// SPDX-License-Identifier: ISC

#include <libbasis/misc.h>
#include <libbasis/term.h>

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

struct tty_reset_list {
	int fd;
	struct termios tcattr;

	struct tty_reset_list *prev;
};
static struct tty_reset_list *tty_reset_head;

static void term_resetconf(void)
{
	struct tty_reset_list *cur = tty_reset_head;

	while (cur) {
		if (tcsetattr(cur->fd, TCSANOW, &cur->tcattr) < 0)
			warn("warning: unable to restore the terminal settings for %d", cur->fd);
		cur = cur->prev;
	}
}

int term_setconf_init(void)
{
	/* TODO: signal handlers */
	if (atexit(term_resetconf) < 0)
		return -1;

	return 0;
}

int term_setconf_raw(int fd, speed_t speed)
{
	struct tty_reset_list *next;
	struct termios tcattr;
	int errsv;

	next = calloc(1, sizeof(*next));
	if (!next)
		return -1;

	next->fd = fd;
	if (tcgetattr(next->fd, &next->tcattr) < 0)
		goto fail;

	tcattr = next->tcattr;

	cfmakeraw(&tcattr);

	if (cfsetspeed(&tcattr, speed) < 0)
		goto fail;

	tcattr.c_cflag &= ~(CSTOPB|CRTSCTS);
	tcattr.c_cflag |= (CLOCAL|CREAD);

	tcattr.c_cc[VTIME] = 1;
	tcattr.c_cc[VMIN] = 1;

	if (tcsetattr(next->fd, TCSAFLUSH, &tcattr) < 0)
		goto fail;

	next->prev = tty_reset_head;
	tty_reset_head = next;

	return 0;

fail:
	errsv = errno;
	free(next);
	errno = errsv;
	return -1;
}

int term_speed_parse(const char *name, speed_t *speed)
{
	/* from termios(3), only the portable subset */
	static const struct {
		speed_t speed;
		const char *name;
	} speed_tbl[] = {
		{ B0,	    "0"	      },
		{ B50,	    "50"      },
		{ B75,	    "75"      },
		{ B110,	    "110"     },
		{ B134,	    "134"     },
		{ B150,	    "150"     },
		{ B200,	    "200"     },
		{ B300,	    "300"     },
		{ B600,	    "600"     },
		{ B1200,    "1200"    },
		{ B1800,    "1800"    },
		{ B2400,    "2400"    },
		{ B4800,    "4800"    },
		{ B9600,    "9600"    },
		{ B19200,   "19200"   },
		{ B38400,   "38400"   },
		{ B57600,   "57600"   },
		{ B115200,  "115200"  },
		{ B230400,  "230400"  },
		{ B460800,  "460800"  },
		{ B500000,  "500000"  },
		{ B576000,  "576000"  },
		{ B921600,  "921600"  },
		{ B1000000, "1000000" },
		{ B1152000, "1152000" },
		{ B1500000, "1500000" },
		{ B2000000, "2000000" },
	};

	for (size_t i = 0; i < ARRAY_SIZE(speed_tbl); ++i) {
		if (!strcmp(speed_tbl[i].name, name)) {
			*speed = speed_tbl[i].speed;
			return 0;
		}
	}

	errno = ENOENT;
	return -1;
}