/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 *
 * http://postgis.net
 *
 * Copyright (C) 2011      Sandro Santilli <strk@kbt.io>
 * Copyright (C) 2009-2011 Paul Ramsey <pramsey@cleverelephant.ca>
 * Copyright (C) 2008      Mark Cave-Ayland <mark.cave-ayland@siriusit.co.uk>
 * Copyright (C) 2004-2007 Refractions Research Inc.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU General Public Licence. See the COPYING file.
 *
 **********************************************************************/

#include <postgres.h>
#include <fmgr.h>
#include <miscadmin.h>
#include <executor/spi.h>
#include <utils/guc.h>
#include <utils/guc_tables.h>

#include "../postgis_config.h"
#include "liblwgeom.h"
#include "lwgeom_pg.h"

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

#define PARANOIA_LEVEL 1

#define PGC_ERRMSG_MAXLEN 256

/**
* Utility to convert cstrings to textp pointers
*/
text*
cstring2text(const char *cstring)
{
	text *output;
	size_t sz;
	
	/* Guard against null input */
	if( !cstring )
		return NULL;
		
	sz = strlen(cstring);
	output = palloc(sz + VARHDRSZ);
	if ( ! output )
		return NULL;
	SET_VARSIZE(output, sz + VARHDRSZ);
	if ( sz )
		memcpy(VARDATA(output),cstring,sz);
	return output;
}

char*
text2cstring(const text *textptr)
{
	size_t size = VARSIZE(textptr) - VARHDRSZ;
	char *str = lwalloc(size+1);
	memcpy(str, VARDATA(textptr), size);
	str[size]='\0';
	return str;
}


/*
 * Error message parsing functions
 *
 * Produces nicely formatted messages for parser/unparser errors with optional HINT
 */

void
pg_parser_errhint(LWGEOM_PARSER_RESULT *lwg_parser_result)
{
	char *hintbuffer;

	/* Only display the parser position if the location is > 0; this provides a nicer output when the first token
	   within the input stream cannot be matched */
	if (lwg_parser_result->errlocation > 0)
	{
		/* Return a copy of the input string start truncated
		 * at the error location */
		hintbuffer = lwmessage_truncate(
			(char *)lwg_parser_result->wkinput, 0,
			lwg_parser_result->errlocation - 1, 40, 0);

		ereport(ERROR,
		        (errmsg("%s", lwg_parser_result->message),
		         errhint("\"%s\" <-- parse error at position %d within geometry", hintbuffer, lwg_parser_result->errlocation))
		       );
	}
	else
	{
		ereport(ERROR,
		        (errmsg("%s", lwg_parser_result->message),
		         errhint("You must specify a valid OGC WKT geometry type such as POINT, LINESTRING or POLYGON"))
		       );
	}
}

void
pg_unparser_errhint(LWGEOM_UNPARSER_RESULT *lwg_unparser_result)
{
	/* For the unparser simply output the error message without any associated HINT */
	elog(ERROR, "%s", lwg_unparser_result->message);
}


static void *
pg_alloc(size_t size)
{
	void * result;

	CHECK_FOR_INTERRUPTS(); /* give interrupter a chance */

	POSTGIS_DEBUGF(5, "  pg_alloc(%d) called", (int)size);

	result = palloc(size);

	POSTGIS_DEBUGF(5, "  pg_alloc(%d) returning %p", (int)size, result);

	if ( ! result )
	{
		ereport(ERROR, (errmsg_internal("Out of virtual memory")));
		return NULL;
	}
	return result;
}

static void *
pg_realloc(void *mem, size_t size)
{
	void * result;

	CHECK_FOR_INTERRUPTS(); /* give interrupter a chance */

	POSTGIS_DEBUGF(5, "  pg_realloc(%p, %d) called", mem, (int)size);

	result = repalloc(mem, size);

	POSTGIS_DEBUGF(5, "  pg_realloc(%p, %d) returning %p", mem, (int)size, result);

	return result;
}

static void
pg_free(void *ptr)
{
	pfree(ptr);
}

static void
pg_error(const char *fmt, va_list ap)
{
	char errmsg[PGC_ERRMSG_MAXLEN+1];

	vsnprintf (errmsg, PGC_ERRMSG_MAXLEN, fmt, ap);

	errmsg[PGC_ERRMSG_MAXLEN]='\0';
	ereport(ERROR, (errmsg_internal("%s", errmsg)));
}

static void
pg_warning(const char *fmt, va_list ap)
{
	char errmsg[PGC_ERRMSG_MAXLEN+1];

	vsnprintf (errmsg, PGC_ERRMSG_MAXLEN, fmt, ap);

	errmsg[PGC_ERRMSG_MAXLEN]='\0';
	ereport(WARNING, (errmsg_internal("%s", errmsg)));
}

static void
pg_notice(const char *fmt, va_list ap)
{
	char errmsg[PGC_ERRMSG_MAXLEN+1];

	vsnprintf (errmsg, PGC_ERRMSG_MAXLEN, fmt, ap);

	errmsg[PGC_ERRMSG_MAXLEN]='\0';
	ereport(NOTICE, (errmsg_internal("%s", errmsg)));
}

static void
pg_debug(int level, const char *fmt, va_list ap)
{
	char errmsg[PGC_ERRMSG_MAXLEN+1];
	vsnprintf (errmsg, PGC_ERRMSG_MAXLEN, fmt, ap);
	errmsg[PGC_ERRMSG_MAXLEN]='\0';
	int pglevel[6] = {NOTICE, DEBUG1, DEBUG2, DEBUG3, DEBUG4, DEBUG5};

	if ( level >= 0 && level <= 5 )
		ereport(pglevel[level], (errmsg_internal("%s", errmsg)));
	else
		ereport(DEBUG5, (errmsg_internal("%s", errmsg)));		
}

void
pg_install_lwgeom_handlers(void)
{
	/* install PostgreSQL handlers */
	lwgeom_set_handlers(pg_alloc, pg_realloc, pg_free, pg_error, pg_notice);
	lwgeom_set_debuglogger(pg_debug);
}

/**
* Utility method to call the serialization and then set the
* PgSQL varsize header appropriately with the serialized size.
*/

/**
* Utility method to call the serialization and then set the
* PgSQL varsize header appropriately with the serialized size.
*/
GSERIALIZED* geography_serialize(LWGEOM *lwgeom)
{
	size_t ret_size = 0;
	GSERIALIZED *g = NULL;
	/** force to geodetic in case it's not **/
	lwgeom_set_geodetic(lwgeom, true);

	g = gserialized_from_lwgeom(lwgeom,  &ret_size);
	if ( ! g ) lwpgerror("Unable to serialize lwgeom.");
	SET_VARSIZE(g, ret_size);
	return g;
}


/**
* Utility method to call the serialization and then set the
* PgSQL varsize header appropriately with the serialized size.
*/
GSERIALIZED* geometry_serialize(LWGEOM *lwgeom)
{
	size_t ret_size = 0;
	GSERIALIZED *g = NULL;

	g = gserialized_from_lwgeom(lwgeom, &ret_size);
	if ( ! g ) lwpgerror("Unable to serialize lwgeom.");
	SET_VARSIZE(g, ret_size);
	return g;
}

void
lwpgnotice(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);

  pg_notice(fmt, ap);

	va_end(ap);
}

void
lwpgwarning(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);

  pg_warning(fmt, ap);

	va_end(ap);
}

void
lwpgerror(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);

  pg_error(fmt, ap);

	va_end(ap);
}


/*
 * the bare comparison function for GUC names
 */
int
postgis_guc_name_compare(const char *namea, const char *nameb)
{
	/*
	 * The temptation to use strcasecmp() here must be resisted, because the
	 * array ordering has to remain stable across setlocale() calls. So, build
	 * our own with a simple ASCII-only downcasing.
	 */
	while (*namea && *nameb)
	{
		char		cha = *namea++;
		char		chb = *nameb++;

		if (cha >= 'A' && cha <= 'Z')
			cha += 'a' - 'A';
		if (chb >= 'A' && chb <= 'Z')
			chb += 'a' - 'A';
		if (cha != chb)
			return cha - chb;
	}
	if (*namea)
		return 1;				/* a is longer */
	if (*nameb)
		return -1;				/* b is longer */
	return 0;
}

/*
 * comparator for qsorting and bsearching guc_variables array
 */
int
postgis_guc_var_compare(const void *a, const void *b)
{
	const struct config_generic *confa = *(struct config_generic * const *) a;
	const struct config_generic *confb = *(struct config_generic * const *) b;

	return postgis_guc_name_compare(confa->name, confb->name);
}

/*
* This is copied from the top half of the find_option function
* in postgresql's guc.c. We search the guc_variables for our option.
* Then we make sure it's not a placeholder. Only then are we sure
* we have a potential conflict, of the sort experienced during an
* extension upgrade.
*/
int
postgis_guc_find_option(const char *name)
{
	const char **key = &name;
	struct config_generic **res;

	/*
	 * By equating const char ** with struct config_generic *, we are assuming
	 * the name field is first in config_generic.
	 */
	res = (struct config_generic **) bsearch((void *) &key,
		 (void *) get_guc_variables(),
		 GetNumConfigOptions(),
		 sizeof(struct config_generic *),
		 postgis_guc_var_compare);
	
	/* Found nothing? Good */
	if ( ! res ) return 0;
	
	/* Hm, you found something, but maybe it's just a placeholder? */
	/* We'll consider a placehold a "not found" */
	if ( (*res)->flags & GUC_CUSTOM_PLACEHOLDER )
		return 0;
		
	return 1;
}