// Copyright 2000-2005 the Contributors, as shown in the revision logs.
// Licensed under the GNU General Public License version 2 ("the License").
// You may not use this file except in compliance with the License.

package org.ibex.graphics;
import org.ibex.util.*;
import java.io.*;
import java.util.Hashtable;
import org.ibex.js.*;
import org.ibex.nestedvm.*;
import org.ibex.plat.*;
import org.ibex.nestedvm.Runtime;

// FEATURE: this could be cleaner
/** encapsulates a single font (a set of Glyphs) */
public class Font {

    private Font(JS stream, int pointsize) { this.stream = stream; this.pointsize = pointsize; }

    public final int pointsize;                 ///< the size of the font
    public final JS stream;                 ///< the stream from which this font was loaded
    public int max_ascent;                      ///< the maximum ascent, in pixels
    public int max_descent;                     ///< the maximum descent, in pixels
    boolean latinCharsPreloaded = false;        ///< true if a request to preload ASCII 32-127 has begun
    public Glyph[] glyphs = new Glyph[65535];          ///< the glyphs that comprise this font

    public abstract static class Glyph {
        protected Glyph(Font font, char c) { this.font = font; this.c = c; }
        public final Font font;
        public final char c;
        public int baseline;                    ///< within the alphamask, this is the y-coordinate of the baseline
        public int advance;                     ///< amount to increment the x-coordinate
        public boolean isLoaded = false;        ///< true iff the glyph is loaded
        public int width = -1;                  ///< the width of the glyph
        public int height = -1;                 ///< the height of the glyph
        public byte[] data = null;              ///< the alpha channel samples for this font
        public String path = null; // FIXME this should be shared across point sizes
        void render() {
            if (!isLoaded) try { renderGlyph(this); } catch (IOException e) { Log.info(Font.class, e); }
            isLoaded = true;
        }
    }


    // Statics //////////////////////////////////////////////////////////////////////

    static final Queue toBeRasterized = new Queue(300);
    static final Queue toBeDisplayed = new Queue(300);
    private static Basket.Map fonts = new Basket.Hash();
    public static Font getFont(JS stream, int pointsize) {
        Basket.Map m = (Basket.Map)fonts.get(stream);
        Font ret = null;
        if (m != null) ret = (Font)m.get(new Integer(pointsize));
        else fonts.put(stream, m = new Basket.Hash());
        if (ret == null) m.put(new Integer(pointsize), ret = new Font(stream, pointsize));
        return ret;
    }


    // Methods //////////////////////////////////////////////////////////////////////

    /**
     *  Rasterize the glyphs of <code>text</code>.
     *  @returns <code>(width&lt;&lt;32)|height</code>
     */
    public String rasterizeGlyphs(String text) {
        StringBuffer path = new StringBuffer(text.length() * 50);
        for(int i=0; i<text.length(); i++) {
            final char c = text.charAt(i);
            Glyph g = glyphs[c];
            if (g == null) glyphs[c] = g = Platform.createGlyph(this, c);
            g.render();
            path.append(g.path);
        }
        return path.toString();
    }
    public long rasterizeGlyphs(String text, PixelBuffer pb, Affine a, Mesh h, Affine ha, int fg, int bg) {
        int width = 0, height = 0;
        if (!latinCharsPreloaded) {       // preload the Latin-1 charset with low priority (we'll probably want it)
            for(int i=48; i<57; i++) if(glyphs[i]==null) toBeRasterized.append(glyphs[i]=Platform.createGlyph(this, (char)i));
            for(int i=32; i<47; i++) if(glyphs[i]==null) toBeRasterized.append(glyphs[i]=Platform.createGlyph(this, (char)i));
            for(int i=57; i<128; i++) if(glyphs[i]==null) toBeRasterized.append(glyphs[i]=Platform.createGlyph(this, (char)i));
            latinCharsPreloaded = true;
        }
        a = a==null ? null : a.copy();
        for(int i=0; i<text.length(); i++) {
            final char c = text.charAt(i);
            Glyph g = glyphs[c];
            if (g == null) glyphs[c] = g = Platform.createGlyph(this, c);
            g.render();
            if (a!=null) a.multiply(Affine.translate(0, g.font.max_ascent - g.baseline));
            if (ha!=null) ha.multiply(Affine.translate(0, g.font.max_ascent - g.baseline));
            if (pb != null) {
                pb.drawGlyph(g, a, h, fg, bg);
                if (h!=null) h.subtract(new Mesh().addRect(0, 0, g.width, g.height), ha);
            }
            if (a!=null) a.multiply(Affine.translate(0, -1 * (g.font.max_ascent - g.baseline)));
            if (ha!=null) ha.multiply(Affine.translate(0, -1 * (g.font.max_ascent - g.baseline)));
            width += g.advance;
            if (a!=null) a.multiply(Affine.translate(g.advance, 0));
            if (ha!=null) ha.multiply(Affine.translate(g.advance, 0));
            height = java.lang.Math.max(height, max_ascent + max_descent);
        }
        return ((((long)width) << 32) | (long)(height & 0xffffffffL));
    }

    // FEATURE do we really need to be caching sizes?
    private static Cache sizeCache = new Cache(1000, true);
    public int textwidth(String s) { return (int)((textsize(s) >>> 32) & 0xffffffff); }
    public int textheight(String s) { return (int)(textsize(s) & 0xffffffffL); }
    public long textsize(String s) {
        Long l = (Long)sizeCache.get(s);
        if (l != null) return ((Long)l).longValue();
        long ret = rasterizeGlyphs(s, null, null, null, null, 0, 0);
        sizeCache.put(s, new Long(ret));
        return ret;
    }

    public Glyph getGlyph(char c) {
        rasterizeGlyphs(c+"", null, null, null, null, 0, 0);
        Glyph g = glyphs[c];
        g.render();
        return g;
    }

    static { new Thread() { public void run() {
        while(true) {
            Glyph g = (Glyph)toBeRasterized.remove(true);
            if (g == null) continue;
            Log.debug(Font.class, "glyphRenderingTask rendering " + g.c + " of " + g.font);
            g.render();
            Log.debug(Glyph.class, "   done rendering glyph " + g.c);
        }
    } }.start(); }


    // FreeType Interface //////////////////////////////////////////////////////////////////////////////

    // FEATURE: use streams, not memoryfont's
    // FEATURE: kerning pairs
    private static final Runtime rt;
    private static JS loadedStream;
    private static int loadedStreamAddr;

    static {
        try {
            rt = (Runtime)Class.forName("org.ibex.util.MIPSApps").newInstance();
        } catch(Exception e) {
            throw new Error("Error instantiating freetype: " + e);
        }
        rt.start(new String[]{"freetype"});
        rt.execute();
        rtCheck();
    }
    
    private static void rtCheck() { if(rt.getState() != Runtime.PAUSED) throw new Error("Freetype exited " + rt.exitStatus()); }
    
    private static void loadFontByteStream(JS res) {
        if(loadedStream == res) return;
        
        try {
            Log.info(Font.class, "loading font " + JSU.str(res));
            InputStream is = JSU.getInputStream(res);
            byte[] fontstream = InputStreamToByteArray.convert(is);
            rt.free(loadedStreamAddr);
            loadedStreamAddr = rt.xmalloc(fontstream.length);
            rt.copyout(fontstream, loadedStreamAddr, fontstream.length);
            if(rt.call("load_font", loadedStreamAddr, fontstream.length) != 0)
                throw new RuntimeException("load_font failed"); // FEATURE: better error
            rtCheck();
            loadedStream = res;
        } catch (Exception e) {
            // FEATURE: Better error reporting (thow an exception?)
            Log.info(Font.class, e);
        }
    }

    private static synchronized void renderGlyph(Font.Glyph glyph) throws IOException {
        try {
            Log.debug(Font.class, "rasterizing glyph " + glyph.c + " of font " + glyph.font);
            if (loadedStream != glyph.font.stream) loadFontByteStream(glyph.font.stream);
            
            long start = System.currentTimeMillis();
            
            rt.call("render",glyph.c,glyph.font.pointsize);
            rtCheck();
            
            glyph.font.max_ascent = rt.getUserInfo(3);
            glyph.font.max_descent = rt.getUserInfo(4);
            glyph.baseline = rt.getUserInfo(5);
            glyph.advance = rt.getUserInfo(6);
            
            glyph.width = rt.getUserInfo(1);
            glyph.height = rt.getUserInfo(2);

            glyph.data = new byte[glyph.width * glyph.height];
            int addr = rt.getUserInfo(0);
            rt.copyin(addr, glyph.data, glyph.width * glyph.height);
            
            byte[] path = new byte[rt.getUserInfo(8)];
            rt.copyin(rt.getUserInfo(7), path, rt.getUserInfo(8));
            glyph.path = new String(path);
            glyph.path += " m " + (64 * glyph.advance) + " 0 "; 

            glyph.isLoaded = true;
        } catch (Exception e) {
            // FEATURE: Better error reporting (thow an exception?)
            Log.info(Font.class, e);
        }
    }
}