package com.bonus.sdk;

import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.HashSet;
import java.util.Set;

public class YoloSdk implements AutoCloseable {

    private long nativeHandle; 
    private static final Set<String> loadedLibraries = new HashSet<>();
    private static Path tempDir; 


    static {
        try {
            tempDir = Files.createTempDirectory("yolo_sdk_native_libs_");
            tempDir.toFile().deleteOnExit();
            loadSdkLibrary(tempDir);

        } catch (IOException e) {
            throw new RuntimeException("CRITICAL: Failed to create temp directory for native libraries", e);
        }
    }

    private static void loadSdkLibrary(Path tempDir) throws IOException {
        String osName = System.getProperty("os.name").toLowerCase();
        String osArch = System.getProperty("os.arch").toLowerCase();
        String libPathInJar;
        String sdkLibName;
        String[] dependencyLibs = {};

        if (osName.contains("win") && osArch.contains("64")) {
            libPathInJar = "/lib/win-x64/";
            dependencyLibs = new String[]{
                    "abseil_dll.dll",
                    "libprotobuf.dll",
                    "zlib1.dll",
                    "onnxruntime.dll",
                    "opencv_core4.dll",
                    "opencv_imgproc4.dll",
                    "opencv_dnn4.dll"
                    // 
            };
            sdkLibName = "my_yolo_sdk.dll";

        } else if ((osName.contains("nix") || osName.contains("nux")) && osArch.contains("64")) {
            libPathInJar = "/lib/linux-x86_64/";
            dependencyLibs = new String[]{
                    "libonnxruntime.so.1.23.2", 
                    "libopencv_core.so.4.6.0",
                    "libopencv_imgproc.so.4.6.0",
                    "libopencv_dnn.so.4.6.0"
            };
            sdkLibName = "libmy_yolo_sdk.so";

        } else {
            throw new UnsupportedOperationException("Unsupported OS/Arch: " + osName + "/" + osArch);
        }

        for (String lib : dependencyLibs) {
            extractLibraryFromJar(libPathInJar + lib, tempDir);
        }
        extractLibraryFromJar(libPathInJar + sdkLibName, tempDir);

        try {
            for (String lib : dependencyLibs) {
                if (!loadedLibraries.contains(lib)) {
                    System.load(tempDir.resolve(lib).toAbsolutePath().toString());
                    loadedLibraries.add(lib);
                }
            }
            if (!loadedLibraries.contains(sdkLibName)) {
                System.load(tempDir.resolve(sdkLibName).toAbsolutePath().toString());
                loadedLibraries.add(sdkLibName);
            }
        } catch (UnsatisfiedLinkError e) {
            System.err.println("--- NATIVE LIBRARY LOAD FAILED ---");
            System.err.println("Failed to load native library. This often means a dependency is missing on the host system.");
            System.err.println("For Windows: Ensure 'Visual C++ Redistributable for Visual Studio (x64)' is installed.");
            System.err.println("Libraries were extracted to: " + tempDir.toAbsolutePath());
            System.err.println("-----------------------------------");
            throw e; 
        }
    }
    private static void extractLibraryFromJar(String pathInJar, Path tempDir) throws IOException {
        String libName = new File(pathInJar).getName();
        
        try (InputStream in = YoloSdk.class.getResourceAsStream(pathInJar)) {
            if (in == null) {
                throw new FileNotFoundException("Library " + pathInJar + " not found in JAR.");
            }

            Path targetFile = tempDir.resolve(libName);
            
            Files.copy(in, targetFile, StandardCopyOption.REPLACE_EXISTING);
            
            targetFile.toFile().deleteOnExit();
        }
    }

    private native long nativeInit(String modelPath, int inputWidth, int inputHeight);
    private native void nativeRelease(long handle);
    private native Detection[] nativePredict(
            long handle, byte[] bgrBytes, int imageWidth, int imageHeight,
            float confThreshold, float iouThreshold
    );

    /**
     * @param modelPath 
     * @param inputWidth 
     * @param inputHeight 
     */
    public YoloSdk(String modelPath, int inputWidth, int inputHeight) {
        this.nativeHandle = nativeInit(modelPath, inputWidth, inputHeight);
        if (this.nativeHandle == 0) {
            throw new RuntimeException("Failed to initialize native YOLO SDK. Check logs for details.");
        }
    }

    /**
     * @param image
     * @param confThreshold
     * @param iouThreshold
     * @return 
     */
    public Detection[] predict(BufferedImage image, float confThreshold, float iouThreshold) {
        if (this.nativeHandle == 0) {
            throw new IllegalStateException("SDK already closed or failed to initialize.");
        }
        byte[] bgrBytes = getBgrBytes(image);
        return nativePredict(
                this.nativeHandle, bgrBytes, image.getWidth(), image.getHeight(),
                confThreshold, iouThreshold
        );
    }

    @Override
    public void close() {
        if (this.nativeHandle != 0) {
            nativeRelease(this.nativeHandle);
            this.nativeHandle = 0;
        }
    }

    /**
     * @param image 
     * @return 
     */
    private byte[] getBgrBytes(BufferedImage image) {
        if (image.getType() == BufferedImage.TYPE_3BYTE_BGR) {
            return ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
        }
        
        BufferedImage bgrImage = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
        bgrImage.getGraphics().drawImage(image, 0, 0, null);
        return ((DataBufferByte) bgrImage.getRaster().getDataBuffer()).getData();
    }
}