storage.c

#include "storage.h"
#include <avr/eeprom.h>
#include <avr/wdt.h>
#include <string.h>

#define MAGIC_NUM 0x4744 // "GD"
#define MAGIC_ADDR 0x00

// Memory layout per game (3 scores of 5 bytes each = 15 bytes per game)
// 0x00 - 0x01: Magic number
// 0x02 - 0x10: Snake scores
// 0x11 - 0x1F: Tetris scores
// 0x20 - 0x2E: Bricks scores

#define SCORE_ADDR_BASE 0x02
#define SCORE_BYTES_PER_GAME 15
#define SCORES_PER_GAME 3

void storageInit(void) {
    uint16_t magic = eeprom_read_word((const uint16_t*)MAGIC_ADDR);
    
    if (magic != MAGIC_NUM) {
        // First boot, or corrupted EEPROM. Format it.
        eeprom_write_word((uint16_t*)MAGIC_ADDR, MAGIC_NUM);
        
        // Zero out all high score data
        for (uint16_t i = SCORE_ADDR_BASE; i < SCORE_ADDR_BASE + (SCORE_BYTES_PER_GAME * 3); i++) {
            eeprom_write_byte((uint8_t*)i, 0);
            wdt_reset(); // Keep watchdog fed during long EEPROM operations
        }
    }
}

void storageGetHighScores(uint8_t gameId, HighScore scores[3]) {
    uint16_t addr = SCORE_ADDR_BASE + (gameId * SCORE_BYTES_PER_GAME);
    
    for (uint8_t i = 0; i < SCORES_PER_GAME; i++) {
        scores[i].score = eeprom_read_word((const uint16_t*)addr);
        addr += 2;
        
        scores[i].name[0] = eeprom_read_byte((const uint8_t*)addr++);
        scores[i].name[1] = eeprom_read_byte((const uint8_t*)addr++);
        scores[i].name[2] = eeprom_read_byte((const uint8_t*)addr++);
        scores[i].name[3] = '\0';
        
        // Handle uninitialized names
        if (scores[i].name[0] == 0 || scores[i].name[0] == 0xFF) {
            strcpy(scores[i].name, "---");
        }
    }
}

bool storageCheckAndSaveScore(uint8_t gameId, uint16_t newScore, const char* name) {
    HighScore scores[3];
    storageGetHighScores(gameId, scores);
    
    int8_t insertIdx = -1;
    for (int8_t i = 0; i < SCORES_PER_GAME; i++) {
        if (newScore > scores[i].score) {
            insertIdx = i;
            break;
        }
    }
    
    if (insertIdx != -1) {
        // Shift lower scores down
        for (int8_t i = SCORES_PER_GAME - 1; i > insertIdx; i--) {
            scores[i] = scores[i-1];
        }
        
        // Insert new score
        scores[insertIdx].score = newScore;
        strncpy(scores[insertIdx].name, name, 3);
        scores[insertIdx].name[3] = '\0';
        
        // Save back to EEPROM
        uint16_t addr = SCORE_ADDR_BASE + (gameId * SCORE_BYTES_PER_GAME);
        for (uint8_t i = 0; i < SCORES_PER_GAME; i++) {
            eeprom_update_word((uint16_t*)addr, scores[i].score);
            addr += 2;
            eeprom_update_byte((uint8_t*)addr++, scores[i].name[0]);
            eeprom_update_byte((uint8_t*)addr++, scores[i].name[1]);
            eeprom_update_byte((uint8_t*)addr++, scores[i].name[2]);
            wdt_reset(); // Feed watchdog during write
        }
        return true;
    }
    
    return false;
}