// remember to sync this with interface/syscalls.c

#include "lib/string/string.h"
#include "lib/printf/printf.h"
#include "fs/ext2.h"
#include "kernel.h"
#include "driver/vesa.h"
#include "fifo.h"
#include "fd.h"
#include "fs/elf.h"
#include "driver/terminal.h"
#include "driver/screen.h"
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/termios.h>
#include <stdbool.h>
#include <stddef.h>
#include "syscalls.h"
#include "scheduler.h"
#include "log.h"
#include "timer.h"
#include "mount.h"
#include "mem.h"
#include "reent.h"
#include "errno.h"
#include "compositor.h"
#include "stdstreams.h"
#include "sys/unistd.h"

#define MAX_PID 200

//TODO move to process.c and implement per process //
static fd  fds[MAX_PID][MAX_FD];
static int tty[MAX_PID]; // keep track of /dev/tty fd for each process :P

static bool open_fd[MAX_PID][MAX_FD];

fd *get_tty(uint32_t pid)
{
    return &(fds[pid][tty[pid]]);
}

void fd_init_std_streams(uint32_t pid) 
{
    fds[pid][0]=fd_from_ringbuffer();
    open_fd[pid][0]=true;

    fds[pid][1]=fd_from_ringbuffer();
    open_fd[pid][1]=true;

    fds[pid][2]=fd_from_ringbuffer();
    open_fd[pid][2]=true;

    return;
}
//

/** errno helper */
void set_errno(int no)
{
    struct _reent *impure_ptr=VMEM_USER_NEWLIB;
    impure_ptr->_errno=no;
}

/** get string represnation of syscall */
char* syscall_get_name(uint32_t num)
{
    switch(num)
    {
	case SYSCALL_EXIT:
	    return "SYSCALL_EXIT"; 
	case SYSCALL_CLOSE:
	    return "SYSCALL_CLOSE"; 
	case SYSCALL_EXECVE:
	    return "SYSCALL_EXECVE"; 
	case SYSCALL_FORK:
	    return "SYSCALL_FORK"; 
	case SYSCALL_GETPID:
	    return "SYSCALL_GETPID"; 
	case SYSCALL_ISATTY:
	    return "SYSCALL_ISATTY"; 
	case SYSCALL_LINK:
	    return "SYSCALL_LINK"; 
	case SYSCALL_LSEEK:
	    return "SYSCALL_LSEEK"; 
	case SYSCALL_OPEN:
	    return "SYSCALL_OPEN"; 
	case SYSCALL_READ:
	    return "SYSCALL_READ"; 
	case SYSCALL_SBRK:
	    return "SYSCALL_SBRK"; 
	case SYSCALL_STAT:
	    return "SYSCALL_STAT"; 
	case SYSCALL_FSTAT:
	    return "SYSCALL_FSTAT"; 
	case SYSCALL_LSTAT:
	    return "SYSCALL_LSTAT"; 
	case SYSCALL_TIMES:
	    return "SYSCALL_TIMES"; 
        case SYSCALL_UNLINK:
	    return "SYSCALL_UNLINK"; 
	case SYSCALL_WAIT:
	    return "SYSCALL_WAIT"; 
	case SYSCALL_WRITE:
	    return "SYSCALL_WRITE"; 
	case SYSCALL_GETTIMEOFDAY:
	    return "SYSCALL_GETTIMEOFDAY"; 
	case SYSCALL_READDIR:
	    return "SYSCALL_READDIR"; 
	case SYSCALL_KILL:
	    return "SYSCALL_KILL"; 
	case SYSCALL_CLONE:
	    return "SYSCALL_CLONE"; 
	case SYSCALL_PIPE:
	    return "SYSCALL_PIPE"; 
	case SYSCALL_DUP2:
	    return "SYSCALL_DUP2"; 
	case SYSCALL_GUI_RECT:
	    return "SYSCALL_GUI_RECT"; 
	case SYSCALL_GUI_WIN:
	    return "SYSCALL_GUI_WIN"; 
	case SYSCALL_SELECT:
	    return "SYSCALL_SELECT"; 
        case SYSCALL_UNIMPLEMENTED:
	    return "SYSCALL_UNKNOWN"; 
    }
    kpanic("UNKNOWN SYSCALL NUM: %d",num);
}

int syscall_gettimeofday(struct timeval *tv, struct timezone *tz,uint32_t none1, uint32_t pid)
{
    if(tv!=NULL)
    {
	uint64_t t=timer_get_ms();
	tv->tv_sec=t/1000+2*3600; // add gmt+2
	tv->tv_usec=1000*(t%1000);
    }

    // tz struct is obsolote
    if(tz!=NULL)
    {
	tz->tz_minuteswest=0;// -21*60; // warsaw
	tz->tz_dsttime=DST_NONE;
    }
    return 0;
}

int syscall_lseek(int file,int ptr,int dir,uint32_t pid) 
{

    if(dir==SEEK_CUR)
    {
	uint32_t *dat=fds[pid][file].data;
	dat[1]+=ptr;
	return dat[1];
    }

    kpanic("not fully handled lseek! dir=%d",dir);
    return 0;
}

// TODO: /dev/console or /dev/tty1 - /dev/ttyN
int syscall_write(int file, char *buf, int len,uint32_t pid)
{
    if(!open_fd[pid][file])kpanic("writing to closed file descriptor");
    for(int i=0;i<len;i++)
    {
        if(!fd_can_write(&fds[pid][file]))return i;
	fd_write(&fds[pid][file],buf[i]);
    }
    return len;
}

/** 
 * __read()__ attemts to read up to _len_ bytes from file descriptor _file_ 
 * into the buffer starting at _buf_. 
 */
int syscall_read(int file, char *buf, int len,uint32_t pid)
{
        if(!open_fd[pid][file])kpanic("reading from closed file descriptor");
	if(fd_eof(&fds[pid][file]))return 0;
        *buf=fd_read(&fds[pid][file]);
	return 1;
}

int syscall_select(int maxxfd,struct timeval *tv, fd_set **fd_sets, uint32_t pid, bool test)
{
    int ret=0;
    
    if(test&&tv!=NULL) // check if time did not run out already
    {
        if(tv->tv_sec==0&&tv->tv_usec==0)return 1;

        uint64_t t=timer_get_ms(); // current time in milliseconds (10^-3)

        uint64_t t0=0;
        t0+=tv->tv_sec*1000;        // seconds * 10^3
        t0+=tv->tv_usec/1000;       // microseconds  * 10^-3

        if(t>t0)return 1; // ready to fire!
    }

    // TODO: wake when timeout runs out!
   
    if(!test)
    {
  //    if(tv==NULL)klog("select with infinite timeout");
//       else klog ("select with timeout: sec=%d, usec=%d",tv->tv_sec,tv->tv_usec);
    }

    for(int i=0;i<maxxfd;i++)
    {
        if(FD_ISSET(i,fd_sets[0]))
        {
  //          klog("%d in readfds",i);
	    if(fd_has(&fds[pid][i])||fd_eof(&fds[pid][i]))
            {
                ret++;
            }
            else
            {
                if(!test)FD_CLR(i,fd_sets[0]);
            }
        }
        if(FD_ISSET(i,fd_sets[1]))
        {
//            klog("%d in writefds",i);

            if(fd_can_write(&fds[pid][i]))
            {
                ret++;
            }
            else
            {
                if(!test)FD_CLR(i,fd_sets[1]);
            }
        }

        if(FD_ISSET(i,fd_sets[2]))
        {
    //        klog("%d in exceptfds",i); // TODO!
        }
    }

    if(!test)FD_ZERO(fd_sets[2]); // we dont give a shit about exceptions! :P TODO!!!


    return ret;



}

//TODO: replace with dirent!
int syscall_readdir(const char *name,fs_dirent *dirs,int *pos,uint32_t pid)
{
    int ret=mount_read_dir(name, dirs, pos);
    if(ret==-1)
    {
	set_errno(ENOENT);
    }
    return ret;
}

/** execve helper */
int copy_args(char **in, char **out)
{
    //klog("copy_args(0x%08x, 0x%08X)",in,out);
    int count=0;
    while(in[count]!=NULL)
    {
//	klog("args(0x%08x: %s)",in[count],out);
	count++;
    };

  //  klog("copy_args : count: %d",count);
    
    char **pos=out;
    pos+=sizeof(char **)*(count+1); 

    int i=0;
    do{
	int l=strlen(in[i]);
	char *var=pos;
	memcpy(var,in[i],l+1);
	pos+=sizeof(char *)*(l+1); 
	out[i]=var;
	i++;
    }while(in[i]!=NULL);
    out[i]=NULL;

    return count;
}

/** does not return on success otherwise -1 and errrno set */
// int execve(const char *filename, char *const argv[], char *const envp[]); 
int syscall_execve(const char *name, char *const argv[], char *const env[], int pid)
{

    fixme("not overwrite yourself?");
    int arg_count=0;
    while(argv[arg_count]!=NULL)arg_count++;

    char **argv1=VMEM_USER_ENV;
    if(argv!=NULL)copy_args(argv,argv1);
    else argv1=NULL;

    char **env1=VMEM_USER_ENV+1024*2;
    if(env!=NULL)copy_args(env,env1);
    else env1=NULL;

    uint32_t alloc;
    uint32_t entry_global=load_elf(name,&alloc);

    if(!entry_global){
	set_errno(ENOENT);
	return -1;
    }

    uint32_t *stack=VMEM_USER_STACK_TOP-4*32;
    *--stack=argv1;
    *--stack=arg_count;
    *--stack=env1;
    task_reset(pid,entry_global,stack,alloc);
    task_set_name(pid,name);

    return 0;
}

/** helper */
int nextfd(int pid)
{
    for(int i=0;i<MAX_FD;i++)
    {
	if(!open_fd[pid][i])
	{
	    open_fd[pid][i]=true;
	    return i;
	}
    }
    return -1;
}

int syscall_open(char *name, int flags, int mode,uint32_t pid)
{
    if(!strcmp("/dev/tty",name))return tty[pid];

    uint32_t fdn=nextfd(pid);
    fds[pid][fdn]=mount_file_open(name);
    if(*(uint32_t *)fds[pid][fdn].data==0)return -1;
    return fdn;
}

// pid_t fork(void);
uint32_t syscall_fork(int none1, int none2, int none3, int pid)
{
    uint32_t newpid=task_fork(pid);

    for(int i=0;i<MAX_FD;i++)
    {
	if(!open_fd[pid][i])continue;
	fds[newpid][i]=fd_dupl(&fds[pid][i]);
	open_fd[newpid][i]=true;
    }
    tty[newpid]=tty[pid];
//    fds[newpid][0]=fd_from_ringbuffer(); // TODO fix
//    open_fd[newpid][0]=true;

    return newpid;
}

uint32_t syscall_clone(int none1, int none2, int none3, int pid)
{
    uint32_t newpid=task_clone(pid);

    for(int i=0;i<MAX_FD;i++) // TODO: use same pid and use same list maybe?
    {
	if(!open_fd[pid][i])continue;
	fds[newpid][i]=fd_dupl(&fds[pid][i]);
	open_fd[newpid][i]=true;
    }
    tty[newpid]=tty[pid];

    return newpid;
}

uint32_t syscall_wait(int none1, int none2, int none3, int pid)
{
    return 0;
}

// void _exit(int status)
uint32_t syscall_exit(int status, uint32_t none1, uint32_t none2,int pid)
{
    fixme("free allll mem");
    klog("pid %d exited with %d",pid,status);
    for(int i=0;i<MAX_FD;i++)
    {
	if(open_fd[pid][i])
	{
	    fd_close(&fds[pid][i]);
	    open_fd[pid][i]=false;
	}

    }
    task_exit(pid);
    return 0;
}

// int close (int fd) (TODO; close or not to close open filedescirptors?)
int syscall_close(int file,int none1,int none2,int pid)  
{
    if(open_fd[pid][file])
    {
	fd_close(&fds[pid][file]);
	open_fd[pid][file]=false;
    }

    return 0;
}

// TODO: check if file is a termminal!
int syscall_isatty(int file,int none1,int none2,int pid)  
{
    return 1;
    if(fds[pid][file].type==FD_TYPE_FIFO)return 1;
    return 0;
}

// TODO: per process basis!
uint32_t syscall_sbrk(uint32_t incr, int none1, int none2, uint32_t pid) 
{
    uint32_t alloc=task_get_brk(pid);
    uint32_t oldalloc=alloc;
    alloc+=incr;
    task_set_brk(pid,alloc);
    fixme("fake syscall_sbrk(0x%08X) return %08X",incr,oldalloc);
    return oldalloc;
}

// stat, fstat, lstat
int syscall_stat(const char *path, struct stat *st,int none,uint32_t pid)
{
    st->st_mode = S_IFCHR;
    return 0;
}

uint32_t syscall_pipe(uint32_t *addr,int none1, int none2, uint32_t pid)
{
    fd pipfds[2];
    int ret=fds_from_pipe(pipfds);

    int fd1=nextfd(pid);
    int fd2=nextfd(pid);

    klog("new pipe read=%d, write=%d",fd1,fd2 );

    fds[pid][fd1]=pipfds[0] ;
    *addr=fd1;
    addr++;

    fds[pid][fd2]=pipfds[1] ;
    *addr=fd2;

    return ret;
}

uint32_t syscall_dup2(uint32_t oldfd,int newfd, int none2, uint32_t pid)
{
    if(newfd==0xffffffff)kpanic("dup mode not supported yet !!!");

    fds[pid][newfd]=fd_dupl(&fds[pid][oldfd]);
    return newfd;
}

 /// testing TODO: 
 struct termios tty1;
 bool   termios_init=false;

uint32_t syscall_tcgetattr(int fd, struct termios *termios_p, uint32_t none, uint32_t pid)
{
    if(!termios_init)
    {
        tty1.c_cc[VMIN]=1; // reading from terminal returns after each byte
        termios_init=true;
    }
    klog("pid %d calls tcgetattr on %d",pid,fd);
    *termios_p=tty1;
    return 0;
}

uint32_t syscall_tcsetattr(int fd, struct termios *termios_p, uint32_t none, uint32_t pid)
{
    klog("pid %d calls tcsetattr on %d",pid,fd);
    klog("c_iflag=%08X",termios_p->c_iflag);
    klog("c_oflag=%08X",termios_p->c_oflag);
    klog("c_cflag=%08X",termios_p->c_cflag);
    klog("c_lflag=%08X",termios_p->c_lflag);
    for(int i=0;i<NCCS;i++)
    {
        if(termios_p->c_cc[i]!=0)
        {
            klog("set c_cc[%d]=%d",i,termios_p->c_cc[i]);
        }
    }
    tty1=*termios_p;
    return 0;
}

uint32_t syscall_gui_rect(uint32_t p1, uint32_t p2, uint32_t p3, uint32_t pid)
{
    compositor_wake();
    return 1;
}
uint32_t syscall_gui_win(uint32_t p1, uint32_t p2, uint32_t p3, uint32_t pid)
{
    uint32_t fdn=nextfd(pid);
    fds[pid][fdn]=fd_from_ringbuffer();
    tty[pid]=fdn;

    task_add_win(pid);

    return 1;
}

/** Generics */
uint32_t syscall_generic_prep(uint32_t nr,uint32_t p1, uint32_t p2, uint32_t p3, uint32_t pid)
{
    struct timeval *tv=p2; 

    switch(nr){
	case  SYSCALL_SELECT :

            // change to absolute time for easier timout
            if(tv!=NULL&&(tv->tv_sec!=0||tv->tv_usec!=0))
            {
	        uint64_t t=timer_get_ms(); // current time in milliseconds (10^-3)
                t+=tv->tv_sec*1000;        // seconds * 10^3
                t+=tv->tv_usec/1000;       // microseconds  * 10^-3

                tv->tv_sec=t/1000;
                tv->tv_usec=(t%1000)*1000;
            }

            break;
    }
    return 1;
}

/** Generics */
uint32_t syscall_generic_test(uint32_t nr,uint32_t p1, uint32_t p2, uint32_t p3, uint32_t pid)
{
    switch(nr){
	case SYSCALL_WAIT :
	    return !task_runs(p1);
	case SYSCALL_READ :
	    return fd_has(&fds[pid][p1])||fd_eof(&fds[pid][p1]);
	case SYSCALL_WRITE :
            return fd_can_write(&fds[pid][p1]);
	case  SYSCALL_SELECT :
	    return syscall_select(p1,p2,p3,pid,true);
    }

    return 1;//other syscalls never block for now.
}

/** Generics */
uint32_t syscall_generic(uint32_t nr,uint32_t p1, uint32_t p2, uint32_t p3, uint32_t pid)
{

//    klog("processing syscall [%s] for pid:%d",syscall_get_name(nr),pid);

    switch(nr){
	case SYSCALL_EXIT :
	    return syscall_exit(p1,p2,p3,pid);
	case  SYSCALL_CLOSE       :
	    return syscall_close(p1,p2,p3,pid);
	case  SYSCALL_EXECVE      :
	    return syscall_execve(p1,p2,p3,pid);
	case  SYSCALL_FORK        :
	    return syscall_fork(p1,p2,p3,pid);
	case  SYSCALL_CLONE        :
	    return syscall_clone(p1,p2,p3,pid);
	case  SYSCALL_GETPID      :
    //	return syscall_getpid(p1,p2,p3);
	    return -1;
	case  SYSCALL_ISATTY      :
	    return syscall_isatty(p1,p2,p3,pid);
	case  SYSCALL_LINK        :
    //	return syscall_link(p1,p2,p3);
	    return -1;
	case  SYSCALL_LSEEK       :
	    return syscall_lseek(p1,p2,p3,pid);
	case  SYSCALL_OPEN        :
	    return syscall_open(p1,p2,p3,pid);
	case  SYSCALL_READ        :
	    return syscall_read(p1,p2,p3,pid);
	case  SYSCALL_SBRK        :
	    return syscall_sbrk(p1,p2,p3,pid);
	case  SYSCALL_STAT        :
	    return syscall_stat(p1,p2,p3,pid);
	case  SYSCALL_FSTAT       :
	    return syscall_stat(p1,p2,p3,pid);
	case  SYSCALL_LSTAT       :
	    return syscall_stat(p1,p2,p3,pid);
	case  SYSCALL_TIMES       :
    //	return syscall_times(p1,p2,p3);
	    return -1;
	case  SYSCALL_UNLINK      :
    //	return syscall_unlink(p1,p2,p3);
	    return -1;
	case  SYSCALL_WAIT        :
	    return syscall_wait(p1,p2,p3,pid);
	case  SYSCALL_WRITE       :
	    return syscall_write(p1,p2,p3,pid);
	case  SYSCALL_GETTIMEOFDAY:
	    return syscall_gettimeofday(p1,p2,p3,pid);
	case  SYSCALL_READDIR     :
	    return syscall_readdir(p1,p2,p3,pid);
	case  SYSCALL_KILL        :
    //	return task_kill(p1,p2,p3);
	    return -1;
	case  SYSCALL_PIPE :
	    return syscall_pipe(p1,p2,p3,pid);
	case  SYSCALL_DUP2 :
	    return syscall_dup2(p1,p2,p3,pid);
	case  SYSCALL_SELECT :
	    return syscall_select(p1,p2,p3,pid,false);
	case  SYSCALL_GUI_RECT :
	    return syscall_gui_rect(p1,p2,p3,pid);
	case  SYSCALL_GUI_WIN :
	    return syscall_gui_win(p1,p2,p3,pid);
        case SYSCALL_TCGETATTR:
            return syscall_tcgetattr(p1,p2,p3,pid);
        case SYSCALL_TCSETATTR:
            return syscall_tcsetattr(p1,p2,p3,pid);
    }
    klog("unknown syscall %s / %d we just return 0",p1,nr);
    return 0;
}