#ifndef OTA_UART_H
#define OTA_UART_H

#include "esp_err.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,
} ota_uart_status_t;

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, esp_ota_end, set boot partition on success. */
esp_err_t ota_uart_finish(bool *success_out);

#endif