/* vim: set sw=8: -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * gog-legend.c :
 *
 * Copyright (C) 2003-2004 Jody Goldberg (jody@gnome.org)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#include <goffice/goffice-config.h>
#include <goffice/graph/gog-legend.h>
#include <goffice/graph/gog-outlined-object.h>
#include <goffice/graph/gog-view.h>
#include <goffice/graph/gog-renderer.h>
#include <goffice/graph/gog-chart.h>
#include <goffice/graph/gog-style.h>
#include <goffice/graph/gog-theme.h>
#include <goffice/utils/go-color.h>
#include <goffice/utils/go-units.h>

#include <gsf/gsf-impl-utils.h>
#include <gtk/gtknotebook.h>
#include <glib/gi18n-lib.h>

#include <math.h>

struct _GogLegend {
	GogOutlinedObject base;

	double	 swatch_size_pts;
	double	 swatch_padding_pts;
	gulong	 chart_cardinality_handle;
	gulong	 chart_child_name_changed_handle;
	unsigned cached_count;
	gboolean names_changed;
};

typedef GogStyledObjectClass GogLegendClass;

enum {
	LEGEND_PROP_0,
	LEGEND_SWATCH_SIZE_PTS,
	LEGEND_SWATCH_PADDING_PTS
};

static GType gog_legend_view_get_type (void);

static GObjectClass *parent_klass;

static void
gog_legend_set_property (GObject *obj, guint param_id,
			 GValue const *value, GParamSpec *pspec)
{
	GogLegend *legend = GOG_LEGEND (obj);

	switch (param_id) {
	case LEGEND_SWATCH_SIZE_PTS :
		legend->swatch_size_pts = g_value_get_double (value);
		break;
	case LEGEND_SWATCH_PADDING_PTS :
		legend->swatch_padding_pts = g_value_get_double (value);
		break;

	default: G_OBJECT_WARN_INVALID_PROPERTY_ID (obj, param_id, pspec);
		 return; /* NOTE : RETURN */
	}
}

static void
gog_legend_get_property (GObject *obj, guint param_id,
			 GValue *value, GParamSpec *pspec)
{
	GogLegend *legend = GOG_LEGEND (obj);

	switch (param_id) {
	case LEGEND_SWATCH_SIZE_PTS :
		g_value_set_double (value, legend->swatch_size_pts);
		break;
	case LEGEND_SWATCH_PADDING_PTS :
		g_value_set_double (value, legend->swatch_padding_pts);
		break;

	default: G_OBJECT_WARN_INVALID_PROPERTY_ID (obj, param_id, pspec);
		 break;
	}
}

static void
cb_chart_names_changed (GogLegend *legend)
{
	if (legend->names_changed)
		return;
	legend->names_changed = TRUE;
	gog_object_request_update (GOG_OBJECT (legend));
}

static void
gog_legend_parent_changed (GogObject *obj, gboolean was_set)
{
	GogObjectClass *gog_object_klass = GOG_OBJECT_CLASS (parent_klass);
	GogLegend *legend = GOG_LEGEND (obj);

	if (was_set) {
		if (legend->chart_cardinality_handle == 0)
			legend->chart_cardinality_handle =
				g_signal_connect_object (G_OBJECT (obj->parent),
					"notify::cardinality-valid",
					G_CALLBACK (gog_object_request_update),
					legend, G_CONNECT_SWAPPED);
		if (legend->chart_child_name_changed_handle == 0)
			legend->chart_child_name_changed_handle =
				g_signal_connect_object (G_OBJECT (obj->parent),
					"child-name-changed",
					G_CALLBACK (cb_chart_names_changed),
					legend, G_CONNECT_SWAPPED);
	} else {
		if (legend->chart_cardinality_handle != 0) {
			g_signal_handler_disconnect (G_OBJECT (obj->parent),
				legend->chart_cardinality_handle);
			legend->chart_cardinality_handle = 0;
		}
		if (legend->chart_child_name_changed_handle != 0) {
			g_signal_handler_disconnect (G_OBJECT (obj->parent),
				legend->chart_child_name_changed_handle);
			legend->chart_child_name_changed_handle = 0;
		}
	}

	gog_object_klass->parent_changed (obj, was_set);
}

static void
gog_legend_update (GogObject *obj)
{
	GogLegend *legend = GOG_LEGEND (obj);
	unsigned visible;
	gog_chart_get_cardinality (GOG_CHART (obj->parent), NULL, &visible);
	if (legend->cached_count != visible)
		legend->cached_count = visible;
	else if (!legend->names_changed)
		return;
	legend->names_changed = FALSE;
	gog_object_emit_changed	(obj, TRUE);
}

static void
gog_legend_populate_editor (GogObject *gobj, 
			    GogEditor *editor, 
			    GogDataAllocator *dalloc, 
			    GOCmdContext *cc)
{
	static guint legend_pref_page = 0;

	(GOG_OBJECT_CLASS(parent_klass)->populate_editor) (gobj, editor, dalloc, cc);
	gog_editor_set_store_page (editor, &legend_pref_page);
}

static void
gog_legend_init_style (GogStyledObject *gso, GogStyle *style)
{
	style->interesting_fields = GOG_STYLE_OUTLINE | GOG_STYLE_FILL | GOG_STYLE_FONT;
	gog_theme_fillin_style (gog_object_get_theme (GOG_OBJECT (gso)),
		style, GOG_OBJECT (gso), 0, FALSE);
}

static void
gog_legend_class_init (GogLegendClass *klass)
{
	static GogObjectRole const roles[] = {
		{ N_("Title"), "GogLabel",	0,
		  GOG_POSITION_COMPASS, GOG_POSITION_N|GOG_POSITION_ALIGN_CENTER, GOG_OBJECT_NAME_BY_ROLE,
		  NULL, NULL, NULL, NULL, NULL, NULL },
	};

	GObjectClass *gobject_klass   = (GObjectClass *) klass;
	GogObjectClass *gog_klass = (GogObjectClass *) klass;
	GogStyledObjectClass *style_klass = (GogStyledObjectClass *) klass;

	parent_klass = g_type_class_peek_parent (klass);
	
	gobject_klass->set_property = gog_legend_set_property;
	gobject_klass->get_property = gog_legend_get_property;
	gog_klass->parent_changed = gog_legend_parent_changed;
	gog_klass->update	  = gog_legend_update;
	gog_klass->populate_editor	= gog_legend_populate_editor;
	gog_klass->view_type	  = gog_legend_view_get_type ();
	style_klass->init_style	  = gog_legend_init_style;
	
	gog_object_register_roles (gog_klass, roles, G_N_ELEMENTS (roles));

	g_object_class_install_property (gobject_klass, LEGEND_SWATCH_SIZE_PTS,
		g_param_spec_double ("swatch_size_pts", "Swatch Size pts",
			"size of the swatches in pts.",
			0, G_MAXDOUBLE, 0, G_PARAM_READWRITE|GOG_PARAM_PERSISTENT));
	g_object_class_install_property (gobject_klass, LEGEND_SWATCH_PADDING_PTS,
		g_param_spec_double ("swatch_padding_pts", "Swatch Padding pts",
			"padding between the swatches in pts.",
			0, G_MAXDOUBLE, 0, G_PARAM_READWRITE|GOG_PARAM_PERSISTENT));
}

static void
gog_legend_init (GogLegend *legend)
{
	legend->swatch_size_pts = GO_CM_TO_PT ((double).25);
	legend->swatch_padding_pts = GO_CM_TO_PT ((double).2);
	legend->cached_count = 0;
}

GSF_CLASS (GogLegend, gog_legend,
	   gog_legend_class_init, gog_legend_init,
	   GOG_OUTLINED_OBJECT_TYPE)

typedef struct {
	GogOutlinedView	base;
	gboolean	is_vertical;
	double		element_width;
	double		element_height;
	unsigned	element_per_blocks;
	unsigned	num_blocks;
	gboolean	uses_lines;
	double		label_offset;
} GogLegendView;

typedef GogOutlinedViewClass	GogLegendViewClass;

#define GOG_LEGEND_VIEW_TYPE	(gog_legend_view_get_type ())
#define GOG_LEGEND_VIEW(o)	(G_TYPE_CHECK_INSTANCE_CAST ((o), GOG_LEGEND_VIEW_TYPE, GogLegendView))
#define IS_GOG_LEGEND_VIEW(o)	(G_TYPE_CHECK_INSTANCE_TYPE ((o), GOG_LEGEND_VIEW_TYPE))

static GogViewClass *lview_parent_klass;

typedef struct {
	GogView const 		*view;
	GogViewRequisition 	 maximum;
	gboolean		 uses_lines;
	GogStyle		*legend_style;
} SizeClosure;

static void
cb_size_elements (unsigned i, GogStyle const *style, 
		  char const *name, SizeClosure *data)
{
	GOGeometryAABR aabr;
	
	gog_renderer_push_style (data->view->renderer, data->legend_style);
	gog_renderer_get_text_AABR (data->view->renderer, name, &aabr);
	gog_renderer_pop_style (data->view->renderer);

	if (data->maximum.w < aabr.w)
		data->maximum.w = aabr.w;
	if (data->maximum.h < aabr.h)
		data->maximum.h = aabr.h;
	if (!data->uses_lines && (style->interesting_fields & GOG_STYLE_LINE))
		data->uses_lines = TRUE;
}

static void
gog_legend_view_size_request (GogView *v, 
			      GogViewRequisition const *available, 
			      GogViewRequisition *req)
{
	GogChart *chart = GOG_CHART (v->model->parent);
	GogLegendView *glv = GOG_LEGEND_VIEW (v);
	GogLegend *l = GOG_LEGEND (v->model);
	GogViewRequisition child_req, residual;
	SizeClosure data;
	double available_space, element_size, swatch_padding;
	unsigned num_elements;

	residual = *available;
	req->w = req->h = 0;
	gog_view_size_child_request (v, available, req, &child_req);
	lview_parent_klass->size_request (v, available, req);
	residual.w -= req->w;
	residual.h -= req->h;

	glv->is_vertical = gog_object_get_position_flags (GOG_OBJECT (l), GOG_POSITION_COMPASS) &
		(GOG_POSITION_E | GOG_POSITION_W);

	gog_chart_get_cardinality (chart, NULL, &num_elements);
	
	data.view = v;
	data.maximum.w = 0.;
	data.maximum.h = gog_renderer_pt2r_y (v->renderer, l->swatch_size_pts) * 1.2;
	data.uses_lines = FALSE;
	data.legend_style = GOG_STYLED_OBJECT (l)->style;

	gog_chart_foreach_elem (chart, TRUE,
		(GogEnumFunc) cb_size_elements, &data);

	swatch_padding = gog_renderer_pt2r_x (v->renderer, l->swatch_padding_pts);
	glv->label_offset = gog_renderer_pt2r_x (v->renderer,
		(data.uses_lines ? 3 : 1) * l->swatch_size_pts + swatch_padding * .5);

	data.maximum.w += glv->label_offset + swatch_padding;
	
	glv->element_height = data.maximum.h;
	glv->element_width = data.maximum.w;
	glv->uses_lines = data.uses_lines;

	available_space = glv->is_vertical ? residual.h : residual.w;
	element_size = glv->is_vertical ? data.maximum.h : data.maximum.w;	
	
	glv->element_per_blocks = available_space > 0. ? floor (available_space / element_size) : 0;
	
	if (glv->element_per_blocks < 1) {
	       	req->w = req->h = -1;
		return;
	}

	glv->num_blocks = floor ((num_elements - 1) / glv->element_per_blocks) + 1;

	if (glv->is_vertical) {
		req->h += MIN (glv->element_per_blocks, num_elements) * data.maximum.h;
		req->w += glv->num_blocks * data.maximum.w - swatch_padding;
	} else {
		req->h += glv->num_blocks * data.maximum.h;
		req->w += MIN (glv->element_per_blocks, num_elements) * data.maximum.w - swatch_padding;
	}

	req->w = MAX (child_req.w, req->w);
	req->h = MAX (child_req.h, req->h);
}

typedef struct {
	GogView const *view;
	double x, y;
	double element_step_x, element_step_y;
	double block_step_x, block_step_y;
	GogViewAllocation swatch;
	ArtVpath line_path[3];
} RenderClosure;

static void
cb_render_elements (unsigned i, GogStyle const *base_style, char const *name,
		    RenderClosure *data)
{
	GogView const *view = data->view;
	GogLegendView *glv = GOG_LEGEND_VIEW (view);
	GogRenderer *renderer = view->renderer;
	GogStyledObject *obj = GOG_STYLED_OBJECT (data->view->model);
	GogStyle *style = NULL;
	GogStyle *legend_style = obj->style;
	GogViewAllocation pos, rectangle;

	if (i > 0) {
		if ((i % glv->element_per_blocks) != 0) {
			data->x += data->element_step_x;
			data->y += data->element_step_y;
		} else {
			data->x += data->block_step_x;
			data->y += data->block_step_y;
		}
	}
	
	if (base_style->interesting_fields & GOG_STYLE_LINE) { /* line and marker */
		style = (GogStyle *)base_style;
		gog_renderer_push_style (renderer, style);
		data->line_path[0].x = data->x;
		data->line_path[1].x = data->x + data->swatch.w * 3.;
		data->line_path[0].y = 
		data->line_path[1].y = data->y + glv->element_height / 2.;
		gog_renderer_draw_sharp_path (renderer, data->line_path);
		gog_renderer_draw_marker (renderer, data->x + data->swatch.w  * 1.5, 
					  data->line_path[0].y);
	} else {					/* area swatch */
		style = gog_style_dup (base_style);
		style->outline.width = 0; 
		style->outline.color = RGBA_BLACK;

		rectangle = data->swatch;
		rectangle.x += data->x;
		rectangle.y += data->y;

		gog_renderer_push_style (renderer, style);
		gog_renderer_draw_sharp_rectangle (renderer, &rectangle);
	}
	gog_renderer_pop_style (renderer);

	pos.x = data->x + glv->label_offset;
	pos.y = data->y + glv->element_height / 2.0;
	pos.w = pos.h = -1;

	gog_renderer_push_style (renderer, legend_style);
	gog_renderer_draw_text (renderer, name, &pos, GTK_ANCHOR_W, NULL);
	gog_renderer_pop_style (renderer);

	if (style != base_style && style != NULL)
		g_object_unref (style);
}

static void
gog_legend_view_render (GogView *v, GogViewAllocation const *bbox)
{
	GogLegendView *glv = GOG_LEGEND_VIEW (v);
	GogLegend *l = GOG_LEGEND (v->model);
	RenderClosure data;

	(lview_parent_klass->render) (v, bbox);
	
	if (glv->element_per_blocks < 1)
		return;

	if (glv->uses_lines) {
		data.line_path[0].code = ART_MOVETO;
		data.line_path[1].code = ART_LINETO;
		data.line_path[2].code = ART_END;
	}
	data.view = v;
	data.x = v->residual.x;
	data.y = v->residual.y;
	data.element_step_x = glv->is_vertical ? 0 : glv->element_width;
	data.element_step_y = glv->is_vertical ? glv->element_height : 0;
	data.block_step_x = glv->is_vertical ? 
		+ glv->element_width : 
		- glv->element_width * (glv->element_per_blocks - 1);
	data.block_step_y = glv->is_vertical ? 
		- glv->element_height * (glv->element_per_blocks - 1) :
		+ glv->element_height;
	data.swatch.w = gog_renderer_pt2r_x (v->renderer, 
					     l->swatch_size_pts);
	data.swatch.h = gog_renderer_pt2r_y (v->renderer, 
					     l->swatch_size_pts);
	data.swatch.x = (glv->label_offset - data.swatch.w -
			 gog_renderer_pt2r_x (v->renderer, l->swatch_padding_pts) * .5) * .5;
	data.swatch.y = (glv->element_height - data.swatch.h) * .5;
	
	gog_chart_foreach_elem (GOG_CHART (v->model->parent), TRUE,
		(GogEnumFunc) cb_render_elements, &data);
}

static void
gog_legend_view_class_init (GogLegendViewClass *gview_klass)
{
	GogViewClass *view_klass    = (GogViewClass *) gview_klass;

	lview_parent_klass = g_type_class_peek_parent (gview_klass);
	view_klass->size_request    = gog_legend_view_size_request;
	view_klass->render	    = gog_legend_view_render;
	view_klass->clip 	    = TRUE;
}

static GSF_CLASS (GogLegendView, gog_legend_view,
		  gog_legend_view_class_init, NULL,
		  GOG_OUTLINED_VIEW_TYPE)