#include <BoardConsole.h>
#include <string.h>
#include <FreeRTOS.h>
#include <semphr.h>
#include "fio.h"

static struct fddef_t fio_fds[MAX_FDS];

static ssize_t stdin_read(void * opaque, void * buf, size_t count) {
    return 0;
}

static ssize_t stdout_write(void * opaque, const void * buf, size_t count) {
    int i;
    const char * data = (const char *) buf;
    
    for (i = 0; i < count; i++)
        BoardConsolePutc(data[i]);
    
    return count;
}

static xSemaphoreHandle fio_sem = NULL;

__attribute__((constructor)) static void fio_init() {
    memset(fio_fds, 0, sizeof(fio_fds));
    fio_fds[0].fdread = stdin_read;
    fio_fds[1].fdwrite = stdout_write;
    fio_fds[2].fdwrite = stdout_write;
    fio_sem = xSemaphoreCreateMutex();
}

struct fddef_t * fio_getfd(int fd) {
    if ((fd < 0) || (fd >= MAX_FDS))
        return NULL;
    return fio_fds + fd;
}

static int fio_is_open_int(int fd) {
    if ((fd < 0) || (fd >= MAX_FDS))
        return 0;
    int r = !((fio_fds[fd].fdread == NULL) &&
              (fio_fds[fd].fdwrite == NULL) &&
              (fio_fds[fd].fdseek == NULL) &&
              (fio_fds[fd].fdclose == NULL) &&
              (fio_fds[fd].opaque == NULL));
    return r;
}

static int fio_findfd() {
    int i;
    
    for (i = 0; i < MAX_FDS; i++) {
        if (!fio_is_open_int(i))
            return i;
    }
    
    return -1;
}

int fio_is_open(int fd) {
    int r = 0;
    xSemaphoreTake(fio_sem, portMAX_DELAY);
    r = fio_is_open_int(fd);
    xSemaphoreGive(fio_sem);
    return r;
}

int fio_open(fdread_t fdread, fdwrite_t fdwrite, fdseek_t fdseek, fdclose_t fdclose, void * opaque) {
    int fd;
    xSemaphoreTake(fio_sem, portMAX_DELAY);
    fd = fio_findfd();
    
    if (fd >= 0) {
        fio_fds[fd].fdread = fdread;
        fio_fds[fd].fdwrite = fdwrite;
        fio_fds[fd].fdseek = fdseek;
        fio_fds[fd].fdclose = fdclose;
        fio_fds[fd].opaque = opaque;
    }
    xSemaphoreGive(fio_sem);
    
    return fd;
}

ssize_t fio_read(int fd, void * buf, size_t count) {
    ssize_t r = 0;
    if (fio_is_open_int(fd)) {
        if (fio_fds[fd].fdread) {
            r = fio_fds[fd].fdread(fio_fds[fd].opaque, buf, count);
        } else {
            r = -3;
        }
    } else {
        r = -2;
    }
    return r;
}

ssize_t fio_write(int fd, const void * buf, size_t count) {
    ssize_t r = 0;
    if (fio_is_open_int(fd)) {
        if (fio_fds[fd].fdwrite) {
            r = fio_fds[fd].fdwrite(fio_fds[fd].opaque, buf, count);
        } else {
            r = -3;
        }
    } else {
        r = -2;
    }
    return r;
}

off_t fio_seek(int fd, off_t offset, int whence) {
    off_t r = 0;
    if (fio_is_open_int(fd)) {
        if (fio_fds[fd].fdseek) {
            r = fio_fds[fd].fdseek(fio_fds[fd].opaque, offset, whence);
        } else {
            r = -3;
        }
    } else {
        r = -2;
    }
    return r;
}

int fio_close(int fd) {
    int r = 0;
    if (fio_is_open_int(fd)) {
        if (fio_fds[fd].fdclose)
            r = fio_fds[fd].fdclose(fio_fds[fd].opaque);
        xSemaphoreTake(fio_sem, portMAX_DELAY);
        memset(fio_fds + fd, 0, sizeof(struct fddef_t));
        xSemaphoreGive(fio_sem);
    } else {
        r = -2;
    }
    return r;
}