#include "vfs.h"
#define MaxDevices 256

#define ReturnInvalid() { File ret; ret.Type = FileTypeInvalid; return ret;}

unsigned CurrentDevice = 0;
unsigned DeviceCount = 0;

FileSystemPointer _FileSystems[MaxDevices];

File VFSOpenFile (const char* FileName)
{
    unsigned Device = CurrentDevice;
    
    // No filename specified.
    if (!FileName) ReturnInvalid();
    
    // File length
    int len = strlen(FileName);
    // File name without drive
    char* Name = 0;
    
    // Check if relative or absolute path
    int i;
    for (i=0; i < len; i++)
        if (FileName[i] == ':') {
            Name = &FileName[i+1];
            FileName[i] = 0;
            len = i;
            }
            
    // If absolute path, find device
    if (Name != 0) {
        for (i=0; i < MaxDevices; i++)
            if (_FileSystems[i]) {
                if (strcmp(_FileSystems[i]->Name, FileName) == 0) Device = i;
            }
        }
    // Drive is nonexistant or current drive not mounted
    if (i==MaxDevices || !_FileSystems[Device]) ReturnInvalid();
    
    // Open file
    return _FileSystems[Device]->Open((Name) ? Name : FileName);
}


int VFSInstallFileSystem(FileSystemPointer fs)
{
    // Sanity check
    if (!fs) return 0;
    
    // Verify device does not exist
    int i;
    for (i=0; i < DeviceCount; i++)
        if (_FileSystems[i]) 
            if (strcmp (fs->Name, _FileSystems[i]->Name) == 0) return 0;
            
    _FileSystems[DeviceCount] = fs; DeviceCount++;
}

void VFSUninstallFileSystem(FileSystemPointer fs)
{
    if (!fs) return;
    
    int i;
    for (i=0; i<DeviceCount; i++)
        if (_FileSystems[i] == fs) {
            _FileSystems[i] = 0;
            return;
        }
    
}

void VFSUninstallFileSystemByName(const char* fs)
{
    if (!fs) return;

    int i;
    for (i=0; i<DeviceCount; i++)
        if (_FileSystems[i])
            if (strcmp(_FileSystems[i]->Name, fs) == 0){
                _FileSystems[i] = 0;
                return;
            }
}

void VFSReadFile (FilePointer f, unsigned char* buffer, unsigned len)
{
    if (!f || !_FileSystems[f->Device]) return;
    _FileSystems[f->Device]->Read (f, buffer, len);
}

void VFSCloseFile (FilePointer f)
{
    if (!f || !_FileSystems[f->Device]) return;
    _FileSystems[f->Device]->Close(f);
}