/* 
 * Copyright 2010 Stefan Lankes, Chair for Operating Systems,
 *                               RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file is part of MetalSVM.
 */

#include <metalsvm/stdarg.h>
#include <metalsvm/stdio.h>
#include <metalsvm/syscall.h>
#include <metalsvm/tasks.h>
#include <metalsvm/string.h>
#include <metalsvm/errno.h>
#include <metalsvm/spinlock.h>
#include <metalsvm/time.h>
#include <lwip/opt.h>

#if defined(CONFIG_LWIP) && LWIP_SOCKET
#include <lwip/mem.h>
#include <lwip/raw.h>
#include <lwip/icmp.h>
#include <lwip/netif.h>
#include <lwip/sys.h>
#include <lwip/timers.h>
#include <lwip/inet_chksum.h>
#include <lwip/ip.h>
#include <lwip/sockets.h>
#include <lwip/inet.h>
#include <lwip/err.h>

#endif

static int get_fildes(){
	int fd; 

	for (fd = 0; fd < NR_OPEN; fd++) {
		if (per_core(current_task)->fildes_table[fd].node == NULL) {
			return fd;
		} 
 	}

	/* can't get any free fd */
	return -EMFILE;
}

static int sys_open(const char* name, int flags, int mode)
{
	int fd, check;
	fildes_t* file = NULL;

	fd = get_fildes();
	/* validate the fd */
	if (fd < 0)
		return fd;

	file = &(per_core(current_task)->fildes_table[fd]);
	file->offset = 0;
	file->mode = mode;
	file->flags = flags;

	check = open_fs(file, (char*) name);
	if (check < 0) {
		/* file doesn't exist! */
		file->node = NULL;
		return check;
 	}
	
	return fd;
}

#if defined(CONFIG_LWIP) && LWIP_SOCKET
static int sys_socket(int domain, int type, int protocol)
{
	int fd;
	fildes_t* file = NULL;

	fd = get_fildes();
	/* validate the fd */
	if (fd < 0)
		return fd;

	file = &(per_core(current_task)->fildes_table[fd]);
	file->offset = lwip_socket(domain, type, protocol);
	file->mode = 0;
	file->flags = 0;
	file->node = findnode_fs("/dev/socket"); 
	
	return fd;
}

static int sys_accept(int s, struct sockaddr* addr, socklen_t* addrlen)
{
	int fd;
	fildes_t* file = NULL;

	fd = get_fildes();
	/* validate the fd */
	if (fd < 0) 
		return fd;

	file = &(per_core(current_task)->fildes_table[fd]);
	file->offset = lwip_accept(s, addr, addrlen);
	file->mode = 0;
	file->flags = 0;
	file->node = findnode_fs("/dev/socket");
	
	return fd;
}

#endif


static int sys_close(int fd)
{
	fildes_t* file = &(per_core(current_task)->fildes_table[fd]);
	close_fs(file);
	file->node = NULL;
	file->offset = 0;
	file->mode = 0;
	file->flags = 0;
	return 0;

}
 
static int sys_lseek(int fd, off_t pos, int origin)
{
	int ret = -EINVAL;
	fildes_t* file = &(per_core(current_task)->fildes_table[fd]);

	if (BUILTIN_EXPECT(!((file->node->type == FS_FILE) 
			|| (file->node->type == FS_CHARDEVICE)), 0))
		return -EINVAL;

	switch(origin) 
	{	
	case SEEK_SET: {	/* set file offset to offset */
			file->offset = pos;
			ret = 0;
			break;
		}
	case SEEK_CUR: {	/* set file offset to current plus offset */
			ret = pos + file->offset;
			break;
		}
	case SEEK_END: {	/* set file offset to EOF plus offset */
			file->offset = pos + file->node->block_size;
			ret = 0;
			break;
		}
	default:
		ret = -EINVAL;
		break;
	}
	return ret;
}

static int sys_sbrk(int incr)
{
	task_t* task = per_core(current_task);
	vma_t* tmp = NULL;
	int ret;

	spinlock_lock(&task->vma_lock);

	tmp = task->vma_list;
        while(tmp && !((task->end_heap >= tmp->start) && (task->end_heap <= tmp->end)))
		tmp = tmp->next;

	ret = (int) task->end_heap;
	task->end_heap += incr;
	if (task->end_heap < task->start_heap)
		task->end_heap = task->start_heap;
	
	// resize virtual memory area
	if (tmp && (tmp->end <= task->end_heap))
		tmp->end = task->end_heap;

	spinlock_unlock(&task->vma_lock);

	return ret;
}

int syscall_handler(uint32_t sys_nr, ...)
{
	int ret = -EINVAL;
	va_list vl;

	check_workqueues();

	va_start(vl, sys_nr);

	switch(sys_nr) 
	{
	case __NR_exit:
		sys_exit(va_arg(vl, uint32_t));
		ret = 0;
		break;
	case __NR_write: {
			int fd = va_arg(vl, int);
			const char* buf = va_arg(vl, const char*);
			size_t len = va_arg(vl, size_t);
			if (fd >= 0)
				ret = write_fs(&(per_core(current_task)->fildes_table[fd]),
					(uint8_t*)buf, len);
			break;
		}
	case __NR_open: {
			const char* name = va_arg(vl, const char*);
			int flags = va_arg(vl, int);
			int mode = va_arg(vl, int);
			ret = sys_open(name, flags, mode);
			break;
		}
	case __NR_close: {
			int fd = va_arg(vl, int);
			if (fd >= 0)
				ret = sys_close(fd);
			break;
 		}
	case __NR_read: {
			int fd = va_arg(vl, int);
			const char* buf = va_arg(vl, const char*);
 			size_t len = va_arg(vl, size_t);
			if (fd >= 0)
				ret = read_fs(&(per_core(current_task)->fildes_table[fd]), 
					(uint8_t*)buf, len);
			break;
		}
	case __NR_lseek: {
			int fd = va_arg(vl, int);
			off_t pos = va_arg(vl, off_t);
 			int origin = va_arg(vl, int);
			if (fd >= 0)
				ret = sys_lseek(fd, pos, origin);
			break;
		}
	case __NR_sbrk: {
			int incr = va_arg(vl, int);

			ret = sys_sbrk(incr);
			break;
		}
	case __NR_getpid:
		ret = per_core(current_task)->id;
		break;
	case __NR_fork:
		ret = sys_fork();
		break;
	case __NR_wait: {
			int32_t* status = va_arg(vl, int32_t*);
	
			ret = wait(status);
			break;
		}
	case __NR_execve: {
			const char* name = va_arg(vl, const char*);
			char** argv = va_arg(vl, char**);
			char** env = va_arg(vl, char**);

			ret = sys_execve(name, argv, env);
			break;
		}
	case __NR_times: {
			struct tms* buffer = va_arg(vl, struct tms*);
			clock_t* clock = va_arg(vl, clock_t*);

			ret = sys_times(buffer, clock);
			break;
		}
#if defined(CONFIG_LWIP) && LWIP_SOCKET
	case __NR_closesocket: {
		int fd = va_arg(vl, int);

		if (fd < 0) {
			ret = -ENOTSOCK;
			break;
		}
		//ret = lwip_close(per_core(current_task)->fildes_table[fd].offset);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_socket: {
		int domain = va_arg(vl, int);
		int type = va_arg(vl, int);
		int protocol = va_arg(vl, int);

		ret = sys_socket(domain, type, protocol);
		break;
	}
	case __NR_connect: {
		int fd = va_arg(vl, int);
		const struct sockaddr* name = va_arg(vl, const struct sockaddr*);
		socklen_t namelen = va_arg(vl, socklen_t);

		if (per_core(current_task)->fildes_table[fd].offset < 0) {
			ret = -ENOTSOCK;
			break;
		}
		//kprintf("lwip_connect: %p with lenght %i and Socket %i", name, namelen, per_core(current_task)->fildes_table[fd].offset);


		ret = lwip_connect(per_core(current_task)->fildes_table[fd].offset, name, namelen);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_bind: {
		int fd = va_arg(vl, int);
		const struct sockaddr* name = va_arg(vl, const struct sockaddr*);
		socklen_t namelen = va_arg(vl, socklen_t);

		if (per_core(current_task)->fildes_table[fd].offset < 0) {
			ret = -ENOTSOCK;
			break;
		}
		ret = lwip_bind(per_core(current_task)->fildes_table[fd].offset, name, namelen);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_listen: {
		int fd = va_arg(vl, int);
		int backlog = va_arg(vl, int);

		if (per_core(current_task)->fildes_table[fd].offset < 0) {
			ret = -ENOTSOCK;
			break;
		}

		ret = lwip_listen(per_core(current_task)->fildes_table[fd].offset, backlog);
		if (ret < 0)
			ret = -errno;
		break;
	}
	case __NR_accept: {
		int fd = va_arg(vl, int);
		struct sockaddr* addr = va_arg(vl, struct sockaddr*);
		socklen_t* addrlen = va_arg(vl, socklen_t*);

		if (per_core(current_task)->fildes_table[fd].offset < 0) {
			ret = -ENOTSOCK;
			break;
		}
		ret = sys_accept(per_core(current_task)->fildes_table[fd].offset, addr, addrlen);
		if (ret < 0)
			ret = -errno;
		break;
	}
#endif
	default:
		kputs("invalid system call\n");
		ret = -ENOSYS;
		break;
	};

	va_end(vl);

	return ret;
}