sql-utilities/tests/Strata.SqlTools.Markdown.Tests/PostgreSql/SqlStatementGeneratorTests.cs

using Strata.SqlTools.Breakdowns.PostgreSql;
using Strata.SqlTools.Markdown.PostgreSql;

namespace Strata.SqlTools.Markdown.Tests.PostgreSql;

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

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

    [Test]
    public void GenerateSequenceDiagram_PostgreSqlQuery_GeneratesValidDiagram()
    {
        // Arrange
        var query = QueryBreakdown.Parse(@"
            SELECT user_id, user_name, email
            FROM users
            WHERE status = 'ACTIVE'
        ");

        // Act
        var result = SqlStatementGenerator.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_WithPostgreSqlCTE_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
        ");

        // Act
        var result = SqlStatementGenerator.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_ComplexPostgreSqlQuery_GeneratesSequenceDiagram()
    {
        // Arrange
        var query = QueryBreakdown.Parse(@"
            SELECT region, product, SUM(sales) AS total_sales
            FROM sales_data
            WHERE sale_date >= $1
            GROUP BY region, product
            HAVING SUM(sales) > 1000
            ORDER BY total_sales DESC
        ");

        // Act
        var result = SqlStatementGenerator.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_PostgreSqlTables_GeneratesERDiagram()
    {
        // Arrange - PostgreSQL typically uses lowercase table names
        var tables = new[] { "customers", "orders", "order_items", "products" };

        // Act
        var result = SqlStatementGenerator.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 - PostgreSQL case-sensitive identifiers
        var tables = new[] { "\"Customers\"", "\"Orders\"", "\"OrderItems\"" };

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

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

    [Test]
    public void GenerateEntityRelationshipDiagram_WithSchemaQualifiedNames_HandlesSchemaDotTable()
    {
        // Arrange - PostgreSQL schema.table qualified names
        var tables = new[] { "public.users", "sales.orders", "inventory.products" };

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

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

    [Test]
    public void GenerateSequenceDiagram_WithPositionalParameters_HandlesParametrizedQuery()
    {
        // Arrange - PostgreSQL positional parameters $1, $2
        var query = QueryBreakdown.Parse(@"
            SELECT product_id, product_name, price
            FROM products
            WHERE category_id = $1 AND price > $2
            ORDER BY price DESC
        ");

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

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