/*
    Copyright (C) 2012, 2013, 2014 Johan Mattsson

    This library is free software; you can redistribute it and/or modify 
    it under the terms of the GNU Lesser General Public License as 
    published by the Free Software Foundation; either version 3 of the 
    License, or (at your option) any later version.

    This library 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 
    Lesser General Public License for more details.
*/

namespace BirdFont {

public class HmtxTable : OtfTable {
	
	uint32 nmetrics;
	uint32 nmonospaced;
		
	uint16* advance_width = null;
	uint16* left_side_bearing = null;
	uint16* left_side_bearing_monospaced = null;
	
	public int16 max_advance = 0;
	public int16 max_extent = 0;
	public int16 min_lsb = int16.MAX; 
	public int16 min_rsb = int16.MAX;
			
	HeadTable head_table;
	GlyfTable glyf_table;
	
	public HmtxTable (HeadTable h, GlyfTable gt) {
		head_table = h;
		glyf_table = gt;
		id = "hmtx";
	}
	
	~HmtxTable () {
		if (advance_width != null) {
			delete advance_width;
		}
		
		if (left_side_bearing != null) {
			delete left_side_bearing;
		}
	}

	public double get_advance (uint32 i) {
		if (i >= nmetrics) {
			warning (@"i >= nmetrics $i >= $nmetrics");
			return 0;
		}
		
		return_val_if_fail (advance_width != null, 0.0);
		
		return advance_width[i] * 1000 / head_table.get_units_per_em ();
	}
		
	/** Get left side bearing relative to xmin. */
	public double get_lsb (uint32 i) {
		return_val_if_fail (i < nmetrics, 0.0);
		return_val_if_fail (left_side_bearing != null, 0.0);
		
		return left_side_bearing[i] * 1000 / head_table.get_units_per_em ();
	}
			
	public new void parse (FontData dis, HheaTable hhea_table, LocaTable loca_table) throws GLib.Error {
		nmetrics = hhea_table.num_horizontal_metrics;
		nmonospaced = loca_table.size - nmetrics;
		
		dis.seek (offset);
		
		if (nmetrics > loca_table.size) {
			warning (@"(nmetrics > loca_table.size) ($nmetrics > $(loca_table.size))");
			return;
		}
		
		printd (@"nmetrics: $nmetrics\n");
		printd (@"loca_table.size: $(loca_table.size)\n");
		
		advance_width = new uint16[nmetrics];
		left_side_bearing = new uint16[nmetrics];
		left_side_bearing_monospaced = new uint16[nmonospaced];
		
		for (int i = 0; i < nmetrics; i++) {
			advance_width[i] = dis.read_ushort ();
			left_side_bearing[i] = dis.read_short ();
		}
		
		for (int i = 0; i < nmonospaced; i++) {
			left_side_bearing_monospaced[i] = dis.read_short ();
		}
	}
	
	public void process () {
		FontData fd = new FontData ();

		int16 advance;
		int16 extent;
		int16 rsb;
		int16 lsb;

		int16 left_guide;		
		int16 right_guide;
		
		double xmin;
		double xmax;
		int i;
		
		Glyph g;
		
		if (advance_width != null) {
			warning ("advance_width is set");
			delete advance_width;
		}
		advance_width = new uint16 [glyf_table.glyphs.size];
		
		// advance and lsb
		nmetrics = 0;
		i = 0;
		foreach (GlyphCollection gc in glyf_table.glyphs) {
			g = gc.get_current ();
			
			return_if_fail (0 <= i < glyf_table.glyf_data.size);
						
			GlyfData gd = glyf_table.glyf_data.get (i);

			xmax = gd.bounding_box_xmax;
			xmin = gd.bounding_box_xmin;
			
			left_guide = (int16) Math.rint (g.left_limit * HeadTable.UNITS);
			right_guide = (int16) Math.rint (g.right_limit * HeadTable.UNITS);
			
			lsb = (int16) xmin;
			advance = right_guide - left_guide;
			
			extent = (int16) xmax;
			rsb = (int16) Math.rint (advance - extent);
						
			fd.add_u16 (advance);
			fd.add_16 (lsb);
			
			if (!g.is_empty_ttf ()) {
				if (advance > max_advance) {
					max_advance = advance;
				}
				
				if (extent > max_extent) {
					max_extent = extent;
				}
				
				if (rsb < min_rsb) {
					min_rsb = rsb;
				}

				if (lsb < min_lsb) {
					min_lsb = lsb;
				}
			}
			
			if (extent < 0) {
				warning ("Negative extent.");
			}
			
			advance_width[nmetrics] = (uint16) extent;
			nmetrics++;
			i++;
		}
		
		// monospaced lsb ...
		
		font_data = fd;
		
		if (max_advance == 0) {
			warning ("max_advance is zero");
		}
	}
	
	public int16 get_average_width () {
		double total_width = 0;
		uint non_zero_glyphs = 0;
		for (int i = 0; i < nmetrics; i++) {
			if (advance_width[i] != 0) {
				total_width += advance_width[i];
				non_zero_glyphs++;
			}
		}
		return (int16) Math.rint (total_width / non_zero_glyphs);
	}
}

}
