/***********************************************************************|
| Optiboot Flash read/write interface library                           |
|                                                                       |
| Flash_iterate.ino                                                     |
|                                                                       |
| A library for interfacing with Optiboot Flash's write functionality   |
| Developed in 2021 by MCUdude                                          |
| https://github.com/MCUdude/                                           |
|                                                                       |
| In this example we fill the flash[] buffer with numbers and write it  |
| to flash page 0. After a reset or power cycle, we read the values     |
| back and prints them to the serial monitor.                           |
|                                                                       |
| A RAM buffer (ram_buffer) is required for this library to work. It    |
| acts as a memory pool you can read from and write to, and recommended |
| size for this buffer is one flash page, 256/128/64 bytes depending on |
| what chip you're using. ram_buffer[] and flash[] is the exact same    |
| array, flash[] is just pointing to ram_buffer[].                      |
|***********************************************************************/

#include <Flash.h>

// RAM buffer needed by the Flash library. Use flash[] to access the buffer
uint8_t ram_buffer[SPM_PAGESIZE];

// Allocate two flash pages for storing data
#define NUMBER_OF_PAGES 2
const uint8_t flashSpace[SPM_PAGESIZE * NUMBER_OF_PAGES] __attribute__((aligned(SPM_PAGESIZE))) = {};

// Flash constructor
Flash flash(flashSpace, sizeof(flashSpace), ram_buffer, sizeof(ram_buffer));

void write_data() {
  // First, make sure there are no content in out buffer
  flash.clear_buffer();

  // Fill buffer with numbers, starting from 0
  for (uint8_t i = 0; i < 64; i++) {
    flash[i] = i + 100;
  }
  // Write buffer to the first allocated flash page (page 0)
  flash.write_page(0);

  // Now let's set a flag on another flash page to indicate that the flash memory contains content
  // Here we're treating the object as an array
  flash.clear_buffer();
  flash[5] = 'X';
  flash.write_page(1);

  Serial.println("Page 0 written to!\nReset your board to view the contents!\n");
}

void read_data() {
  // Fetch first flash page
  flash.fetch_page(0);

  for (uint16_t i = 0; i < flash.buffer_size(); i++) {
    Serial.print("Addr: ");
    Serial.print(i);
    Serial.print(" \tData: ");
    Serial.println(flash[i]);
  }
}

void setup() {
  delay(2000);
  Serial.begin(9600);

  if (!flash.check_writable()) {
    Serial.println("Incompatible or no bootloader present! Please burn correct bootloader");
    while (1);
  }

  // Fetch flash page 1, where we may have a flag
  flash.fetch_page(1);

  // Check if our flag is present
  if (flash[5] == 'X') {
    Serial.println("Content found!");
    read_data();
  } else {
    Serial.print("Flash page size for this chip: ");
    Serial.print(SPM_PAGESIZE);
    Serial.print(" bytes\nTotal assigned flash space: ");
    Serial.print(NUMBER_OF_PAGES * SPM_PAGESIZE);
    Serial.println(" bytes");

    Serial.println("No content found! Writing new content...");
    write_data();
  }
}

void loop() {

}