/* SPDX-License-Identifier: GPL-3.0-only */
/* Persistent HTTPS identity and shared network-administration credentials. */

#pragma once

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

#include "esp_err.h"

#ifdef __cplusplus
extern "C" {
#endif

#define WEB_SECURITY_NVS_NAMESPACE "web_sec"
#define WEB_SECURITY_NVS_BLOB_KEY "material"

#define WEB_SECURITY_USERNAME_CAPACITY 16U
#define WEB_SECURITY_PASSWORD_CAPACITY 32U
#define WEB_SECURITY_PASSWORD_LENGTH 24U
#define WEB_SECURITY_PRIVATE_KEY_DER_CAPACITY 256U
#define WEB_SECURITY_CERTIFICATE_DER_CAPACITY 1024U
#define WEB_SECURITY_SHA256_LENGTH 32U
#define WEB_SECURITY_COMMON_NAME_CAPACITY 32U
#define WEB_SECURITY_DNS_NAME_CAPACITY 40U

#define WEB_SECURITY_CERT_NOT_BEFORE "20250101000000"
#define WEB_SECURITY_CERT_NOT_AFTER "20491231235959"

typedef enum {
    WEB_SECURITY_LOAD_STORED = 0,
    WEB_SECURITY_LOAD_GENERATED_MISSING = 1,
} web_security_load_result_t;

/*
 * This intentionally contains a displayable secret. UART callers should call
 * secure_wipe() on it immediately after rendering the length-delimited fields.
 */
typedef struct {
    size_t username_length;
    size_t password_length;
    char username[WEB_SECURITY_USERNAME_CAPACITY + 1U];
    char password[WEB_SECURITY_PASSWORD_CAPACITY + 1U];
} web_security_credentials_t;

typedef struct {
    uint32_t material_generation;
    uint8_t sha256_fingerprint[WEB_SECURITY_SHA256_LENGTH];
    char common_name[WEB_SECURITY_COMMON_NAME_CAPACITY];
    char dns_name[WEB_SECURITY_DNS_NAME_CAPACITY];
    uint8_t ipv4_address[4];
    char not_before[sizeof(WEB_SECURITY_CERT_NOT_BEFORE)];
    char not_after[sizeof(WEB_SECURITY_CERT_NOT_AFTER)];
} web_security_certificate_metadata_t;

/*
 * NVS must already be initialized. Missing material is generated and saved;
 * an existing wrong-version blob returns ESP_ERR_INVALID_VERSION, while any
 * malformed or cryptographically inconsistent blob returns
 * ESP_ERR_INVALID_RESPONSE and is never overwritten. Call before radio startup
 * so secure_random_init() can seed from the pre-radio entropy source.
 */
esp_err_t web_security_init(web_security_load_result_t *load_result);

/*
 * Query with both outputs NULL/capacities zero. Certificate and key are copied
 * under one lock so a concurrent rotation can never produce a mismatched pair.
 */
esp_err_t web_security_copy_tls_material(
    uint8_t *certificate, size_t certificate_capacity,
    size_t *certificate_length,
    uint8_t *private_key, size_t private_key_capacity,
    size_t *private_key_length);
esp_err_t web_security_copy_username(char *output, size_t capacity,
                                     size_t *output_length);

/* Protocol-neutral authentication for the shared HTTPS and SSH administrator. */
esp_err_t web_security_authenticate_admin(const uint8_t *username,
                                          size_t username_length,
                                          const uint8_t *password,
                                          size_t password_length,
                                          bool *authenticated);

/* Compatibility name for decoded HTTP Basic components. */
esp_err_t web_security_authenticate_basic(const uint8_t *username,
                                          size_t username_length,
                                          const uint8_t *password,
                                          size_t password_length,
                                          bool *authenticated);

/* Explicit secret-bearing API intended for a physically attached UART CLI. */
esp_err_t web_security_show_credentials(web_security_credentials_t *credentials);
esp_err_t web_security_get_certificate_metadata(
    web_security_certificate_metadata_t *metadata);

/* Mutations become visible only after a complete blob has committed to NVS. */
esp_err_t web_security_rotate_credentials(web_security_credentials_t *new_credentials);
esp_err_t web_security_rotate_certificate(void);

/* Explicitly replaces missing, valid, or incompatible stored material. */
esp_err_t web_security_reset_all(web_security_credentials_t *new_credentials);

#ifdef __cplusplus
}
#endif