#define FOOLOS_MODULE_NAME "syscalls"

#include "lib/buffer/ringbuffer.h"
#include "lib/logger/log.h"
#include "lib/bool/bool.h"
#include "fs/fs.h"
#include "fs/ext2.h"
#include "kernel/console.h"
#include "kernel/config.h"
#include <sys/stat.h>


int syscall_unhandled(int nr)
{
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"syscall: %d", nr);
    panic(FOOLOS_MODULE_NAME,"unhandled syscall");
}

int syscall_lseek(int file,int ptr,int dir) 
{
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"lseek (file=%d, ptr=%d, dir=%d)", file,ptr,dir);
    #endif

    panic(FOOLOS_MODULE_NAME,"unhandled syscall");

    return 0;

}


// TODO: /dev/console or /dev/tty1 - /dev/ttyN
int syscall_write(int file, char *buf, int len)
{

    //x86_int_disable();
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"[%d] write(file=%d, buf=0x%08X, len=%d)", task_get_current_pid(),file,buf,len);
    #endif

    if(file!=1&&file!=2) panic(FOOLOS_MODULE_NAME,"unhandled syscall");

    //stderr and stdout go to console
    for(int i=0;i<len;i++)
    {
	console_put_char_green(buf[i]);
    }
    //x86_int_enable();
    return len;
}

// TODO: /dev/kb
int syscall_read(int file, char *buf, int len)
{
    static bool eof=false;

    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"read(file=%d, buf=0x%08X, len=%d)", file,buf,len);
    #endif

    // stdin TODO: other descroptiors!
    if(file!=0) panic(FOOLOS_MODULE_NAME,"unhandled syscall");
    {
	if(eof)
	{
	    eof=false;
	    return 0;
	}
    
	char c;
	int l=0;

	while(1)
	{
	    bool ret=ringbuffer_get(&c);
	    
	    if(ret)
	    {
		if(c==0x08)
		{
		    if(l>0)
		    {
			console_del_char();
			buf--;
			l--;
		    }
		}
		else{

		    *buf=c;
		    buf++;
		    l++;
		    if(c!=0x04)console_put_char_white(c);
		    if(c=='\n')return l;
		    if(c==0x04)
		    {
			l--;
			buf--;
			eof=true;
			return l;
		    }
		}
		
	    }

	}
    }

}

//TODO: replace with dirent!
int syscall_readdir(const char *name,fs_dirent *dirs,int max)
{

    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"readdir(name=0x%08X, dirs=0x%08X,  %d)", name,dirs,max);
    #endif

    return fs_readdir(name,dirs,max);
}


int syscall_execve(char *name, char **argv1, char **env1)
{

    int temp=0x1;
    uint32_t *entry=temp;
    temp+=4;

    char *force_argv[]={"",NULL};
    char *force_env[]={"PS1=$","PWD=/home/miguel","PATH=/bin",NULL};
    if(argv1==NULL)argv1=force_argv;
    if(env1==NULL)env1=force_env;

    int env_count=0;
    do{env_count++;}while(env1[env_count]!=NULL);

    int arg_count=0;
    do{arg_count++;}while(argv1[arg_count]!=NULL);

    char **env=temp;
    temp+=sizeof(char **)*(env_count+1); 
    char **argv=temp;
    temp+=sizeof(char **)*(arg_count+1); 

    int i=0;
    do{
	int l=strlen(env1[i]);
	char *env_var=temp;
	temp+=sizeof(char *)*(l+1); 
	memcpy(env_var,env1[i],l+1);
	env[i]=env_var;
	i++;
    }while(env1[i]!=NULL);
    env[i]=NULL;

    i=0;
    do{
	int l=strlen(argv1[i]);
	char *arg_var=temp;
	temp+=sizeof(char *)*(l+1); 
	memcpy(arg_var,argv1[i],l+1);
	argv[i]=arg_var;
	i++;
    }while(argv1[i]!=NULL);
    argv[i]=NULL;


    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"execve (name=0x%08X(%s), argvs=0x%08X,  env=0x%08X)", name,name,argv1,env1);
    #endif
    

    if(!entry)
    {
	#ifdef LOG_SYSCALLS
	log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"execve: bailing out!");
	#endif
	return -1; // errror loading
    }

    /* try to move this to asm */
    //asm volatile("jmp .");
    asm volatile("mov $0x8fff000,%esp"); // set stack at high end of process image
 
    uint32_t alloc;
    *entry=load_elf(name,&alloc);

    // TODO: avoid code duplication for argv and env!!
    char **env_new=alloc;
    alloc+=sizeof(char **)*(env_count+1); 

    i=0;
    do{
	int l=strlen(env[i]);
	char *env_var=alloc;
	alloc+=sizeof(char)*l+1;
	memcpy(env_var,env[i],l+1);
	env_new[i]=env_var;
        #ifdef LOG_SYSCALLS
        log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"envr %d : 0x%08X : %s" ,i,env_new[i],env_new[i]);
        #endif
	i++;
    }while(env[i]!=NULL);
    env_new[i]=NULL;

    char **argv_new=alloc;
    alloc+=sizeof(char **)*(arg_count+1);
    i=0;
    do{
	int l=strlen(argv[i]);
	char *arg_var=alloc;
	alloc+=sizeof(char)*l+1;
	memcpy(arg_var,argv[i],l+1);
	argv_new[i]=arg_var;
	#ifdef LOG_SYSCALLS
        log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"arg %d : 0x%08X : %s" ,i,argv_new[i],argv_new[i]);
        #endif
	i++;
    }while(argv[i]!=NULL);


    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"argc: %d" ,arg_count);
    #endif

    task_set_brk(alloc);


    asm volatile ("push %0" :: "r" (argv_new));
    asm volatile ("push %0" :: "r" (arg_count));
    asm volatile ("push %0" :: "r" (env_new));

    // push addr and return to it
    asm volatile ("push %0"::"r"(*entry));
    
    asm volatile ("sti");
    asm volatile ("ret");


    // this is never reached!
}

int syscall_open(char *name, int flags, int mode)
{
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"open (name=0x%08X(\"%s\"), flags=%d,  mode=%d)",name, name,flags,mode);
    #endif
    panic(FOOLOS_MODULE_NAME,"unhandled syscall");

}


//newcomers
//
int syscall_close(int file,int none1,int none2)  
{
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"close (file=%d)", file);
    #endif

    if(file!=0&&file!=1&&file!=2)
        panic(FOOLOS_MODULE_NAME,"unhandled syscall");

    return -1;
}

// TODO: check if file is termminal!
int syscall_isatty(int file,int none1,int none2)  
{
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"isatty (file=%d)", file);
    #endif

    return 1;
}

// TODO: per process basis!
uint32_t syscall_sbrk(int incr, int none1, int none2) 
{
    uint32_t alloc=task_get_brk();
    uint32_t oldalloc=alloc;
    alloc+=incr;
    task_set_brk(alloc);

    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"sbrk (incr=%d) = 0x%08X", incr,oldalloc);
    #endif
    return oldalloc;
}


// stat, fstat, lstat
int syscall_stat(const char *path, struct stat *st,int none)
{
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"stat (path=0x%08X,stat=0x%08X)", path,st);
    #endif

    st->st_mode = S_IFCHR;
    return 0;
}

int syscall_fstat(int file, struct stat *st,int none)
{
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"fstat (file=%d,stat=0x%08X)", file,st);
    #endif

    st->st_mode = S_IFCHR;
    return 0;
}


int syscall_lstat(const char *path, struct stat *st,int none)
{
    #ifdef LOG_SYSCALLS
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"lstat (path=0x%08X,stat=0x%08X)", path,st);
    #endif

    st->st_mode = S_IFCHR;
    return 0;
}