/* Copyright Yann Weber <asmsh@yannweb.net>
   This file is part of asmsh.

   asmsh is free software: you can redistribute it and/or modify it under the
   terms of the GNU General Public License as published by the Free Software
   Foundation, either version 3 of the License, or any later version.
   
   asmsh is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
   details.
   
   You should have received a copy of the GNU General Public License along
   with asmsh. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef ASMSH_SHELL_CMDS_H
#define ASMSH_SHELL_CMDS_H
#include "config.h"

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "logger.h"

#define ASMSH_CMD_MAXLEN 31
#define ASMSH_CMD_MAXARG 15

typedef struct asmsh_cmd_s asmsh_cmd_t;
typedef struct asmsh_cmd_args_s asmsh_cmd_args_t;
#include "shell.h"

/** @return <0 on recoverable error 0 on ok, 1+status on exit */
typedef int (asmsh_cmd_f)(asmsh_t*, asmsh_cmd_args_t*);

/** Represent a single command */
struct asmsh_cmd_s
{
	/** The command (with the leading '.') */
	const char *str;
	/** The command function pointer */
	asmsh_cmd_f *cmd;
	/**If non-zero indicate the minimum of chars to
	 * match. ".quit" while have 2 to match starting
	 * from ".q"
	 */
	unsigned char sm;

	/* Help information */
	/** Small command name  (like .h(elp) )*/
	const char *sms;
	/** Command usage */
	const char *usage;
	/** Command description */
	const char *desc;
};

/** A command arguments with command name & NULL terminated array of args */
struct asmsh_cmd_args_s
{
	char cmd[ASMSH_CMD_MAXLEN+1];
	int argc;
	char *args[ASMSH_CMD_MAXARG+1];
};


/**@param const char* the text to match
 * @param int the len of the text to match
 * @return a ptr or NULL
 */
const asmsh_cmd_t *asmsh_cmd_match(const char *cmd, int stop);

/** @return NULL on error or ptr on new cmd args */
asmsh_cmd_args_t *asmsh_cmd_parse(const char *cmd);

static void asmsh_cmd_args_free(asmsh_cmd_args_t *args)
{
	if(!args) { return; }
	for(char **a=args->args; *a; a++)
	{
		free(*a);
	}
	free(args);
}


const char *asmsh_cmd_help(asmsh_t *sh);



/*
 * Commands declaration
 *
 * A command can return 0  if no errors, -X for a recoverable error
 * 1 for exit with status 0,  1+S for exit with status S
 */

// Quit the shell
static int _quit(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	asmsh_cleanup(sh);
	return 1;
}

// Print an instruction bytecode 
int asmsh_cmd_bcode(asmsh_t *sh, char *buf, int bufsz, int argc, char **args);

static int _bcode(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	char str[256];
	int ret;

	ret = asmsh_cmd_bcode(sh, str, 256, args->argc, args->args);
	if(ret)
	{
		return ret;
	}
	printf("%s\n", str);
	return 0;
}

// Print the registers
static int _print_regs(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	asmsh_env_t *env = sh->env;
	asmsh_env_update_regs(env);
	struct user_regs_struct *r = &env->regs;
	
#define FLG(b, l) ( (r->eflags & (1<<b))?l:'-' )

	printf("rax: %016lx rbx: %016lx rcx: %016lx rdx: %016lx\n\
rbp: %016lx rsi: %016lx rdi: %016lx rsp: %016lx\n\
 r8: %016lx  r9: %016lx r10: %016lx r11: %016lx\n\
r12: %016lx r13: %016lx r14: %016lx r15: %016lx\n\
rip: %016lx flg: %016lx\n\
cs: %04x ds: %04x es: %04x fs:%04x gs: %04x ss:%04x\n\
flags: %c%c%c%c|%c%c%c\n\
       ODSZ|APC\n\
",	r->rax, r->rbx, r->rcx, r->rdx,\
	r->rbp, r->rsi, r->rdi, r->rsp,\
	r->r8, r->r9, r->r10, r->r11,\
	r->r12, r->r13, r->r14, r->r15,\
	r->rip, r->eflags,\
	r->cs, r->ds, r->es, r->fs, r->gs, r->ss,
	FLG(11,'O'), FLG(10, 'D'), FLG(7, 'S'), FLG(6, 'Z'),
	FLG(4, 'A'), FLG(2, 'P'), FLG(0, 'C'));

#undef FLG
	return 0;
}

// Reset the shell (restart the child etc)
static int _reset(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	char *childpath = strdup(sh->child_path);
	asmsh_cleanup(sh);
	asmsh_init(sh, childpath);
	free(childpath);
}

// Display CPU flag resister values
static int _flags(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	printf("Flags :\n");
#define printFLG(name, b) printf(" (%2d)%16s : %d\n", b, name,\
		(sh->env->regs.eflags & (1<<b))?1:0);
	printFLG("Overflow", 11);
	printFLG("Direction", 10);
	printFLG("Sign", 7);
	printFLG("Zero", 6);
	printFLG("Auxiliary carry", 4);
	printFLG("Parity", 2);
	printFLG("Carry", 0);
#undef printFLG
#define EFLG(b,n) ((sh->env->regs.eflags & (1<<b))?n:'-')
	printf("%c%c%c%c %c%c%c\n",
			EFLG(11,'O'), EFLG(10, 'D'), EFLG(7,'S'), EFLG(6,'Z'),
			EFLG(4,'A'), EFLG(2, 'P'), EFLG(0, 'C'));
	return 0;
}

// Declared because referenced in command list but not implemented
// because the _help function needs a reference to the command list
static int _help(asmsh_t *sh, asmsh_cmd_args_t *args);


/* 
 * The list of shell commands
 */
static const asmsh_cmd_t asmsh_CMDS[] = {
	{".bytecode", _bcode, 2,
	 ".b(ytecode)", "",
	 "display last instruction bytecode"},
	{".flags", _flags, 2,
	 ".f(lags)", "",
	 "display CPU flags"},
	{".help", _help, 2,
	 ".h(elp)","[cmd]",
	 "display this help or the help of specified command"},
	{".quit", _quit, 2,
	 ".q(uit)","",
	 "quit asmsh"},
	{".regs", _print_regs, 1,
	".(regs)", "",
	"display registers value"},
	{".reset", _reset, 0,
	 ".reset", "",
	 "reset the shell"},
	{NULL, NULL, 0},
};


// Print help (command list + help)
static int _help(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	char buf[4096], abuf[64];
	int ret, pret;

	ret = snprintf(buf, 4096, "Available commands :\n");
	pret = ret;
	for(const asmsh_cmd_t *cmd = asmsh_CMDS; cmd->str; cmd++)
	{
		snprintf(abuf, 64, "%s %s", cmd->sms, cmd->usage);
		ret += snprintf(buf+ret, 4096-ret, "  %-18s : %s\n", 
				abuf, cmd->desc);
	}
	dprintf(2, buf);
	return 0;
}

#endif