/**
 * @file app_spi_command.cpp
 * @brief APP 运行期 SPI 链路与命令路由实现。
 *
 * 本模块现在只负责：
 * - SPI0 从机链路初始化（GPIO/SPI/DMA/EXTI）
 * - CS、DMA、中断驱动的帧接收与发送
 * - 公共帧格式解析与应答构建
 * - 业务命令的注册与分发
 *
 * 具体命令处理逻辑已经拆到独立的 app_spi_cmd_*.cpp，
 * 通过 registerHandler() 注册进来，后续新增 SPI 业务时
 * 只需要新增命令处理器，不再继续膨胀本文件。
 *
 * 握手架构（线与 SPIready，PB6<->ESP32 GPIO10 开漏单线）：
 * - 命令处理在 onCsRelease() EXTI ISR 内同步完成（对齐 BOOT 的 isrProcessFrame），
 *   不再推迟到主循环，消除 PB6 拉高延迟。
 * - GD32 可通过 requestEsp32Read() 下拉 SPIready 主动按铃请求 ESP32 来读。
 */

#include "device/spi/app_spi_command.h"
#include "device/spi/spi_command_handler.h"
#include "device/spi/app_spi_command_defs.h"

extern "C" {
#include "gd32e50x_exti.h"
}
#include "gd32e50x_gpio.h"
#include "gd32e50x_misc.h"
#include "gd32e50x_rcu.h"
#include "gd32e50x_dma.h"
#include "gd32e50x_spi.h"
#include "sys/config.h"
#include "sys/critical.h"
#include "sys/task_manager.h"
#include "sys/ota_boot_request.h"
#include "sys/systick.h"
#include "main.h"
#include <cstdio>
#include <cstring>

/* ============================================================
 * 本地别名：保持当前实现文件内部风格不变
 * ============================================================ */
static constexpr uint8_t kSof           = SpiDefs::kSof;
static constexpr uint8_t kTypeBootReq   = SpiDefs::kTypeBootReq;
static constexpr uint8_t kTypeCanSend   = SpiDefs::kTypeCanSend;
static constexpr uint8_t kTypeOtaReq    = SpiDefs::kTypeOtaReq;
static constexpr uint8_t kTypeAppPing   = SpiDefs::kTypeAppPing;
static constexpr uint8_t kTypeOtaData   = SpiDefs::kTypeOtaData;
static constexpr uint8_t kTypeOtaCancel = SpiDefs::kTypeOtaCancel;
static constexpr uint8_t kRspAck        = SpiDefs::kRspAck;
static constexpr uint8_t kRspWait       = SpiDefs::kRspWait;
static constexpr uint8_t kRspError      = SpiDefs::kRspError;
static constexpr uint16_t kFrameOverhead = SpiDefs::kFrameOverhead;

/* DMA 配置（与 BOOT SpiOta 一致：DMA0_CH2 用于 SPI0 TX） */
#define SPI_TX_DMA_PERIPH   DMA0
#define SPI_TX_DMA_CH       DMA_CH2

static void startSpiTxDma(const uint8_t *buf, uint16_t len)
{
    DMA_CHCTL(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH) &= ~DMA_CHXCTL_CHEN;
    DMA_INTC(SPI_TX_DMA_PERIPH) |= DMA_FLAG_ADD(DMA_CHINTF_RESET_VALUE, SPI_TX_DMA_CH);
    DMA_CHMADDR(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH) = (uint32_t)buf;
    DMA_CHCNT(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH) = len;
    DMA_CHCTL(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH) |= DMA_CHXCTL_CHEN;
}

static bool isAllBytesValue(const uint8_t *data, uint16_t len, uint8_t value)
{
    if (!data || len == 0U) {
        return false;
    }
    for (uint16_t i = 0U; i < len; ++i) {
        if (data[i] != value) {
            return false;
        }
    }
    return true;
}

static bool shouldIgnoreTransaction(const uint8_t *data, uint16_t len)
{
    if (!data || len == 0U) {
        return true;
    }

    if (isAllBytesValue(data, len, 0xFFU) || isAllBytesValue(data, len, 0x00U)) {
        return true;
    }

    /* APP 侧只接受两类事务：
     * 1) 旧式单字节 0xB0
     * 2) 完整协议帧（至少 5 字节）
     * 短于 5 字节且不是 0xB0 的事务只能是启动切换期的残包，直接忽略。 */
    return (len < kFrameOverhead) &&
           !(len == 1U && data[0] == CONFIG_SPI_APP_OTA_BOOT_CMD);
}

static bool isFlashRelatedFrame(uint8_t frame_type)
{
    switch (frame_type) {
    case kTypeOtaReq:
    case kTypeOtaData:
    case kTypeOtaCancel:
    case kTypeBootReq:
        return true;
    default:
        return false;
    }
}

/* ============================================================
 * CRC8 / 帧构建 / 帧解析（与 BOOT SpiOta 一致）
 * ============================================================ */

static constexpr uint8_t  kSyncSof0     = 0xA5U;
static constexpr uint8_t  kSyncSof1     = 0x5AU;
static constexpr uint16_t kSyncHeaderLen = 6U;
static constexpr uint16_t kSyncCrcLen    = 4U;
static constexpr uint16_t kSyncOverhead  = (uint16_t)(kSyncHeaderLen + kSyncCrcLen);

/* 扫描前 16 字节查找同步帧头 SOF0 SOF1，容忍 RXORERR 导致的首字节偏移。
 * 与 spi_try_parse_frame 的偏移扫描逻辑对齐。 */
static bool containsSyncSof(const uint8_t *data, uint16_t len)
{
    if (!data || len < 2U) { return false; }
    uint16_t last = (len < 16U) ? (uint16_t)(len - 1U) : 16U;
    for (uint16_t i = 0U; i < last; ++i) {
        if (data[i] == kSyncSof0 && data[i + 1U] == kSyncSof1) { return true; }
    }
    return false;
}

/* GD32 APP 侧同步状态机（ISR 与主循环只读/原子写，避免临界区开销）。 */
static volatile uint8_t  g_localCredit = 8U;
static volatile uint8_t  g_remoteCredit = 8U;

static void putU16Le(uint8_t *pp, uint16_t v)
{
    pp[0] = (uint8_t)(v & 0xFFU);
    pp[1] = (uint8_t)((v >> 8) & 0xFFU);
}

static uint16_t getU16Le(const uint8_t *pp)
{
    return (uint16_t)(pp[0] | ((uint16_t)pp[1] << 8));
}

static void putU32Le(uint8_t *pp, uint32_t v)
{
    pp[0] = (uint8_t)(v & 0xFFU);
    pp[1] = (uint8_t)((v >> 8) & 0xFFU);
    pp[2] = (uint8_t)((v >> 16) & 0xFFU);
    pp[3] = (uint8_t)((v >> 24) & 0xFFU);
}

static uint32_t getU32Le(const uint8_t *pp)
{
    return (uint32_t)pp[0] | ((uint32_t)pp[1] << 8) |
           ((uint32_t)pp[2] << 16) | ((uint32_t)pp[3] << 24);
}

static uint32_t spi_crc32(const uint8_t *data, uint16_t len)
{
    uint32_t crc = 0xFFFFFFFFU;
    for (uint16_t i = 0U; i < len; ++i) {
        crc ^= (uint32_t)data[i] << 24;
        for (int b = 0; b < 8; ++b) {
            if (crc & 0x80000000U) {
                crc = (crc << 1) ^ 0x04C11DB7U;
            } else {
                crc <<= 1;
            }
        }
    }
    return crc;
}

static uint8_t spi_crc8(const uint8_t *data, uint16_t len)
{
    uint8_t crc = 0x00U;
    for (uint16_t i = 0U; i < len; ++i) { crc ^= data[i]; }
    return crc;
}

/* 构建新同步帧；上层接口（type/payload）保持不变，handler 无需改动。
 * kFrameOverhead 旧常量仍保留供旧路径使用。 */
static bool spi_build_frame(uint8_t type, const uint8_t *payload, uint16_t payload_len,
                            uint8_t *out, uint16_t *out_len)
{
    if (!out || !out_len) { return false; }
    uint16_t total = (uint16_t)(kSyncOverhead + payload_len);
    if (total > AppSpiCommand::kTxBufSize) { return false; }

    out[0] = kSyncSof0;
    out[1] = kSyncSof1;
    out[2] = g_localCredit;
    out[3] = type;
    putU16Le(&out[4], payload_len);
    if (payload && payload_len > 0U) {
        memcpy(&out[kSyncHeaderLen], payload, payload_len);
    }
    uint32_t crc = spi_crc32(out, (uint16_t)(kSyncHeaderLen + payload_len));
    putU32Le(&out[kSyncHeaderLen + payload_len], crc);
    *out_len = total;
    return true;
}

/* 解析：新同步帧优先；失败回退旧 0xA5 帧（含首字节偏移容错）。 */
static bool spi_try_parse_frame(const uint8_t *frame, uint16_t frame_len,
                                uint8_t *type, const uint8_t **payload, uint16_t *payload_len)
{
    if (!frame || !type || !payload || !payload_len) { return false; }

    for (uint16_t s = 0U; s + kSyncOverhead <= frame_len; ++s) {
        if (frame[s] != kSyncSof0 || frame[s + 1U] != kSyncSof1) { continue; }
        uint16_t plen = getU16Le(&frame[s + 4U]);
        uint16_t total = (uint16_t)(kSyncOverhead + plen);
        if ((uint16_t)(frame_len - s) < total) { continue; }
        uint32_t expect = getU32Le(&frame[s + kSyncHeaderLen + plen]);
        uint32_t calc = spi_crc32(&frame[s], (uint16_t)(kSyncHeaderLen + plen));
        if (expect != calc) { continue; }

        uint8_t  credit = frame[s + 2U];
        *type = frame[s + 3U];
        *payload = (plen > 0U) ? &frame[s + kSyncHeaderLen] : nullptr;
        *payload_len = plen;
        g_remoteCredit = credit;
        return true;
    }

    /* 旧 0xA5 帧兼容：首字节可能偏移，扫描 SOF。 */
    uint16_t s = 0U;
    while (s < frame_len && frame[s] != kSof) { ++s; }
    if (s > 0U && s < frame_len) {
        const uint16_t shifted_len = (uint16_t)(frame_len - s);
        if (shifted_len >= kFrameOverhead) {
            const uint16_t len_field = (uint16_t)frame[s + 2U] | ((uint16_t)frame[s + 3U] << 8);
            const uint16_t expected = (uint16_t)(kFrameOverhead + len_field);
            if (shifted_len >= expected &&
                spi_crc8(&frame[s], (uint16_t)(4U + len_field)) == frame[s + 4U + len_field]) {
                *type = frame[s + 1U];
                *payload = &frame[s + 4U];
                *payload_len = len_field;
                return true;
            }
        }
    }

    if (frame_len < kFrameOverhead) { return false; }
    if (frame[0] != kSof) { return false; }

    uint16_t len = (uint16_t)frame[2] | ((uint16_t)frame[3] << 8);
    uint16_t expected = (uint16_t)(kFrameOverhead + len);
    if (frame_len < expected) { return false; }
    if (spi_crc8(frame, (uint16_t)(4U + len)) != frame[4U + len]) { return false; }

    *type = frame[1];
    *payload = &frame[4];
    *payload_len = len;
    return true;
}

/* ============================================================
 * 调试日志辅助
 * ============================================================ */

void AppSpiCommand::postLog(const char *msg)
{
#if (CONFIG_SPI_APP_LOG_ENABLE != 0)
    if (!msg) return;
    snprintf(m_logBuf, kLogBufSize, "[SPI-APP] %s", msg);
    m_logPending = true;
#else
    (void)msg;
#endif
}

void AppSpiCommand::postLogFmt(const char *fmt, uint8_t val)
{
#if (CONFIG_SPI_APP_LOG_ENABLE != 0)
    if (!fmt) return;
    snprintf(m_logBuf, kLogBufSize, fmt, val);
    m_logPending = true;
#else
    (void)fmt;
    (void)val;
#endif
}

void AppSpiCommand::buildResponse(uint8_t *tx_buf, uint16_t tx_buf_size,
                                  uint16_t *tx_len, uint8_t rsp_type,
                                  const uint8_t *payload, uint16_t payload_len)
{
    if (!tx_buf || !tx_len || tx_buf_size == 0U) {
        return;
    }

    uint16_t built_len = 0U;
    const bool ok = spi_build_frame(rsp_type, payload, payload_len, tx_buf, &built_len);
    if (ok) {
        *tx_len = built_len;
    }
}

/* ============================================================
 * 硬件配置
 * ============================================================ */

void AppSpiCommand::configureGpio()
{
    rcu_periph_clock_enable(RCU_GPIOA);
    rcu_periph_clock_enable(RCU_GPIOB);
    rcu_periph_clock_enable(RCU_AF);

    gpio_pin_remap_config(GPIO_SPI0_REMAP, ENABLE);
    gpio_pin_remap_config(GPIO_SWJ_SWDPENABLE_REMAP, ENABLE);

    gpio_init(GPIOB, GPIO_MODE_IN_FLOATING, GPIO_OSPEED_50MHZ, GPIO_PIN_3 | GPIO_PIN_5);
    gpio_init(GPIOB, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_4);
    gpio_init(GPIOA, GPIO_MODE_IPU, GPIO_OSPEED_50MHZ, GPIO_PIN_15);

    /* PB6 复用为 SPI Ready 握手线（开漏输出，线与）。
     * 开漏模式：写 BRR = 下拉驱动低；写 BSRR = 高阻释放，靠外部/对端上拉拉高。
     * 默认释放（HIGH），允许主机立刻发起首帧。 */
    gpio_init(CONFIG_SPI_READY_PORT, GPIO_MODE_OUT_OD, GPIO_OSPEED_50MHZ, CONFIG_SPI_READY_PIN);
    gpio_bit_set(CONFIG_SPI_READY_PORT, CONFIG_SPI_READY_PIN);
}

void AppSpiCommand::setSpiReady(bool ready)
{
    /* 开漏线与：ready=true 释放（BSRR，高阻，靠上拉拉高）；
     *          ready=false 下拉（BRR，驱动低）。 */
    if (ready) {
        gpio_bit_set(CONFIG_SPI_READY_PORT, CONFIG_SPI_READY_PIN);
    } else {
        gpio_bit_reset(CONFIG_SPI_READY_PORT, CONFIG_SPI_READY_PIN);
    }
}

void AppSpiCommand::configureSpi0()
{
    rcu_periph_clock_enable(RCU_SPI0);
    spi_i2s_deinit(SPI0);

    spi_parameter_struct spi_init_struct;
    spi_struct_para_init(&spi_init_struct);
    spi_init_struct.device_mode = SPI_SLAVE;
    spi_init_struct.trans_mode = SPI_TRANSMODE_FULLDUPLEX;
    spi_init_struct.frame_size = SPI_FRAMESIZE_8BIT;
    spi_init_struct.nss = SPI_NSS_SOFT;
    spi_init_struct.endian = SPI_ENDIAN_MSB;
    spi_init_struct.clock_polarity_phase = SPI_CK_PL_LOW_PH_1EDGE;
    spi_init_struct.prescale = SPI_PSC_8;
    spi_init(SPI0, &spi_init_struct);

    spi_nss_internal_low(SPI0);
    (void)spi_i2s_data_receive(SPI0);
    spi_i2s_data_transmit(SPI0, 0xFFU);
    spi_i2s_interrupt_enable(SPI0, SPI_I2S_INT_RBNE);
    spi_i2s_interrupt_enable(SPI0, SPI_I2S_INT_ERR);
    spi_i2s_interrupt_disable(SPI0, SPI_I2S_INT_TBE);
    nvic_irq_enable(SPI0_IRQn, CONFIG_IRQ_PREEMPT_SPI_USART, 0U);
    spi_enable(SPI0);
}

void AppSpiCommand::configureDma()
{
    rcu_periph_clock_enable(RCU_DMA0);
    dma_deinit(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH);

    dma_parameter_struct dma_cfg;
    dma_struct_para_init(&dma_cfg);
    dma_cfg.periph_addr  = (uint32_t)(SPI0 + 0x0CU);  /* SPI0_DATA 寄存器 */
    dma_cfg.periph_width = DMA_PERIPHERAL_WIDTH_8BIT;
    dma_cfg.memory_addr  = (uint32_t)m_txBuf;
    dma_cfg.memory_width = DMA_MEMORY_WIDTH_8BIT;
    dma_cfg.number       = 0U;
    dma_cfg.priority     = DMA_PRIORITY_HIGH;
    dma_cfg.periph_inc   = DMA_PERIPH_INCREASE_DISABLE;
    dma_cfg.memory_inc   = DMA_MEMORY_INCREASE_ENABLE;
    dma_cfg.direction    = DMA_MEMORY_TO_PERIPHERAL;
    dma_init(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH, &dma_cfg);
    dma_circulation_disable(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH);
    dma_channel_disable(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH);
}

void AppSpiCommand::configureExti()
{
    gpio_exti_source_select(GPIO_PORT_SOURCE_GPIOA, GPIO_PIN_SOURCE_15);
    exti_init(EXTI_15, EXTI_INTERRUPT, EXTI_TRIG_BOTH);
    exti_interrupt_enable(EXTI_15);
    exti_interrupt_flag_clear(EXTI_15);
    nvic_irq_enable(EXTI10_15_IRQn, CONFIG_IRQ_PREEMPT_SPI_USART, 1U);
}

void AppSpiCommand::configureSpiReadyExti()
{
    /* PB6 已在 configureGpio() 配置为开漏输出，此处启用 EXTI6 上升沿检测。
     * EXTI 检测引脚实际电平（IDR），与 GPIO 输出模式兼容。
     * 用于检测 ESP32 releaseReady 产生的上升沿（线从忙碌→空闲），
     * 作为 ESP32 完成上一帧处理的可靠信号。 */
    gpio_exti_source_select(GPIO_PORT_SOURCE_GPIOB, GPIO_PIN_SOURCE_6);
    exti_init(EXTI_6, EXTI_INTERRUPT, EXTI_TRIG_RISING);
    exti_interrupt_enable(EXTI_6);
    exti_interrupt_flag_clear(EXTI_6);
    nvic_irq_enable(EXTI5_9_IRQn, CONFIG_IRQ_PREEMPT_SPI_USART, 1U);
}

void AppSpiCommand::onSpiReadyExti()
{
    if (exti_interrupt_flag_get(EXTI_6) != RESET) {
        exti_interrupt_flag_clear(EXTI_6);
        /* 线升高（空闲）：ESP32 已 releaseReady，上一帧处理完 */
        m_linkState.onEsp32Complete();
    }
}


/* ============================================================
 * 默认命令注册入口（由各 app_spi_cmd_*.cpp 提供）
 * ============================================================ */
extern void registerSpiBootRequestCommand(AppSpiCommand &bus);
extern void registerSpiOtaWaitCommand(AppSpiCommand &bus);
extern void registerSpiAppPingCommand(AppSpiCommand &bus);
extern void registerSpiCanBridgeCommand(AppSpiCommand &bus);
extern void registerSpiCanFeedbackCommand(AppSpiCommand &bus);
extern void registerSpiIdSnapshotCommand(AppSpiCommand &bus);
AppSpiCommand AppSpiCommandBus;
void AppSpiCommand::init()
{
    m_csActive = false;
    m_rxLen = 0U;
    m_txLen = 0U;
    m_txPos = 0U;
    m_logPending = false;
    m_txActiveThisCs = false;
    m_commandCount = 0U;
    m_ringPending = false;
    m_ringDeadline = 0U;
    m_ringTxLen = 0U;
    m_linkState.reset();
    memset(m_txBuf, 0xFF, sizeof(m_txBuf));
    memset(m_logBuf, 0, sizeof(m_logBuf));
    memset(m_commands, 0, sizeof(m_commands));

    registerSpiBootRequestCommand(AppSpiCommandBus);
    registerSpiOtaWaitCommand(AppSpiCommandBus);
    registerSpiAppPingCommand(AppSpiCommandBus);
    registerSpiCanBridgeCommand(AppSpiCommandBus);
    registerSpiCanFeedbackCommand(AppSpiCommandBus);
    registerSpiIdSnapshotCommand(AppSpiCommandBus);

    configureGpio();
    configureSpi0();
    configureDma();
    configureExti();
    configureSpiReadyExti();
}

/* ============================================================
 * 命令路由
 * ============================================================ */

void AppSpiCommand::registerHandler(ISpiCommandHandler *handler)
{
    if (!handler || m_commandCount >= kMaxCommands) {
        return;
    }
    m_commands[m_commandCount++] = handler;
}

void AppSpiCommand::processCommand()
{
    if (m_rxLen == 0U) {
        return;
    }

    /* 尝试按协议帧解析 */
    uint8_t frame_type = 0U;
    const uint8_t *payload = nullptr;
    uint16_t payload_len = 0U;

    if (spi_try_parse_frame(m_rxBuf, m_rxLen, &frame_type, &payload, &payload_len)) {
        if (CONFIG_SPI_APP_LOG_ENABLE != 0 && !isFlashRelatedFrame(frame_type)) {
            postLogFmt("[SPI-APP] 收到非刷写 SPI type=0x%02X", frame_type);
        }

        /* 合法帧：按 TYPE 分发给已注册命令处理器 */
        uint16_t tx_len = 0U;
        bool handled = false;

        SpiCommandContext ctx{};
        ctx.frame_type = frame_type;
        ctx.payload = payload;
        ctx.payload_len = payload_len;
        ctx.tx_buf = m_txBuf;
        ctx.tx_buf_size = kTxBufSize;
        ctx.tx_len = &tx_len;

        for (uint8_t i = 0U; i < m_commandCount; ++i) {
            ISpiCommandHandler *handler = m_commands[i];
            if (handler && handler->canHandle(frame_type)) {
                handler->handle(AppSpiCommandBus, ctx);
                handled = true;
                break;
            }
        }

        if (!handled) {
            postLogFmt("[SPI-APP] 未知 type=0x%02X -> ERROR", frame_type);
            uint8_t err = 0xEEU;
            spi_build_frame(kRspError, &err, 1U, m_txBuf, &tx_len);
        }

        if (tx_len == 0U) {
            /* 兜底：避免残留上一次应答帧 */
            uint8_t err = 0xEEU;
            spi_build_frame(kRspError, &err, 1U, m_txBuf, &tx_len);
        }

        m_txLen = tx_len;
        m_txPos = 0U;
    } else {
        /* 非标准帧：保留旧式单字节 0xB0 通道，后续新命令建议走注册式帧协议 */
        const uint8_t first_valid = m_rxBuf[0U];
        if (first_valid == CONFIG_SPI_APP_OTA_BOOT_CMD) {
            postLog("旧式0xB0 -> 进BOOT");

            uint16_t tx_len_legacy = 0U;
            SpiCommandContext ctx{};
            ctx.frame_type = first_valid;
            ctx.payload = nullptr;
            ctx.payload_len = 0U;
            ctx.tx_buf = m_txBuf;
            ctx.tx_buf_size = kTxBufSize;
            ctx.tx_len = &tx_len_legacy;

            bool handled = false;
            for (uint8_t i = 0U; i < m_commandCount; ++i) {
                ISpiCommandHandler *handler = m_commands[i];
                if (handler && handler->canHandle(first_valid)) {
                    handler->handle(AppSpiCommandBus, ctx);
                    handled = true;
                    break;
                }
            }

            if (!handled) {
                /* 兜底路径（handler 未注册时的死代码保护）：
                 * 同样使用异步路径，避免在 ISR 内执行 Flash 操作。
                 * 先装 0xB5 ACK，再设 pending 标志。 */
                m_txBuf[0] = CONFIG_SPI_APP_OTA_BOOT_ACK_OK;
                m_txBuf[1] = CONFIG_SPI_APP_OTA_BOOT_CMD;
                m_txBuf[2] = 0x4FU;
                m_txBuf[3] = 0x54U;
                tx_len_legacy = 4U;
                OtaBootRequest::requestEnterBootAsync();
                TaskManager::set(1UL << TASK_HEARTBEAT);
            }

            m_txLen = tx_len_legacy;
            m_txPos = 0U;
        } else {
            /* 无法识别 */
            postLogFmt("[SPI-APP] 非协议 0x%02X -> ERROR", first_valid);
            uint16_t tx_len = 0U;
            uint8_t err = 0xEEU;
            spi_build_frame(kRspError, &err, 1U, m_txBuf, &tx_len);
            m_txLen = tx_len;
            m_txPos = 0U;
        }
    }

    if (m_logPending) {
        /* 置位 TASK_SPI_LOG，唤醒主循环立刻打印日志 */
        TaskManager::set(1UL << TASK_SPI_LOG);
    }

    /* 应答帧已就绪：拉高 PB6（释放 SPIready）通知主机可发起下一笔事务。
     * 命令处理已在 ISR 内同步完成，无需 m_cmdPending 推迟机制。 */

    /* 有响应待发时，设置按铃标志阻止主循环 canFeedbackPushStep() 覆盖 m_txBuf。
     * ESP32 下次 CS assert 时 DMA 输出响应，onCsRelease 清除 m_ringPending。
     * 50ms 超时后 cancelRing() 清除，恢复 CAN 反馈推送。 */
    if (m_txLen > 0U) {
        m_ringPending = true;
        m_ringDeadline = SysTickTimer::getMs() + kRingTimeoutMs;
    }
    setSpiReady(true);
}

/* ============================================================
 * GD32 主动按铃：下拉 SPIready 请求 ESP32 来读
 * ============================================================ */

void AppSpiCommand::cancelRing()
{
    m_ringPending = false;
    m_ringTxLen = 0U;
    /* 清除待发响应，防止超时后残留帧在下一次 CS assert 时被错误输出 */
    m_txLen = 0U;
    m_txPos = 0U;
    /* 超时后允许重试，不依赖 ESP32 releaseReady 上升沿 */
    m_linkState.onRingTimeout();
    /* 释放 SPIready（高阻），避免永久占用线 */
    setSpiReady(true);
}

bool AppSpiCommand::requestEsp32Read(uint8_t frame_type, const uint8_t *payload, uint16_t payload_len)
{
    /* 若上一次按铃尚未被 ESP32 读走，拒绝重复按铃 */
    if (m_ringPending) {
        return false;
    }

    /* 构建请求帧到 m_txBuf（ESP32 下次读事务时通过 DMA 输出到 MISO） */
    uint16_t built_len = 0U;
    if (!spi_build_frame(frame_type, payload, payload_len, m_txBuf, &built_len)) {
        return false;
    }

    m_ringTxLen = built_len;
    m_txLen = built_len;
    m_txPos = 0U;
    m_ringDeadline = SysTickTimer::getMs() + kRingTimeoutMs;
    m_ringPending = true;
    /* 消费完成 flag，等 ESP32 releaseReady 触发 EXTI6 上升沿 */
    m_linkState.onRingStart();

    /* 下拉 SPIready，通知 ESP32「我有请求帧要给你读」 */
    setSpiReady(false);
    return true;
}

/* ============================================================
 * 主循环轮询：打印延迟日志 + 按铃超时看护
 * ============================================================ */

void AppSpiCommand::poll()
{
    /* 打印 ISR 推迟的日志 */
    char log_copy[kLogBufSize] = {};
    bool has_log = false;

    uint32_t save = RT_CRITICAL_SAVE();
    if (m_logPending) {
        memcpy(log_copy, m_logBuf, sizeof(log_copy));
        m_logPending = false;
        has_log = true;
    }
    RT_CRITICAL_RESTORE(save);

    if (has_log) {
        printf("%s\r\n", log_copy);
    }

    /* 按铃超时看护：ESP32 未在 kRingTimeoutMs 内来读则放弃本次按铃。
     * 防止 ESP32 不响应时永久占用 SPIready 线导致双方死锁。 */
    if (m_ringPending) {
        uint32_t save2 = RT_CRITICAL_SAVE();
        if (m_ringPending) {
            if ((int32_t)(SysTickTimer::getMs() - m_ringDeadline) >= 0) {
                printf("[SPI-APP] 按铃超时取消 (ESP32 未响应, 释放 SPIready 重试)\r\n");
                cancelRing();
            }
        }
        RT_CRITICAL_RESTORE(save2);
    }
}

/* ============================================================
 * CS 边沿处理
 * ============================================================ */

void AppSpiCommand::onCsAssert()
{
    if (m_csActive) {
        return;
    }
    m_csActive = true;
    /* CS 下降沿立即拉低 PB6:表示从机即将忙碌，
     * 防止主机在 onCsRelease 准备好响应前抢跑发起下一笔 CS。
     * (若此帧被 shouldIgnoreTransaction 忽略,onCsRelease 会恢复 HIGH) */
    setSpiReady(false);
    m_rxLen = 0U;
    m_txPos = 0U;
    m_txActiveThisCs = false;

    /* 停止 DMA 并清理旧状态 */
    DMA_CHCTL(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH) &= ~DMA_CHXCTL_CHEN;
    spi_dma_disable(SPI0, SPI_DMA_TRANSMIT);

    /* 与 BOOT 一致：清除 SPI 双缓冲中的残留数据 */
    spi_i2s_data_transmit(SPI0, 0xFFU);
    if (spi_i2s_flag_get(SPI0, SPI_FLAG_TBE) != RESET) {
        spi_i2s_data_transmit(SPI0, 0xFFU);
    }

    /* 清除错误标志 */
    if (spi_i2s_interrupt_flag_get(SPI0, SPI_I2S_INT_FLAG_RXORERR) != RESET) {
        (void)spi_i2s_data_receive(SPI0);
    }
    if (spi_i2s_interrupt_flag_get(SPI0, SPI_I2S_INT_FLAG_FERR) != RESET) {
        spi_i2s_format_error_clear(SPI0, SPI_FLAG_FERR);
    }

    /* 启动 DMA 发送响应帧（与 BOOT 完全一致） */
    if (m_txLen > 0U) {
        m_txActiveThisCs = true;
        spi_dma_enable(SPI0, SPI_DMA_TRANSMIT);
        startSpiTxDma(m_txBuf, m_txLen);
    } else {
        /* 无响应时发送全 0xFF 填充 */
        spi_dma_enable(SPI0, SPI_DMA_TRANSMIT);
        startSpiTxDma(m_txBuf, kTxBufSize);
    }
}

void AppSpiCommand::onCsRelease()
{
    if (!m_csActive) {
        return;
    }
    m_csActive = false;

    /* 停止 DMA */
    DMA_CHCTL(SPI_TX_DMA_PERIPH, SPI_TX_DMA_CH) &= ~DMA_CHXCTL_CHEN;
    spi_dma_disable(SPI0, SPI_DMA_TRANSMIT);

    if (spi_i2s_interrupt_flag_get(SPI0, SPI_I2S_INT_FLAG_RBNE) != RESET) {
        uint8_t last_byte = (uint8_t)(spi_i2s_data_receive(SPI0) & 0xFFU);
        if (m_rxLen < sizeof(m_rxBuf)) {
            m_rxBuf[m_rxLen++] = last_byte;
        }
    }

    /* 若本次 CS 事务是 ESP32 响应 GD32 按铃来读请求帧，
     * 则 GD32 的请求帧已通过 DMA 输出到 MISO，取消按铃状态。
     *
     * 但需区分：ESP32 发的是 dummy 读（按铃响应）还是 0xB0 命令（OTA 请求）。
     * 若 GD32 正在按铃时 ESP32 发 0xB0，会因 m_ringPending=true 被误吞，
     * 导致 OTA 无法启动。检测到 0xB0 时取消按铃并走正常命令处理。 */
    if (m_ringPending) {
        if (m_rxLen >= 1U && m_rxBuf[0] == CONFIG_SPI_APP_OTA_BOOT_CMD) {
            /* ESP32 发的是 0xB0 Bootloader 请求，不是按铃响应。
             * 取消按铃，清空 TX 让 processCommand() 重新装载 0xB5 应答。
             * 不释放 SPIready，processCommand() 末尾会释放。 */
            m_ringPending = false;
            m_ringTxLen = 0U;
            m_txLen = 0U;
            m_txPos = 0U;
            memset(m_txBuf, 0xFF, sizeof(m_txBuf));
            /* 继续走 shouldIgnoreTransaction + processCommand()，不 return */
        } else if (containsSyncSof(m_rxBuf, m_rxLen)) {
            /* ESP32 发的是协议帧（如 PING/OTA 等），不是按铃响应。
             * 取消按铃，清空 TX 让 processCommand() 重新装载对应应答。
             * 不释放 SPIready，processCommand() 末尾会释放。 */
            m_ringPending = false;
            m_ringTxLen = 0U;
            m_txLen = 0U;
            m_txPos = 0U;
            memset(m_txBuf, 0xFF, sizeof(m_txBuf));
            /* 继续走 shouldIgnoreTransaction + processCommand()，不 return */
        } else {
            /* 正常按铃响应：请求帧已被读走，取消按铃状态 */
            m_ringPending = false;
            m_ringTxLen = 0U;
            /* 请求帧已被读走，清空 TX 防止下次事务重复输出 */
            m_txLen = 0U;
            m_txPos = 0U;
            memset(m_txBuf, 0xFF, sizeof(m_txBuf));
            /* 释放 SPIready，通知 ESP32 本帧完成 */
            setSpiReady(true);
            /* 上层若需要 ESP32 处理该请求帧，由 ESP32 侧读到的帧 TYPE 决定后续动作 */
            return;
        }
    }

    if (shouldIgnoreTransaction(m_rxBuf, m_rxLen)) {
        m_rxLen = 0U;
        if (m_txActiveThisCs) {
            m_txLen = 0U;
            m_txPos = 0U;
            memset(m_txBuf, 0xFF, sizeof(m_txBuf));
        }
        m_txActiveThisCs = false;
        /* 忽略事务(空轮询/残包)后恢复 PB6=HIGH，
         * 避免 PB6 卡 LOW 导致 ESP32 等待上升沿超时 */
        setSpiReady(true);
        return;
    }

    m_txLen = 0U;
    m_txPos = 0U;
    m_txActiveThisCs = false;
    memset(m_txBuf, 0xFF, sizeof(m_txBuf));

    /* 命令处理在 EXTI ISR 内同步完成（对齐 BOOT 的 isrProcessFrame 模式），
     * 消除主循环延迟。处理完成后 processCommand() 末尾释放 SPIready。 */
    processCommand();
}

/* ============================================================
 * SPI0 / EXTI 中断处理
 * ============================================================ */

void AppSpiCommand::onInterrupt()
{
    if (spi_i2s_interrupt_flag_get(SPI0, SPI_I2S_INT_FLAG_RBNE) != RESET) {
        if (!m_csActive && gpio_input_bit_get(GPIOA, GPIO_PIN_15) == RESET) {
            onCsAssert();
        }
        uint8_t byte = (uint8_t)(spi_i2s_data_receive(SPI0) & 0xFFU);
        if (m_csActive && m_rxLen < sizeof(m_rxBuf)) {
            m_rxBuf[m_rxLen++] = byte;
        }
    }

    /* TBE 已由 DMA 替代，不再处理 */

    if (spi_i2s_interrupt_flag_get(SPI0, SPI_I2S_INT_FLAG_RXORERR) != RESET) {
        /* 读取并丢弃 overrun 字节以清除标志，但保留已收到的帧数据。
         * 丢失的字节会导致 CRC 校验失败，由 spi_try_parse_frame 优雅处理
         * （返回 false -> processCommand 构建 ERROR 响应），
         * 而不是重置 m_rxLen 导致整帧丢失。 */
        (void)spi_i2s_data_receive(SPI0);
    }

    if (spi_i2s_interrupt_flag_get(SPI0, SPI_I2S_INT_FLAG_FERR) != RESET) {
        spi_i2s_format_error_clear(SPI0, SPI_FLAG_FERR);
    }
}

void AppSpiCommand::onCsExtiInterrupt()
{
    if (exti_interrupt_flag_get(EXTI_15) != RESET) {
        exti_interrupt_flag_clear(EXTI_15);
        if (gpio_input_bit_get(GPIOA, GPIO_PIN_15) == RESET) {
            onCsAssert();
        } else {
            onCsRelease();
        }
    }
}

extern "C" void SPI0_IRQHandler(void)
{
    AppSpiCommandBus.onInterrupt();
}

extern "C" void EXTI10_15_IRQHandler(void)
{
    AppSpiCommandBus.onCsExtiInterrupt();
}

extern "C" void EXTI5_9_IRQHandler(void)
{
    AppSpiCommandBus.onSpiReadyExti();
}