#include <AP_HAL/AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_PX4

#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <nuttx/progmem.h>

#include "Storage.h"
using namespace PX4;

/*
  This stores eeprom data in the PX4 MTD interface with a 4k size, and
  a in-memory buffer. This keeps the latency and devices IOs down.
*/

// name the storage file after the sketch so you can use the same sd
// card for ArduCopter and ArduPlane
#define STORAGE_DIR "/fs/microsd/APM"
//#define SAVE_STORAGE_FILE STORAGE_DIR "/" SKETCHNAME ".sav"
#define MTD_PARAMS_FILE "/fs/mtd"

extern const AP_HAL::HAL& hal;

PX4Storage::PX4Storage(void) :
    _perf_storage(perf_alloc(PC_ELAPSED, "APM_storage")),
    _perf_errors(perf_alloc(PC_COUNT, "APM_storage_errors"))
{
}

void PX4Storage::_storage_open(void)
{
    if (_initialised) {
        return;
    }

    _dirty_mask.clearall();

    // load from storage backend
#if USE_FLASH_STORAGE
    _flash_load();
#else
    _mtd_load();
#endif

#ifdef SAVE_STORAGE_FILE
    fd = open(SAVE_STORAGE_FILE, O_WRONLY|O_CREAT|O_TRUNC, 0644);
    if (fd != -1) {
        write(fd, _buffer, sizeof(_buffer));
        close(fd);
        ::printf("Saved storage file %s\n", SAVE_STORAGE_FILE);
    }
#endif
    _initialised = true;
}

/*
  mark some lines as dirty. Note that there is no attempt to avoid
  the race condition between this code and the _timer_tick() code
  below, which both update _dirty_mask. If we lose the race then the
  result is that a line is written more than once, but it won't result
  in a line not being written.
*/
void PX4Storage::_mark_dirty(uint16_t loc, uint16_t length)
{
    uint16_t end = loc + length;
    for (uint16_t line=loc>>PX4_STORAGE_LINE_SHIFT;
         line <= end>>PX4_STORAGE_LINE_SHIFT;
         line++) {
        _dirty_mask.set(line);
    }
}

void PX4Storage::read_block(void *dst, uint16_t loc, size_t n)
{
    if (loc >= sizeof(_buffer)-(n-1)) {
        return;
    }
    _storage_open();
    memcpy(dst, &_buffer[loc], n);
}

void PX4Storage::write_block(uint16_t loc, const void *src, size_t n)
{
    if (loc >= sizeof(_buffer)-(n-1)) {
        return;
    }
    if (memcmp(src, &_buffer[loc], n) != 0) {
        _storage_open();
        memcpy(&_buffer[loc], src, n);
        _mark_dirty(loc, n);
    }
}

void PX4Storage::bus_lock(bool lock)
{
#if defined (CONFIG_ARCH_BOARD_PX4FMU_V4)
    /*
      this is needed on Pixracer where the ms5611 may be on the same
      bus as FRAM, and the NuttX ramtron driver does not go via the
      PX4 spi bus abstraction. The ramtron driver relies on
      SPI_LOCK(). We need to prevent the ms5611 reads which happen in
      interrupt context from interfering with the FRAM operations. As
      the px4 spi bus abstraction just uses interrupt blocking as the
      locking mechanism we need to block interrupts here as well.
    */
    if (lock) {
        irq_state = irqsave();
    } else {
        irqrestore(irq_state);
    }
#endif
}

void PX4Storage::_timer_tick(void)
{
    if (!_initialised || _dirty_mask.empty()) {
        return;
    }
    perf_begin(_perf_storage);

    if (_fd == -1) {
        _fd = open(MTD_PARAMS_FILE, O_WRONLY);
        if (_fd == -1) {
            perf_end(_perf_storage);
            perf_count(_perf_errors);
            return;
        }
    }

    // write out the first dirty line. We don't write more
    // than one to keep the latency of this call to a minimum
    uint16_t i;
    for (i=0; i<PX4_STORAGE_NUM_LINES; i++) {
        if (_dirty_mask.get(i)) {
            break;
        }
    }
    if (i == PX4_STORAGE_NUM_LINES) {
        // this shouldn't be possible
        perf_end(_perf_storage);
        perf_count(_perf_errors);
        return;
    }

    // save to storage backend
#if USE_FLASH_STORAGE
    _flash_write(i);
#else
    _mtd_write(i);
#endif
    
    perf_end(_perf_storage);
}

/*
  write one storage line. This also updates _dirty_mask. 
*/
void PX4Storage::_mtd_write(uint16_t line)
{
    uint16_t ofs = line * PX4_STORAGE_LINE_SIZE;
    if (lseek(_fd, ofs, SEEK_SET) != ofs) {
        return;
    }

    // mark the line clean
    _dirty_mask.clear(line);
    
    bus_lock(true);
    ssize_t ret = write(_fd, &_buffer[ofs], PX4_STORAGE_LINE_SIZE);
    bus_lock(false);

    if (ret != PX4_STORAGE_LINE_SIZE) {
        // write error - likely EINTR
        _dirty_mask.set(line);
        close(_fd);
        _fd = -1;
        perf_count(_perf_errors);
    }
}

/*
  load all data from mtd
 */
void PX4Storage::_mtd_load(void)
{
    int fd = open(MTD_PARAMS_FILE, O_RDONLY);
    if (fd == -1) {
        AP_HAL::panic("Failed to open " MTD_PARAMS_FILE);
    }
    const uint16_t chunk_size = 128;
    for (uint16_t ofs=0; ofs<sizeof(_buffer); ofs += chunk_size) {
        bus_lock(true);
        ssize_t ret = read(fd, &_buffer[ofs], chunk_size);
        bus_lock(false);
        if (ret != chunk_size) {
            ::printf("storage read of %u bytes at %u to %p failed - got %d errno=%d\n",
                     (unsigned)sizeof(_buffer), (unsigned)ofs, &_buffer[ofs], (int)ret, (int)errno);
            AP_HAL::panic("Failed to read " MTD_PARAMS_FILE);
        }
    }
    close(fd);
}

/*
  load all data from flash
 */
void PX4Storage::_flash_load(void)
{
    _flash_page = up_progmem_npages() - 2;
    if (up_progmem_pagesize(_flash_page) != 128*1024U ||
        up_progmem_pagesize(_flash_page+1) != 128*1024U) {
        AP_HAL::panic("Bad flash page sizes %u %u",
                      up_progmem_pagesize(_flash_page),
                      up_progmem_pagesize(_flash_page+1));
    }
        
    printf("Storage: Using flash pages %u and %u\n", _flash_page, _flash_page+1);
    
    if (!_flash.init()) {
        AP_HAL::panic("unable to init flash storage");
    }
}

/*
  write one storage line. This also updates _dirty_mask. 
*/
void PX4Storage::_flash_write(uint16_t line)
{
    if (_flash.write(line*PX4_STORAGE_LINE_SIZE, PX4_STORAGE_LINE_SIZE)) {
        // mark the line clean
        _dirty_mask.clear(line);        
    } else {
        perf_count(_perf_errors);
    }
}

/*
  callback to write data to flash
 */
bool PX4Storage::_flash_write_data(uint8_t sector, uint32_t offset, const uint8_t *data, uint16_t length)
{
    size_t base_address = up_progmem_getaddress(_flash_page+sector);
    return up_progmem_write(base_address+offset, data, length) == length;
}

/*
  callback to read data from flash
 */
bool PX4Storage::_flash_read_data(uint8_t sector, uint32_t offset, uint8_t *data, uint16_t length)
{
    size_t base_address = up_progmem_getaddress(_flash_page+sector);
    const uint8_t *b = ((const uint8_t *)base_address)+offset;
    memcpy(data, b, length);
    return true;
}

/*
  callback to erase flash sector
 */
bool PX4Storage::_flash_erase_sector(uint8_t sector)
{
    return up_progmem_erasepage(_flash_page+sector) > 0;
}

#endif // CONFIG_HAL_BOARD