/* ext_relay.c - 485 扩展继电器板(4 路带反馈)主机侧支持
 *
 * 硬件: 与称重秤共用 USART2 RS485 总线(9600-8N1, DMA+IDLE 定帧)
 * 协议: Modbus RTU, 从机地址 0x10, 详见 Docs/RS485扩展继电器协议.md
 *   FC05 写单线圈(线圈0~3=继电器1~4, 0xFF00吸合/0x0000断开), 从机回显
 *   FC03 读保持寄存器 0x0000 起 4 个: 输出状态/反馈状态/故障标志/固件版本
 * 时序: 总线静默 >=50ms 才发帧(与秤查询共用 rs485_bus 时间戳);
 *       应答超时 300ms 补发 1 次; 空闲每 2s 轮询一次状态兼在线检测
 */

#include "ext_relay.h"
#include "relay.h"
#include "uart.h"
#include "log.h"
#include "network.h"
#include "FreeRTOS.h"
#include "task.h"
#include <string.h>
#include <stdio.h>

#define EXT_RESP_TIMEOUT_MS   300u    /* 应答超时 */
#define EXT_FB_SETTLE_MS      150u    /* 命令回显后等触点/负载稳定再读反馈 */
#define EXT_POLL_INTERVAL_MS  2000u   /* 空闲轮询周期 */
#define EXT_OFFLINE_MISS      3u      /* 连续失败次数判离线 */

/* Modbus CRC16(与秤同款多项式) */
static uint16_t ext_crc16(const uint8_t *data, uint16_t len)
{
    uint16_t crc = 0xFFFF;
    for (uint16_t i = 0; i < len; i++) {
        crc ^= data[i];
        for (uint8_t j = 0; j < 8; j++) {
            crc = (crc & 0x0001) ? ((crc >> 1) ^ 0xA001) : (crc >> 1);
        }
    }
    return crc;
}

/* 总线发送: 等 50ms 静默 + 清接收缓冲(防陈旧帧) + 发送 + 刷新时间戳 */
static void ext_tx(const uint8_t *frame, uint16_t len)
{
    uint32_t dt = HAL_GetTick() - rs485_bus_last_tick();
    if (dt < 50u) vTaskDelay(50u - dt);
    USART2_FlushRxBuf();
    HAL_UART_Transmit(&huart2, (uint8_t *)frame, len, 100);
    rs485_bus_touch();
}

static void ext_send_fc05(uint8_t ch, uint8_t on)
{
    uint8_t f[8];
    f[0] = EXT_RELAY_ADDR;
    f[1] = 0x05;
    f[2] = 0x00;
    f[3] = (uint8_t)(ch - 1);            /* 线圈地址 0~3 */
    f[4] = on ? 0xFF : 0x00;
    f[5] = 0x00;
    uint16_t c = ext_crc16(f, 6);
    f[6] = (uint8_t)(c & 0xFF);
    f[7] = (uint8_t)(c >> 8);
    ext_tx(f, 8);
}

static void ext_send_fc03(void)
{
    uint8_t f[8];
    f[0] = EXT_RELAY_ADDR;
    f[1] = 0x03;
    f[2] = 0x00; f[3] = 0x00;            /* 起始寄存器 0x0000 */
    f[4] = 0x00; f[5] = 0x04;            /* 读 4 个 */
    uint16_t c = ext_crc16(f, 6);
    f[6] = (uint8_t)(c & 0xFF);
    f[7] = (uint8_t)(c >> 8);
    ext_tx(f, 8);
}

/* 扩展板状态(最近一轮 FC03 应答) */
static uint8_t  s_online = 0;
static uint8_t  s_state = 0;    /* REG0 输出状态 bit0~3 */
static uint8_t  s_fb = 0;       /* REG1 反馈状态 */
static uint8_t  s_fault = 0;    /* REG2 故障标志 */
static uint16_t s_ver = 0;      /* REG3 从机版本 */
static uint8_t  s_miss = 0;     /* 连续无应答计数 */
static uint32_t s_last_poll = 0;

/* 命令状态机 */
static uint8_t  cmd_pending = 0;   /* 有命令待发送 */
static uint8_t  cmd_stage = 0;     /* 0闲 1等FC05回显 2触点稳定延时 3等FC03应答 */
static uint8_t  cmd_ch = 0, cmd_on = 0, cmd_retry = 0;
static uint8_t  cmd_is_poll = 0;   /* 当前事务是轮询(不应答平台) */
static uint32_t cmd_tick = 0;
static char     cmd_id[20] = {0};

/* 帧事件(on_frame 置位, process 消费; 同在 app_task 单线程) */
static uint8_t rx_echo_ok = 0;
static uint8_t rx_state_ok = 0;
static uint8_t rx_exc = 0;

uint8_t ext_relay_online(void)     { return s_online; }
uint8_t ext_relay_state_mask(void) { return s_state; }
uint8_t ext_relay_fault_mask(void) { return s_fault; }

static void ext_note_success(void)
{
    s_miss = 0;
    if (!s_online) {
        s_online = 1;
        log_info("> EXT: 扩展继电器板上线 (从机版本 V%u.%02X)", s_ver >> 8, s_ver & 0xFF);
        relayStatueUpdata();   /* 上线后补一次全状态, 平台刷新 sw5~sw8 */
    }
}

static void ext_note_fail(void)
{
    if (s_miss < 255) s_miss++;
    if (s_online && s_miss >= EXT_OFFLINE_MISS) {
        s_online = 0;
        log_warn("> EXT: 扩展继电器板离线(连续 %u 次无应答)", EXT_OFFLINE_MISS);
    }
}

static void ext_respond(int ok, const char *msg)
{
    if (cmd_id[0]) {
        NET_publish_response(cmd_id, ok, msg);
        cmd_id[0] = 0;
    }
}

void ext_relay_cmd(uint8_t ch, uint8_t on, const char *id)
{
    if (ch < 1 || ch > EXT_RELAY_CH) return;
    if (!s_online) {
        log_warn("> EXT: 扩展板离线, 拒绝 SW%d 命令", ch + 4);
        if (id) NET_publish_response(id, 0, "ext relay board offline");
        return;
    }
    if (cmd_pending || cmd_stage != 0) {
        log_warn("> EXT: 上一命令未完成, 拒绝 SW%d 命令", ch + 4);
        if (id) NET_publish_response(id, 0, "ext relay busy");
        return;
    }
    cmd_ch = ch;
    cmd_on = on ? 1 : 0;
    if (id) {
        strncpy(cmd_id, id, sizeof(cmd_id) - 1);
        cmd_id[sizeof(cmd_id) - 1] = 0;
    } else {
        cmd_id[0] = 0;
    }
    cmd_pending = 1;
    log_info("> EXT: SW%d %s (下发扩展板)", ch + 4, on ? "开" : "关");
}

/* 485 帧处理: feed_scale 收帧后按站号 0x10 分发到这里 */
void ext_relay_on_frame(const uint8_t *b, uint16_t len)
{
    if (len < 5) return;
    uint16_t c = ext_crc16(b, (uint16_t)(len - 2));
    uint16_t r = (uint16_t)(((uint16_t)b[len - 1] << 8) | b[len - 2]);
    if (c != r) {
        log_warn("> EXT: 帧 CRC 错误 (len=%u)", (unsigned)len);
        return;
    }
    if (b[1] & 0x80) {   /* Modbus 异常应答 */
        log_warn("> EXT: 异常应答 FC=%02X 码=%02X", b[1] & 0x7F, b[2]);
        rx_exc = 1;
        return;
    }
    if (b[1] == 0x05 && len == 8) {
        /* 回显校验: 线圈地址与通断值必须与请求一致 */
        if (b[2] == 0x00 && b[3] == (uint8_t)(cmd_ch - 1) &&
            ((b[4] == 0xFF && cmd_on) || (b[4] == 0x00 && !cmd_on)) && b[5] == 0x00) {
            rx_echo_ok = 1;
        } else {
            log_warn("> EXT: FC05 回显与请求不符");
        }
        return;
    }
    if (b[1] == 0x03 && len == 13 && b[2] == 0x08) {
        /* 4 个寄存器大端: 输出/反馈/故障只用低字节 */
        s_state = b[4] & 0x0F;
        s_fb    = b[6] & 0x0F;
        s_fault = b[8] & 0x0F;
        s_ver   = (uint16_t)(((uint16_t)b[9] << 8) | b[10]);
        rx_state_ok = 1;
        return;
    }
    log_warn("> EXT: 未识别帧 FC=%02X len=%u", b[1], (unsigned)len);
}

void ext_relay_process(void)
{
    uint32_t now = HAL_GetTick();
    if (now < 3000u) return;   /* 上电稳定期, 与秤首次查询对齐 */

    /* 取新命令(仅空闲时) */
    if (cmd_pending && cmd_stage == 0) {
        cmd_pending = 0;
        cmd_is_poll = 0;
        cmd_retry = 0;
        cmd_stage = 1;
        ext_send_fc05(cmd_ch, cmd_on);
        cmd_tick = now;
        return;
    }

    if (cmd_stage == 1) {   /* 等 FC05 回显 */
        if (rx_echo_ok) {
            rx_echo_ok = 0;
            ext_note_success();
            cmd_stage = 2;
            cmd_tick = now;
        } else if (rx_exc || (now - cmd_tick) > EXT_RESP_TIMEOUT_MS) {
            rx_exc = 0;
            if (cmd_retry < 1) {
                cmd_retry++;
                ext_send_fc05(cmd_ch, cmd_on);
                cmd_tick = now;
            } else {
                log_warn("> EXT: SW%d 命令无应答", cmd_ch + 4);
                ext_respond(0, "ext relay no response");
                ext_note_fail();
                cmd_stage = 0;
            }
        }
        return;
    }

    if (cmd_stage == 2) {   /* 触点/负载稳定延时 */
        if ((now - cmd_tick) >= EXT_FB_SETTLE_MS) {
            cmd_retry = 0;
            cmd_stage = 3;
            ext_send_fc03();
            cmd_tick = now;
        }
        return;
    }

    if (cmd_stage == 3) {   /* 等 FC03 状态应答(命令收尾或周期轮询共用) */
        if (rx_state_ok) {
            rx_state_ok = 0;
            ext_note_success();
            if (cmd_is_poll) {
                cmd_is_poll = 0;
                if (s_fault) {
                    log_warn("> EXT: 反馈异常标志=%02X (输出=%02X 反馈=%02X)", s_fault, s_state, s_fb);
                }
            } else {
                uint8_t bit = (uint8_t)(1u << (cmd_ch - 1));
                int ok = (((s_state & bit) != 0) == cmd_on) && ((s_fault & bit) == 0);
                if (ok) {
                    log_info("> EXT: SW%d %s成功 (反馈=%02X)", cmd_ch + 4, cmd_on ? "开" : "关", s_fb);
                    ext_respond(1, "OK");
                } else {
                    log_warn("> EXT: SW%d %s未生效 (输出=%02X 反馈=%02X 故障=%02X)",
                             cmd_ch + 4, cmd_on ? "开" : "关", s_state, s_fb, s_fault);
                    ext_respond(0, "ext relay failed / load unpowered");
                }
                relayStatueUpdata();   /* 命令完成后上报全状态 */
            }
            cmd_stage = 0;
        } else if (rx_exc || (now - cmd_tick) > EXT_RESP_TIMEOUT_MS) {
            rx_exc = 0;
            if (cmd_retry < 1) {
                cmd_retry++;
                ext_send_fc03();
                cmd_tick = now;
            } else {
                if (!cmd_is_poll) {
                    log_warn("> EXT: SW%d 状态确认无应答", cmd_ch + 4);
                    ext_respond(0, "ext relay no response");
                }
                cmd_is_poll = 0;
                ext_note_fail();
                cmd_stage = 0;
            }
        }
        return;
    }

    /* 空闲: 周期轮询(兼在线检测) */
    if ((now - s_last_poll) >= EXT_POLL_INTERVAL_MS) {
        s_last_poll = now;
        cmd_is_poll = 1;
        cmd_retry = 0;
        cmd_stage = 3;
        ext_send_fc03();
        cmd_tick = now;
    }
}