#include <stdio.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

#include "postgres.h"
#include "plpgsql.h"
#include "miscadmin.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/explain.h"
#include "executor/executor.h"
#include "executor/instrument.h"
#include "executor/spi.h"
#include "nodes/params.h"
#include "parser/parser.h"
#include "parser/parse_target.h"
#include "parser/parse_node.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "utils/lsyscache.h"


PG_MODULE_MAGIC;

static MemoryContext MyMemoryContext = NULL;
static needs_fmgr_hook_type prev_needs_fmgr_hook = NULL;
static fmgr_hook_type prev_fmgr_hook = NULL;

void _PG_fini(void);
void _PG_init(void);

static void
do_stuff()
{
	MemoryContext oldcxt;
	ResourceOwner oldowner = CurrentResourceOwner;


	oldcxt = MemoryContextSwitchTo(MyMemoryContext);
	BeginInternalSubTransaction(NULL);
	PG_TRY();
	{
		elog(ERROR, "BIG LETTERS");
	}
	PG_CATCH();
	{
		ErrorData *edata;

		MemoryContextSwitchTo(MyMemoryContext);
		edata = CopyErrorData();
		FlushErrorState();

		RollbackAndReleaseCurrentSubTransaction();
		MemoryContextSwitchTo(oldcxt);
		CurrentResourceOwner = oldowner;
		
		//SPI_restore_connection();

		FreeErrorData(edata);
	}
	PG_END_TRY();
}

static bool
cleanup_test_needs_fmgr_hook(Oid functionId)
{
	return true;
}

static void
cleanup_test_fmgr_hook(FmgrHookEventType event, FmgrInfo *flinfo,
						   Datum *args)
{
	if (prev_fmgr_hook)
		(*prev_fmgr_hook) (event, flinfo, args);

	switch (event)
	{
		case FHET_START:
			do_stuff();
			break;
		case FHET_ABORT:
		case FHET_END:
			break;
		default:
			elog(ERROR, "unknown FmgtHookEventType %d", event);

	}
}

void
_PG_init(void)
{
	MyMemoryContext = AllocSetContextCreate(TopTransactionContext,
											"mymemcxt",
											ALLOCSET_DEFAULT_MINSIZE,
											ALLOCSET_DEFAULT_INITSIZE,
											ALLOCSET_DEFAULT_MAXSIZE);

	prev_needs_fmgr_hook = needs_fmgr_hook;
	needs_fmgr_hook = cleanup_test_needs_fmgr_hook;
	prev_fmgr_hook = fmgr_hook;
	fmgr_hook = cleanup_test_fmgr_hook;
}

void
_PG_fini(void)
{
	needs_fmgr_hook = prev_needs_fmgr_hook;
	prev_needs_fmgr_hook = NULL;
	fmgr_hook = prev_fmgr_hook;
	prev_fmgr_hook = NULL;

	MemoryContextDelete(MyMemoryContext);
	MyMemoryContext = NULL;
}