/**************************************************************
 *
 * userprog/ksyscall.h
 *
 * Kernel interface for systemcalls 
 *
 * by Marcus Voelp  (c) Universitaet Karlsruhe
 *
 **************************************************************/

#ifndef __USERPROG_KSYSCALL_H__ 
#define __USERPROG_KSYSCALL_H__ 

#define INT_BUF_LENGTH 13

#include "kernel.h"

#include "synchconsole.h"


void SysHalt()
{
  kernel->interrupt->Halt();
}

int SysAdd(int op1, int op2)
{
  return op1 + op2;
}

int SysCreate(char *filename)
{
  // return value
  // 1: success
  // 0: failed
  return kernel->interrupt->CreateFile(filename);
}

void SysPrintInt(int value) {
  kernel->interrupt->PrintInt(value);
}

OpenFileId SysOpen(char *name) {
  for (int i = 0; i < 20; i++)
    if (kernel->fileSystem->fileDescriptorTable[i] == NULL) {
      kernel->fileSystem->fileDescriptorTable[i]
        = kernel->fileSystem->Open(name);
      if (kernel->fileSystem->fileDescriptorTable[i] == NULL)
        return -1;
      return i + 2;  // OpenFileId starts from 2 (0=stdin, 1=stdout reserved)
    }
  return -1;
}

int SysWrite(char *buffer, int size, OpenFileId id) {
  if (size < 0)  // Invalid size
    return -1;
  if (id == 1) {  // Console output (stdout)
    for (int i = 0; i < size; i++)
      kernel->synchConsoleOut->PutChar(buffer[i]);
    return size;
  }
  int idx = id - 2;  // Convert to 0-based index (ids 2+ are files)
  if (idx < 0 || idx >= 20 || kernel->fileSystem->fileDescriptorTable[idx] == NULL)
    return -1;
  return kernel->fileSystem->fileDescriptorTable[idx]->Write(buffer, size);
}

int SysRead(char *buffer, int size, OpenFileId id) {
  if (size < 0)  // Invalid size
    return -1;
  if (id == 0) {  // Console input (stdin)
    for (int i = 0; i < size; i++)
      buffer[i] = kernel->synchConsoleIn->GetChar();
    return size;
  }
  int idx = id - 2;  // Convert to 0-based index (ids 2+ are files)
  if (idx < 0 || idx >= 20 || kernel->fileSystem->fileDescriptorTable[idx] == NULL)
    return -1;
  return kernel->fileSystem->fileDescriptorTable[idx]->Read(buffer, size);
}

int SysClose(OpenFileId id) {
  if (id == 0 || id == 1)  // Cannot close console
    return 0;
  int idx = id - 2;  // Convert to 0-based index (ids 2+ are files)
  if (idx < 0 || idx >= 20 || kernel->fileSystem->fileDescriptorTable[idx] == NULL)
    return 0;
  delete kernel->fileSystem->fileDescriptorTable[idx];
  kernel->fileSystem->fileDescriptorTable[idx] = NULL;
  return 1;
}


#endif /* ! __USERPROG_KSYSCALL_H__ */