - Snowflake typically uses uppercase table names
        var tables = new[] { "CUSTOMERS", "ORDERS", "ORDER_ITEMS", "PRODUCTS" };

        // Act
        var result = _generator.GenerateEntityRelationshipDiagram(tables, "E-Commerce Schema");

        // Assert
        Assert.That(result, Does.Contain("```mermaid"));
        Assert.That(result, Does.Contain("erDiagram"));
        Assert.That(result, Does.Contain("### E-Commerce Schema"));
        Assert.That(result, Does.Contain("CUSTOMERS"));
        Assert.That(result, Does.Contain("ORDERS"));
        Assert.That(result, Does.Contain("ORDER_ITEMS"));
        Assert.That(result, Does.Contain("PRODUCTS"));
    }

    [Test]
    public void GenerateEntityRelationshipDiagram_WithDoubleQuotedNames_HandlesQuotedIdentifiers()
    {
        // Arrange - Snowflake case-sensitive identifiers
        var tables = new[] { "\"customers\"", "\"orders\"", "\"orderItems\"" };

        // Act
        var result = _generator.GenerateEntityRelationshipDiagram(tables);

        // Assert
        Assert.That(result, Does.Contain("erDiagram"));
        Assert.That(result, Does.Contain("```"));
    }

    [Test]
    public void GenerateEntityRelationshipDiagram_SingleTable_GeneratesDiagram()
    {
        // Arrange
        var tables = new[] { "USERS" };

        // Act
        var result = _generator.GenerateEntityRelationshipDiagram(tables);

        // Assert
        Assert.That(result, Does.Contain("erDiagram"));
        Assert.That(result, Does.Contain("USERS"));
    }

    [Test]
    public void GenerateSequenceDiagram_NullTitle_GeneratesWithoutTitle()
    {
        // Arrange
        var query = new QueryBreakdown("ORDER_ID", "ORDERS");

        // Act
        var result = _generator.GenerateSequenceDiagram(query, null);

        // Assert
        Assert.That(result, Does.Not.Contain("###"));
        Assert.That(result, Does.Contain("sequenceDiagram"));
    }
}