/*******************************************************************************
 * Copyright (c) 2005, 2011 Intel Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 * Intel Corporation - Initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.internal.core.envvar;

import org.eclipse.cdt.core.envvar.IEnvironmentContributor;
import org.eclipse.cdt.core.envvar.IEnvironmentVariable;
import org.eclipse.cdt.core.settings.model.ICConfigurationDescription;
import org.eclipse.cdt.internal.core.cdtvariables.DefaultVariableContextInfo;
import org.eclipse.cdt.internal.core.cdtvariables.EnvironmentVariableSupplier;
import org.eclipse.cdt.internal.core.cdtvariables.ICoreVariableContextInfo;
import org.eclipse.cdt.utils.cdtvariables.ICdtVariableSupplier;
import org.eclipse.cdt.utils.cdtvariables.IVariableContextInfo;
import org.eclipse.cdt.utils.cdtvariables.IVariableSubstitutor;
import org.eclipse.cdt.utils.cdtvariables.SupplierBasedCdtVariableManager;
import org.eclipse.cdt.utils.envvar.EnvVarOperationProcessor;

/**
 * This is the Environment Variable Supplier used to supply variables
 * defined by the tool-integrator
 *
 * @since 3.0
 */
public class BuildSystemEnvironmentSupplier implements ICoreEnvironmentVariableSupplier {

	/**
	 * EnvironmentVariableProvider passed to the tool-integrator provided
	 * suppliers.
	 * Accepts only contexts lower than the one passed to a suppler
	 *
	 * @since 3.0
	 */
	private class ExtensionEnvVarProvider extends EnvironmentVariableManager {
		private IEnvironmentContextInfo fStartInfo;
		private Object fStartLevel;
		private boolean fStartInitialized;
		private int fStartType;
		private Object fStartData;
		private IVariableContextInfo fStartMacroContextInfo;
		private boolean fStartMacroInfoInitialized;

		public ExtensionEnvVarProvider(Object level) {
			fStartLevel = level;
			fStartType = getMacroContextTypeFromContext(level);
			fStartData = level;
		}

		/* (non-Javadoc)
		 * @see org.eclipse.cdt.managedbuilder.envvar.IEnvironmentVariableProvider#getVariable(java.lang.String, java.lang.Object, boolean)
		 */
		@Override
		public IEnvironmentVariable getVariable(String variableName, ICConfigurationDescription cfg,
				boolean resolveMacros) {
			if ((variableName = getValidName(variableName)) == null)
				return null;
			return super.getVariable(variableName, cfg, resolveMacros);
		}

		@Override
		public IEnvironmentVariable[] getVariables(ICConfigurationDescription cfg, boolean resolveMacros) {
			return filterVariables(super.getVariables(cfg, resolveMacros));
		}

		/* (non-Javadoc)
		 * @see org.eclipse.cdt.managedbuilder.internal.envvar.EnvironmentVariableProvider#getContextInfo(java.lang.Object)
		 */
		@Override
		public IEnvironmentContextInfo getContextInfo(Object level) {
			IEnvironmentContextInfo startInfo = getStartInfo();
			if (level == fStartLevel)
				return startInfo;

			IEnvironmentContextInfo info = super.getContextInfo(level);
			if (info == null)
				return null;

			if (checkParentContextRelation(startInfo, info))
				return info;
			return null;
		}

		protected IEnvironmentContextInfo getStartInfo() {
			if (fStartInfo == null && !fStartInitialized) {
				IEnvironmentContextInfo info = super.getContextInfo(fStartLevel);
				if (info != null) {
					ICoreEnvironmentVariableSupplier suppliers[] = info.getSuppliers();
					suppliers = filterValidSuppliers(suppliers);
					if (suppliers != null)
						fStartInfo = new DefaultEnvironmentContextInfo(fStartLevel, suppliers);
					else
						fStartInfo = info.getNext();
					fStartInitialized = true;
				}
				fStartInitialized = true;
			}
			return fStartInfo;
		}

		@Override
		public IVariableSubstitutor getVariableSubstitutor(IVariableContextInfo info, String inexistentMacroValue,
				String listDelimiter) {
			return super.getVariableSubstitutor(getSubstitutorMacroContextInfo(info), inexistentMacroValue,
					listDelimiter);
		}

		protected IVariableContextInfo getSubstitutorMacroContextInfo(IVariableContextInfo info) {
			IVariableContextInfo startInfo = getStartMacroContextInfo();
			if (info == null)
				return null;

			if (info instanceof ICoreVariableContextInfo) {
				ICoreVariableContextInfo coreInfo = (ICoreVariableContextInfo) info;
				if (coreInfo.getContextType() == fStartType && coreInfo.getContextData() == fStartData)
					return startInfo;
			}

			if (SupplierBasedCdtVariableManager.checkParentContextRelation(startInfo, info))
				return info;
			return null;
		}

		protected IVariableContextInfo getStartMacroContextInfo() {
			if (fStartMacroContextInfo == null && !fStartMacroInfoInitialized) {
				final IVariableContextInfo info = getMacroContextInfoForContext(fStartLevel);
				if (info != null) {
					fStartMacroContextInfo = new DefaultVariableContextInfo(fStartType, fStartData) {
						@Override
						protected ICdtVariableSupplier[] getSuppliers(int type, Object data) {
							ICdtVariableSupplier suppliers[] = info.getSuppliers();
							return filterValidMacroSuppliers(suppliers);
						}

						@Override
						public IVariableContextInfo getNext() {
							return info.getNext();
						}
					};
					fStartInitialized = true;
				}
				fStartInitialized = true;
			}
			return fStartMacroContextInfo;
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.managedbuilder.envvar.IEnvironmentVariableSupplier#getVariable()
	 */
	@Override
	public IEnvironmentVariable getVariable(String name, Object context) {
		if (context == null)
			return null;
		if ((name = getValidName(name)) == null)
			return null;

		if (context instanceof ICConfigurationDescription) {
			ICConfigurationDescription cfg = (ICConfigurationDescription) context;
			if (cfg.getBuildSetting() == null)
				return null;
			IEnvironmentContributor supplier = cfg.getBuildSetting().getBuildEnvironmentContributor();
			if (supplier == null)
				return null;
			return supplier.getVariable(name, new ExtensionEnvVarProvider(context));
		}
		return null;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.managedbuilder.envvar.IEnvironmentVariableSupplier#getVariables()
	 */
	@Override
	public IEnvironmentVariable[] getVariables(Object context) {
		if (context == null)
			return new IEnvironmentVariable[0];
		IEnvironmentVariable variables[] = null;
		if (context instanceof ICConfigurationDescription) {
			ICConfigurationDescription cfg = (ICConfigurationDescription) context;
			if (cfg.getBuildSetting() == null)
				return new IEnvironmentVariable[0];
			IEnvironmentContributor supplier = cfg.getBuildSetting().getBuildEnvironmentContributor();
			if (supplier == null)
				return new IEnvironmentVariable[0];
			variables = supplier.getVariables(new ExtensionEnvVarProvider(context));
		}

		return filterVariables(variables);
	}

	protected ICoreEnvironmentVariableSupplier[] filterValidSuppliers(ICoreEnvironmentVariableSupplier suppliers[]) {
		if (suppliers == null)
			return null;

		int i = 0, j = 0;
		for (i = 0; i < suppliers.length; i++) {
			if (suppliers[i] == this)
				break;
		}

		if (i >= suppliers.length)
			return null;

		int startNum = i + 1;

		ICoreEnvironmentVariableSupplier validSuppliers[] = new ICoreEnvironmentVariableSupplier[suppliers.length
				- startNum];

		for (i = startNum, j = 0; i < suppliers.length; i++, j++)
			validSuppliers[j] = suppliers[i];

		return validSuppliers;
	}

	protected String getValidName(String name) {
		name = EnvVarOperationProcessor.normalizeName(name);
		if (name == null)
			return null;
		return name;
	}

	protected IEnvironmentVariable[] filterVariables(IEnvironmentVariable variables[]) {
		return EnvVarOperationProcessor.filterVariables(variables, null);
	}

	protected ICdtVariableSupplier[] filterValidMacroSuppliers(ICdtVariableSupplier suppliers[]) {
		if (suppliers == null)
			return null;

		int i = 0, j = 0;
		for (i = 0; i < suppliers.length; i++) {
			if (suppliers[i] instanceof EnvironmentVariableSupplier)
				break;
		}

		if (i >= suppliers.length)
			return suppliers;

		int startNum = i + 1;

		ICdtVariableSupplier validSuppliers[] = new ICdtVariableSupplier[suppliers.length - startNum];

		for (i = startNum, j = 0; i < suppliers.length; i++, j++)
			validSuppliers[j] = suppliers[i];

		return validSuppliers;
	}

	@Override
	public boolean appendEnvironment(Object context) {
		// TODO
		return true;
	}

}
