/* 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/>.
*/
#include "shell.h"

int asmsh_init(asmsh_t *sh, const char *child_path)
{
	bzero(sh, sizeof(asmsh_t));
	if(!(sh->env = asmsh_env(child_path)))
	{
		asmsh_log_fatal("Unable to start child env");
		goto err;
	}
	if(!(sh->cctx = asmsh_asmc_ctx_default()))
	{
		asmsh_log_fatal("Unable to start compilation context");
		asmsh_env_free(sh->env);
		goto err;
	}
	sh->child_path = strdup(child_path); // TODO check error
	return 0;
err:
	bzero(sh, sizeof(asmsh_t));
	return -1;
}


void asmsh_cleanup(asmsh_t *sh)
{
	if(!sh){ return; }
	if(sh->cctx)
	{
		asmsh_asmc_ctx_free(sh->cctx);
	}
	if(sh->env)
	{
		asmsh_env_free(sh->env);
	}
	if(sh->child_path)
	{
		free(sh->child_path);
	}
	if(sh->last_instr)
	{
		free(sh->last_instr);
	}
	bzero(sh, sizeof(asmsh_t));
}

/** Attempt to compile and step if sucess */
static int _compile_step(asmsh_t *sh, const char *cmd);
/** Attempt to handle given shell internal command (starting with  '.') */
static int _handle_command(asmsh_t *sh, const char *cmd);
int asmsh_exec(asmsh_t *sh, const char *cmd)
{
	if(!cmd)
	{
		errno=EINVAL;
		return -1;
	}

	int clen, ret;
	//lstrip whitespace
	for(cmd; *cmd && (*cmd == ' ' || *cmd == '\t'); cmd++);
	if(!*cmd) { return 0; }

	switch(*cmd)
	{
		case '.':
			ret = _handle_command(sh, cmd);
			break;
		default:
			ret = _compile_step(sh, cmd);
			break;
	}
	return ret;
}

static int _compile_step(asmsh_t *sh, const char *cmd)
{
	int ret, status;
	asmsh_bytecode_t bcode;

	if(asmsh_asmc_compile(sh->cctx, cmd, &bcode) < 0)
	{
		return -1;
	}
	if(!bcode.size)
	{
		asmsh_log_error("No bytecode returned...");
		return -1;
	}
	sh->last_bcode = bcode;
	if(sh->last_instr) { free(sh->last_instr); }
	sh->last_instr = strdup(cmd);

char buf[256];
int _ret;
_ret = snprintf(buf, 255, "'%s' = 0x", cmd);
for(int _i=0; _i<bcode.size; _i++)
{
	_ret += snprintf(buf+_ret, 255-_ret, "%02x", bcode.bytes[_i]);
}
_ret += snprintf(buf+_ret, 255-_ret, "(%d)", bcode.size);
buf[_ret] = '\0';
asmsh_log_info(buf);

	if(asmsh_env_write_code(sh->env, &bcode))
	{
		return -1;
	}

	status=0;
	ret = asmsh_env_step(sh->env, &status);
	if(ret < 0)
	{
		perror("Unable to step");
		asmsh_log_fatal("Error will child step");
		return -1;
	}
	else if(ret > 0)
	{
		asmsh_log_fatal("Child exited with non-zero status");
		return 1+WEXITSTATUS(status);
	}
	return 0;
}

static int _handle_command(asmsh_t *sh, const char *cmd)
{
	const int clen = strlen(cmd);
	const asmsh_cmd_t *match;
	int ret;

	asmsh_cmd_args_t *args;

	args = asmsh_cmd_parse(cmd);
	if(!args)
	{
		asmsh_log_error("Parse error"); // TODO better error
		return -1;
	}

	match = asmsh_cmd_match(args->cmd, strlen(args->cmd));
	if(!match)
	{
		asmsh_log_error("Unknow command");
		return -1;
	}
	ret = match->cmd(sh, args);
	asmsh_cmd_args_free(args);
	return ret;
}