/*
 * This file is part of ComputerCraft - http://www.computercraft.info
 * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
 * Send enquiries to dratcliffe@gmail.com
 */

package dan200.computercraft.client.gui;

import dan200.computercraft.core.terminal.TextBuffer;
import dan200.computercraft.shared.util.Palette;
import net.minecraft.client.Minecraft;
import net.minecraft.client.renderer.BufferBuilder;
import net.minecraft.client.renderer.GlStateManager;
import net.minecraft.client.renderer.Tessellator;
import net.minecraft.client.renderer.texture.TextureManager;
import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
import net.minecraft.util.ResourceLocation;
import org.lwjgl.opengl.GL11;

import java.util.Arrays;

public final class FixedWidthFontRenderer
{
    private static final ResourceLocation FONT = new ResourceLocation( "computercraft", "textures/gui/term_font.png" );
    public static final ResourceLocation BACKGROUND = new ResourceLocation( "computercraft", "textures/gui/term_background.png" );

    public static final int FONT_HEIGHT = 9;
    public static final int FONT_WIDTH = 6;

    private static FixedWidthFontRenderer instance;

    public static FixedWidthFontRenderer instance()
    {
        if( instance != null ) return instance;
        return instance = new FixedWidthFontRenderer();
    }

    private final TextureManager m_textureManager;

    private FixedWidthFontRenderer()
    {
        m_textureManager = Minecraft.getInstance().getTextureManager();
    }

    private static void greyscaleify( double[] rgb )
    {
        Arrays.fill( rgb, (rgb[0] + rgb[1] + rgb[2]) / 3.0f );
    }

    private void drawChar( BufferBuilder renderer, double x, double y, int index, int color, Palette p, boolean greyscale )
    {
        int column = index % 16;
        int row = index / 16;

        double[] colour = p.getColour( 15 - color );
        if( greyscale )
        {
            greyscaleify( colour );
        }
        float r = (float) colour[0];
        float g = (float) colour[1];
        float b = (float) colour[2];

        int xStart = 1 + column * (FONT_WIDTH + 2);
        int yStart = 1 + row * (FONT_HEIGHT + 2);

        renderer.pos( x, y, 0.0 ).tex( xStart / 256.0, yStart / 256.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).tex( xStart / 256.0, (yStart + FONT_HEIGHT) / 256.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x + FONT_WIDTH, y, 0.0 ).tex( (xStart + FONT_WIDTH) / 256.0, yStart / 256.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x + FONT_WIDTH, y, 0.0 ).tex( (xStart + FONT_WIDTH) / 256.0, yStart / 256.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).tex( xStart / 256.0, (yStart + FONT_HEIGHT) / 256.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x + FONT_WIDTH, y + FONT_HEIGHT, 0.0 ).tex( (xStart + FONT_WIDTH) / 256.0, (yStart + FONT_HEIGHT) / 256.0 ).color( r, g, b, 1.0f ).endVertex();
    }

    private void drawQuad( BufferBuilder renderer, double x, double y, int color, double width, Palette p, boolean greyscale )
    {
        double[] colour = p.getColour( 15 - color );
        if( greyscale )
        {
            greyscaleify( colour );
        }
        float r = (float) colour[0];
        float g = (float) colour[1];
        float b = (float) colour[2];

        renderer.pos( x, y, 0.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x + width, y, 0.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x + width, y, 0.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x, y + FONT_HEIGHT, 0.0 ).color( r, g, b, 1.0f ).endVertex();
        renderer.pos( x + width, y + FONT_HEIGHT, 0.0 ).color( r, g, b, 1.0f ).endVertex();
    }

    private boolean isGreyScale( int colour )
    {
        return colour == 0 || colour == 15 || colour == 7 || colour == 8;
    }

    public void drawStringBackgroundPart( int x, int y, TextBuffer backgroundColour, double leftMarginSize, double rightMarginSize, boolean greyScale, Palette p )
    {
        // Draw the quads
        Tessellator tessellator = Tessellator.getInstance();
        BufferBuilder renderer = tessellator.getBuffer();
        renderer.begin( GL11.GL_TRIANGLES, DefaultVertexFormats.POSITION_COLOR );
        if( leftMarginSize > 0.0 )
        {
            int colour1 = "0123456789abcdef".indexOf( backgroundColour.charAt( 0 ) );
            if( colour1 < 0 || (greyScale && !isGreyScale( colour1 )) )
            {
                colour1 = 15;
            }
            drawQuad( renderer, x - leftMarginSize, y, colour1, leftMarginSize, p, greyScale );
        }
        if( rightMarginSize > 0.0 )
        {
            int colour2 = "0123456789abcdef".indexOf( backgroundColour.charAt( backgroundColour.length() - 1 ) );
            if( colour2 < 0 || (greyScale && !isGreyScale( colour2 )) )
            {
                colour2 = 15;
            }
            drawQuad( renderer, x + backgroundColour.length() * FONT_WIDTH, y, colour2, rightMarginSize, p, greyScale );
        }
        for( int i = 0; i < backgroundColour.length(); i++ )
        {
            int colour = "0123456789abcdef".indexOf( backgroundColour.charAt( i ) );
            if( colour < 0 || (greyScale && !isGreyScale( colour )) )
            {
                colour = 15;
            }
            drawQuad( renderer, x + i * FONT_WIDTH, y, colour, FONT_WIDTH, p, greyScale );
        }
        GlStateManager.disableTexture2D();
        tessellator.draw();
        GlStateManager.enableTexture2D();
    }

    public void drawStringTextPart( int x, int y, TextBuffer s, TextBuffer textColour, boolean greyScale, Palette p )
    {
        // Draw the quads
        Tessellator tessellator = Tessellator.getInstance();
        BufferBuilder renderer = tessellator.getBuffer();
        renderer.begin( GL11.GL_TRIANGLES, DefaultVertexFormats.POSITION_TEX_COLOR );
        for( int i = 0; i < s.length(); i++ )
        {
            // Switch colour
            int colour = "0123456789abcdef".indexOf( textColour.charAt( i ) );
            if( colour < 0 || (greyScale && !isGreyScale( colour )) )
            {
                colour = 0;
            }

            // Draw char
            int index = s.charAt( i );
            if( index < 0 || index > 255 )
            {
                index = '?';
            }
            drawChar( renderer, x + i * FONT_WIDTH, y, index, colour, p, greyScale );
        }
        tessellator.draw();
    }

    public void drawString( TextBuffer s, int x, int y, TextBuffer textColour, TextBuffer backgroundColour, double leftMarginSize, double rightMarginSize, boolean greyScale, Palette p )
    {
        // Draw background
        if( backgroundColour != null )
        {
            // Bind the background texture
            m_textureManager.bindTexture( BACKGROUND );

            // Draw the quads
            drawStringBackgroundPart( x, y, backgroundColour, leftMarginSize, rightMarginSize, greyScale, p );
        }

        // Draw text
        if( s != null && textColour != null )
        {
            // Bind the font texture
            bindFont();

            // Draw the quads
            drawStringTextPart( x, y, s, textColour, greyScale, p );
        }
    }

    public int getStringWidth( String s )
    {
        if( s == null )
        {
            return 0;
        }
        return s.length() * FONT_WIDTH;
    }

    public void bindFont()
    {
        m_textureManager.bindTexture( FONT );
        GlStateManager.texParameteri( GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_CLAMP );
    }
}