////////////////////////////////////////////////////////////
//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2018 Marco Antognini (antognini.marco@gmail.com),
//                         Laurent Gomila (laurent@sfml-dev.org)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
//    you must not claim that you wrote the original software.
//    If you use this software in a product, an acknowledgment
//    in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
//    and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Window/OSX/WindowImplCocoa.hpp>
#include <cmath>

#import <SFML/Window/OSX/SFOpenGLView.h>
#import <SFML/Window/OSX/SFOpenGLView+mouse_priv.h>


////////////////////////////////////////////////////////////
/// In this file, we implement mouse handling for SFOpenGLView
///
////////////////////////////////////////////////////////////

@implementation SFOpenGLView (mouse)

////////////////////////////////////////////////////////
-(void)setCursor:(NSCursor*)cursor
{
    m_cursor = cursor;

    // indirect call to resetCursorRects to set the cursor
    [self.window invalidateCursorRectsForView:self]; 
}


////////////////////////////////////////////////////////
-(void)resetCursorRects
{
    // addCursorRect:cursor: has to be called from within this function!
    [self addCursorRect:[self frame] cursor:m_cursor];
    [m_cursor setOnMouseEntered:YES];
}


////////////////////////////////////////////////////////
-(BOOL)isMouseInside
{
    NSPoint relativeToWindow = [[self window] mouseLocationOutsideOfEventStream];
    NSPoint relativeToView = [self convertPoint:relativeToWindow fromView:nil];

    return NSPointInRect(relativeToView, [self bounds]);
}


////////////////////////////////////////////////////////
-(void)updateMouseState
{
    // Update in/out state
    BOOL mouseWasIn = m_mouseIsIn;
    m_mouseIsIn = [self isMouseInside];

    // Send event if needed.
    if (m_requester != 0)
    {
        if (mouseWasIn && !m_mouseIsIn)
            m_requester->mouseMovedOut();
        else if (!mouseWasIn && m_mouseIsIn)
            m_requester->mouseMovedIn();
    }
}


////////////////////////////////////////////////////////
-(void)setCursorGrabbed:(BOOL)grabbed
{
    m_cursorGrabbed = grabbed;

    [self updateCursorGrabbed];
}


////////////////////////////////////////////////////////
-(void)mouseDown:(NSEvent*)theEvent
{
    [self handleMouseDown:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] mouseDown:theEvent];
}


////////////////////////////////////////////////////////
-(void)rightMouseDown:(NSEvent*)theEvent
{
    [self handleMouseDown:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] rightMouseDown:theEvent];
}


////////////////////////////////////////////////////////
-(void)otherMouseDown:(NSEvent*)theEvent
{
    [self handleMouseDown:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] otherMouseDown:theEvent];
}


////////////////////////////////////////////////////////
-(void)handleMouseDown:(NSEvent*)theEvent
{
    sf::Mouse::Button button = [SFOpenGLView mouseButtonFromEvent:theEvent];

    if (m_requester != 0)
    {
        NSPoint loc = [self cursorPositionFromEvent:theEvent];

        if (button != sf::Mouse::ButtonCount)
            m_requester->mouseDownAt(button, loc.x, loc.y);
    }
}


////////////////////////////////////////////////////////
-(void)mouseUp:(NSEvent*)theEvent
{
    [self handleMouseUp:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] mouseUp:theEvent];
}


////////////////////////////////////////////////////////
-(void)rightMouseUp:(NSEvent*)theEvent
{
    [self handleMouseUp:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] rightMouseUp:theEvent];
}


////////////////////////////////////////////////////////
-(void)otherMouseUp:(NSEvent*)theEvent
{
    [self handleMouseUp:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] otherMouseUp:theEvent];
}


////////////////////////////////////////////////////////////
-(void)handleMouseUp:(NSEvent*)theEvent
{
    sf::Mouse::Button button = [SFOpenGLView mouseButtonFromEvent:theEvent];

    if (m_requester != 0)
    {
        NSPoint loc = [self cursorPositionFromEvent:theEvent];

        if (button != sf::Mouse::ButtonCount)
            m_requester->mouseUpAt(button, loc.x, loc.y);
    }
}


////////////////////////////////////////////////////////
-(void)mouseMoved:(NSEvent*)theEvent
{
    [self handleMouseMove:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] mouseMoved:theEvent];
}


////////////////////////////////////////////////////////
-(void)rightMouseDragged:(NSEvent*)theEvent
{
    [self handleMouseMove:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] rightMouseDragged:theEvent];
}


////////////////////////////////////////////////////////
-(void)mouseDragged:(NSEvent*)theEvent
{
    [self handleMouseMove:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] mouseDragged:theEvent];
}


////////////////////////////////////////////////////////
-(void)otherMouseDragged:(NSEvent*)theEvent
{
    [self handleMouseMove:theEvent];

    // Transmit to non-SFML responder
    [[self nextResponder] otherMouseUp:theEvent];
}


////////////////////////////////////////////////////////
-(void)handleMouseMove:(NSEvent*)theEvent
{
    NSPoint loc = [self cursorPositionFromEvent:theEvent];

    // If the cursor is grabbed, cursorPositionFromEvent: will
    // return its correct position but not move actually it
    // so we do it now.
    if ([self isCursorCurrentlyGrabbed])
        [self moveCursorTo:loc];

    // Make sure the point is inside the view.
    // (mouseEntered: and mouseExited: are not immediately called
    //  when the mouse is dragged. That would be too easy!)
    [self updateMouseState];
    if ((m_requester != 0) && m_mouseIsIn)
        m_requester->mouseMovedAt(loc.x, loc.y);
}


////////////////////////////////////////////////////////
-(BOOL)isCursorCurrentlyGrabbed
{
    return [[self window] isKeyWindow] && m_cursorGrabbed;
}


////////////////////////////////////////////////////////
-(void)updateCursorGrabbed
{
    // Disable/enable normal movements of the cursor
    // and project the cursor if needed.
    if ([self isCursorCurrentlyGrabbed])
    {
        CGAssociateMouseAndMouseCursorPosition(NO);

        // Similarly to handleMouseMove: but without event.
        NSPoint loc = [self cursorPositionFromEvent:nil];
        [self moveCursorTo:loc];
    }
    else
    {
        CGAssociateMouseAndMouseCursorPosition(YES);
    }
}


////////////////////////////////////////////////////////
-(void)moveCursorTo:(NSPoint)loc
{
    // Convert the point from SFML coord system to screen coord system.
    NSPoint screenLocation = [self computeGlobalPositionOfRelativePoint:loc];

    // This won't produce a move event, which is perfect if the cursor was grabbed
    // as we move it manually based on delta values of the cursor.
    CGDisplayMoveCursorToPoint([self displayId], NSPointToCGPoint(screenLocation));
}


////////////////////////////////////////////////////////
-(CGDirectDisplayID)displayId
{
    NSScreen* screen = [[self window] screen];
    NSNumber* displayId = [[screen deviceDescription] objectForKey:@"NSScreenNumber"];
    return [displayId intValue];
}


////////////////////////////////////////////////////////
-(void)scrollWheel:(NSEvent*)theEvent
{
    if (m_requester != 0)
    {
        NSPoint loc = [self cursorPositionFromEvent:theEvent];
        m_requester->mouseWheelScrolledAt([theEvent deltaX], [theEvent deltaY], loc.x, loc.y);
    }

    // Transmit to non-SFML responder
    [[self nextResponder] scrollWheel:theEvent];
}


////////////////////////////////////////////////////////
-(void)mouseEntered:(NSEvent*)theEvent
{
    (void)theEvent;
    [self updateMouseState];
}


////////////////////////////////////////////////////////
-(void)mouseExited:(NSEvent*)theEvent
{
    (void)theEvent;
    [self updateMouseState];
}


////////////////////////////////////////////////////////
-(NSPoint)cursorPositionFromEvent:(NSEvent*)eventOrNil
{
    NSPoint rawPos;

    // If no event given then get current mouse pos.
    if (eventOrNil == nil)
        rawPos = [[self window] mouseLocationOutsideOfEventStream];
    else
        rawPos = [eventOrNil locationInWindow];

    if ([self isCursorCurrentlyGrabbed])
    {
        if (eventOrNil != nil)
        {
            // Special case when the mouse is grabbed:
            // we need to take into account the delta since the cursor
            // is dissociated from its position.

            // Ignore any non-move related event
            if (([eventOrNil type] == NSMouseMoved)        ||
                ([eventOrNil type] == NSLeftMouseDragged)  ||
                ([eventOrNil type] == NSRightMouseDragged) ||
                ([eventOrNil type] == NSOtherMouseDragged))
            {
                // Without this factor, the cursor flies around waaay too fast!
                // But I don't know if it because of retina display or because
                // some event are sent twice (and that in itself is another mystery).
                CGFloat factor = 2;

                // Also, this factor is not the same when keeping track of how much
                // we move the cursor (buffers) when projecting the cursor into the
                // view when grabbing the cursor for the first time.
                CGFloat factorBuffer = m_fullscreen ? 1 : 2;

                CGFloat deltaX = [eventOrNil deltaX];
                CGFloat deltaY = [eventOrNil deltaY];

                // If the buffer for X is empty, move the cursor;
                // otherwise decrement this buffer a bit.
                if (m_deltaXBuffer <= 0)
                    rawPos.x += deltaX / factor;
                else
                    m_deltaXBuffer -= std::abs(deltaX / factorBuffer);

                // Rinse and repeat for Y.
                if (m_deltaYBuffer <= 0)
                    rawPos.y -= deltaY / factor;
                else
                    m_deltaYBuffer -= std::abs(deltaY / factorBuffer);
            }
        }

        // We also make sure the new point is inside the view
        NSSize  size   = [self frame].size;
        NSPoint origin = [self frame].origin;
        NSPoint oldPos = rawPos;
        rawPos.x = std::min(std::max(origin.x, rawPos.x), origin.x + size.width - 1);
        rawPos.y = std::min(std::max(origin.y + 1, rawPos.y), origin.y + size.height);
        // Note: the `-1` and `+1` on the two lines above prevent the user to click
        // on the left or below the window, repectively, and therefore prevent the
        // application to lose focus by accident. The sign of this offset is determinded
        // by the direction of the x and y axis.

        // Increase X and Y buffer with the distance of the projection
        m_deltaXBuffer += std::abs(rawPos.x - oldPos.x);
        m_deltaYBuffer += std::abs(rawPos.y - oldPos.y);
    }

    NSPoint loc = [self convertPoint:rawPos fromView:nil];

    // Don't forget to change to SFML coord system.
    float h = [self frame].size.height;
    loc.y = h - loc.y;

    return loc;
}


////////////////////////////////////////////////////////
+(sf::Mouse::Button)mouseButtonFromEvent:(NSEvent*)event
{
    switch ([event buttonNumber])
    {
        case 0:     return sf::Mouse::Left;
        case 1:     return sf::Mouse::Right;
        case 2:     return sf::Mouse::Middle;
        case 3:     return sf::Mouse::XButton1;
        case 4:     return sf::Mouse::XButton2;
        default:    return sf::Mouse::ButtonCount; // Never happens! (hopefully)
    }
}


@end
