/**
 * @file uart_trans.h
 * @brief UART transparent transmission module for TCP2UART
 * 
 * - UART2 <-> TCP Server (via StreamBuffer)
 * - UART3 <-> TCP Client (via StreamBuffer)
 * - DMA + IDLE interrupt for efficient reception
 */

#ifndef __UART_TRANS_H__
#define __UART_TRANS_H__

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

#ifdef __cplusplus
extern "C" {
#endif

/* UART channel definitions */
typedef enum {
    UART_CHANNEL_SERVER = 0,    /* UART2 - TCP Server channel */
    UART_CHANNEL_CLIENT = 1,    /* UART3 - TCP Client channel */
    UART_CHANNEL_MAX
} uart_channel_t;

/* DMA buffer sizes */
#define UART_RX_DMA_BUFFER_SIZE     128
#define UART_TX_DMA_BUFFER_SIZE     128

/* UART configuration */
typedef struct {
    uint32_t baudrate;
    uint8_t  data_bits;     /* 8 or 9 */
    uint8_t  stop_bits;     /* 1 or 2 */
    uint8_t  parity;        /* 0=None, 1=Odd, 2=Even */
} uart_config_t;

/* Default configurations */
#define UART_DEFAULT_BAUDRATE       115200
#define UART_DEFAULT_DATA_BITS      8
#define UART_DEFAULT_STOP_BITS      1
#define UART_DEFAULT_PARITY         0

/* UART statistics */
typedef struct {
    uint32_t rx_bytes;
    uint32_t tx_bytes;
    uint32_t rx_packets;
    uint32_t tx_packets;
    uint32_t errors;
} uart_stats_t;

/**
 * @brief Initialize UART transparent transmission module
 * @return 0 on success, negative on error
 */
int uart_trans_init(void);

/**
 * @brief Configure UART channel parameters
 * @param channel UART channel (SERVER or CLIENT)
 * @param config UART configuration
 * @return 0 on success, negative on error
 */
int uart_trans_config(uart_channel_t channel, const uart_config_t *config);

/**
 * @brief Start UART reception (enable DMA + IDLE interrupt)
 * @param channel UART channel
 * @return 0 on success, negative on error
 */
int uart_trans_start(uart_channel_t channel);

/**
 * @brief Stop UART reception
 * @param channel UART channel
 * @return 0 on success, negative on error
 */
int uart_trans_stop(uart_channel_t channel);

/**
 * @brief Set StreamBuffer handles for TCP integration
 * @param channel UART channel
 * @param rx_stream StreamBuffer to receive data from TCP (for UART TX)
 * @param tx_stream StreamBuffer to send data to TCP (from UART RX)
 */
void uart_trans_set_streams(uart_channel_t channel, 
                            void *rx_stream, 
                            void *tx_stream);

/**
 * @brief Get UART statistics
 * @param channel UART channel
 * @param stats Pointer to statistics structure
 */
void uart_trans_get_stats(uart_channel_t channel, uart_stats_t *stats);

/**
 * @brief Reset UART statistics
 * @param channel UART channel
 */
void uart_trans_reset_stats(uart_channel_t channel);

/**
 * @brief UART IDLE interrupt handler - call from stm32f1xx_it.c
 * @param channel UART channel
 * 
 * Usage in stm32f1xx_it.c USART2_IRQHandler:
 *   if (__HAL_UART_GET_FLAG(&huart2, UART_FLAG_IDLE)) {
 *       __HAL_UART_CLEAR_IDLEFLAG(&huart2);
 *       uart_trans_idle_handler(UART_CHANNEL_SERVER);
 *   }
 */
void uart_trans_idle_handler(uart_channel_t channel);

/**
 * @brief UART DMA RX half complete callback - call from HAL callback
 * @param channel UART channel
 */
void uart_trans_rx_half_cplt_handler(uart_channel_t channel);

/**
 * @brief UART DMA RX complete callback - call from HAL callback
 * @param channel UART channel
 */
void uart_trans_rx_cplt_handler(uart_channel_t channel);

/**
 * @brief UART DMA TX complete callback - call from HAL callback
 * @param channel UART channel
 */
void uart_trans_tx_cplt_handler(uart_channel_t channel);

/**
 * @brief Server transparent transmission task (UART2 <-> TCP Server)
 * @param argument Task argument (unused)
 */
void uart_server_trans_task(void *argument);

/**
 * @brief Client transparent transmission task (UART3 <-> TCP Client)
 * @param argument Task argument (unused)
 */
void uart_client_trans_task(void *argument);

#ifdef __cplusplus
}
#endif

#endif /* __UART_TRANS_H__ */