/*
 * Copyright © 2012 Keith Packard
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Keith Packard
 *
 * Contributor(s):
 *      Keith Packard <keithp@keithp.com>
 */

autoload Nichrome;

extend namespace Nichrome {
    public namespace Textline {

	protected typedef bool (&widget_t widget, string key) callback_t;
	
	public typedef widget_t + struct {
	    string  		text;
	    int	    		caret;
	    int			num_chars;
	    string  		font;
	    rgba_color_t	color;
	    bool		clicked;
	    real		click_x;
	    callback_t		callback;
	} textline_t;
	
	typedef struct {
	    real x, y;
	    real pad;
	    real caret_x, caret_y, caret_height;
	    real width, height;
	    real preferred_width, preferred_height;
	} metrics_t;
	
	real text_x(cr, &textline_t widget, int pos) {
	    text_extents_t t = text_extents(cr, String::substr(widget.text, 0, pos));
	    return t.x_advance;
	}

	int text_hit(cr, &textline_t widget, real x) {
	    int i;
	    for (i = 0; i < String::length(widget.text); i++)
		if (x < text_x(cr, &widget, i+1))
		    break;
	    return i;
	}

	metrics_t get_metrics (cairo_t cr, &textline_t widget) {
	    set_font (cr, widget.font);

	    if (widget.clicked) {
		widget.clicked = false;
		widget.caret = text_hit(cr, &widget, widget.click_x);
	    }
	    real caret_x = text_x (cr, &widget, widget.caret);
	    text_extents_t m = text_extents (cr, "M");
	    text_extents_t x = text_extents (cr, "x");
	    font_extents_t font = font_extents(cr);
	    metrics_t metrics;
	    
	    real pad = m.height / 2;
	    metrics.pad = pad;
	    metrics.preferred_width = pad + x.width * widget.num_chars + pad;
	    metrics.preferred_height = pad + m.height + pad;
	    metrics.width = max (widget.geometry.width, metrics.preferred_width);
	    metrics.height = max (widget.geometry.height, metrics.preferred_height);
	    real text_height = (x.height + m.height) / 2;
	    real text_bearing = (x.y_bearing + m.y_bearing) / 2;
	    metrics.y = floor ((metrics.height - text_height) / 2 
			       - text_bearing + 0.5);
	    metrics.x = floor (pad);
	    metrics.caret_x = metrics.x + caret_x + 0.5;
	    metrics.caret_y = metrics.y + m.height / 4;
	    metrics.caret_height = m.height * 1.5;
	    return metrics;
	}
	
	public void natural (cairo_t cr, &textline_t widget) {
	    metrics_t	metrics = get_metrics (cr, &widget);

	    rectangle (cr, 0, 0, metrics.preferred_width, metrics.preferred_height);
	}
	
	public void outline (cairo_t cr, &textline_t widget) {
	    return natural(cr, &widget);
	}
	
	public void draw (cairo_t cr, &textline_t widget) {
	    metrics_t	metrics = get_metrics (cr, &widget);
	    move_to (cr, metrics.x, metrics.y);
	    set_source_rgba (cr, widget.color.red, widget.color.green,
			     widget.color.blue, widget.color.alpha);
	    show_text (cr, widget.text);
	    if (&widget == &widget.nichrome.key_focus) {
		set_line_width(cr, 1);
		move_to (cr, metrics.caret_x, metrics.caret_y);
		rel_line_to (cr, 0, -metrics.caret_height);
		stroke (cr);
	    }
	}
	
	protected void focus(&textline_t widget, bool focus) {
	    Widget::redraw(&widget);
	}

	protected void button(&textline_t widget, &button_event_t event) {
	    if (event.type == button_type_t.press) {
		widget.clicked = true;
		widget.click_x = event.x;
		Widget::redraw(&widget);
		Nichrome::set_key_focus(&widget.nichrome, &widget);
	    }
	}

	protected void caret(&textline_t widget, int pos) {
	    if (pos < 0)
		pos = 0;
	    if (pos > String::length(widget.text))
		pos = String::length(widget.text);
	    if (pos != widget.caret) {
		widget.caret = pos;
		Widget::redraw(&widget);
	    }
	}

	protected void insert(&textline_t widget, int c) {
	    string	before = String::substr(widget.text,
						0,
						widget.caret);
	    string	after = String::substr(widget.text,
					       widget.caret,
					       String::length(widget.text) - widget.caret);
	    widget.text = before + String::new(c) + after;
	    widget.caret++;
	    Widget::redraw(&widget);
	}

	protected void delete(&textline_t widget, int count) {
	    int	len = String::length(widget.text);

	    if (count < 0)
		count = 0;
	    if (count > len - widget.caret)
		count = len - widget.caret;
	    if (count > 0) {
		string	before = String::substr(widget.text,
						0,
						widget.caret);
		string	after = String::substr(widget.text,
					       widget.caret + count,
					       len - (widget.caret + count));
		widget.text = before + after;
		Widget::redraw(&widget);
	    }
	}

	protected void backspace (&textline_t widget, int count) {
	    while (count-- > 0) {
		if (widget.caret > 0) {
		    caret (&widget, widget.caret - 1);
		    delete (&widget, 1);
		}
	    }
	}

	protected void key(&textline_t widget, &key_event_t event) {
	    if (event.type != key_type_t.press)
		return;
	    if (!is_uninit(&widget.callback))
		if (widget.callback(&widget, event.key))
		    return;

	    switch (event.key) {
	    case "Left":
		caret (&widget, widget.caret - 1);
		break;
	    case "Right":
		caret (&widget, widget.caret + 1);
		break;
	    case "BackSpace":
		backspace(&widget, 1);
		break;
	    case "Return":
		break;
	    default:
		for (int i = 0; i < String::length(event.text); i++)
		{
		    int c = event.text[i];
		    switch (c) {
		    case '\b':
			backspace (&widget, 1);
			break;
		    default:
			if (Ctype::isprint(c))
			    insert(&widget, c);
			break;
		    }
		}
		break;
	    }
	}

	protected void print (&textline_t widget, int indent) {
	    do_indent(indent);
	    printf("text %s %v\n", widget.text, widget.geometry);
	}

	public void set_text(&textline_t widget, string new_text) {
	    widget.text = new_text;
	    Widget::redraw(&widget);
	    widget.caret = 0;
	}

	public void set_caret(&textline_t widget, int caret) {
	    if (caret < 0) caret = 0;
	    widget.caret = min (caret, String::length(widget.text));
	}

	public void init (&textline_t widget, &nichrome_t nichrome, int num_chars) {
	    Widget::init (&nichrome, &widget);
	    widget.text = "";
	    widget.num_chars = num_chars;
	    widget.caret = 0;
	    widget.font = Widget::default_font;
	    widget.draw = draw;
	    widget.outline = outline;
	    widget.natural = natural;
	    widget.focus = focus;
	    widget.button = button;
	    widget.key = key;
	    widget.clicked = false;
	    widget.color = (rgba_color_t) {
		red = 0, green = 0, blue = 0, alpha = 1
	    };
	    widget.print = print;
	}
	
	public *widget_t new (&nichrome_t nichrome, int num_chars) {
	    textline_t	widget;

	    init (&widget, &nichrome, num_chars);
	    return &widget;
	}
    }
}