/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
 * Copyright (C) 2012-2017 Kicad Developers, see change_log.txt for contributors.
 *
 * Graphics Abstraction Layer (GAL) - base class
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

#include <wx/log.h>

#include <gal/graphics_abstraction_layer.h>
#include <gal/definitions.h>

#include <cmath>

using namespace KIGFX;


const double GAL::METRIC_UNIT_LENGTH = 1e9;


GAL::GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions ) :
    options( aDisplayOptions ),
    strokeFont( this )
{
    // Set the default values for the internal variables
    SetIsFill( false );
    SetIsStroke( true );
    SetFillColor( COLOR4D( 0.0, 0.0, 0.0, 0.0 ) );
    SetStrokeColor( COLOR4D( 1.0, 1.0, 1.0, 1.0 ) );
    SetLookAtPoint( VECTOR2D( 0, 0 ) );
    SetZoomFactor( 1.0 );
    SetWorldUnitLength( 1.0 / METRIC_UNIT_LENGTH * 2.54 );   // 1 inch in nanometers
    SetScreenDPI( 106 );                                     // Display resolution setting
    SetDepthRange( VECTOR2D( GAL::MIN_DEPTH, GAL::MAX_DEPTH ) );
    SetLayerDepth( 0.0 );
    SetFlip( false, false );
    SetLineWidth( 1.0 );
    computeWorldScale();
    SetAxesEnabled( false );

    // Set grid defaults
    SetGridVisibility( true );
    SetCoarseGrid( 10 );
    gridLineWidth = 0.5;
    gridStyle = GRID_STYLE::LINES;
    gridMinSpacing = 10;

    // Initialize the cursor shape
    SetCursorColor( COLOR4D( 1.0, 1.0, 1.0, 1.0 ) );
    fullscreenCursor = false;
    forceDisplayCursor = false;
    SetCursorEnabled( false );

    // Initialize text properties
    ResetTextAttributes();

    strokeFont.LoadNewStrokeFont( newstroke_font, newstroke_font_bufsize );

    // subscribe for settings updates
    observerLink = options.Subscribe( this );
}


GAL::~GAL()
{
}


void GAL::OnGalDisplayOptionsChanged( const GAL_DISPLAY_OPTIONS& aOptions )
{
    // defer to the child class first
    updatedGalDisplayOptions( aOptions );

    // there is no refresh to do at this level
}


bool GAL::updatedGalDisplayOptions( const GAL_DISPLAY_OPTIONS& aOptions )
{
    bool refresh = false;

    if( options.m_gridStyle != gridStyle )
    {
        gridStyle = options.m_gridStyle ;
        refresh = true;
    }

    if( options.m_gridLineWidth != gridLineWidth )
    {
        gridLineWidth = options.m_gridLineWidth ;
        refresh = true;
    }

    if( options.m_gridMinSpacing != gridMinSpacing )
    {
        gridMinSpacing = options.m_gridMinSpacing;
        refresh = true;
    }

    if( options.m_axesEnabled != axesEnabled )
    {
        axesEnabled = options.m_axesEnabled;
        refresh = true;
    }

    if( options.m_forceDisplayCursor != forceDisplayCursor )
    {
        forceDisplayCursor = options.m_forceDisplayCursor;
        refresh = true;
    }

    if( options.m_fullscreenCursor != fullscreenCursor )
    {
        fullscreenCursor = options.m_fullscreenCursor;
        refresh = true;
    }

    // tell the derived class if the base class needs an update or not
    return refresh;
}


void GAL::SetTextAttributes( const EDA_TEXT* aText )
{
    SetGlyphSize( VECTOR2D( aText->GetTextSize() ) );
    SetHorizontalJustify( aText->GetHorizJustify() );
    SetVerticalJustify( aText->GetVertJustify() );
    SetFontBold( aText->IsBold() );
    SetFontItalic( aText->IsItalic() );
    SetTextMirrored( aText->IsMirrored() );
}


void GAL::ResetTextAttributes()
{
     // Tiny but non-zero - this will always need setting
     // there is no built-in default
    SetGlyphSize( { 1.0, 1.0 } );

    SetHorizontalJustify( GR_TEXT_HJUSTIFY_CENTER );
    SetVerticalJustify( GR_TEXT_VJUSTIFY_CENTER );

    SetFontBold( false );
    SetFontItalic( false );
    SetTextMirrored( false );
}


VECTOR2D GAL::GetTextLineSize( const UTF8& aText ) const
{
    // Compute the X and Y size of a given text.
    // Because computeTextLineSize expects a one line text,
    // aText is expected to be only one line text.
    return strokeFont.computeTextLineSize( aText );
}


void GAL::ComputeWorldScreenMatrix()
{
    computeWorldScale();

    worldScreenMatrix.SetIdentity();

    MATRIX3x3D translation;
    translation.SetIdentity();
    translation.SetTranslation( 0.5 * VECTOR2D( screenSize ) );

    MATRIX3x3D scale;
    scale.SetIdentity();
    scale.SetScale( VECTOR2D( worldScale, worldScale ) );

    MATRIX3x3D flip;

    flip.SetIdentity();
    flip.SetScale( VECTOR2D( globalFlipX ? -1.0 : 1.0, globalFlipY ? -1.0 : 1.0 ) );

    MATRIX3x3D lookat;
    lookat.SetIdentity();
    lookat.SetTranslation( -lookAtPoint );

    worldScreenMatrix = translation * flip * scale * lookat * worldScreenMatrix;
    screenWorldMatrix = worldScreenMatrix.Inverse();
}


double GAL::computeMinGridSpacing() const
{
    // just return the current value. This could be cleverer and take
    // into account other settings in future
    return gridMinSpacing;
}


void GAL::DrawGrid()
{
    SetTarget( TARGET_NONCACHED );

    // Draw the grid
    // For the drawing the start points, end points and increments have
    // to be calculated in world coordinates
    VECTOR2D worldStartPoint = screenWorldMatrix * VECTOR2D( 0.0, 0.0 );
    VECTOR2D worldEndPoint   = screenWorldMatrix * VECTOR2D( screenSize );

    const double gridThreshold = computeMinGridSpacing();

    int gridScreenSizeDense  = KiROUND( gridSize.x * worldScale );
    int gridScreenSizeCoarse = KiROUND( gridSize.x * static_cast<double>( gridTick ) * worldScale );

    // Compute the line marker or point radius of the grid
    // Note: generic grids can't handle sub-pixel lines without
    // either losing fine/course distinction or having some dots
    // fail to render
    double marker = std::max( 1.0, gridLineWidth ) / worldScale;
    double doubleMarker = 2.0 * marker;

    // Draw axes if desired
    if( axesEnabled )
    {
        SetIsFill( false );
        SetIsStroke( true );
        SetStrokeColor( axesColor );
        SetLineWidth( marker );

        drawGridLine( VECTOR2D( worldStartPoint.x, 0 ),
                      VECTOR2D( worldEndPoint.x, 0 ) );

        drawGridLine( VECTOR2D( 0, worldStartPoint.y ),
                      VECTOR2D( 0, worldEndPoint.y ) );
    }

    if( !gridVisibility )
        return;

    // Check if the grid would not be too dense
    if( std::max( gridScreenSizeDense, gridScreenSizeCoarse ) <= gridThreshold )
        return;

    // Compute grid staring and ending indexes to draw grid points on the
    // visible screen area
    // Note: later any point coordinate will be offsetted by gridOrigin
    int gridStartX = KiROUND( ( worldStartPoint.x - gridOrigin.x ) / gridSize.x );
    int gridEndX = KiROUND( ( worldEndPoint.x - gridOrigin.x ) / gridSize.x );
    int gridStartY = KiROUND( ( worldStartPoint.y - gridOrigin.y ) / gridSize.y );
    int gridEndY = KiROUND( ( worldEndPoint.y - gridOrigin.y ) / gridSize.y );

    // Ensure start coordinate > end coordinate
    if( gridStartX > gridEndX )
        std::swap( gridStartX, gridEndX );

    if( gridStartY > gridEndY )
        std::swap( gridStartY, gridEndY );

    // Ensure the grid fills the screen
    --gridStartX; ++gridEndX;
    --gridStartY; ++gridEndY;

    // Draw the grid behind all other layers
    SetLayerDepth( depthRange.y * 0.75 );

    if( gridStyle == GRID_STYLE::LINES )
    {
        SetIsFill( false );
        SetIsStroke( true );
        SetStrokeColor( gridColor );

        // Now draw the grid, every coarse grid line gets the double width

        // Vertical lines
        for( int j = gridStartY; j <= gridEndY; j++ )
        {
            const double y = j * gridSize.y + gridOrigin.y;

            if( axesEnabled && y == 0 )
                continue;

            if( j % gridTick == 0 && gridScreenSizeDense > gridThreshold )
                SetLineWidth( doubleMarker );
            else
                SetLineWidth( marker );

            if( ( j % gridTick == 0 && gridScreenSizeCoarse > gridThreshold )
                || gridScreenSizeDense > gridThreshold )
            {
                drawGridLine( VECTOR2D( gridStartX * gridSize.x + gridOrigin.x, y ),
                              VECTOR2D( gridEndX * gridSize.x + gridOrigin.x, y ) );
            }
        }

        // Horizontal lines
        for( int i = gridStartX; i <= gridEndX; i++ )
        {
            const double x = i * gridSize.x + gridOrigin.x;

            if( axesEnabled && x == 0 )
                continue;

            if( i % gridTick == 0 && gridScreenSizeDense > gridThreshold )
                SetLineWidth( doubleMarker );
            else
                SetLineWidth( marker );

            if( ( i % gridTick == 0 && gridScreenSizeCoarse > gridThreshold )
                || gridScreenSizeDense > gridThreshold )
            {
                drawGridLine( VECTOR2D( x, gridStartY * gridSize.y + gridOrigin.y ),
                              VECTOR2D( x, gridEndY * gridSize.y + gridOrigin.y ) );
            }
        }
    }
    else if( gridStyle == GRID_STYLE::SMALL_CROSS )
    {
        SetIsFill( false );
        SetIsStroke( true );
        SetStrokeColor( gridColor );

        SetLineWidth( marker );
        double lineLen = GetLineWidth() * 2;

        // Vertical positions:
        for( int j = gridStartY; j <= gridEndY; j++ )
        {
            if( ( j % gridTick == 0 && gridScreenSizeCoarse > gridThreshold )
                || gridScreenSizeDense > gridThreshold )
            {
                int posY =  j * gridSize.y + gridOrigin.y;

                // Horizontal positions:
                for( int i = gridStartX; i <= gridEndX; i++ )
                {
                    if( ( i % gridTick == 0 && gridScreenSizeCoarse > gridThreshold )
                        || gridScreenSizeDense > gridThreshold )
                    {
                        int posX = i * gridSize.x + gridOrigin.x;

                        drawGridLine( VECTOR2D( posX - lineLen, posY ),
                                        VECTOR2D( posX + lineLen,   posY ) );

                        drawGridLine( VECTOR2D( posX, posY - lineLen ),
                                        VECTOR2D( posX, posY + lineLen ) );
                    }
                }
            }
        }
    }
    else    // Dotted grid
    {
        bool tickX, tickY;
        SetIsFill( true );
        SetIsStroke( false );
        SetFillColor( gridColor );

        for( int j = gridStartY; j <= gridEndY; j++ )
        {
            if( j % gridTick == 0 && gridScreenSizeDense > gridThreshold )
                tickY = true;
            else
                tickY = false;

            for( int i = gridStartX; i <= gridEndX; i++ )
            {
                if( i % gridTick == 0 && gridScreenSizeDense > gridThreshold )
                    tickX = true;
                else
                    tickX = false;

                if( tickX || tickY || gridScreenSizeDense > gridThreshold )
                {
                    double radius = ( ( tickX && tickY ) ? doubleMarker : marker ) / 2.0;
                    DrawRectangle( VECTOR2D( i * gridSize.x - radius + gridOrigin.x,
                                                j * gridSize.y - radius + gridOrigin.y ),
                                    VECTOR2D( i * gridSize.x + radius + gridOrigin.x,
                                                j * gridSize.y + radius + gridOrigin.y ) );
                }
            }
        }
    }
}


VECTOR2D GAL::GetGridPoint( const VECTOR2D& aPoint ) const
{
#if 0
    // This old code expects a non zero grid size, which can be wrong here.
    return VECTOR2D( KiROUND( ( aPoint.x - gridOffset.x ) / gridSize.x ) * gridSize.x + gridOffset.x,
                     KiROUND( ( aPoint.y - gridOffset.y ) / gridSize.y ) * gridSize.y + gridOffset.y );
#else
    // if grid size == 0.0 there is no grid, so use aPoint as grid reference position
    double cx = gridSize.x > 0.0 ? KiROUND( ( aPoint.x - gridOffset.x ) / gridSize.x ) * gridSize.x + gridOffset.x
            : aPoint.x;
    double cy = gridSize.y > 0.0 ? KiROUND( ( aPoint.y - gridOffset.y ) / gridSize.y ) * gridSize.y + gridOffset.y
            : aPoint.y;

    return VECTOR2D( cx, cy );
#endif
}

const int GAL::MIN_DEPTH = -1024;
const int GAL::MAX_DEPTH = 1023;
const int GAL::GRID_DEPTH = MAX_DEPTH - 1;


COLOR4D GAL::getCursorColor() const
{
    auto color = cursorColor;

    // dim the cursor if it's only on because it was forced
    // (this helps to provide a hint for active tools)
    if( !isCursorEnabled )
    {
        color.a = color.a * 0.5;
    }

    return color;
}