/*

 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.nashorn.internal.runtime;

import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup;

import static jdk.nashorn.internal.codegen.CompilerConstants.virtualField;

import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

import javax.script.ScriptException;

import jdk.nashorn.api.scripting.NashornException;

import jdk.nashorn.internal.codegen.CompilerConstants.Call;

import jdk.nashorn.internal.codegen.CompilerConstants.FieldAccess;

/**

 * Exception used to implement ECMAScript "throw" from scripts. The actual thrown

 * object from script need not be a Java exception and so it is wrapped as an

 * instance field called "thrown" here. This exception class is also used to

 * represent ECMA errors thrown from runtime code (for example, TypeError,

 * ReferenceError thrown from Nashorn engine runtime).

 */

@SuppressWarnings("serial")

public final class ECMAException extends NashornException {

    /**

     * Method handle pointing to the constructor {@link ECMAException#create(Object, String, int, int)},

     */

    public static final Call CREATE = staticCallNoLookup(ECMAException.class, "create", ECMAException.class, Object.class, String.class, int.class, int.class);

    /** Field handle to the{@link ECMAException#thrown} field, so that it can be accessed from generated code */

    public static final FieldAccess THROWN = virtualField(ECMAException.class, "thrown", Object.class);

    private static final String EXCEPTION_PROPERTY = "nashornException";

    /** Object thrown. */

    public final Object thrown;

    /**

     * Constructor. Called from the factory method 'create'.

     *

     * @param thrown    object to be thrown

     * @param fileName  script file name

     * @param line      line number of throw

     * @param column    column number of throw

     */

    private ECMAException(final Object thrown, final String fileName, final int line, final int column) {

        super(ScriptRuntime.safeToString(thrown), asThrowable(thrown), fileName, line, column);

        this.thrown = thrown;

        setExceptionToThrown();

    }

    /**

     * Constructor. This is called from the runtime code.

     *

     * @param thrown   object to be thrown

     * @param cause    Java exception that triggered this throw

     */

    public ECMAException(final Object thrown, final Throwable cause) {

        super(ScriptRuntime.safeToString(thrown), cause);

        this.thrown = thrown;

        setExceptionToThrown();

    }

    /**

     * Factory method to retrieve the underlying exception or create an exception.

     * This method is called from the generated code.

     *

     * @param thrown    object to be thrown

     * @param fileName  script file name

     * @param line      line number of throw

     * @param column    column number of throw

     * @return ECMAException object

     */

    public static ECMAException create(final Object thrown, final String fileName, final int line, final int column) {

        // If thrown object is an Error or sub-object like TypeError, then

        // an ECMAException object has been already initialized at constructor.

        if (thrown instanceof ScriptObject) {

            final Object exception = getException((ScriptObject)thrown);

            if (exception instanceof ECMAException) {

                final ECMAException ee = (ECMAException)exception;

                // Make sure exception has correct thrown reference because that's what will end up getting caught.

                if (ee.getThrown() == thrown) {

                    // copy over file name, line number and column number.

                    ee.setFileName(fileName);

                    ee.setLineNumber(line);

                    ee.setColumnNumber(column);

                    return ee;

                }

            }

        }

        return new ECMAException(thrown, fileName, line, column);

    }

    /**

     * Get the thrown object

     * @return thrown object

     */

    @Override

    public Object getThrown() {

        return thrown;

    }

    @Override

    public String toString() {

        final StringBuilder sb = new StringBuilder();

        final String fileName = getFileName();

        final int line = getLineNumber();

        final int column = getColumnNumber();

        if (fileName != null) {

            sb.append(fileName);

            if (line >= 0) {

                sb.append(':');

                sb.append(line);

            }

            if (column >= 0) {

                sb.append(':');

                sb.append(column);

            }

            sb.append(' ');

        } else {

            sb.append("ECMAScript Exception: ");

        }

        sb.append(getMessage());

        return sb.toString();

    }

    /**

     * Get the {@link ECMAException}, i.e. the underlying Java object for the

     * JavaScript error object from a {@link ScriptObject} representing an error

     *

     * @param errObj the error object

     * @return a {@link ECMAException}

     */

    public static Object getException(final ScriptObject errObj) {

        // Exclude inherited properties that may belong to errors in the prototype chain.

        if (errObj.hasOwnProperty(ECMAException.EXCEPTION_PROPERTY)) {

            return errObj.get(ECMAException.EXCEPTION_PROPERTY);

        }

        return null;

    }

    /**

     * Print the stack trace for a {@code ScriptObject} representing an error

     *

     * @param errObj the error object

     * @return undefined

     */

    public static Object printStackTrace(final ScriptObject errObj) {

        final Object exception = getException(errObj);

        if (exception instanceof Throwable) {

            ((Throwable)exception).printStackTrace(Context.getCurrentErr());

        } else {

            Context.err("<stack trace not available>");

        }

        return UNDEFINED;

    }

    /**

     * Get the line number for a {@code ScriptObject} representing an error

     *

     * @param errObj the error object

     * @return the line number, or undefined if wrapped exception is not a ParserException

     */

    public static Object getLineNumber(final ScriptObject errObj) {

        final Object e = getException(errObj);

        if (e instanceof NashornException) {

            return ((NashornException)e).getLineNumber();

        } else if (e instanceof ScriptException) {

            return ((ScriptException)e).getLineNumber();

        }

        return UNDEFINED;

    }

    /**

     * Get the column number for a {@code ScriptObject} representing an error

     *

     * @param errObj the error object

     * @return the column number, or undefined if wrapped exception is not a ParserException

     */

    public static Object getColumnNumber(final ScriptObject errObj) {

        final Object e = getException(errObj);

        if (e instanceof NashornException) {

            return ((NashornException)e).getColumnNumber();

        } else if (e instanceof ScriptException) {

            return ((ScriptException)e).getColumnNumber();

        }

        return UNDEFINED;

    }

    /**

     * Get the file name for a {@code ScriptObject} representing an error

     *

     * @param errObj the error object

     * @return the file name, or undefined if wrapped exception is not a ParserException

     */

    public static Object getFileName(final ScriptObject errObj) {

        final Object e = getException(errObj);

        if (e instanceof NashornException) {

            return ((NashornException)e).getFileName();

        } else if (e instanceof ScriptException) {

            return ((ScriptException)e).getFileName();

        }

        return UNDEFINED;

    }

    /**

     * Stateless string conversion for an error object

     *

     * @param errObj the error object

     * @return string representation of {@code errObj}

     */

    public static String safeToString(final ScriptObject errObj) {

        Object name = UNDEFINED;

        try {

            name = errObj.get("name");

        } catch (final Exception e) {

            //ignored

        }

        if (name == UNDEFINED) {

            name = "Error";

        } else {

            name = ScriptRuntime.safeToString(name);

        }

        Object msg = UNDEFINED;

        try {

            msg = errObj.get("message");

        } catch (final Exception e) {

            //ignored

        }

        if (msg == UNDEFINED) {

            msg = "";

        } else {

            msg = ScriptRuntime.safeToString(msg);

        }

        if (((String)name).isEmpty()) {

            return (String)msg;

        }

        if (((String)msg).isEmpty()) {

            return (String)name;

        }

        return name + ": " + msg;

    }

    private static Throwable asThrowable(final Object obj) {

        return (obj instanceof Throwable)? (Throwable)obj : null;

    }

    private void setExceptionToThrown() {

        /*

         * Nashorn extension: errorObject.nashornException

         * Expose this exception via "nashornException" property of on the

         * thrown object. This exception object can be used to print stack

         * trace and fileName, line number etc. from script code.

         */

        if (thrown instanceof ScriptObject) {

            final ScriptObject sobj = (ScriptObject)thrown;

            if (!sobj.has(EXCEPTION_PROPERTY)) {

                sobj.addOwnProperty(EXCEPTION_PROPERTY, Property.NOT_ENUMERABLE, this);

            } else {

                sobj.set(EXCEPTION_PROPERTY, this, 0);

            }

        }

    }

}