/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM 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:
 *     IBM Corporation - initial API and implementation
 *     Jesper Steen Møller <jesper@selskabet.org> - Bug 430839
 *******************************************************************************/
package org.eclipse.jdt.internal.debug.core.model;

import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.eclipse.debug.core.DebugException;
import org.eclipse.jdt.core.Signature;
import org.eclipse.jdt.debug.core.IJavaClassObject;
import org.eclipse.jdt.debug.core.IJavaFieldVariable;
import org.eclipse.jdt.debug.core.IJavaObject;
import org.eclipse.jdt.debug.core.IJavaReferenceType;
import org.eclipse.jdt.debug.core.IJavaValue;

import com.sun.jdi.AbsentInformationException;
import com.sun.jdi.ArrayType;
import com.sun.jdi.ClassLoaderReference;
import com.sun.jdi.ClassNotLoadedException;
import com.sun.jdi.Field;
import com.sun.jdi.ObjectReference;
import com.sun.jdi.ReferenceType;
import com.sun.jdi.Type;
import com.sun.jdi.Value;
import com.sun.jdi.VirtualMachine;

/**
 * References a class, interface, or array type.
 */
public abstract class JDIReferenceType extends JDIType implements
		IJavaReferenceType {

	// field names declared in this type
	private String[] fDeclaredFields = null;
	// field names declared in this type, super types, implemented interfaces
	// and super-interfaces
	private String[] fAllFields = null;

	/**
	 * Constructs a new reference type in the given target.
	 *
	 * @param target
	 *            associated VM
	 * @param type
	 *            reference type
	 */
	public JDIReferenceType(JDIDebugTarget target, Type type) {
		super(target, type);
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getAvailableStrata()
	 */
	@Override
	public String[] getAvailableStrata() {
		List<String> strata = getReferenceType().availableStrata();
		return strata.toArray(new String[strata.size()]);
	}

	/**
	 * Returns the underlying reference type.
	 *
	 * @return the underlying reference type
	 */
	protected ReferenceType getReferenceType() {
		return (ReferenceType) getUnderlyingType();
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getDefaultStratum()
	 */
	@Override
	public String getDefaultStratum() throws DebugException {
		try {
			return getReferenceType().defaultStratum();
		} catch (RuntimeException e) {
			targetRequestFailed(JDIDebugModelMessages.JDIReferenceType_1, e);
		}
		// execution will not reach here
		return null;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see
	 * org.eclipse.jdt.debug.core.IJavaReferenceType#getField(java.lang.String)
	 */
	@Override
	public IJavaFieldVariable getField(String name) throws DebugException {
		try {
			ReferenceType type = (ReferenceType) getUnderlyingType();
			Field field = type.fieldByName(name);
			if (field != null && field.isStatic()) {
				return new JDIFieldVariable(getJavaDebugTarget(), field, type);
			}
		} catch (RuntimeException e) {
			targetRequestFailed(
					MessageFormat.format(
							JDIDebugModelMessages.JDIClassType_exception_while_retrieving_field,
							e.toString(), name), e);
		}
		// it is possible to return null
		return null;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getClassObject()
	 */
	@Override
	public IJavaClassObject getClassObject() throws DebugException {
		try {
			ReferenceType type = (ReferenceType) getUnderlyingType();
			return (IJavaClassObject) JDIValue.createValue(
					getJavaDebugTarget(), type.classObject());
		} catch (RuntimeException e) {
			targetRequestFailed(
					MessageFormat.format(
							JDIDebugModelMessages.JDIClassType_exception_while_retrieving_class_object,
							e.toString()), e);
		}
		// execution will not fall through to here,
		// as #requestFailed will throw an exception
		return null;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getAllFieldNames()
	 */
	@Override
	public String[] getAllFieldNames() throws DebugException {
		if (fAllFields == null) {
			try {
				List<Field> fields = ((ReferenceType) getUnderlyingType()).allFields();
				fAllFields = new String[fields.size()];
				Iterator<Field> iterator = fields.iterator();
				int i = 0;
				while (iterator.hasNext()) {
					Field field = iterator.next();
					fAllFields[i] = field.name();
					i++;
				}
			} catch (RuntimeException e) {
				targetRequestFailed(JDIDebugModelMessages.JDIReferenceType_2, e);
			}
		}
		return fAllFields;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see
	 * org.eclipse.jdt.debug.core.IJavaReferenceType#getDeclaredFieldNames()
	 */
	@Override
	public String[] getDeclaredFieldNames() throws DebugException {
		if (fDeclaredFields == null) {
			try {
				List<Field> fields = ((ReferenceType) getUnderlyingType()).fields();
				fDeclaredFields = new String[fields.size()];
				Iterator<Field> iterator = fields.iterator();
				int i = 0;
				while (iterator.hasNext()) {
					Field field = iterator.next();
					fDeclaredFields[i] = field.name();
					i++;
				}
			} catch (RuntimeException e) {
				targetRequestFailed(JDIDebugModelMessages.JDIReferenceType_3, e);
			}
		}
		return fDeclaredFields;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see
	 * org.eclipse.jdt.debug.core.IJavaReferenceType#getSourcePaths(java.lang
	 * .String)
	 */
	@Override
	public String[] getSourcePaths(String stratum) throws DebugException {
		try {
			List<String> sourcePaths = getReferenceType().sourcePaths(stratum);
			return sourcePaths
					.toArray(new String[sourcePaths.size()]);
		} catch (AbsentInformationException e) {
		} catch (RuntimeException e) {
			requestFailed(JDIDebugModelMessages.JDIReferenceType_4, e,
					DebugException.TARGET_REQUEST_FAILED);
		}
		return null;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getSourceName()
	 */
	@Override
	public String getSourceName() throws DebugException {
		try {
			return getReferenceType().sourceName();
		} catch (AbsentInformationException e) {
		} catch (RuntimeException e) {
			requestFailed(JDIDebugModelMessages.JDIReferenceType_4, e,
					DebugException.TARGET_REQUEST_FAILED);
		}
		return null;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see
	 * org.eclipse.jdt.debug.core.IJavaReferenceType#getSourceNames(java.lang
	 * .String)
	 */
	@Override
	public String[] getSourceNames(String stratum) throws DebugException {
		try {
			List<String> sourceNames = getReferenceType().sourceNames(stratum);
			return sourceNames
					.toArray(new String[sourceNames.size()]);
		} catch (AbsentInformationException e) {
		} catch (RuntimeException e) {
			requestFailed(JDIDebugModelMessages.JDIReferenceType_4, e,
					DebugException.TARGET_REQUEST_FAILED);
		}
		return null;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getClassLoaderObject()
	 */
	@Override
	public IJavaObject getClassLoaderObject() throws DebugException {
		try {
			ReferenceType type = (ReferenceType) getUnderlyingType();
			ClassLoaderReference classLoader = type.classLoader();
			if (classLoader != null) {
				return (IJavaObject) JDIValue.createValue(getJavaDebugTarget(),
						classLoader);
			}
		} catch (RuntimeException e) {
			targetRequestFailed(MessageFormat.format(
					JDIDebugModelMessages.JDIReferenceType_0,
					e.toString()), e);
		}
		return null;
	}

	static public String getGenericName(ReferenceType type)
			throws DebugException {
		if (type instanceof ArrayType) {
			try {
				Type componentType;
				componentType = ((ArrayType) type).componentType();
				if (componentType instanceof ReferenceType) {
					return getGenericName((ReferenceType) componentType) + "[]"; //$NON-NLS-1$
				}
				return type.name();
			} catch (ClassNotLoadedException e) {
				// we cannot create the generic name using the component type,
				// just try to create one with the information
			}
		}
		String signature = type.signature();
		StringBuilder res = new StringBuilder(getTypeName(signature));
		String genericSignature = type.genericSignature();
		if (genericSignature != null) {
			String[] typeParameters = Signature
					.getTypeParameters(genericSignature);
			if (typeParameters.length > 0) {
				res.append('<').append(
						Signature.getTypeVariable(typeParameters[0]));
				for (int i = 1; i < typeParameters.length; i++) {
					res.append(',').append(
							Signature.getTypeVariable(typeParameters[i]));
				}
				res.append('>');
			}
		}
		return res.toString();
	}

	/**
	 * Return the name from the given signature. Keep the '$' characters.
	 *
	 * @param genericTypeSignature
	 *            the signature to derive the type name from
	 * @return the type name
	 */
	public static String getTypeName(String genericTypeSignature) {
		int arrayDimension = 0;
		while (genericTypeSignature.charAt(arrayDimension) == '[') {
			arrayDimension++;
		}
		int parameterStart = genericTypeSignature.indexOf('<');
		StringBuilder name = new StringBuilder();
		if (parameterStart < 0) {
			name.append(genericTypeSignature.substring(arrayDimension + 1,
					genericTypeSignature.length() - 1).replace('/', '.'));
		} else {
			if (parameterStart != 0) {
				name.append(genericTypeSignature.substring(arrayDimension + 1,
						parameterStart).replace('/', '.'));
			}
			try {
				String sig = Signature.toString(genericTypeSignature)
						.substring(
								Math.max(parameterStart - 1, 0)
										- arrayDimension);
				name.append(sig.replace('/', '.'));
			} catch (IllegalArgumentException iae) {
				// do nothing
				name.append(genericTypeSignature);
			}
		}
		for (int i = 0; i < arrayDimension; i++) {
			name.append("[]"); //$NON-NLS-1$
		}
		return name.toString();
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getGenericSignature()
	 */
	@Override
	public String getGenericSignature() throws DebugException {
		return getReferenceType().genericSignature();
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getInstances(long)
	 */
	@Override
	public IJavaObject[] getInstances(long max) throws DebugException {
		try {
			List<ObjectReference> list = getReferenceType().instances(max);
			IJavaObject[] instances = new IJavaObject[list.size()];
			for (int i = 0; i < instances.length; i++) {
				instances[i] = (IJavaObject) JDIValue.createValue(
						getJavaDebugTarget(), list.get(i));
			}
			return instances;
		} catch (RuntimeException e) {
			targetRequestFailed(JDIDebugModelMessages.JDIReferenceType_5, e);
		}
		return null;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jdt.debug.core.IJavaReferenceType#getInstanceCount()
	 */
	@Override
	public long getInstanceCount() throws DebugException {
		JDIDebugTarget target = getJavaDebugTarget();
		if (target.supportsInstanceRetrieval()) {
			Type type = getUnderlyingType();
			if(type instanceof ReferenceType) {
				ArrayList<ReferenceType> list = new ArrayList<>(2);
				list.add((ReferenceType) type);
				VirtualMachine vm = getVM();
				try {
					long[] counts = vm.instanceCounts(list);
					return counts[0];
				} catch (RuntimeException e) {
					targetRequestFailed(JDIDebugModelMessages.JDIReferenceType_5, e);
				}
			}
		}
		return -1;
	}

	/**
	 * Utility method to convert argument array to an argument list.
	 *
	 * @param args
	 *            array of arguments, as <code>IJavaValue</code>s, possibly
	 *            <code>null</code> or empty
	 * @return a list of underlying <code>Value</code>s
	 */
	protected List<Value> convertArguments(IJavaValue[] args) {
		List<Value> arguments = null;
		if (args == null) {
			arguments = Collections.EMPTY_LIST;
		} else {
			arguments = new ArrayList<>(args.length);
			for (IJavaValue arg : args) {
				arguments.add(((JDIValue) arg).getUnderlyingValue());
			}
		}
		return arguments;
	}

}