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package com.diozero.util;

/*
 * #%L
 * Organisation: diozero
 * Project:      diozero - Core
 * Filename:     LibraryLoader.java
 * 
 * This file is part of the diozero project. More information about this project
 * can be found at https://www.diozero.com/.
 * %%
 * Copyright (C) 2016 - 2021 diozero
 * %%
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 * #L%
 */

import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.HashMap;
import java.util.Map;

import org.tinylog.Logger;

import com.diozero.sbc.LocalBoardInfoUtil;
import com.diozero.sbc.LocalSystemInfo;

public class LibraryLoader {
	private static final Map LOADED_LIBRARIES = new HashMap<>();

	/**
	 * Load the diozero system utility JNI library (diozero-system-utils).
	 */
	public static void loadSystemUtils() {
		/*-
		int hash_code = new Object().hashCode();
		System.out.println("loadSystemUtils() - START - " + hash_code);
		for (StackTraceElement ste : Thread.currentThread().getStackTrace()) {
			System.out.println(ste.toString());
		}
		*/

		// Possibly replace with this library?
		// https://github.com/vsergeev/c-periphery
		// Also look at this library: https://github.com/google/periph/tree/master/host
		// XXX Note that SystemInto.lookupLocalBoardInfo also calls loadSystemUtils when
		// intialising the pins...
		loadLibrary(LibraryLoader.class, "diozero-system-utils",
				LocalBoardInfoUtil.lookupLocalBoardInfo().getLibraryPath());
		// System.out.println("loadSystemUtils() - END - " + hash_code);
	}

	public static void loadLibrary(Class clz, String libName, String libraryPath) throws UnsatisfiedLinkError {
		LocalSystemInfo sys_info = LocalSystemInfo.getInstance();
		synchronized (LibraryLoader.class) {
			if (LOADED_LIBRARIES.get(libName) == null) {
				boolean loaded = false;

				// First try load the library from within the JAR file
				String lib_file;
				if (libraryPath != null) {
					lib_file = String.format("/lib/%s/lib%s.%s", libraryPath, libName, sys_info.getLibFileExtension());
				} else {
					lib_file = String.format("/lib/lib%s.%s", libName, sys_info.getLibFileExtension());
				}
				Logger.debug("Looking for lib '" + lib_file + "' on classpath");
				try (InputStream is = clz.getResourceAsStream(lib_file)) {
					if (is != null) {
						Path path = Files.createTempFile("lib" + libName, sys_info.getLibFileExtension());
						path.toFile().deleteOnExit();
						Files.copy(is, path, StandardCopyOption.REPLACE_EXISTING);
						Runtime.getRuntime().load(path.toString());
						path.toFile().delete();
						loaded = true;
						Logger.debug("Loaded library '{}' from classpath", libName);
					}
				} catch (Throwable t) {
					Logger.warn("Error loading library '{}' from classpath, trying System.loadLibrary: {}", libName,
							t.getMessage());
				}
				if (!loaded) {
					// Try load from the Java system library path (-Djava.library.path)
					Logger.debug("Looking for lib '" + libName + "' on library path");
					try {
						System.loadLibrary(libName);
						loaded = true;
						Logger.info("Loaded library '{}' from system library path", libName);
					} catch (Throwable t) {
						Logger.error("Error loading library '{}' from system library path: {}", libName, t);
					}
				}
				LOADED_LIBRARIES.put(libName, Boolean.valueOf(loaded));
			}
		}
	}
}