#ifndef OTA_UART_H
#define OTA_UART_H

#include "esp_err.h"
#include "esp_partition.h"
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

#define OTA_UART_HOST_CHUNK_SIZE 200u
#define OTA_UART_FLASH_BLOCK_SIZE 4096u

/** OtaStatusPayload.status values (device → host). */
typedef enum {
  OTA_UART_ST_PREPARING = 1,
  OTA_UART_ST_READY = 2,
  OTA_UART_ST_BLOCK_ACK = 3,
  OTA_UART_ST_SUCCESS = 4,
  OTA_UART_ST_FAILED = 5,
  /** ESP-NOW slave distribution in progress (see OTA_DIST_* in cmd_ota.c). */
  OTA_UART_ST_DISTRIBUTING = 6,
} ota_uart_status_t;

/** OtaStatusPayload.error when status == OTA_UART_ST_DISTRIBUTING. */
#define OTA_DIST_AGGREGATE 0u
#define OTA_DIST_PER_SLAVE 1u

typedef enum {
  OTA_FEED_OK = 0,
  OTA_FEED_BLOCK_WRITTEN,
  OTA_FEED_ERROR,
} ota_feed_result_t;

bool ota_uart_is_active(void);

/** 0/1 while session active, else -1. */
int ota_uart_target_slot(void);

/** Begin OTA on the inactive app partition (esp_ota_begin). Returns target slot 0/1. */
int ota_uart_prepare(uint32_t total_size);

void ota_uart_abort(void);

/** Append up to 200 bytes; flushes 4 KiB blocks to flash when full. */
ota_feed_result_t ota_uart_feed(const uint8_t *data, size_t len);

uint32_t ota_uart_bytes_written(void);

/**
 * Flush remainder and esp_ota_end. When set_boot is false, the staged image
 * remains readable via ota_uart_get_staged_image() until ota_uart_apply_boot().
 */
esp_err_t ota_uart_finish(bool set_boot, bool *success_out);

/** Staged partition after ota_uart_finish(false, …); valid until apply_boot or abort. */
bool ota_uart_get_staged_image(const esp_partition_t **partition_out,
                               uint32_t *size_out);

/** Set boot partition to the last staged image (after slave distribution). */
esp_err_t ota_uart_apply_boot(void);

void ota_uart_clear_staged(void);

#endif