package stirling.software.common.util.misc;

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

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.file.Files;

import javax.imageio.ImageIO;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.graphics.color.PDColor;
import org.apache.pdfbox.pdmodel.graphics.color.PDDeviceRGB;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.core.io.InputStreamResource;
import org.springframework.http.MediaType;
import org.springframework.mock.web.MockMultipartFile;
import org.springframework.web.multipart.MultipartFile;

import stirling.software.common.model.api.misc.ReplaceAndInvert;

class InvertFullColorStrategyTest {

    private InvertFullColorStrategy strategy;

    /** Helper method to create a simple PDF with a colored rectangle for testing */
    private static byte[] createSimplePdfWithRectangle() throws IOException {
        PDDocument document = new PDDocument();
        PDPage page = new PDPage(PDRectangle.A4);
        document.addPage(page);

        // Add a filled rectangle with a specific color
        PDPageContentStream contentStream = new PDPageContentStream(document, page);
        contentStream.setNonStrokingColor(
                new PDColor(new float[] {0.8f, 0.2f, 0.2f}, PDDeviceRGB.INSTANCE));
        contentStream.addRect(100, 100, 400, 400);
        contentStream.fill();
        contentStream.close();

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        document.save(baos);
        document.close();

        return baos.toByteArray();
    }

    @BeforeEach
    void setUp() throws Exception {
        // Create a simple PDF document for testing
        byte[] pdfBytes = createSimplePdfWithRectangle();
        MultipartFile mockPdfFile =
                new MockMultipartFile(
                        "file", "test.pdf", MediaType.APPLICATION_PDF_VALUE, pdfBytes);

        // Create the strategy instance
        strategy = new InvertFullColorStrategy(mockPdfFile, ReplaceAndInvert.FULL_INVERSION);
    }

    @Test
    void testReplace() throws IOException {
        // Test the replace method
        InputStreamResource result = strategy.replace();

        // Verify that the result is not null
        assertNotNull(result, "The result should not be null");
    }

    @Test
    void testInvertImageColors()
            throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        // Create a test image with known colors
        BufferedImage image = new BufferedImage(10, 10, BufferedImage.TYPE_INT_ARGB);
        java.awt.Graphics graphics = image.getGraphics();
        graphics.setColor(new Color(200, 100, 50)); // RGB color to be inverted
        graphics.fillRect(0, 0, 10, 10);
        graphics.dispose();

        // Get the color of a pixel before inversion
        Color originalColor = new Color(image.getRGB(5, 5), true);

        // Access private method using reflection
        Method invertMethodRef =
                InvertFullColorStrategy.class.getDeclaredMethod(
                        "invertImageColors", BufferedImage.class);
        invertMethodRef.setAccessible(true);

        // Invoke the private method
        invertMethodRef.invoke(strategy, image);

        // Get the color of the same pixel after inversion
        Color invertedColor = new Color(image.getRGB(5, 5), true);

        // Assert that the inversion worked correctly
        assertEquals(
                255 - originalColor.getRed(),
                invertedColor.getRed(),
                "Red channel should be inverted");
        assertEquals(
                255 - originalColor.getGreen(),
                invertedColor.getGreen(),
                "Green channel should be inverted");
        assertEquals(
                255 - originalColor.getBlue(),
                invertedColor.getBlue(),
                "Blue channel should be inverted");
    }

    @Test
    void testConvertToBufferedImageTpFile()
            throws NoSuchMethodException,
                    InvocationTargetException,
                    IllegalAccessException,
                    IOException {
        // Create a test image
        BufferedImage image = new BufferedImage(10, 10, BufferedImage.TYPE_INT_ARGB);

        // Access private method using reflection
        Method convertMethodRef =
                InvertFullColorStrategy.class.getDeclaredMethod(
                        "convertToBufferedImageTpFile", BufferedImage.class);
        convertMethodRef.setAccessible(true);

        // Invoke the private method
        File result = (File) convertMethodRef.invoke(strategy, image);

        try {
            // Assert that the file exists and is not empty
            assertNotNull(result, "Result should not be null");
            assertTrue(result.exists(), "File should exist");
            assertTrue(result.length() > 0, "File should not be empty");

            // Check that the file can be read back as an image
            BufferedImage readBack = ImageIO.read(result);
            assertNotNull(readBack, "Should be able to read back the image");
            assertEquals(10, readBack.getWidth(), "Image width should match");
            assertEquals(10, readBack.getHeight(), "Image height should match");
        } finally {
            // Clean up
            if (result != null && result.exists()) {
                Files.delete(result.toPath());
            }
        }
    }
}
