/*
 * Copyright (c) 2011, 2016, 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
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 */

package sun.lwawt.macosx;

import sun.awt.SunToolkit;
import sun.lwawt.LWWindowPeer;
import sun.lwawt.PlatformEventNotifier;

import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import java.awt.event.InputEvent;
import java.awt.event.MouseWheelEvent;
import java.awt.event.KeyEvent;
import java.util.Locale;

/**
 * Translates NSEvents/NPCocoaEvents into AWT events.
 */
final class CPlatformResponder {

    private final PlatformEventNotifier eventNotifier;
    private final boolean isNpapiCallback;
    private int lastKeyPressCode = KeyEvent.VK_UNDEFINED;
    private final DeltaAccumulator deltaAccumulatorX = new DeltaAccumulator();
    private final DeltaAccumulator deltaAccumulatorY = new DeltaAccumulator();

    CPlatformResponder(final PlatformEventNotifier eventNotifier,
                       final boolean isNpapiCallback) {
        this.eventNotifier = eventNotifier;
        this.isNpapiCallback = isNpapiCallback;
    }

    /**
     * Handles mouse events.
     */
    void handleMouseEvent(int eventType, int modifierFlags, int buttonNumber,
                          int clickCount, int x, int y, int absX, int absY) {
        final SunToolkit tk = (SunToolkit)Toolkit.getDefaultToolkit();
        if ((buttonNumber > 2 && !tk.areExtraMouseButtonsEnabled())
                || buttonNumber > tk.getNumberOfButtons() - 1) {
            return;
        }

        int jeventType = isNpapiCallback ? NSEvent.npToJavaEventType(eventType) :
                                           NSEvent.nsToJavaEventType(eventType);

        int jbuttonNumber = MouseEvent.NOBUTTON;
        int jclickCount = 0;

        if (jeventType != MouseEvent.MOUSE_MOVED &&
            jeventType != MouseEvent.MOUSE_ENTERED &&
            jeventType != MouseEvent.MOUSE_EXITED)
        {
            jbuttonNumber = NSEvent.nsToJavaButton(buttonNumber);
            jclickCount = clickCount;
        }

        int jmodifiers = NSEvent.nsToJavaModifiers(modifierFlags);
        boolean jpopupTrigger = NSEvent.isPopupTrigger(jmodifiers);

        eventNotifier.notifyMouseEvent(jeventType, System.currentTimeMillis(), jbuttonNumber,
                x, y, absX, absY, jmodifiers, jclickCount,
                jpopupTrigger, null);
    }

    /**
     * Handles scroll events.
     */
    void handleScrollEvent(final int x, final int y, final int absX,
                           final int absY, final int modifierFlags,
                           final double deltaX, final double deltaY,
                           final int scrollPhase) {
        int jmodifiers = NSEvent.nsToJavaModifiers(modifierFlags);
        final boolean isShift = (jmodifiers & InputEvent.SHIFT_DOWN_MASK) != 0;

        int roundDeltaX = deltaAccumulatorX.getRoundedDelta(deltaX, scrollPhase);
        int roundDeltaY = deltaAccumulatorY.getRoundedDelta(deltaY, scrollPhase);

        // Vertical scroll.
        if (!isShift && (deltaY != 0.0 || roundDeltaY != 0)) {
            dispatchScrollEvent(x, y, absX, absY, jmodifiers, roundDeltaY, deltaY);
        }
        // Horizontal scroll or shirt+vertical scroll.
        final double delta = isShift && deltaY != 0.0 ? deltaY : deltaX;
        final int roundDelta = isShift && roundDeltaY != 0 ? roundDeltaY : roundDeltaX;
        if (delta != 0.0 || roundDelta != 0) {
            jmodifiers |= InputEvent.SHIFT_DOWN_MASK;
            dispatchScrollEvent(x, y, absX, absY, jmodifiers, roundDelta, delta);
        }
    }

    private void dispatchScrollEvent(final int x, final int y, final int absX,
                                     final int absY, final int modifiers,
                                     final int roundDelta, final double delta) {
        final long when = System.currentTimeMillis();
        final int scrollType = MouseWheelEvent.WHEEL_UNIT_SCROLL;
        final int scrollAmount = 1;
        // invert the wheelRotation for the peer
        eventNotifier.notifyMouseWheelEvent(when, x, y, absX, absY, modifiers,
                                            scrollType, scrollAmount,
                                            -roundDelta, -delta, null);
    }

    /**
     * Handles key events.
     */
    void handleKeyEvent(int eventType, int modifierFlags, String chars, String charsIgnoringModifiers,
                        short keyCode, boolean needsKeyTyped, boolean needsKeyReleased) {
        boolean isFlagsChangedEvent =
            isNpapiCallback ? (eventType == CocoaConstants.NPCocoaEventFlagsChanged) :
                              (eventType == CocoaConstants.NSFlagsChanged);

        int jeventType = KeyEvent.KEY_PRESSED;
        int jkeyCode = KeyEvent.VK_UNDEFINED;
        int jkeyLocation = KeyEvent.KEY_LOCATION_UNKNOWN;
        boolean postsTyped = false;
        boolean spaceKeyTyped = false;

        char testChar = KeyEvent.CHAR_UNDEFINED;
        boolean isDeadChar = (chars!= null && chars.length() == 0);

        if (isFlagsChangedEvent) {
            int[] in = new int[] {modifierFlags, keyCode};
            int[] out = new int[3]; // [jkeyCode, jkeyLocation, jkeyType]

            NSEvent.nsKeyModifiersToJavaKeyInfo(in, out);

            jkeyCode = out[0];
            jkeyLocation = out[1];
            jeventType = out[2];
        } else {
            if (chars != null && chars.length() > 0) {
                testChar = chars.charAt(0);

                //Check if String chars contains SPACE character.
                if (chars.trim().isEmpty()) {
                    spaceKeyTyped = true;
                }
            }

            char testCharIgnoringModifiers = charsIgnoringModifiers != null && charsIgnoringModifiers.length() > 0 ?
                    charsIgnoringModifiers.charAt(0) : KeyEvent.CHAR_UNDEFINED;

            int[] in = new int[] {testCharIgnoringModifiers, isDeadChar ? 1 : 0, modifierFlags, keyCode};
            int[] out = new int[3]; // [jkeyCode, jkeyLocation, deadChar]

            postsTyped = NSEvent.nsToJavaKeyInfo(in, out);
            if (!postsTyped) {
                testChar = KeyEvent.CHAR_UNDEFINED;
            }

            if(isDeadChar){
                testChar = (char) out[2];
                if(testChar == 0){
                    return;
                }
            }

            // If Pinyin Simplified input method is selected, CAPS_LOCK key is supposed to switch
            // input to latin letters.
            // It is necessary to use testCharIgnoringModifiers instead of testChar for event
            // generation in such case to avoid uppercase letters in text components.
            LWCToolkit lwcToolkit = (LWCToolkit)Toolkit.getDefaultToolkit();
            if (lwcToolkit.getLockingKeyState(KeyEvent.VK_CAPS_LOCK) &&
                    Locale.SIMPLIFIED_CHINESE.equals(lwcToolkit.getDefaultKeyboardLocale())) {
                testChar = testCharIgnoringModifiers;
            }

            jkeyCode = out[0];
            jkeyLocation = out[1];
            jeventType = isNpapiCallback ? NSEvent.npToJavaEventType(eventType) :
                                           NSEvent.nsToJavaEventType(eventType);
        }

        char javaChar = NSEvent.nsToJavaChar(testChar, modifierFlags, spaceKeyTyped);
        // Some keys may generate a KEY_TYPED, but we can't determine
        // what that character is. That's likely a bug, but for now we
        // just check for CHAR_UNDEFINED.
        if (javaChar == KeyEvent.CHAR_UNDEFINED) {
            postsTyped = false;
        }

        int jmodifiers = NSEvent.nsToJavaModifiers(modifierFlags);
        long when = System.currentTimeMillis();

        if (jeventType == KeyEvent.KEY_PRESSED) {
            lastKeyPressCode = jkeyCode;
        }
        eventNotifier.notifyKeyEvent(jeventType, when, jmodifiers,
                jkeyCode, javaChar, jkeyLocation);

        // Current browser may be sending input events, so don't
        // post the KEY_TYPED here.
        postsTyped &= needsKeyTyped;

        // That's the reaction on the PRESSED (not RELEASED) event as it comes to
        // appear in MacOSX.
        // Modifier keys (shift, etc) don't want to send TYPED events.
        // On the other hand we don't want to generate keyTyped events
        // for clipboard related shortcuts like Meta + [CVX]
        if (jeventType == KeyEvent.KEY_PRESSED && postsTyped &&
                (jmodifiers & KeyEvent.META_DOWN_MASK) == 0) {
            // Enter and Space keys finish the input method processing,
            // KEY_TYPED and KEY_RELEASED events for them are synthesized in handleInputEvent.
            if (needsKeyReleased && (jkeyCode == KeyEvent.VK_ENTER || jkeyCode == KeyEvent.VK_SPACE)) {
                return;
            }
            eventNotifier.notifyKeyEvent(KeyEvent.KEY_TYPED, when, jmodifiers,
                    KeyEvent.VK_UNDEFINED, javaChar,
                    KeyEvent.KEY_LOCATION_UNKNOWN);
            //If events come from Firefox, released events should also be generated.
            if (needsKeyReleased) {
                eventNotifier.notifyKeyEvent(KeyEvent.KEY_RELEASED, when, jmodifiers,
                        jkeyCode, javaChar,
                        KeyEvent.KEY_LOCATION_UNKNOWN);
            }
        }
    }

    void handleInputEvent(String text) {
        if (text != null) {
            int index = 0, length = text.length();
            char c = 0;
            while (index < length) {
                c = text.charAt(index);
                eventNotifier.notifyKeyEvent(KeyEvent.KEY_TYPED,
                        System.currentTimeMillis(),
                        0, KeyEvent.VK_UNDEFINED, c,
                        KeyEvent.KEY_LOCATION_UNKNOWN);
                index++;
            }
            eventNotifier.notifyKeyEvent(KeyEvent.KEY_RELEASED,
                    System.currentTimeMillis(),
                    0, lastKeyPressCode, c,
                    KeyEvent.KEY_LOCATION_UNKNOWN);
        }
    }

    void handleWindowFocusEvent(boolean gained, LWWindowPeer opposite) {
        eventNotifier.notifyActivation(gained, opposite);
    }

    static class DeltaAccumulator {

        static final double MIN_THRESHOLD = 0.1;
        static final double MAX_THRESHOLD = 0.5;
        double accumulatedDelta;

        int getRoundedDelta(double delta, int scrollPhase) {

            int roundDelta = (int) Math.round(delta);

            if (scrollPhase == NSEvent.SCROLL_PHASE_UNSUPPORTED) { // mouse wheel
                if (roundDelta == 0 && delta != 0) {
                    roundDelta = delta > 0 ? 1 : -1;
                }
            } else { // trackpad
                boolean begin = scrollPhase == NSEvent.SCROLL_PHASE_BEGAN;
                boolean end = scrollPhase == NSEvent.SCROLL_MASK_PHASE_ENDED
                        || scrollPhase == NSEvent.SCROLL_MASK_PHASE_CANCELLED;

                if (begin) {
                    accumulatedDelta = 0;
                }

                accumulatedDelta += delta;

                double absAccumulatedDelta = Math.abs(accumulatedDelta);
                if (absAccumulatedDelta > MAX_THRESHOLD) {
                    roundDelta = (int) Math.round(accumulatedDelta);
                    accumulatedDelta -= roundDelta;
                }

                if (end) {
                    if (roundDelta == 0 && absAccumulatedDelta > MIN_THRESHOLD) {
                        roundDelta = accumulatedDelta > 0 ? 1 : -1;
                    }
                }
            }

            return roundDelta;
        }
    }
}