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

#include <main.h>
#include <usart.h>
#include <PontCoopScheduler.h>
#include <mbusComm.h>
#include <loopCtrl.h>
#include <show.h>
#include <logger.h>
#include <frontend.h>


typedef enum {
    MBCS_IDLE,
    MBCS_SEND,
    MBCS_SEND_CONT,
    MBCS_SENDING_DONE,
    MBCS_ENABLE_FRONTEND,
    MBCS_START1,
    MBCS_LENGTH1,
    MBCS_LENGTH2,
    MBCS_START2,
    MBCS_C_FIELD,
    MBCS_A_FIELD,
    MBCS_CI_FIELD,
    MBCS_USERDATA,
    MBCS_CHKSUM,
    MBCS_STOP,
    MBCS_DONE,
    MBCS_TIMEOUT,
    MBCS_DISABLE_FRONTEND,
    MBCS_ERROR
} e_mbusCommState;

typedef struct {
    e_mbusCommState state;
    uint8_t retryCnt;
    uint8_t cmd;
    uint8_t addr;
    uint8_t sendBuf[5];
    uint8_t receiveCnt;
    uint8_t receivedOctet;
    bool receiving;
    t_mbusCommResult result;
    t_longframe frame;
} t_mbusCommHandle;

static t_mbusCommHandle mbusCommHandle = { .state = MBCS_IDLE, .retryCnt = 0, .cmd = 0, .addr = 0, .receiveCnt = 0, .receivedOctet = 0, .receiving = false };



static void printFrame(t_longframe *frame) {
    logMsg("frame: %02x %02x %02x %02x",
           frame->start1, frame->length1, frame->length2, frame->start2);
    logMsg("frame: C:%02x A:%02x CI:%02x",
           frame->c, frame->a, frame->ci);
    logMsg("frame: userdata ...");
    logMsg("frame: CHKSUM:%02x", frame->chksum);
    logMsg("frame: %02x", frame->stop);
}

static void handleRequestEngine(void *handle);
static void timeoutHandler(void *handle) {
    logMsg("mbc timeout");
    t_mbusCommHandle *localMbusCommHandle = (t_mbusCommHandle*) handle;
    localMbusCommHandle->state = MBCS_TIMEOUT;
    localMbusCommHandle->receiving = false;
    handleRequestEngine(handle);
}

static void receiveNext(t_mbusCommHandle *localMbusCommHandle) {
    localMbusCommHandle->receiving = true;
    HAL_UART_Receive_IT(&mbusUart, &(localMbusCommHandle->receivedOctet), 1);
}

static void handleRequestEngine(void *handle) {
    t_mbusCommHandle *localMbusCommHandle = (t_mbusCommHandle*) handle;

    static uint8_t userdataIdx = 0;
    static uint8_t calculatedChksum = 0;

    switch (localMbusCommHandle->state) {
        case MBCS_IDLE:
        logMsg("hre state IDLE");
        break;

        case MBCS_SEND:
        logMsg("hre state SEND");
        localMbusCommHandle->sendBuf[0] = 0x10;
        localMbusCommHandle->sendBuf[1] = localMbusCommHandle->cmd;
        localMbusCommHandle->sendBuf[2] = localMbusCommHandle->addr;
        localMbusCommHandle->sendBuf[3] = localMbusCommHandle->cmd + localMbusCommHandle->addr; // checksum
        localMbusCommHandle->sendBuf[4] = 0x16;
        localMbusCommHandle->state = MBCS_SEND_CONT;
        // no break !!

        case MBCS_SEND_CONT:
        logMsg("hre state SEND_CONT");
        show(LED_RED, OFF);
        if (! loopActive) {
            logMsg("hre enabling loop, try %d", localMbusCommHandle->retryCnt);
            localMbusCommHandle->retryCnt++;
            loopEnable();
            schAdd(handleRequestEngine, handle, 10, 0); // give 10ms to settled the loop
        } else {
            localMbusCommHandle->retryCnt = 0;
            HAL_UART_Transmit_IT(&mbusUart, localMbusCommHandle->sendBuf, 5);
            // transition from here to SENDING_DONE is initiate by mbusCommTxCpltCallback
            // interrupt callback
            localMbusCommHandle->state = MBCS_SENDING_DONE;
        }
        break;

        case MBCS_SENDING_DONE:
        logMsg("hre state SENDING_DONE");
        localMbusCommHandle->state = MBCS_ENABLE_FRONTEND;
        schAdd(handleRequestEngine, handle, 3, 0);
        break;

        case MBCS_ENABLE_FRONTEND:
        logMsg("hre state ENABLE_FRONTEND");
        frontendEnable();
        schAdd(timeoutHandler, handle, 2500, 0);
        calculatedChksum = 0;
        userdataIdx = 0;
        localMbusCommHandle->state = MBCS_START1;
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_START1:
        //logMsg("hre state START1");
        if (localMbusCommHandle->receivedOctet == 0x68) {
            localMbusCommHandle->frame.start1 = localMbusCommHandle->receivedOctet;
            localMbusCommHandle->state = MBCS_LENGTH1;
        } else {
            logMsg("hre err: invalid start1 symbol %02x", localMbusCommHandle->receivedOctet);
            localMbusCommHandle->result = MBCR_ERROR_STATE_ENGINE__START1;
            localMbusCommHandle->state = MBCS_ERROR;
        }
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_LENGTH1:
        //logMsg("hre state LENGTH1");
        if (localMbusCommHandle->receivedOctet <= 3) {
            logMsg("hre err: length to small %02x", localMbusCommHandle->receivedOctet);
            localMbusCommHandle->result = MBCR_ERROR_STATE_ENGINE__LENGTH1;
            localMbusCommHandle->state = MBCS_ERROR;
        } else {
            localMbusCommHandle->frame.length1 = localMbusCommHandle->receivedOctet;
            localMbusCommHandle->frame.userdata = (uint8_t*) malloc(localMbusCommHandle->frame.length1 - 3);
            if (! localMbusCommHandle->frame.userdata) {
                logMsg("hre err: unable to allocate memory for userdata");
                localMbusCommHandle->result = MBCR_ERROR_OUT_OF_MEMORY__USERDATA;
                localMbusCommHandle->state = MBCS_ERROR;
            } else {
                localMbusCommHandle->state = MBCS_LENGTH2;
            }
        }
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_LENGTH2:
        //logMsg("hre state LENGTH2");
        if (localMbusCommHandle->frame.length1 != localMbusCommHandle->receivedOctet) {
            logMsg("hre err: invalid length2 %02x vs. %02x", localMbusCommHandle->frame.length1, localMbusCommHandle->receivedOctet);
            localMbusCommHandle->result = MBCR_ERROR_STATE_ENGINE__LENGTH2;
            localMbusCommHandle->state = MBCS_ERROR;
        } else {
            localMbusCommHandle->frame.length2 = localMbusCommHandle->receivedOctet;
            localMbusCommHandle->state = MBCS_START2;
        }
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_START2:
        //logMsg("hre state START2");
        if (localMbusCommHandle->receivedOctet == 0x68) {
            localMbusCommHandle->frame.start2 = localMbusCommHandle->receivedOctet;
            localMbusCommHandle->state = MBCS_C_FIELD;
        } else {
            logMsg("hre err: invalid start2 symbol %02x", localMbusCommHandle->receivedOctet);
            localMbusCommHandle->result = MBCR_ERROR_STATE_ENGINE__START2;
            localMbusCommHandle->state = MBCS_ERROR;
        }
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_C_FIELD:
        //logMsg("hre state C_FIELD");
        localMbusCommHandle->frame.c = localMbusCommHandle->receivedOctet;
        calculatedChksum += localMbusCommHandle->receivedOctet;
        localMbusCommHandle->state = MBCS_A_FIELD;
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_A_FIELD:
        //logMsg("hre state A_FIELD");
        localMbusCommHandle->frame.a = localMbusCommHandle->receivedOctet;
        calculatedChksum += localMbusCommHandle->receivedOctet;
        localMbusCommHandle->state = MBCS_CI_FIELD;
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_CI_FIELD:
        //logMsg("hre state CI_FIELD");
        localMbusCommHandle->frame.ci = localMbusCommHandle->receivedOctet;
        calculatedChksum += localMbusCommHandle->receivedOctet;
        localMbusCommHandle->state = MBCS_USERDATA;
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_USERDATA:
        //logMsg("hre state USERDATA");
        localMbusCommHandle->frame.userdata[userdataIdx] = localMbusCommHandle->receivedOctet;
        calculatedChksum += localMbusCommHandle->receivedOctet;
        userdataIdx++;
        if (userdataIdx == (localMbusCommHandle->frame.length1 - 3)) {
            localMbusCommHandle->state = MBCS_CHKSUM;
        }
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_CHKSUM:
        //logMsg("hre state CHKSUM");
        if (localMbusCommHandle->receivedOctet != calculatedChksum) {
            logMsg("hre err: invalid checksum %02x vs %02x", calculatedChksum, localMbusCommHandle->receivedOctet);
            localMbusCommHandle->result = MBCR_ERROR_STATE_ENGINE__INVALID_CHKSUM;
            localMbusCommHandle->state = MBCS_ERROR;
        } else {
            localMbusCommHandle->frame.chksum = localMbusCommHandle->receivedOctet;
            localMbusCommHandle->state = MBCS_STOP;
        }
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_STOP:
        //logMsg("hre state STOP");
        if (localMbusCommHandle->receivedOctet == 0x16) {
            localMbusCommHandle->frame.stop = localMbusCommHandle->receivedOctet;
            localMbusCommHandle->state = MBCS_DONE;
            schAdd(handleRequestEngine, handle, 0, 0);
        } else {
            logMsg("hre err: invalid stop symbol %02x", localMbusCommHandle->receivedOctet);
            localMbusCommHandle->result = MBCR_ERROR_STATE_ENGINE__STOP;
            localMbusCommHandle->state = MBCS_ERROR;
            receiveNext(localMbusCommHandle);
        }
        break;

        case MBCS_DONE:
        logMsg("hre state DONE");
        printFrame(&(localMbusCommHandle->frame));
        if (localMbusCommHandle->frame.userdata != NULL) {
            free(localMbusCommHandle->frame.userdata);
            localMbusCommHandle->frame.userdata = NULL;
        }
        localMbusCommHandle->result = MBCR_SUCCESS;
        localMbusCommHandle->state = MBCS_DISABLE_FRONTEND;
        schDel(timeoutHandler, handle);
        schAdd(handleRequestEngine, handle, 0, 0);
        break;

        case MBCS_ERROR:
        logMsg("hre state ERROR");
        show(LED_RED, ON);
        logMsg("hre err: already error, read the rest (now: %02x) until timeout", localMbusCommHandle->receivedOctet);
        receiveNext(localMbusCommHandle);
        break;

        case MBCS_TIMEOUT:
        logMsg("hre state TIMEOUT");
        localMbusCommHandle->receiving = false;        
        if (localMbusCommHandle->frame.userdata != NULL) {
            free(localMbusCommHandle->frame.userdata);
            localMbusCommHandle->frame.userdata = NULL;
        }
        HAL_UART_AbortReceive(&mbusUart);
        uint8_t kitchenSink[16];
        memset(kitchenSink, 0, 16);
        HAL_StatusTypeDef r = HAL_UART_Receive(&mbusUart, kitchenSink, 16, 100);
        logMsg("hre abort, last receive result: %02x", r);
        // no break

        case MBCS_DISABLE_FRONTEND:
        logMsg("hre state DISABLE_FRONTEND");
        frontendDisable();
        localMbusCommHandle->state = MBCS_IDLE;
        break;
        

        default:
        localMbusCommHandle->state = MBCS_IDLE;
        break;
    }
}

void mbusCommTxCpltCallback(UART_HandleTypeDef *huart) {
    schAdd(handleRequestEngine, (void*) &mbusCommHandle, 0, 0);
}

void mbusCommRxCpltCallback(UART_HandleTypeDef *huart) {
    if (mbusCommHandle.receiving) {
        schAdd(handleRequestEngine, (void*) &mbusCommHandle, 0, 0);
        mbusCommHandle.receiving = false;
    } else {
        logMsg("mcrx: received 0x%02x but not expected", mbusCommHandle.receivedOctet);
    }
}

void mbusCommRequest(uint8_t cmd, uint8_t addr) {
    if (mbusCommHandle.state == MBCS_IDLE) {
        mbusCommHandle.state = MBCS_SEND;
        mbusCommHandle.retryCnt = 0;
        mbusCommHandle.cmd = cmd;
        mbusCommHandle.addr = addr;
        schAdd(handleRequestEngine, (void*) &mbusCommHandle, 0, 0);
    } else {
        // busy
    }
}