/*******************************************************************************
 * Copyright (c) 2014, 2014 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Bruno Medeiros - initial API and implementation
 *******************************************************************************/
package dtool.engine.compiler_installs;

import java.util.ArrayList;
import java.util.List;

import melnorme.lang.utils.SearchPathEnvOperation;
import melnorme.utilbox.misc.Location;
import dtool.engine.StandardLibraryResolution.MissingStandardLibraryResolution;

public abstract class SearchCompilersOnPathOperation extends SearchPathEnvOperation {
	
	public static final String DUB_COMPILERS_PATH__ENV_VAR = "DUB_COMPILERS_PATH";
	
	protected final CompilerInstallDetector detector = new CompilerInstallDetector();
	protected final List<CompilerInstall> foundInstalls = new ArrayList<>();
	
	public SearchCompilersOnPathOperation searchForCompilersInDefaultPathEnvVars() {
		searchEnvironmentVar(DUB_COMPILERS_PATH__ENV_VAR);
		searchEnvironmentVar("PATH");
		return this;
	}
	
	@Override
	protected void searchPathEntry(Location pathEntry) {
		Location exePath;
		if((exePath = executableExists(pathEntry, "dmd")) != null) {
			addPossibleInstall(detector.detectDMDInstall(exePath));
		}
		if((exePath = executableExists(pathEntry, "gdc")) != null) {
			addPossibleInstall(detector.detectGDCInstall(exePath));
		}
		if((exePath = executableExists(pathEntry, "ldc")) != null ||
			(exePath = executableExists(pathEntry, "ldc2")) != null) {
			addPossibleInstall(detector.detectLDCInstall(exePath));
		}
	}
	
	protected void addPossibleInstall(CompilerInstall install) {
		if(install != null) {
			foundInstalls.add(install);
		}
	}
	
	protected Location executableExists(Location pathEntry, String executableFileName) {
		Location exePath;
		exePath = pathEntry.resolveOrNull(executableFileName);
		if(exePath != null && exePath.toFile().exists()) {
			return exePath;
		}
		exePath = pathEntry.resolveOrNull(executableFileName + ".exe");
		if(exePath != null && exePath.toFile().exists()) {
			return exePath;
		}
		return null;
	}
	
	public List<CompilerInstall> getFoundInstalls() {
		return foundInstalls;
	}
	
	/** @return a preferred compiler install. Not null. */
	public CompilerInstall getPreferredInstall() {
		if(foundInstalls != null && foundInstalls.size() > 0) {
			return foundInstalls.get(0);
		}
		return MissingStandardLibraryResolution.NULL_COMPILER_INSTALL;
	}
	
}