#include <rtthread.h>
#include <dfs.h>
#include <dfs_fs.h>

#include "devfs.h"

/* introduce from kservice.c */
#define rt_list_entry(node, type, member) \
    ((type *)((char *)(node) - (unsigned long)(&((type *)0)->member)))

struct device_dirent
{
	rt_device_t *devices;
	rt_uint16_t read_index;
	rt_uint16_t device_count;
};

int dfs_device_fs_mount(struct dfs_filesystem* fs, unsigned long rwflag, const void* data)
{
	return DFS_STATUS_OK;
}

int dfs_device_fs_ioctl(struct dfs_fd* file, int cmd, void* args)
{
	rt_err_t result;
	rt_device_t dev_id;

	RT_ASSERT(file != RT_NULL);

	/* get device handler */
	dev_id = (rt_device_t)file->data;
	RT_ASSERT(dev_id != RT_NULL);

	/* close device handler */
	result = rt_device_control(dev_id, cmd, args);
	if (result == RT_EOK)
		return DFS_STATUS_OK;

	return -DFS_STATUS_EIO;
}

int dfs_device_fs_read(struct dfs_fd* file, void *buf, rt_size_t count)
{
	int result;
	rt_device_t dev_id;

	RT_ASSERT(file != RT_NULL);

	/* get device handler */
	dev_id = (rt_device_t)file->data;
	RT_ASSERT(dev_id != RT_NULL);

	/* read device data */
	result = rt_device_read(dev_id, file->pos, buf, count);
	file->pos += result;

	return result;
}

int dfs_device_fs_write(struct dfs_fd* file, const void *buf, rt_size_t count)
{
	int result;
	rt_device_t dev_id;

	RT_ASSERT(file != RT_NULL);

	/* get device handler */
	dev_id = (rt_device_t)file->data;
	RT_ASSERT(dev_id != RT_NULL);

	/* read device data */
	result = rt_device_write(dev_id, file->pos, buf, count);
	file->pos += result;

	return result;
}

int dfs_device_fs_close(struct dfs_fd* file)
{
	rt_err_t result;
	rt_device_t dev_id;

	RT_ASSERT(file != RT_NULL);

	if (file->type == FT_DIRECTORY)
	{
		struct device_dirent *root_dirent;

		root_dirent = (struct device_dirent*)file->data;
		RT_ASSERT(root_dirent != RT_NULL);
		
		/* release dirent */
		rt_free(root_dirent);
		return DFS_STATUS_OK;
	}

	/* get device handler */
	dev_id = (rt_device_t)file->data;
	RT_ASSERT(dev_id != RT_NULL);

	/* close device handler */
	result = rt_device_close(dev_id);
	if (result == RT_EOK)
	{
		file->data = RT_NULL;
		return DFS_STATUS_OK;
	}

	return -DFS_STATUS_EIO;
}

int dfs_device_fs_open(struct dfs_fd* file)
{
	rt_device_t device;

	if (file->flags & DFS_O_CREAT) return -DFS_STATUS_EINVAL;

	/* open root directory */
	if ((file->path[0] == '/') && (file->path[1] == '\0') &&
		(file->flags & DFS_O_DIRECTORY))
	{
		struct rt_object* object;
		struct rt_list_node* node;
		struct rt_object_information *information;
		struct device_dirent* root_dirent;
		rt_uint32_t count = 0;
		
		extern struct rt_object_information rt_object_container[];

		/* lock scheduler */
		rt_enter_critical();

		/* traverse device object */
		information = &rt_object_container[RT_Object_Class_Device];
		for (node = information->object_list.next; node != &(information->object_list); node = node->next)
		{
			count ++;
		}

		root_dirent = (struct device_dirent*) rt_malloc (sizeof(struct device_dirent) + 
			count * sizeof(rt_device_t));
		if (root_dirent != RT_NULL)
		{
			root_dirent->devices = (rt_device_t *)(root_dirent + 1);
			root_dirent->read_index = 0;
			root_dirent->device_count = count;
			count = 0;
			/* get all device node */
			for (node = information->object_list.next; node != &(information->object_list); node = node->next)
			{
				object = rt_list_entry(node, struct rt_object, list);
				root_dirent->devices[count] = (rt_device_t)object;
				count ++;
			}
		}
		rt_exit_critical();

		/* set data */
		file->data = root_dirent;
		return DFS_STATUS_OK;
	}

	device = rt_device_find(&file->path[1]);
	if (device == RT_NULL)
		return -DFS_STATUS_ENODEV;

	file->data = device;
	return DFS_STATUS_OK;
}

int dfs_device_fs_stat(struct dfs_filesystem* fs, const char *path, struct stat *st)
{
	/* stat root directory */
	if ((path[0] == '/') && (path[1] == '\0'))
	{
		st->st_dev   = 0;

		st->st_mode = DFS_S_IFREG | DFS_S_IRUSR | DFS_S_IRGRP | DFS_S_IROTH |
			DFS_S_IWUSR | DFS_S_IWGRP | DFS_S_IWOTH;
		st->st_mode &= ~DFS_S_IFREG;
		st->st_mode |= DFS_S_IFDIR | DFS_S_IXUSR | DFS_S_IXGRP | DFS_S_IXOTH;

		st->st_size  = 0;
		st->st_mtime = 0;
		st->st_blksize = 512;
		return DFS_STATUS_OK;
	}
	else
	{
		rt_device_t dev_id;

		dev_id = rt_device_find(&path[1]);
		if (dev_id != RT_NULL)
		{
			st->st_dev   = 0;

			st->st_mode = DFS_S_IRUSR | DFS_S_IRGRP | DFS_S_IROTH |
				DFS_S_IWUSR | DFS_S_IWGRP | DFS_S_IWOTH;

			if (dev_id->type == RT_Device_Class_Char)
				st->st_mode |= DFS_S_IFCHR;
			else if (dev_id->type == RT_Device_Class_Block)
				st->st_mode |= DFS_S_IFBLK;
			else
				st->st_mode |= DFS_S_IFREG;

			st->st_size  = 0;
			st->st_mtime = 0;
			st->st_blksize = 512;
			return DFS_STATUS_OK;
		}
	}

	return -DFS_STATUS_ENOENT;
}

int dfs_device_fs_getdents(struct dfs_fd* file, struct dirent* dirp, rt_uint32_t count)
{
	rt_uint32_t index;
	rt_object_t object;
	struct dirent* d;
	struct device_dirent *root_dirent;

	root_dirent = (struct device_dirent*)file->data;
	RT_ASSERT(root_dirent != RT_NULL);

	/* make integer count */
	count = (count / sizeof(struct dirent));
	if ( count == 0 ) return -DFS_STATUS_EINVAL;

	for (index = 0; index < count && index + root_dirent->read_index < root_dirent->device_count; 
		index ++)
	{
		object = (rt_object_t)root_dirent->devices[root_dirent->read_index + index];

		d = dirp + index;
		d->d_type = DFS_DT_REG;
		d->d_namlen = RT_NAME_MAX;
		d->d_reclen = (rt_uint16_t)sizeof(struct dirent);
		rt_strncpy(d->d_name, object->name, RT_NAME_MAX);
	}

	root_dirent->read_index += index;

	return index * sizeof(struct dirent);
}

static const struct dfs_filesystem_operation _device_fs = 
{
	"devfs",
	dfs_device_fs_mount,
	RT_NULL,
	RT_NULL,
	RT_NULL,

	dfs_device_fs_open,
	dfs_device_fs_close,
	dfs_device_fs_ioctl,
	dfs_device_fs_read,
	dfs_device_fs_write,
	RT_NULL,
	RT_NULL,
	dfs_device_fs_getdents,
	RT_NULL,
	dfs_device_fs_stat,
	RT_NULL,
};

int devfs_init(void)
{
    /* register rom file system */
    dfs_register(&_device_fs);

	return 0;
}