// Persistent state: master secret, signature counter and resident credentials.
#pragma once

#include <stdbool.h>
#include <stdint.h>

#include "cred.h"

#define RK_SLOTS 64
#define RK_MAX_USER_ID 64
#define RK_MAX_RP_ID 128
#define RK_MAX_NAME 64

// One resident (discoverable) credential. Exactly one 512-byte flash slot.
typedef struct {
    uint32_t magic;    // managed by storage.c
    uint32_t created;  // signature counter at creation, orders credentials
    uint8_t rp_id_hash[32];
    uint8_t cred_id[CRED_ID_LEN];
    uint8_t user_id_len;
    uint8_t user_id[RK_MAX_USER_ID];
    uint8_t rp_id_len;
    char rp_id[RK_MAX_RP_ID];
    uint8_t user_name_len;
    char user_name[RK_MAX_NAME];
    uint8_t display_name_len;
    char display_name[RK_MAX_NAME];
    uint8_t reserved[99];
} rk_record_t;

_Static_assert(sizeof(rk_record_t) == 512, "rk_record_t must fill one slot");

void storage_init(void);
const uint8_t *storage_master_secret(void);

// Increments the global signature counter and returns the new value.
uint32_t storage_counter_next(void);

// Generates a new master secret and deletes all resident credentials and the PIN.
void storage_reset(void);

// Returns false if the slot does not hold a credential.
bool storage_rk_read(int slot, rk_record_t *out);

// Stores a credential, replacing any with the same RP and user ID. Returns a
// CTAP status code.
int storage_rk_save(const rk_record_t *rec);

void storage_rk_delete(int slot);

// PIN state. The PIN itself is never stored, only LEFT(SHA-256(PIN), 16).
typedef struct {
    bool set;
    uint8_t retries;
    uint8_t hash[16];
} pin_state_t;

// Returns false if no PIN state was saved since the last reset.
bool storage_pin_load(pin_state_t *out);
void storage_pin_save(const pin_state_t *state);