/*
 * Copyright (C) 2018 Gunar Schorcht
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @ingroup     cpu_esp8266
 * @{
 *
 * @file
 * @brief       Implementation of required system calls
 *
 * @author      Gunar Schorcht <gunar@schorcht.net>
 *
 * @}
 */

#define ENABLE_DEBUG    0
#define MEMLEAK_DEBUG   0
#include "debug.h"

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/reent.h>
#include <sys/stat.h>

#include <stdarg.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "ets_sys.h"
#include "c_types.h"

#include "common.h"
#include "cpu_conf.h"
#include "irq.h"
#include "kernel_defines.h"
#include "log.h"
#include "mutex.h"
#include "rmutex.h"
#include "sched.h"
#include "syscalls.h"

#include "esp/xtensa_ops.h"
#include "esp/common_macros.h"

#include "sdk/sdk.h"

int IRAM puts(const char * str)
{
    char c;
    while ((c = *str) != 0) {
        ets_putc(c);
        ++str;
    }
    ets_putc('\n');
    return true;
}

int IRAM putchar(int c)
{
    /* function is neccessary to avoid unproducable results */
    ets_putc(c);
    return true;
}

char _printf_buf[PRINTF_BUFSIZ];

int /* IRAM */ printf(const char* format, ...)
{
    va_list arglist;
    va_start(arglist, format);

    int ret = vsnprintf(_printf_buf, PRINTF_BUFSIZ, format, arglist);

    if (ret > 0) {
        ets_printf (_printf_buf);
    }

    va_end(arglist);

    return ret;
}

#ifdef SDK_HEAP_USED
/**
 * Map memory management functions to SDK memory management functions.
 * This is necessary to use the same heap as the SDK internally does.
 * Furthermore, these functions do at least avoid interrupts during the
 * execution of memory management functions. Memory management function
 * of ETS are not used and have not to considered therefore.
 */
extern void *pvPortMalloc (size_t size, const char *, unsigned);
extern void vPortFree (void *ptr, const char *, unsigned);
extern void *pvPortZalloc (size_t size, const char *, unsigned);
extern void *pvPortCalloc (size_t nmemb, size_t size, const char *, unsigned);
extern void *pvPortRealloc (void *ptr, size_t size, const char *, unsigned);
extern unsigned int xPortGetFreeHeapSize(void);

void* IRAM malloc(size_t size)
{
    #if MEMLEAK_DEBUG
    static const char mem_debug_file[] ICACHE_RODATA_ATTR STORE_ATTR = __FILE__;
    return pvPortMalloc(size, mem_debug_file, __LINE__);
    #else
    return pvPortMalloc(size, "", 0);
    #endif
}

void IRAM free(void *ptr)
{
    #if MEMLEAK_DEBUG
    static const char mem_debug_file[] ICACHE_RODATA_ATTR STORE_ATTR = __FILE__;
    return vPortFree (ptr, mem_debug_file, __LINE__);
    #else
    return vPortFree (ptr, "", 0);
    #endif
}

void* IRAM calloc(size_t nmemb, size_t size)
{
    #if MEMLEAK_DEBUG
    static const char mem_debug_file[] ICACHE_RODATA_ATTR STORE_ATTR = __FILE__;
    return pvPortCalloc(nmemb, size, mem_debug_file, __LINE__);
    #else
    return pvPortCalloc(nmemb, size, "", 0);
    #endif
}

void* IRAM realloc(void *ptr, size_t size)
{
    #if MEMLEAK_DEBUG
    static const char mem_debug_file[] ICACHE_RODATA_ATTR STORE_ATTR = __FILE__;
    return pvPortRealloc(ptr, size, mem_debug_file, __LINE__);
    #else
    return pvPortRealloc(ptr, size, "", 0);
    #endif
}

void* IRAM _malloc_r (struct _reent *r, size_t size)
{
    return malloc (size);
}

void IRAM _free_r (struct _reent *r, void *ptr)
{
    free (ptr);
}

unsigned int get_free_heap_size (void)
{
    return xPortGetFreeHeapSize();
}

void IRAM syscalls_init (void) {}

#else   /* SDK_HEAP_USED */
/*
 * To use the same heap SDK memory management functions have to be replaced by
 * newlib memory functions. In that case the _malloc_lock/_unlock functions
 * have to be defined. Memory management functions of ETS are not used and
 * have not to considered here.
 */

void* IRAM pvPortMalloc (size_t size, const char *file, unsigned line)
{
    (void)file;
    (void)line;

    return malloc (size);
}

void IRAM vPortFree (void *ptr, const char *file, unsigned line)
{
    (void)file;
    (void)line;

    free (ptr);
}

void* IRAM pvPortCalloc (size_t nmemb, size_t size, const char *file, unsigned line)
{
    (void)file;
    (void)line;

    void *ptr = malloc (nmemb*size);
    if (ptr) {
        memset (ptr, 0x0, nmemb*size);
    }
    return ptr;
}

void* IRAM pvPortZalloc (size_t size, const char *file, unsigned line)
{
    (void)file;
    (void)line;

    void *ptr = malloc (size);
    if (ptr) {
        memset (ptr, 0x0, size);
    }
    return ptr;
}

void* IRAM pvPortRealloc (void *ptr, size_t size, const char *file, unsigned line)
{
    (void)file;
    (void)line;

    return realloc (ptr, size);
}

size_t IRAM xPortWantedSizeAlign(size_t size)
{
    /* allign the size to a multiple of 8 */
    return (size & 0x7) ? (size & ~0x7) + 8 : size;
}

size_t IRAM xPortGetFreeHeapSize (void)
{
    return get_free_heap_size ();
}

/*
 * Following function implement the lock mechanism in newlib. The only static
 * mutex defined here is the __malloc_recursive_mutex to avoid that memory
 * management functions try to lock before RIOT's threads are running.
 */

extern _lock_t __malloc_recursive_mutex;

static rmutex_t _malloc_rmtx = RMUTEX_INIT;

void IRAM syscalls_init (void)
{
    __malloc_recursive_mutex = (_lock_t)&_malloc_rmtx;
}

void IRAM _lock_init(_lock_t *lock)
{
    CHECK_PARAM (sched_active_thread != 0);
    CHECK_PARAM (lock != NULL);
    CHECK_PARAM (*lock != ((_lock_t)&_malloc_rmtx));

    mutex_t* mtx = malloc (sizeof(mutex_t));

    if (mtx) {
        memset (mtx, 0, sizeof(mutex_t));
        *lock = (_lock_t)mtx;
    }
}

void IRAM _lock_init_recursive(_lock_t *lock)
{
    CHECK_PARAM (sched_active_thread != 0);
    CHECK_PARAM (lock != NULL);
    CHECK_PARAM (*lock != ((_lock_t)&_malloc_rmtx));

    rmutex_t* rmtx = malloc (sizeof(rmutex_t));

    if (rmtx) {
        memset (rmtx, 0, sizeof(rmutex_t));
        *lock = (_lock_t)rmtx;
    }
}

void IRAM _lock_close(_lock_t *lock)
{
    CHECK_PARAM (lock != NULL);
    CHECK_PARAM (*lock != ((_lock_t)&_malloc_rmtx));

    free ((void*)*lock);
    *lock = 0;
}

void IRAM _lock_close_recursive(_lock_t *lock)
{
    CHECK_PARAM (lock != NULL);
    CHECK_PARAM (*lock != ((_lock_t)&_malloc_rmtx));

    free ((void*)*lock);
    *lock = 0;
}

void IRAM _lock_acquire(_lock_t *lock)
{
    CHECK_PARAM (sched_active_thread != 0);
    CHECK_PARAM (lock != NULL && *lock != 0);

    mutex_lock ((mutex_t*)*lock);
}

void IRAM _lock_acquire_recursive(_lock_t *lock)
{
    CHECK_PARAM (sched_active_thread != 0);
    CHECK_PARAM (lock != NULL && *lock != 0);

    rmutex_lock ((rmutex_t*)*lock);
}

int IRAM _lock_try_acquire(_lock_t *lock)
{
    CHECK_PARAM_RET (sched_active_thread != 0, 0);
    CHECK_PARAM_RET (lock != NULL && *lock != 0, 0);

    return rmutex_trylock ((rmutex_t*)*lock);
}

int IRAM _lock_try_acquire_recursive(_lock_t *lock)
{
    CHECK_PARAM_RET (sched_active_thread != 0, 0);
    CHECK_PARAM_RET (lock != NULL && *lock != 0, 0);

    return mutex_trylock ((mutex_t*)*lock);
}

void IRAM _lock_release(_lock_t *lock)
{
    CHECK_PARAM (sched_active_thread != 0);
    CHECK_PARAM (lock != NULL && *lock != 0);

    mutex_unlock ((mutex_t*)*lock);
}

void IRAM _lock_release_recursive(_lock_t *lock)
{
    CHECK_PARAM (sched_active_thread != 0);
    CHECK_PARAM (lock != NULL && *lock != 0);

    rmutex_unlock ((rmutex_t*)*lock);
}


#ifdef MODULE_NEWLIB_SYSCALLS_DEFAULT

#define _cheap heap_top

extern char *heap_top;
extern char _eheap;     /* end of heap (defined in esp8266.riot-os.app.ld) */

#else /* MODULE_NEWLIB_SYSCALLS_DEFAULT */

static uint8_t* _cheap = 0; /* last allocated chunk of heap */
extern uint8_t  _eheap;     /* end of heap (defined in esp8266.riot-os.app.ld) */
extern uint8_t  _sheap;     /* start of heap (defined in esp8266.riot-os.app.ld) */

void* IRAM _sbrk_r (struct _reent *r, ptrdiff_t incr)
{
    uint8_t* _cheap_old;

    /* initial _cheap */
    if (_cheap == NULL) {
        _cheap = &_sheap;
    }

    /* save old _cheap */
    _cheap_old = _cheap;

    /* check whether _cheap + incr overflows the heap */
    if (_cheap + incr >= &_eheap) {
        r->_errno = ENOMEM;
        return (caddr_t)-1;
    }

    /* set new _cheap */
    _cheap += incr;

    #if ENABLE_DEBUG
    uint32_t remaining = &_eheap - _cheap;
    printf ("%s %lu byte allocated in %p .. %p, remaining %u\n",
            __func__, incr, _cheap_old, _cheap, remaining);
    #endif

    /* return allocated memory */
    return (void*) _cheap_old;
}



#endif  /* MODULE_NEWLIB_SYSCALLS_DEFAULT */

unsigned int IRAM get_free_heap_size (void)
{
    return (_cheap) ? &_eheap - _cheap : 0;
}

#endif /* SDK_HEAP_USED */

#if !defined(MODULE_NEWLIB_SYSCALLS_DEFAULT)

NORETURN void _exit(int status)
{
    UNREACHABLE();
}

static int _no_sys_func (struct _reent *r, const char* f)
{
    LOG_ERROR("system function %s does not exist\n", f);
    r->_errno = ENOSYS;
    return -1;
}

int _open_r(struct _reent *r, const char *path, int flag, int m)
{
    return _no_sys_func (r, __func__);
}

int _close_r(struct _reent *r, int fd)
{
    return _no_sys_func (r, __func__);
}

int _fstat_r(struct _reent *r, int fdes, struct stat *stat)
{
    return _no_sys_func (r, __func__);
}

int _stat_r(struct _reent *r, const char *path, struct stat *buff)
{
    return _no_sys_func (r, __func__);
}

int _lseek_r(struct _reent *r, int fdes, int off, int w)
{
    return _no_sys_func (r, __func__);
}

int _write_r(struct _reent *r, int fd, const void *buff, size_t cnt)
{
    return _no_sys_func (r, __func__);
}

int _read_r(struct _reent *r, int fd, void *buff, size_t cnt)
{
    return _no_sys_func (r, __func__);
}

#include <sys/time.h>

int _gettimeofday_r(struct _reent *r, struct timeval *tv, void *tz)
{
    (void) tz;
    if (tv) {
        uint32_t microseconds = system_get_time();
        tv->tv_sec = microseconds / 1000000;
        tv->tv_usec = microseconds % 1000000;
    }
    return 0;
}

#endif /* MODULE_NEWLIB_SYSCALLS_DEFAULT */

int _rename_r (struct _reent *r, const char* old, const char* new)
{
    DEBUG("%s: system function does not exist\n", __func__);
    r->_errno = ENOSYS;
    return -1;
}

#include <math.h>

double __ieee754_remainder(double x, double y) {
    return x - y * floor(x/y);
}

float __ieee754_remainderf(float x, float y) {
    return x - y * floor(x/y);
}