package com.example.demo.util;

import com.example.demo.entity.Author;
import com.example.demo.entity.Book;
import org.junit.jupiter.api.Test;

import java.util.Arrays;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertTrue;

class MyBatisGeneratorUtilsTest {

    @Test
    void testGenerateSql_Simple() {
        List<String> fields = Arrays.asList("title", "isbn");
        String sql = MyBatisGeneratorUtils.generateSql(Book.class, fields);
        
        System.out.println("=== Simple SQL ===");
        System.out.println(sql);
        
        assertTrue(sql.contains("SELECT"));
        // Root fields should NOT have prefix (to match standard ResultMap)
        // book.title AS title
        assertTrue(sql.contains("book.title AS title"));
        assertTrue(sql.contains("FROM book book"));
    }

    @Test
    void testGenerateSql_OneToMany_List() {
        // Author -> List<Book>
        // Request: author.name, author.books.title
        List<String> fields = Arrays.asList("name", "books.title");
        String sql = MyBatisGeneratorUtils.generateSql(Author.class, fields);
        
        System.out.println("=== OneToMany List SQL ===");
        System.out.println(sql);
        
        // Root: author
        assertTrue(sql.contains("FROM author author"));
        assertTrue(sql.contains("author.name AS name"));
        // Check Forced ID
        assertTrue(sql.contains("author.id AS id"));
        
        // Join: author -> book (OneToMany)
        // mappedBy="author" in Author means Book has "author" field.
        // Join condition should be: author.id = books.author_id
        assertTrue(sql.contains("LEFT JOIN book author$books"));
        
        // Correct Join Condition for OneToMany
        // author.id = author$books.author_id (assuming default convention or @JoinColumn on Book.author)
        // Book.java: @JoinColumn(name = "author_id") private Author author;
        assertTrue(sql.contains("author.id = author$books.author_id"));
        
        // Check Child Columns
        assertTrue(sql.contains("author$books.title AS books$title"));
        // Check Child Forced ID
        assertTrue(sql.contains("author$books.id AS books$id"));
    }

    @Test
    void testGenerateMapperXml() {
        List<String> fields = Arrays.asList("title", "author.name", "author.books");
        String xml = MyBatisGeneratorUtils.generateMapperXml(Book.class, "com.example.demo.mapper.BookMapper", fields);
        
        System.out.println("=== Generated Mapper XML ===");
        System.out.println(xml);
        
        assertTrue(xml.contains("<mapper namespace=\"com.example.demo.mapper.BookMapper\">"));
        assertTrue(xml.contains("<resultMap id=\"BookMap\""));
        assertTrue(xml.contains("<resultMap id=\"AuthorMap\""));
        
        // Verify BookMap -> AuthorMap association
        assertTrue(xml.contains("<association property=\"author\" resultMap=\"AuthorMap\" columnPrefix=\"author$\"/>"));
        
        // Verify AuthorMap -> Books collection
        assertTrue(xml.contains("<collection property=\"books\" resultMap=\"BookMap\" columnPrefix=\"books$\"/>"));
        
        // Verify SQL is included
        assertTrue(xml.contains("SELECT"));
        // Use column name in alias (publish_month)
        assertTrue(xml.contains("book$author$books.publish_month AS author$books$publish_month"));
    }

    @Test
    void testGenerateSql_NestedJoin() {
        List<String> fields = Arrays.asList("title", "author.name", "author.region.name");
        String sql = MyBatisGeneratorUtils.generateSql(Book.class, fields);

        System.out.println("=== Nested Join SQL ===");
        System.out.println(sql);

        // Verify Joins
        assertTrue(sql.contains("LEFT JOIN author book$author"));
        assertTrue(sql.contains("LEFT JOIN region book$author$region"));
        
        // Verify Columns
        // Child fields SHOULD have relative prefix
        // book$author.name AS author$name
        assertTrue(sql.contains("book$author.name AS author$name"));
        // book$author$region.name AS author$region$name
        assertTrue(sql.contains("book$author$region.name AS author$region$name"));
    }
    
    @Test
    void testGenerateSql_ExpandObject() {
        // "periodical" is an object, should expand to periodical.name, periodical.publishMonth etc.
        List<String> fields = Arrays.asList("title", "periodical");
        String sql = MyBatisGeneratorUtils.generateSql(Book.class, fields);

        System.out.println("=== Expand Object SQL ===");
        System.out.println(sql);

        assertTrue(sql.contains("LEFT JOIN periodical book$periodical"));
        assertTrue(sql.contains("book$periodical.name AS periodical$name"));
        // Use column name in alias: publish_month
        assertTrue(sql.contains("book$periodical.publish_month AS periodical$publish_month"));
    }
    @Test
    void testGenerateSql_CompositeKeyJoin() {
        List<String> fields = Arrays.asList("title", "periodical.name");
        String sql = MyBatisGeneratorUtils.generateSql(Book.class, fields);

        System.out.println("=== Composite Key Join SQL ===");
        System.out.println(sql);

        // Verify Composite Join Condition (publisher_id AND publish_month)
        assertTrue(sql.contains("LEFT JOIN periodical book$periodical"));
        assertTrue(sql.contains("book.publisher_id = book$periodical.publisher_id"));
        assertTrue(sql.contains("book.publish_month = book$periodical.publish_month"));
    }
}