// vfs.c
// Author: Josh Holtrop
// Date: 08/22/04
// Modified: 12/20/04

#include "hos_defines.h"
#include "kout.h"
#include "fs/vfs.h"
#include "fs/ext2.h"
#include "kernel.h"
#include "mm/vmm.h"

vfs_fs_t *fses[VFS_MAX_FS];
vfs_node_t *vfsMountTree;

int	vfs_init()
{
	k_check(ext2_init(FS_EXT2), "ext2_init() failed!");
	return 0;
}

int	vfs_register_fs(int fsn, vfs_fs_t *fs)
{
	if (fsn < 0 || fsn >= VFS_MAX_FS || fses[fsn])
	{
		kprintf("Invalid filesystem register: %d\n", fsn);
		return -1;
	}
	fses[fsn] = fs;
	return 0;
}

int	vfs_mount(major_t maj, minor_t min, int fsType, char *mountPoint)
{
	if (mountPoint[0] != '/')
		return -1;				// mount point must be absolute
	if (fsType < 0 || fsType >= VFS_MAX_FS || !fses[fsType])
		return -2;				// invalid filesystem type
	if (vfs_find_mount(mountPoint))
	{
		return -5;				// mount point already mounted
	}
	void *super = fses[fsType]->mount_super(maj, min);
	if (!super)
		return -6;				// filesystem superblock not correctly identified
	vfs_mount_t *mnt = New(vfs_mount_t);
	if (!mnt)
		return -3;				// could not allocate memory
	mnt->refs = 0;
	mnt->major = maj;
	mnt->minor = min;
	mnt->super = super;
	if (vfs_add_mount(mnt, mountPoint))
	{
		kfree(mnt);
		return -4;				// could not add mount
	}
	return 0;
}

int	vfs_add_mount(vfs_mount_t *mnt, char *mountPoint)
{
	vfs_node_t *node = vfsMountTree;
	char *mp = mountPoint;
	if (!vfsMountTree)
	{
		vfsMountTree = New(vfs_node_t);
		node = vfsMountTree;
		node->chr = *mp;
		node->up = NULL;
		node->next = NULL;
		node->down = NULL;
		node->mount = NULL;
	}
	for (;;)
	{
		if (node->chr == *mp)				// got a match
		{
			mp++;
			if (*mp == 0)
			{
				if (node->mount)
					return -1;		// mount point already taken
				node->mount = mnt;
				return 0;
			}
			if (node->down)
				node = node->down;
			else
			{
				node->down = New(vfs_node_t);
				node->down->up = node;
				node = node->down;
				node->next = NULL;
				node->down = NULL;
				node->mount = NULL;
				node->chr = *mp;
			}
		}
		else if (node->next)
		{
			node = node->next;
		}
		else						// add a node for this character
		{
			node->next = New(vfs_node_t);
			node->next->up = node->up;
			node = node->next;
			node->next = NULL;
			node->down = NULL;
			node->mount = NULL;
			node->chr = *mp;
		}
	}	
}

vfs_mount_match_t vfs_get_rel_path(char *path)
{
	vfs_mount_match_t matched;
	char *pp = path;
	int length = 0;
	vfs_node_t *node = vfsMountTree;
	while (*pp)
	{
		if (!node)
			break;
		if (node->chr == *pp)			// got a character match
		{
			if (node->mount)		// and there is something mounted here
			{
				matched.major = node->mount->major;
				matched.minor = node->mount->minor;
				matched.length = length;
			}
			pp++;
			length++;
			node = node->down;
		}
		else
			node = node->next;
	}
	return matched;
}

vfs_mount_t *vfs_find_mount(char *mountPoint)
{
	char *mp = mountPoint;
	vfs_node_t *node = vfsMountTree;
	while (node)
	{
		if (node->chr == *mp)
		{
			mp++;
			if (*mp == 0)			// we matched the whole mount point string
				return node->mount;
			node = node->down;
		}
		else
			node = node->next;
	}
	return NULL;
}

/*void	vfs_dump_tree()
{
	vfs_dump_node(vfsMountTree, 0);
}

void	vfs_dump_node(vfs_node_t *node, int level)
{
	int i;
	for (i = 0; i < level; i++)
	{
		putc(' ');
	}
	kprintf("%c (0x%x) mount: 0x%x, up: 0x%x, next:0x%x, down:0x%x\n", node->chr, node, node->mount, node->up, node->next, node->down);
	node = node->down;
	if (!node)
		return;
	while (node)
	{
		vfs_dump_node(node, level + 1);
		node = node->next;
	}
}*/