/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*- */
/*
 * viking -- GPS Data and Topo Analyzer, Explorer, and Manager
 *
 * Copyright (C) 2015, Rob Norris <rw_norris@hotmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
#include <mapnik/version.hpp>
#include <mapnik/map.hpp>
#include <mapnik/datasource_cache.hpp>
#include <mapnik/agg_renderer.hpp>
#include <mapnik/load_map.hpp>
#include <mapnik/projection.hpp>
#if MAPNIK_VERSION < 300000
#include <mapnik/graphics.hpp>
#else
#include <mapnik/value.hpp>
#endif
#include <mapnik/image_util.hpp>

#include <exception>
#include <iostream>
#include <memory>
#include <string>
#include <stdlib.h>

#include <glib.h>
#include <glib/gstdio.h>
#include <glib/gi18n.h>

#include "mapnik_interface.h"
#include "globals.h"
#include "settings.h"

#if MAPNIK_VERSION < 200000
#include <mapnik/envelope.hpp>
#define image_32 Image32
#define image_data_32 ImageData32
#define box2d Envelope
#define zoom_to_box zoomToBox
#else
#include <mapnik/box2d.hpp>
#if MAPNIK_VERSION >= 300000
// In Mapnik3 'image_32' has changed names once again
#define image_32 image_rgba8
#define raw_data data
#endif
#endif

#define MAPNIK_INTERFACE_TYPE            (mapnik_interface_get_type ())
#define MAPNIK_INTERFACE(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), MAPNIK_INTERFACE_TYPE, MapnikInterface))
#define MAPNIK_INTERFACE_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), MAPNIK_INTERFACE_TYPE, MapnikInterfaceClass))
#define IS_MAPNIK_INTERFACE(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), MAPNIK_INTERFACE_TYPE))
#define IS_MAPNIK_INTERFACE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), MAPNIK_INTERFACE_TYPE))

typedef struct _MapnikInterfaceClass MapnikInterfaceClass;
typedef struct _MapnikInterface MapnikInterface;

GType mapnik_interface_get_type ();
struct _MapnikInterfaceClass
{
	GObjectClass object_class;
};

static void mapnik_interface_class_init ( MapnikInterfaceClass *mic )
{
}

static void mapnik_interface_init ( MapnikInterface *mi )
{
}

struct _MapnikInterface {
	GObject obj;
	mapnik::Map *myMap;
	gchar *copyright; // Cached Mapnik parameter to save looking it up each time
};

G_DEFINE_TYPE (MapnikInterface, mapnik_interface, G_TYPE_OBJECT)

// Can't change prj after init - but ATM only support drawing in Spherical Mercator
static mapnik::projection prj( mapnik::MAPNIK_GMERC_PROJ );

MapnikInterface* mapnik_interface_new ()
{
	MapnikInterface* mi = MAPNIK_INTERFACE ( g_object_new ( MAPNIK_INTERFACE_TYPE, NULL ) );
	mi->myMap = new mapnik::Map;
	mi->copyright = NULL;
	return mi;
}

void mapnik_interface_free (MapnikInterface* mi)
{
	if ( mi ) {
		g_free ( mi->copyright );
		delete mi->myMap;
	}
	g_object_unref ( G_OBJECT(mi) );
}

/**
 * mapnik_interface_initialize:
 */
void mapnik_interface_initialize (const char *plugins_dir, const char* font_dir, int font_dir_recurse)
{
	g_debug ("using mapnik version %s", MAPNIK_VERSION_STRING );
	try {
		if ( plugins_dir )
#if MAPNIK_VERSION >= 200200
			mapnik::datasource_cache::instance().register_datasources(plugins_dir);
#else
			mapnik::datasource_cache::instance()->register_datasources(plugins_dir);
#endif
		if ( font_dir )
			if ( ! mapnik::freetype_engine::register_fonts(font_dir, font_dir_recurse ? true : false) )
				g_warning ("%s: No fonts found", __FUNCTION__);
	} catch (std::exception const& ex) {
		g_warning ("An error occurred while initialising mapnik: %s", ex.what());
	} catch (...) {
		g_warning ("An unknown error occurred while initialising mapnik");
	}
}

/**
 *  caching this answer instead of looking it up each time
 */
static void set_copyright ( MapnikInterface* mi )
{
	g_free ( mi->copyright );
	mi->copyright = NULL;

	mapnik::parameters pmts = mi->myMap->get_extra_parameters();
#if MAPNIK_VERSION < 300000
	for (mapnik::parameters::const_iterator ii = pmts.begin(); ii != pmts.end(); ii++) {
		if ( ii->first == "attribution" || ii->first == "copyright" ) {
			std::stringstream ss;
			ss << ii->second;
			// Copy it
			mi->copyright = g_strdup ( (gchar*)ss.str().c_str() );
			break;
		}
	}
#else
	if ( pmts.get<std::string>("attribution") )
		mi->copyright = g_strdup ( (*pmts.get<std::string>("attribution")).c_str() );

	if ( !mi->copyright )
		if ( pmts.get<std::string>("copyright") )
			mi->copyright = g_strdup ( (*pmts.get<std::string>("copyright")).c_str() );
#endif
}

#define VIK_SETTINGS_MAPNIK_BUFFER_SIZE "mapnik_buffer_size"

/**
 * mapnik_interface_load_map_file:
 *
 * Returns NULL on success otherwise a string about what went wrong.
 *  This string should be freed once it has been used.
 */
gchar* mapnik_interface_load_map_file ( MapnikInterface* mi,
                                        const gchar *filename,
                                        guint width,
                                        guint height )
{
	gchar *msg = NULL;
	if ( !mi ) return g_strdup ("Internal Error");
	try {
		mi->myMap->remove_all(); // Support reloading
		mapnik::load_map(*mi->myMap, filename);

		mi->myMap->resize(width,height);
		mi->myMap->set_srs ( mapnik::MAPNIK_GMERC_PROJ ); // ONLY WEB MERCATOR output supported ATM

		// IIRC This size is the number of pixels outside the tile to be considered so stuff is shown (i.e. particularly labels)
		// Only set buffer size if the buffer size isn't explicitly set in the mapnik stylesheet.
		// Alternatively render a bigger 'virtual' tile and then only use the appropriate subset
		if (mi->myMap->buffer_size() == 0) {
			gint buffer_size = (width+height/4); // e.g. 128 for a 256x256 image.
			gint tmp;
			if ( a_settings_get_integer ( VIK_SETTINGS_MAPNIK_BUFFER_SIZE, &tmp ) )
				buffer_size = tmp;

			mi->myMap->set_buffer_size(buffer_size);
		}

		set_copyright ( mi );

		g_debug ("%s layers: %d", __FUNCTION__, (guint)mi->myMap->layer_count() );
	} catch (std::exception const& ex) {
		msg = g_strdup ( ex.what() );
	} catch (...) {
		msg = g_strdup ("unknown error");
	}
	return msg;
}

// GdkPixbufDestroyNotify
static void destroy_fn ( guchar *pixels, gpointer data )
{
	g_free ( pixels );
}

/**
 * mapnik_interface_render:
 *
 * Returns a #GdkPixbuf of the specified area. #GdkPixbuf may be NULL
 */
GdkPixbuf* mapnik_interface_render ( MapnikInterface* mi, double lat_tl, double lon_tl, double lat_br, double lon_br )
{
	if ( !mi ) return NULL;

	// Copy main object to local map variable
	//  This enables rendering to work when this function is called from different threads
	mapnik::Map myMap(*mi->myMap);

	// Note prj & bbox want stuff in lon,lat order!
	double p0x = lon_tl;
	double p0y = lat_tl;
	double p1x = lon_br;
	double p1y = lat_br;

	// Convert into projection coordinates for bbox
	prj.forward(p0x, p0y);
	prj.forward(p1x, p1y);

	GdkPixbuf *pixbuf = NULL;
	try {
		unsigned width  = myMap.width();
		unsigned height = myMap.height();
		mapnik::image_32 image(width,height);
		mapnik::box2d<double> bbox(p0x, p0y, p1x, p1y);
		myMap.zoom_to_box(bbox);
		// FUTURE: option to use cairo / grid renderers?
		mapnik::agg_renderer<mapnik::image_32> render(myMap,image);
		render.apply();

		if ( image.painted() ) {
			unsigned char *ImageRawDataPtr = (unsigned char *) g_malloc(width * 4 * height);
			if (!ImageRawDataPtr)
				return NULL;
			memcpy(ImageRawDataPtr, image.raw_data(), width * height * 4);
			pixbuf = gdk_pixbuf_new_from_data(ImageRawDataPtr, GDK_COLORSPACE_RGB, TRUE, 8, width, height, width * 4, destroy_fn, NULL);
		}
		else
			g_warning ("%s not rendered", __FUNCTION__ );
	}
	catch (const std::exception & ex) {
		g_warning ("An error occurred while rendering: %s", ex.what());
	} catch (...) {
		g_warning ("An unknown error occurred while rendering");
	}

	return pixbuf;
}

/**
 * Copyright/Attribution information about the Map - string maybe NULL
 *
 * Free returned string  after use
 */
gchar* mapnik_interface_get_copyright ( MapnikInterface* mi )
{
	if ( !mi ) return NULL;
	return mi->copyright;
}

/**
 * 'Parameter' information about the Map configuration
 *
 * Free every string element and the returned GArray itself after use
 */
GArray* mapnik_interface_get_parameters ( MapnikInterface* mi )
{
	GArray *array = g_array_new (FALSE, TRUE, sizeof(gchar*));

	mapnik::parameters pmts = mi->myMap->get_extra_parameters();
	// Simply want the strings of each parameter so we can display something...
#if MAPNIK_VERSION < 300000
	for (mapnik::parameters::const_iterator pmt = pmts.begin(); pmt != pmts.end(); pmt++) {
		std::stringstream ss;
		ss << pmt->first << ": " << pmt->second;
#else
	for (auto const& pmt : pmts) {
		std::stringstream ss;
		ss << pmt.first << ": " << *(pmts.get<std::string>(pmt.first,"empty"));
#endif
		// Copy - otherwise ss goes output scope and junk memory would be referenced.
		gchar *str2 = g_strdup ( (gchar*)ss.str().c_str() );
		g_array_append_val ( array, str2 );
	}

	return array;
}

/**
 * General information about Mapnik
 *
 * Free the returned string after use
 */
gchar * mapnik_interface_about ( void )
{
	// Normally about 10 plugins so list them all
#if MAPNIK_VERSION >= 200200
	std::vector<std::string> plugins = mapnik::datasource_cache::instance().plugin_names();
#else
	std::vector<std::string> plugins = mapnik::datasource_cache::instance()->plugin_names();
#endif
	std::string str;
	for (uint nn = 0; nn < plugins.size(); nn++ )
		str += plugins[nn] + ',';
	str += '\n';
	// NB Can have a couple hundred fonts loaded when using system directories
	//  So ATM don't list them all - otherwise need better GUI feedback display.
	gchar *msg = g_strdup_printf ( _("%s %s\nPlugins=%sFonts loaded=%d"),
	                               _("Mapnik"),
	                               MAPNIK_VERSION_STRING,
	                               str.c_str(),
	                               (guint)mapnik::freetype_engine::face_names().size() );
	return msg;
}