/*-
 * SPDX-License-Identifier: Beerware
 *
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
 * ----------------------------------------------------------------------------
 *
 */

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/ctype.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/sbuf.h>
#include <sys/sx.h>
#include <sys/systm.h>
#include <sys/uio.h>

#include <dev/led/led.h>

struct ledsc {
        LIST_ENTRY(ledsc)       list;
        char                    *name;
        void                    *private;
        int                     unit;
        led_t                   *func;
        struct cdev *dev;
        struct sbuf             *spec;
        char                    *str;
        char                    *ptr;
        int                     count;
        time_t                  last_second;
};

static struct unrhdr *led_unit;
static struct mtx led_mtx;
static struct sx led_sx;
static LIST_HEAD(, ledsc) led_list = LIST_HEAD_INITIALIZER(led_list);
static struct callout led_ch;
static int blinkers = 0;

static MALLOC_DEFINE(M_LED, "LED", "LED driver");

static void
led_timeout(void *p)
{
        struct ledsc    *sc;

        LIST_FOREACH(sc, &led_list, list) {
                if (sc->ptr == NULL)
                        continue;
                if (sc->count > 0) {
                        sc->count--;
                        continue;
                }
                if (*sc->ptr == '.') {
                        sc->ptr = NULL;
                        blinkers--;
                        continue;
                } else if (*sc->ptr == 'U' || *sc->ptr == 'u') {
                        if (sc->last_second == time_second)
                                continue;
                        sc->last_second = time_second;
                        sc->func(sc->private, *sc->ptr == 'U');
                } else if (*sc->ptr >= 'a' && *sc->ptr <= 'j') {
                        sc->func(sc->private, 0);
                        sc->count = (*sc->ptr & 0xf) - 1;
                } else if (*sc->ptr >= 'A' && *sc->ptr <= 'J') {
                        sc->func(sc->private, 1);
                        sc->count = (*sc->ptr & 0xf) - 1;
                }
                sc->ptr++;
                if (*sc->ptr == '\0')
                        sc->ptr = sc->str;
        }
        if (blinkers > 0)
                callout_reset(&led_ch, hz / 10, led_timeout, p);
}

static int
led_state(struct ledsc *sc, struct sbuf **sb, int state)
{
        struct sbuf *sb2 = NULL;

        sb2 = sc->spec;
        sc->spec = *sb;
        if (*sb != NULL) {
                sc->str = sbuf_data(*sb);
                if (sc->ptr == NULL) {
                        blinkers++;
                        callout_reset(&led_ch, hz / 10, led_timeout, NULL);
                }
                sc->ptr = sc->str;
        } else {
                sc->str = NULL;
                if (sc->ptr != NULL)
                        blinkers--;
                sc->ptr = NULL;
                sc->func(sc->private, state);
        }
        sc->count = 0;
        *sb = sb2;
        return(0);
}

static int
led_parse(const char *s, struct sbuf **sb, int *state)
{
        int i, error;

        /*
         * Handle "on" and "off" immediately so people can flash really
         * fast from userland if they want to
         */
        if (*s == '0' || *s == '1') {
                *state = *s & 1;
                return (0);
        }

        *state = 0;
        *sb = sbuf_new_auto();
        if (*sb == NULL)
                return (ENOMEM);
        switch(s[0]) {
                /*
                 * Flash, default is 100msec/100msec.
                 * 'f2' sets 200msec/200msec etc.
                 */
                case 'f':
                        if (s[1] >= '1' && s[1] <= '9')
                                i = s[1] - '1';
                        else
                                i = 0;
                        sbuf_printf(*sb, "%c%c", 'A' + i, 'a' + i);
                        break;
                /*
                 * Digits, flashes out numbers.
                 * 'd12' becomes -__________-_-______________________________
                 */
                case 'd':
                        for(s++; *s; s++) {
                                if (!isdigit(*s))
                                        continue;
                                i = *s - '0';
                                if (i == 0)
                                        i = 10;
                                for (; i > 1; i--) 
                                        sbuf_cat(*sb, "Aa");
                                sbuf_cat(*sb, "Aj");
                        }
                        sbuf_cat(*sb, "jj");
                        break;
                /*
                 * String, roll your own.
                 * 'a-j' gives "off" for n/10 sec.
                 * 'A-J' gives "on" for n/10 sec.
                 * no delay before repeat
                 * 'sAaAbBa' becomes _-_--__-
                 */
                case 's':
                        for(s++; *s; s++) {
                                if ((*s >= 'a' && *s <= 'j') ||
                                    (*s >= 'A' && *s <= 'J') ||
                                    *s == 'U' || *s <= 'u' ||
                                        *s == '.')
                                        sbuf_bcat(*sb, s, 1);
                        }
                        break;
                /*
                 * Morse.
                 * '.' becomes _-
                 * '-' becomes _---
                 * ' ' becomes __
                 * '\n' becomes ____
                 * 1sec pause between repeats
                 * '... --- ...' -> _-_-_-___---_---_---___-_-_-__________
                 */
                case 'm':
                        for(s++; *s; s++) {
                                if (*s == '.')
                                        sbuf_cat(*sb, "aA");
                                else if (*s == '-')
                                        sbuf_cat(*sb, "aC");
                                else if (*s == ' ')
                                        sbuf_cat(*sb, "b");
                                else if (*s == '\n')
                                        sbuf_cat(*sb, "d");
                        }
                        sbuf_cat(*sb, "j");
                        break;
                default:
                        sbuf_delete(*sb);
                        return (EINVAL);
        }
        error = sbuf_finish(*sb);
        if (error != 0 || sbuf_len(*sb) == 0) {
                *sb = NULL;
                return (error);
        }
        return (0);
}

static int
led_write(struct cdev *dev, struct uio *uio, int ioflag)
{
        struct ledsc    *sc;
        char *s;
        struct sbuf *sb = NULL;
        int error, state = 0;

        if (uio->uio_resid > 512)
                return (EINVAL);
        s = malloc(uio->uio_resid + 1, M_DEVBUF, M_WAITOK);
        s[uio->uio_resid] = '\0';
        error = uiomove(s, uio->uio_resid, uio);
        if (error) {
                free(s, M_DEVBUF);
                return (error);
        }
        error = led_parse(s, &sb, &state);
        free(s, M_DEVBUF);
        if (error)
                return (error);
        mtx_lock(&led_mtx);
        sc = dev->si_drv1;
        if (sc != NULL)
                error = led_state(sc, &sb, state);
        mtx_unlock(&led_mtx);
        if (sb != NULL)
                sbuf_delete(sb);
        return (error);
}

int
led_set(char const *name, char const *cmd)
{
        struct ledsc    *sc;
        struct sbuf *sb = NULL;
        int error, state = 0;

        error = led_parse(cmd, &sb, &state);
        if (error)
                return (error);
        mtx_lock(&led_mtx);
        LIST_FOREACH(sc, &led_list, list) {
                if (strcmp(sc->name, name) == 0)
                        break;
        }
        if (sc != NULL)
                error = led_state(sc, &sb, state);
        else
                error = ENOENT;
        mtx_unlock(&led_mtx);
        if (sb != NULL)
                sbuf_delete(sb);
        return (error);
}

static struct cdevsw led_cdevsw = {
        .d_version =    D_VERSION,
        .d_write =      led_write,
        .d_name =       "LED",
};

struct cdev *
led_create(led_t *func, void *priv, char const *name)
{

        return (led_create_state(func, priv, name, 0));
}
struct cdev *
led_create_state(led_t *func, void *priv, char const *name, int state)
{
        struct ledsc    *sc;

        sc = malloc(sizeof *sc, M_LED, M_WAITOK | M_ZERO);

        sx_xlock(&led_sx);
        sc->name = strdup(name, M_LED);
        sc->unit = alloc_unr(led_unit);
        sc->private = priv;
        sc->func = func;
        sc->dev = make_dev(&led_cdevsw, sc->unit,
            UID_ROOT, GID_WHEEL, 0600, "led/%s", name);
        sx_xunlock(&led_sx);

        mtx_lock(&led_mtx);
        sc->dev->si_drv1 = sc;
        LIST_INSERT_HEAD(&led_list, sc, list);
        if (state != -1)
                sc->func(sc->private, state != 0);
        mtx_unlock(&led_mtx);

        return (sc->dev);
}

void
led_destroy(struct cdev *dev)
{
        struct ledsc *sc;

        mtx_lock(&led_mtx);
        sc = dev->si_drv1;
        dev->si_drv1 = NULL;
        if (sc->ptr != NULL)
                blinkers--;
        LIST_REMOVE(sc, list);
        if (LIST_EMPTY(&led_list))
                callout_stop(&led_ch);
        mtx_unlock(&led_mtx);

        sx_xlock(&led_sx);
        free_unr(led_unit, sc->unit);
        destroy_dev(dev);
        if (sc->spec != NULL)
                sbuf_delete(sc->spec);
        free(sc->name, M_LED);
        free(sc, M_LED);
        sx_xunlock(&led_sx);
}

static void
led_drvinit(void *unused)
{

        led_unit = new_unrhdr(0, INT_MAX, NULL);
        mtx_init(&led_mtx, "LED mtx", NULL, MTX_DEF);
        sx_init(&led_sx, "LED sx");
        callout_init_mtx(&led_ch, &led_mtx, 0);
}

SYSINIT(leddev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, led_drvinit, NULL);