/**
 * ZhaTianRX - STC8H1K08 接收机固件
 * 主程序: NRF24L01 接收 + 4路舵机PWM + SBUS输出 + 串口命令
 *
 * MCU:   STC8H1K08 (SOP16/SOP20)
 * 编译:  SDCC -mmcs51 --model-small
 *
 * 引脚分配:
 *   CH1(P3.7) CH2(P3.6) CH3(P3.5) CH4(P3.4) - 舵机PWM输出 50Hz
 *   BAT_ADC(P3.3/ADC11) - 电池电压分压输入
 *   LED(P3.2) - 状态指示灯 (低电平亮)
 *   TX(P3.1) - UART1 TX / SBUS 输出 (经板上三极管反相)
 *   RX(P3.0) - UART1 RX / 命令输入
 *
 * NRF24L01 (硬件SPI):
 *   SCK(P1.5) CE(P1.6) IRQ(P1.7) CSN(P5.4) MISO(P1.3) MOSI(P1.4)
 */
# ifndef CONFIG
# define CONFIG
# include "CONFIG.h"
# endif

#include "NRF24.h"
#include "UART.h"

/* ========================================================================
 * 函数声明
 * ======================================================================== */

static void System_Init(void);
static void GPIO_Init(void);
static void Timer0_Init(void);
static void UART1_Init(void);
static void ADC_Init(void);
static void IAP_Init(void);

static uint8_t IAP_ReadByte(uint16_t addr);
static void IAP_WriteByte(uint16_t addr, uint8_t dat);
static void IAP_EraseSector(uint16_t addr);

static void EEPROM_LoadConfig(void);
static void EEPROM_SaveConfig(void);
static uint8_t EEPROM_IsBound(void);

static void LED_SetMode(uint8_t mode);
static void LED_Update(void);

static void PWM_SetChannel(uint8_t ch, uint16_t pulse_us);
static void PWM_SetAllFailsafe(void);

static void UART1_SendByte(uint8_t dat);
static void UART1_SendString(const char *s);
static void UART1_SendStringLen(const char *s, uint8_t len);

static void SBUS_SendFrame(void);
static void SBUS_Init(void);

static void CRFS_SendFrame(void);
static void CRFS_Init(void);

static void Cmd_Parse(void);
static void Cmd_Respond(const char *resp);

static void NRF_ProcessPacket(void);
static void NRF_EnterBindMode(void);
static uint8_t NRF_DoBindScan(void);
static void NRF_SendTelemetry(void);

/* ========================================================================
 * 系统初始化
 * ======================================================================== */

static void System_Init(void) {

}

static void GPIO_Init(void) {
    
}

/* ========================================================================
 * 定时器0 - PWM 时基 (4us 中断)
 * ======================================================================== */

static void Timer0_Init(void) {

}

/* T0 中断服务 - 4us一次, 生成4路PWM */
void tm0_isr(void) __interrupt(1) {
    static uint16_t pwm_cnt = 0;

    pwm_cnt++;
    if (pwm_cnt >= PWM_PERIOD) {
        pwm_cnt = 0;
    }

    /* 4路舵机PWM (P3.4-P3.7) */
    if (pwm_cnt < pwm_ch[0]) P37 = 1; else P37 = 0;
    if (pwm_cnt < pwm_ch[1]) P36 = 1; else P36 = 0;
    if (pwm_cnt < pwm_ch[2]) P35 = 1; else P35 = 0;
    if (pwm_cnt < pwm_ch[3]) P34 = 1; else P34 = 0;

    /* 系统滴答 (每10ms) */
    if (pwm_cnt == 0) {
        sys_tick++;
    }
}

/* ========================================================================
 * ADC - 电池电压检测 (P3.3/ADC11)
 * ======================================================================== */

static void ADC_Init(void) {
    ADCCFG = ADC_RESFMT;        /* 右对齐, 12位结果 */
    ADC_CONTR = ADC_POWER;      /* 开启ADC电源 */
    /* 选择通道11 (P3.3) */
    ADC_CONTR = (ADC_CONTR & 0xF0) | 0x0B;
}

/* 读取指定ADC通道 */
static uint16_t ADC_ReadChannel(uint8_t ch) {
    ADC_CONTR = (ADC_CONTR & 0xF0) | ch;  /* 切换通道 */
    __asm nop __endasm;                    /* 等待通道切换稳定 */
    __asm nop __endasm;
    ADC_CONTR |= ADC_START;               /* 启动转换 */
    while (!(ADC_CONTR & ADC_FLAG));      /* 等待完成 */
    ADC_CONTR &= ~ADC_FLAG;               /* 清除标志 */
    return ((uint16_t)ADC_RES << 8) | ADC_RESL;
}

static uint16_t ADC_Read(void) {
    return ADC_ReadChannel(0x0B);  /* P3.3/ADC11 */
}

/* 读取内部带隙基准电压 (通道14), 用于反算VCC */
/* VCC(mV) = 1190 * 4096 / bandgap_adc */
static uint16_t ADC_ReadBandgap(void) {
    return ADC_ReadChannel(0x0E);  /* 内部带隙基准 */
}

/* ========================================================================
 * LED 控制 (P3.2, 低电平亮)
 * ======================================================================== */

static void LED_SetMode(uint8_t mode) {
    static uint8_t current_mode = 0xFF;
    if (mode != current_mode) {
        current_mode = mode;
        switch (mode) {
            case LED_ON:    P32 = 0; break;  /* 常亮 */
            case LED_OFF:   P32 = 1; break;  /* 熄灭 */
            default: break;  /* 闪烁模式由 LED_Update 处理 */
        }
    }
}

static void LED_Update(void) {
    uint8_t mode;
    if (nrf_hw_error) {
        mode = LED_BLINK_DOUBLE;
    } else if (rx_state == RX_STATE_BINDING) {
        mode = LED_BLINK_FAST;
    } else if (rx_state == RX_STATE_CONNECTED) {
        mode = LED_ON;
    } else {
        mode = LED_BLINK_SLOW;
    }

    switch (mode) {
        case LED_BLINK_SLOW:  /* 1Hz: 500ms亮/500ms灭 */
            P32 = (sys_tick % 100 < 50) ? 0 : 1;
            break;
        case LED_BLINK_FAST:  /* 3Hz: ~167ms亮/~167ms灭 */
            P32 = (sys_tick % 30 < 15) ? 0 : 1;
            break;
        case LED_BLINK_DOUBLE: /* 双闪: 100ms亮+100ms灭+100ms亮+700ms灭 */
            {
                uint16_t t = sys_tick % 100;
                if (t < 10)       P32 = 0;  /* 亮 100ms */
                else if (t < 20)  P32 = 1;  /* 灭 100ms */
                else if (t < 30)  P32 = 0;  /* 亮 100ms */
                else              P32 = 1;  /* 灭 700ms */
            }
            break;
        case LED_ON:
            P32 = 0;
            break;
        default:
            P32 = 1;
            break;
    }
}

/* ========================================================================
 * PWM 通道设置
 * ======================================================================== */

static void PWM_SetChannel(uint8_t ch, uint16_t pulse_us) {
    if (ch >= CHANNEL_COUNT) return;

    /* 限制脉宽范围: 1.0ms ~ 2.0ms */
    if (pulse_us < 1000) pulse_us = 1000;
    if (pulse_us > 2000) pulse_us = 2000;

    /* 转换为4us步长 */
    pwm_ch[ch] = pulse_us / 4;
}

static void PWM_SetAllFailsafe(void) {
    /* 失控保护: 所有通道回到中位 */
    for (uint8_t i = 0; i < CHANNEL_COUNT; i++) {
        pwm_ch[i] = PWM_MID;
    }
}

/* ========================================================================
 * 串口命令解析
 * ======================================================================== */

static void Cmd_Respond(const char *resp) {
    UART1_SendString(resp);
    UART1_SendString("\r\n");
}

static void Cmd_Parse(void) {
    if (!uart_cmd_ready) return;
    uart_cmd_ready = 0;

    char *cmd = (char *)uart_rx_buf;

    /* MODEL(SBUS) - 切换到SBUS模式 */
    if (strcmp(cmd, "MODEL(SBUS)") == 0) {
        out_mode = OUT_MODE_SBUS;
        SBUS_Init();
        Cmd_Respond("OK");
        return;
    }

    /* MODEL(PWM) - 切换到PWM模式 */
    if (strcmp(cmd, "MODEL(PWM)") == 0) {
        out_mode = OUT_MODE_PWM;
        /* 重新初始化UART1为115200 */
        UART1_Init();
        Cmd_Respond("OK");
        return;
    }

    /* MODEL(UART) - 切换到UART模式 (占位) */
    if (strcmp(cmd, "MODEL(UART)") == 0) {
        out_mode = OUT_MODE_UART;
        UART1_Init();
        Cmd_Respond("OK");
        return;
    }

    /* MODEL(CRFS) - 切换到CRFS/CRSF输出模式 */
    if (strcmp(cmd, "MODEL(CRFS)") == 0) {
        out_mode = OUT_MODE_CRFS;
        CRFS_Init();
        Cmd_Respond("OK");
        return;
    }

    /* ADDR(0xHH HH HH HH HH) - 切换NRF24L01地址 */
    if (cmd[0] == 'A' && cmd[1] == 'D' && cmd[2] == 'D' && cmd[3] == 'R') {
        /* 解析: ADDR(0xHH HH HH HH HH) */
        static uint8_t __xdata new_addr[NRF_ADDR_WIDTH];
        uint8_t ok = 1;
        char *p = cmd + 5;  /* 跳过 "ADDR(" */
        for (uint8_t i = 0; i < NRF_ADDR_WIDTH; i++) {
            /* 跳过 "0x" */
            if (*p == '0' && (*(p+1) == 'x' || *(p+1) == 'X')) p += 2;
            /* 跳过空格 */
            while (*p == ' ') p++;
            /* 解析两位十六进制 */
            uint8_t hi = 0, lo = 0;
            if (*p >= '0' && *p <= '9') hi = *p - '0';
            else if (*p >= 'A' && *p <= 'F') hi = *p - 'A' + 10;
            else if (*p >= 'a' && *p <= 'f') hi = *p - 'a' + 10;
            else { ok = 0; break; }
            p++;
            if (*p >= '0' && *p <= '9') lo = *p - '0';
            else if (*p >= 'A' && *p <= 'F') lo = *p - 'A' + 10;
            else if (*p >= 'a' && *p <= 'f') lo = *p - 'a' + 10;
            else { ok = 0; break; }
            p++;
            new_addr[i] = (hi << 4) | lo;
        }
        if (ok) {
            for (uint8_t i = 0; i < NRF_ADDR_WIDTH; i++)
                tx_addr[i] = new_addr[i];
            NRF24L01_WriteBuf(NRF_TX_ADDR, tx_addr, NRF_ADDR_WIDTH);
            NRF24L01_WriteBuf(NRF_RX_ADDR_P0, tx_addr, NRF_ADDR_WIDTH);
            Cmd_Respond("OK");
        } else {
            Cmd_Respond("ERR_ADDR");
        }
        return;
    }

    /* TUN(N) - 切换RF频道 */
    if (cmd[0] == 'T' && cmd[1] == 'U' && cmd[2] == 'N') {
        uint8_t ch = 0;
        char *p = cmd + 4;  /* 跳过 "TUN(" */
        while (*p >= '0' && *p <= '9') {
            ch = ch * 10 + (*p - '0');
            p++;
        }
        if (ch <= NRF_MAX_CHANNEL) {
            NRF24L01_SetChannel(ch);
            Cmd_Respond("OK");
        } else {
            Cmd_Respond("ERR_RANGE");
        }
        return;
    }

    /* DEL(BIND) - 清除对频信息 */
    if (strcmp(cmd, "DEL(BIND)") == 0) {
        /* 擦除EEPROM中的对频标志 */
        IAP_EraseSector(0x0000);
        IAP_WriteByte(EEPROM_ADDR_BIND_FLAG, 0x00);
        rx_state = RX_STATE_BINDING;
        NRF_EnterBindMode();
        Cmd_Respond("OK");
        return;
    }

    /* PHRASE(xxxxxx) - 设置对频短语, 1~6位字母数字 */
    if (cmd[0] == 'P' && cmd[1] == 'H' && cmd[2] == 'R' && cmd[3] == 'A'
        && cmd[4] == 'S' && cmd[5] == 'E') {
        uint8_t i;
        char *p = cmd + 7;  /* 跳过 "PHRASE(" */
        /* 计算短语长度 (直到 ')' 或结束) */
        uint8_t len = 0;
        while (p[len] && p[len] != ')' && len < RF_PHRASE_LEN) {
            char c = p[len];
            /* 只允许字母和数字 */
            if (!((c >= '0' && c <= '9') ||
                  (c >= 'A' && c <= 'Z') ||
                  (c >= 'a' && c <= 'z'))) {
                Cmd_Respond("ERR");
                return;
            }
            len++;
        }
        if (len < 1 || len > RF_PHRASE_LEN) {
            Cmd_Respond("ERR_RANGE");
            return;
        }
        /* 复制新短语 */
        for (i = 0; i < len; i++)
            bind_phrase[i] = (uint8_t)p[i];
        /* 剩余部分用空格填充 */
        for (i = len; i < RF_PHRASE_LEN; i++)
            bind_phrase[i] = ' ';
        /* 保存到EEPROM */
        IAP_EraseSector(0x0000);
        IAP_WriteByte(EEPROM_ADDR_BIND_FLAG, EEPROM_BIND_MAGIC);
        for (i = 0; i < NRF_ADDR_WIDTH; i++)
            IAP_WriteByte(EEPROM_ADDR_TX_ADDR + i, tx_addr[i]);
        IAP_WriteByte(EEPROM_ADDR_RF_CH, rf_channel);
        for (i = 0; i < RF_PHRASE_LEN; i++)
            IAP_WriteByte(EEPROM_ADDR_BIND_PHRASE + i, bind_phrase[i]);
        /* 重新初始化NRF以使用新短语 */
        NRF24L01_Init();
        NRF24L01_RXMode();
        Cmd_Respond("OK");
        return;
    }

    /* TELEM(N) - 设置回传频率 1~10Hz */
    if (cmd[0] == 'T' && cmd[1] == 'E' && cmd[2] == 'L' && cmd[3] == 'E'
        && cmd[4] == 'M') {
        uint8_t hz = 0;
        char *p = cmd + 6;  /* 跳过 "TELEM(" */
        while (*p >= '0' && *p <= '9') {
            hz = hz * 10 + (*p - '0');
            p++;
        }
        if (hz >= 1 && hz <= 10) {
            telem_rate_hz = hz;
            Cmd_Respond("OK");
        } else {
            Cmd_Respond("ERR_RANGE");
        }
        return;
    }

    /* 未知命令 */
    Cmd_Respond("UNK");
}

/* ========================================================================
 * 主函数
 * ======================================================================== */

void main(void) {
    /* 系统初始化 */
    System_Init();
    GPIO_Init();
    Timer0_Init();
    UART1_Init();
    ADC_Init();
    IAP_Init();

    /* 初始PWM: 中位 */
    PWM_SetAllFailsafe();

    /* 从EEPROM加载配置 */
    EEPROM_LoadConfig();

    /* 初始化NRF24L01 */
    NRF24L01_Init();

    /* 检测NRF模块 */
    if (!NRF24L01_Check()) {
        /* NRF模块未检测到, 设置硬件错误标志, LED双闪 */
        nrf_hw_error = 1;
    }

    /* 进入接收模式 */
    if (rx_state == RX_STATE_BINDING) {
        NRF_EnterBindMode();
    } else {
        NRF24L01_RXMode();
    }

    /* 主循环 */
    while (1) {
        /* 处理串口命令 */
        Cmd_Parse();

        /* NRF 硬件错误时定期重检 */
        if (nrf_hw_error) {
            static uint16_t last_check_tick = 0;
            if (sys_tick - last_check_tick >= 50) {  /* 每 500ms 重检一次 */
                last_check_tick = sys_tick;
                NRF24L01_Init();
                if (NRF24L01_Check()) {
                    nrf_hw_error = 0;
                    NRF24L01_RXMode();
                }
            }
            LED_Update();
            continue;
        }

        /* 对频模式 */
        if (rx_state == RX_STATE_BINDING) {
            if (NRF_DoBindScan()) {
                /* 对频成功, 继续 */
            }
            /* 更新LED */
            LED_Update();
            continue;
        }

        /* 接收数据包 */
        if (NRF24L01_IsDataReady()) {
            NRF_ProcessPacket();
        } else {
            lost_packet_cnt++;
            /* 每 100 个丢失包更新一次丢包率 (滑动窗口) */
            static uint16_t loss_window_cnt = 0;
            static uint16_t loss_window_pkts = 0;
            loss_window_cnt++;
            loss_window_pkts++;
            if (loss_window_cnt >= 100) {
                /* 如果连续100次都没收到, 丢包率上升 */
                if (telem_packet_loss < 99) telem_packet_loss++;
                loss_window_cnt = 0;
                loss_window_pkts = 0;
            }
            if (lost_packet_cnt > LOST_PACKET_TIMEOUT) {
                if (rx_state == RX_STATE_CONNECTED) {
                    rx_state = RX_STATE_DISCONNECTED;
                    PWM_SetAllFailsafe();
                }
            }
        }

        /* 回传发送 (PWM/SBUS 模式通过 NRF, CRFS 模式通过 UART) */
        if (rx_state == RX_STATE_CONNECTED) {
            static uint16_t last_telem_tick = 0;
            uint16_t telem_interval = 100 / telem_rate_hz;  /* sys_tick=10ms单位 */
            if (telem_interval < 1) telem_interval = 1;
            if (sys_tick - last_telem_tick >= telem_interval) {
                last_telem_tick = sys_tick;

                if (out_mode == OUT_MODE_CRFS) {
                    /* CRFS 模式: 通过 CRSF 链路回传电压/RSSI/丢包
                     * CRSF 遥测帧: type=0x02 (GPS), 或 type=0x08 (Battery sensor)
                     * 这里使用 Battery sensor type=0x08
                     * 帧: 0xEE + len + 0x08 + voltage(2B)+current(2B)+capacity(3B)+remaining(1B) + crc
                     * 简化: 直接发一个精简遥测帧
                     */
                    static uint8_t __xdata telem_frame[14];
                    telem_frame[0] = 0xEE;
                    telem_frame[1] = 10;  /* len */
                    telem_frame[2] = 0x08;  /* Battery sensor */
                    telem_frame[3] = (uint8_t)((bat_voltage_mv / 10) >> 8);   /* voltage high (10mV单位) */
                    telem_frame[4] = (uint8_t)((bat_voltage_mv / 10) & 0xFF); /* voltage low */
                    telem_frame[5] = 0;    /* current high */
                    telem_frame[6] = 0;    /* current low */
                    telem_frame[7] = 0;    /* capacity */
                    telem_frame[8] = 0;
                    telem_frame[9] = 0;
                    telem_frame[10] = telem_rssi;  /* remaining = RSSI */
                    telem_frame[11] = CRSF_CalcCRC(telem_frame + 2, 9);
                    for (uint8_t i = 0; i < 12; i++) {
                        SBUF = telem_frame[i];
                        while (!TI);
                        TI = 0;
                    }
                } else {
                    /* PWM/SBUS 模式: 通过 NRF 回传 */
                    NRF_SendTelemetry();
                }
            }
        }

        /* SBUS 输出模式 (每10ms发送一帧) */
        if (out_mode == OUT_MODE_SBUS && rx_state == RX_STATE_CONNECTED) {
            static uint16_t last_sbus_tick = 0;
            if (sys_tick - last_sbus_tick >= 10) {
                last_sbus_tick = sys_tick;
                SBUS_SendFrame();
            }
        }

        /* CRFS 输出模式 (每10ms发送一帧) */
        if (out_mode == OUT_MODE_CRFS && rx_state == RX_STATE_CONNECTED) {
            static uint16_t last_crfs_tick = 0;
            if (sys_tick - last_crfs_tick >= 10) {
                last_crfs_tick = sys_tick;
                CRFS_SendFrame();
            }

            /* 转发飞控发来的 CRSF 帧到 NRF 回传通道 */
            if (crfs_forward_len >= 3) {
                uint8_t frame_len = crfs_forward_buf[1] + 2;
                if (crfs_forward_len >= frame_len) {
                    /* 通过 NRF 转发给发射机 */
                    NRF24L01_TXMode();
                    NRF_CSN = 0;
                    NRF_SPI_TransferByte(NRF_CMD_FLUSH_TX);
                    NRF_CSN = 1;
                    NRF_CSN = 0;
                    NRF_SPI_TransferByte(NRF_CMD_W_TX_PAYLOAD);
                    for (uint8_t i = 0; i < frame_len && i < RF_PACKET_SIZE; i++)
                        NRF_SPI_TransferByte(crfs_forward_buf[i]);
                    NRF_CSN = 1;
                    NRF_CE = 1;
                    for (volatile uint16_t d = 0; d < 100; d++);
                    NRF_CE = 0;
                    NRF24L01_RXMode();
                    NRF24L01_FlushRX();
                    crfs_forward_len = 0;
                }
            }
        }

        /* 读取电池电压 (每100ms) */
        static uint16_t last_adc_tick = 0;
        if (sys_tick - last_adc_tick >= 100) {
            last_adc_tick = sys_tick;

            /* 读取电池分压 ADC (P3.3/ADC11) */
            uint16_t bat_adc = ADC_Read();

            /* 读取内部带隙基准 (通道14), 反算 VCC */
            uint16_t bg_adc = ADC_ReadBandgap();

            /* VCC(mV) = 1190 * 4096 / bg_adc
             * V_bat(mV) = bat_adc * VCC / 4096 * 11  (分压比 1K:10K = 1/11)
             * 合并: V_bat(mV) = bat_adc * 1190 * 11 / bg_adc
             *                  = bat_adc * 13090 / bg_adc
             */
            if (bg_adc > 0) {
                uint32_t tmp = (uint32_t)bat_adc * 13090UL / bg_adc;
                bat_voltage_mv = (uint16_t)tmp;
            }
        }

        /* 更新LED */
        LED_Update();
    }
}