#include <Arduino.h>
#include "eeprom.hpp"
#include "util.hpp"

using namespace eeprom;

constexpr uint8_t WRITE_MS = 3;
constexpr uint8_t ADDR = 0x50;

static uint32_t at = 0;
static uint32_t last_block_end = 0;

static bool is_responsive(uint8_t i2c_addr) {
	bool s = mem.start_write(i2c_addr);
	return s;
}

static void wait_for_responsive(uint8_t i2c_addr) {
	while(!is_responsive(i2c_addr)) {
		delay(1);
	}
}

static uint8_t get_i2c_addr(uint32_t at) {
	return ADDR ^ (at >> 16);
}

static void set_address(uint8_t i2c_addr, uint16_t at) {
	char addr_bytes[2] = {at >> 8, at};
	mem.start_write(i2c_addr);
	mem.write(at >> 8);
	mem.write(at);
}

void eeprom::init() {
	mem.begin();
}

void eeprom::jump(uint32_t p_at) {
	last_block_end = 0;
	at = p_at;
}

void eeprom::read(char* data, uint16_t data_size) {
	uint16_t recorded = 0;

	while(recorded < data_size && at < LENGTH) {

		uint32_t block_end = at / BLOCK_SIZE * BLOCK_SIZE + BLOCK_SIZE;
		uint8_t read_len = min(min(block_end - at, data_size - recorded), 255);
		uint8_t i2c_addr = get_i2c_addr(at);

		if(block_end != last_block_end) {
			set_address(i2c_addr, at);
			last_block_end = block_end;
		}

		mem.start_read(i2c_addr);
		mem.read(data + recorded, read_len, true);
		recorded += read_len;
		at += read_len;
	}

	mem.end();

	for(uint16_t i = recorded; i < data_size; i++) {
		data[i] = 0;
	}
}

void eeprom::page_write(uint32_t at, const char* data) {
	if(at >= LENGTH) return;
	uint8_t i2c_addr = get_i2c_addr(at);
	wait_for_responsive(i2c_addr);
	mem.start_write(i2c_addr);
	mem.write(at >> 8);
	mem.write(at);
	mem.write(data, PAGE_SIZE - (at % PAGE_SIZE));
	mem.end();
	delay(WRITE_MS);
	last_block_end = 0;
}

uint32_t eeprom::get_addr() {
	return at;
}