#include <stdio.h>
#include <stdlib.h>
#include <Serial.h>
#include <math.h>
#include <Devices.h>
#include "string.h"
#include <stdbool.h>
#include <time.h>
#include "SerialHelper.h"
#include "coprocessorjs.h"

IOParam outgoingSerialPortReference;
IOParam incomingSerialPortReference;
// #define PRINT_ERRORS 1
// #define DEBUGGING 1
#define MAX_ATTEMPTS 10
#define RECEIVE_WINDOW_SIZE 32767 // receive in up to 32kb chunks
#define MAX_RECEIVE_SIZE 32767 // matching RECEIVE_WINDOW_SIZE for now
char *GlobalSerialInputBuffer;
char *tempOutput;
char *application_id;
int call_counter = 0;

// from: https://stackoverflow.com/questions/29847915/implementing-strtok-whose-delimiter-has-more-than-one-character
// basically multichar delimter strtok
char *strtokm(char *str, const char *delim) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: strtokm");
    #endif
    static char *tok;
    static char *next;
    char *m;

    if (delim == NULL) return NULL;

    tok = (str) ? str : next;
    if (tok == NULL) return NULL;

    m = strstr(tok, delim);

    if (m) {
        next = m + strlen(delim);
        *m = '\0';
    } else {
        next = NULL;
    }

    return tok;
}

/*
// http://mirror.informatimago.com/next/developer.apple.com/documentation/mac/Devices/Devices-320.html
Read more: http://stason.org/TULARC/os-macintosh/programming/7-1-How-do-I-get-at-the-serial-ports-Communications-and-N.html#ixzz4cIxU3Tob this one is only useful for enumerating ports
// https://developer.apple.com/library/archive/documentation/mac/pdf/Devices/Serial_Driver.pdf
Serial implementation:

https://opensource.apple.com/source/gdb/gdb-186.1/src/gdb/ser-mac.c?txt another example of a serial library
http://mirror.informatimago.com/next/developer.apple.com/documentation/mac/Devices/Devices-320.html
*/

// notes from above article:
// You can use OpenDriver, SetReset, SetHShake, SetSetBuf, SerGetBuf and
// the other Serial Manager functions on these drivers.

// To write to the
// serial port, use FSWrite for synchronous writes that wait until all is
// written, or PBWrite asynchronously for queuing up data that is supposed
// to go out but you don't want to wait for it.

// At least once each time
// through your event loop, you should call SerGetBuf on the in driver
// reference number you got from OpenDriver, and call FSRead for that many
// bytes - neither more nor less.

// TODO: handle all OSErr - they are all unhandled at the moment
void setupPBControlForSerialPort(short serialPortShort) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: setupPBControlForSerialPort");
    #endif

    CntrlParam cb;
    cb.ioCRefNum = serialPortShort; // TODO: this is always 0 - does it matter? should we hard code 0 here? research
    cb.csCode = 8; // TODO: need to look up and document what csCode = 8 means
    cb.csParam[0] = stop10 | noParity | data8 | baud28800; // 28.8k has been pretty reliable on my Macintosh Classic...
    OSErr err = PBControl ((ParmBlkPtr) & cb, 0); // PBControl definition: http://mirror.informatimago.com/next/developer.apple.com/documentation/mac/Networking/Networking-296.html

    #ifdef PRINT_ERRORS

        char errMessage[100];
        sprintf(errMessage, "err:%d\n", err);
        writeSerialPortDebug(boutRefNum, errMessage);
    #endif

    if (err < 0) {

        return;
    }
}

void setupSerialPort(const char *name) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: setupSerialPort");
    #endif
#define MODEM_PORT_OUT   "\p.AOut"
#define MODEM_PORT_IN    "\p.AIn"
#define PRINTER_PORT_OUT "\p.BOut"
#define PRINTER_PORT_IN  "\p.BIn"

    const unsigned char* serialPortOutputName = "\p";
    const unsigned char* serialPortInputName = "\p";

    if (strcmp (name, "modem") == 0) {

        serialPortOutputName = (const unsigned char *)MODEM_PORT_OUT;
        serialPortInputName = (const unsigned char *)MODEM_PORT_IN;
    } else if (strcmp (name, "printer") == 0) {

        serialPortOutputName = (const unsigned char *)PRINTER_PORT_OUT;
        serialPortInputName = (const unsigned char *)MODEM_PORT_IN;
    } else {

        return;
    }

    short serialPortOutput = 0; // TODO: why is this always 0? is this right?
    short serialPortInput = 0; // TODO: not realy sure what this should be - just incrementing from the last item here

    OSErr err = MacOpenDriver(serialPortOutputName, &serialPortOutput);
    
    #ifdef PRINT_ERRORS

        char errMessage[100];
        sprintf(errMessage, "err:%d\n", err);
        writeSerialPortDebug(boutRefNum, errMessage);
    #endif

    if (err < 0) {

        return;
    }

    err = MacOpenDriver(serialPortInputName, &serialPortInput);

    #ifdef PRINT_ERRORS

        char errMessage[100];
        sprintf(errMessage, "err:%d\n", err);
        writeSerialPortDebug(boutRefNum, errMessage);
    #endif

    if (err < 0) {

        return;
    }

    // From https://developer.apple.com/library/archive/documentation/mac/pdf/Devices/Serial_Driver.pdf
    // Set baud rate and data format. Note that you only need to set the
    // output driver; the settings are reflected on the input side
    setupPBControlForSerialPort(serialPortOutput);

    outgoingSerialPortReference.ioRefNum = serialPortOutput;
    incomingSerialPortReference.ioRefNum = serialPortInput;
    
    // the next 2 commands set up the receive window size to whatever we want, in bytes.
    // as far as i can tell, this needs to be set before any data begins flowing, so it seemed
    // like a good call to make the buffer a global that gets instantiated at serial port setup
    incomingSerialPortReference.ioBuffer = (Ptr)GlobalSerialInputBuffer;
    SerSetBuf(incomingSerialPortReference.ioRefNum, incomingSerialPortReference.ioBuffer, RECEIVE_WINDOW_SIZE);
}

void wait(float timeInSeconds) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: wait");
    #endif

    // from "Inside Macintosh: Macintosh Toolbox Essentials" pg 2-112 
    // You can use the TickCount function to get the current number of ticks (a tick is
    // approximately 1/60 of a second) since the system last started up.
    // FUNCTION TickCount: LongInt;

    // previous implementation, which might work on more modern platforms (which is why this is left as a comment), was:
    // note that this appeared to sometimes be off by as much as 1s on a Macintosh classic (using other normal C time functions to measure...)
    // time_t start;
    // time_t end;

    // time(&start);

    // do {

    //     time(&end);
    // } while (difftime(end, start) <= timeInSeconds);

    long start; 
    long end;
    long waitTicks = (long)timeInSeconds * 60;

    start = TickCount();

    do {

        end = TickCount();
    } while (end - start <= waitTicks);

    // char log[255];
    // sprintf(log, "start time was %ld end time was %ld split was %ld and wait ticks were %ld, input was %f\n ", start, end, end - start, waitTicks, timeInSeconds);
    // printf(log);
}

const int MAX_RECIEVE_LOOP_ITERATIONS = 1000;

// void because this function re-assigns respo
void readSerialPort(char* output) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: readSerialPort");
    #endif

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "readSerialPort");
    #endif
    
    // make sure output variable is clear
    memset(output, '\0', MAX_RECEIVE_SIZE);
    memset(tempOutput, '\0', MAX_RECEIVE_SIZE);

    bool done = false;
    long int totalByteCount = 0;
    incomingSerialPortReference.ioReqCount = 0;
    int loopCounter = 0;

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "readSerialPort, enter loop");
    #endif

    // wait a moment for the buffer to fill
    wait(0.01);

    while (!done) {

        if (loopCounter++ > MAX_RECIEVE_LOOP_ITERATIONS) {
            #ifdef DEBUGGING
                writeSerialPortDebug(boutRefNum, "coprocessor.readSerialPort MAX RECEIVE ITERATIONS");
            #endif

            char *errorMessage = "TIMEOUT_ERROR";

            strncat(output, errorMessage, strlen(output) - 1);

            // once we are done reading the buffer entirely, we need to clear it. i'm not sure if this is the best way or not but seems to work
            memset(GlobalSerialInputBuffer, '\0', MAX_RECEIVE_SIZE);

            return;
        }

        long int byteCount = 0;
        long int lastByteCount = 0;
        bool doByteCountsMatch = false;

        // the byteCount != lastByteCount portion of the loop means that we want to wait 
        // for the byteCounts to match between SerGetBuf calls - this means that the buffer
        // is full and ready to be read
        while (!doByteCountsMatch || byteCount == 0) {

            #ifdef DEBUGGING
                char debugMessage[100];
                sprintf(debugMessage, "receive loop: byteCount: %ld, lastByteCount: %ld\n", byteCount, lastByteCount);
                writeSerialPortDebug(boutRefNum, debugMessage);
            #endif

            lastByteCount = (long int)byteCount;

            wait(0.01); // give the buffer a moment to fill

            #ifdef PRINT_ERRORS
                short serGetBufStatus = SerGetBuf(incomingSerialPortReference.ioRefNum, &byteCount);

                if (serGetBufStatus != 0) {

                    writeSerialPortDebug(boutRefNum, "potential problem with serGetBufStatus:\n");
                    char debugMessage[100];
                    sprintf(debugMessage, "serGetBufStatus: %d\n", serGetBufStatus);
                    writeSerialPortDebug(boutRefNum, debugMessage);
                }
            #else
                SerGetBuf(incomingSerialPortReference.ioRefNum, &byteCount);
            #endif

            // basically, we're stating that if we have a stall for 2 iterations of the loop where the byteCounts are matching, then
            // we assume we are no longer receiving communication. could have bugs? ie, we could be "done" reading before the data is all written
            if (byteCount == lastByteCount && byteCount != 0 && lastByteCount != 0) {

                #ifdef DEBUGGING
                    char debugMessage[100];
                    sprintf(debugMessage, "receive loop setting last doByteCountsMatch to true: byteCount: %ld, lastByteCount: %ld\n", byteCount, lastByteCount);
                    writeSerialPortDebug(boutRefNum, debugMessage);
                #endif

                doByteCountsMatch = true;
            }
        }

        #ifdef DEBUGGING
            char debugMessage[100];
            sprintf(debugMessage, "receive loop complete: byteCount: %ld, lastByteCount: %ld", byteCount, lastByteCount);
            writeSerialPortDebug(boutRefNum, debugMessage);
        #endif

        incomingSerialPortReference.ioReqCount = byteCount;

        #ifdef PRINT_ERRORS
            OSErr err = PBRead((ParmBlkPtr)&incomingSerialPortReference, 0);

            char errMessage[100];
            sprintf(errMessage, "err:%d", err);
            writeSerialPortDebug(boutRefNum, errMessage);
        #else

            PBRead((ParmBlkPtr)&incomingSerialPortReference, 0);
        #endif

        memcpy(tempOutput, GlobalSerialInputBuffer, byteCount);

        totalByteCount += byteCount;

        if (strstr(tempOutput, ";;@@&&") != NULL) {

            #ifdef DEBUGGING

                writeSerialPortDebug(boutRefNum, "done building temp output");
                writeSerialPortDebug(boutRefNum, tempOutput);

                // char debugOutput[255];
                // char tempString[MAX_RECEIVE_SIZE];
                // strncat(tempString, tempOutput, totalByteCount);
                // sprintf(debugOutput, "\n'%ld'\n", strlen(tempString));
                // writeSerialPortDebug(boutRefNum, debugOutput);
                // writeSerialPortDebug(boutRefNum, "\ndone with output\n");
                // writeSerialPortDebug(boutRefNum, "\n");
            #endif

            done = true;
        } else {

            #ifdef DEBUGGING
                writeSerialPortDebug(boutRefNum, "receive loop complete, but terminator is missing");
                writeSerialPortDebug(boutRefNum, tempOutput);
            #endif

            done = true;
        }
    }

    // attach the gathered up output from the buffer to the output variable
    memcpy(output, tempOutput, totalByteCount);

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "coprocessor.readSerialPort complete, output:");
        writeSerialPortDebug(boutRefNum, output);
    #endif

    // once we are done reading the buffer entirely, we need to clear it. i'm not sure if this is the best way or not but seems to work
    memset(GlobalSerialInputBuffer, '\0', MAX_RECEIVE_SIZE);

    return;
}


OSErr writeSerialPort(const char* stringToWrite) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: writeSerialPort");
    #endif
    
    #ifdef DEBUGGING
        
        writeSerialPortDebug(boutRefNum, "writeSerialPort");
    #endif

    outgoingSerialPortReference.ioBuffer = (Ptr)stringToWrite;
    outgoingSerialPortReference.ioReqCount = strlen(stringToWrite);
    
    #ifdef DEBUGGING

        writeSerialPortDebug(boutRefNum, "attempting to write string to serial port");
        // writeSerialPortDebug(boutRefNum, stringToWrite);
    #endif

    // PBWrite Definition From Inside Macintosh Volume II-185:
    // PBWrite takes ioReqCount bytes from the buffer pointed to by ioBuffer and attempts to write them to the device driver having the reference number ioRefNum.
    // The drive number, if any, of the device to be written to is specified by ioVRefNum. After the write is completed, the position is returned in ioPosOffset and the number of bytes actually written is returned in ioActCount.
    OSErr err = PBWrite((ParmBlkPtr)& outgoingSerialPortReference, 0);
    
    #ifdef PRINT_ERRORS

        char errMessage[100];
        sprintf(errMessage, "err:%d\n", err);
        writeSerialPortDebug(boutRefNum, errMessage);
    #endif

    return err;
}

void setupCoprocessor(char *applicationId, const char *serialDeviceName) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: setupCoprocessor");
    #endif

    GlobalSerialInputBuffer = malloc(sizeof(char) * MAX_RECEIVE_SIZE);
    tempOutput = malloc(sizeof(char) * MAX_RECEIVE_SIZE);
    application_id = malloc(sizeof(char) * 255);
    
    strcpy(application_id, applicationId);

    setupSerialPort(serialDeviceName);

    return;
}

OSErr closeSerialPort() {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: closeSerialPort");
    #endif

    OSErr err = MacCloseDriver(outgoingSerialPortReference.ioRefNum);
    
    #ifdef PRINT_ERRORS

        char errMessage[100];
        sprintf(errMessage, "err:%d\n", err);
        writeSerialPortDebug(boutRefNum, errMessage);
    #endif

    return err;
}

// return value is char but this is only for error messages - final param is output variable that will be re-assigned within this function
char* _getReturnValueFromResponse(char* response, char* application_id, char* call_counter, char* operation, char* output) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: _getReturnValueFromResponse");
    #endif
    
    #ifdef DEBUGGING
        
        writeSerialPortDebug(boutRefNum, "_getReturnValueFromResponse\n");
        writeSerialPortDebug(boutRefNum, response);
        writeSerialPortDebug(boutRefNum, "\n");
    #endif

    // get the first token in to memory
    char *token = strtokm(response, ";;;");
    
    // we need to track the token that we are on because the coprocessor.js responses are standardized
    // so the tokens at specific positions will map to specific items in the response
    int tokenCounter = 0;

    // loop through the string to extract all other tokens
    while (token != NULL) {

        if (tokenCounter > MAX_ATTEMPTS) {

            return "max attempts exceeded";
        }

        #ifdef DEBUGGING

            char debugOutput[MAX_RECEIVE_SIZE];
            sprintf(debugOutput, "inspect token %d: %s\n", tokenCounter, token);
            writeSerialPortDebug(boutRefNum, debugOutput);
        #endif

        switch (tokenCounter) {

            case 0: // APPLICATION ID

                if (strcmp(token, application_id) != 0) {

                    return "application id mismatch"; // TODO figure out better error handling
                }

                break;
            case 1: // CALL COUNTER

                if (strcmp(token, call_counter) != 0) {

                    return "call counter mismatch"; // TODO figure out better error handling
                }
 
                break;
            case 2: // OPERATION

                if (strcmp(token, operation) != 0) {

                    return "operation mismatch"; // TODO figure out better error handling
                }

                break;
            case 3: // STATUS

                if (strcmp(token, "SUCCESS") != 0) {

                    return "operation failed"; // TODO figure out better error handling
                }

                break;
            case 4:;
            
                #ifdef DEBUGGING

                    writeSerialPortDebug(boutRefNum, "setting output to token:\n");
                    writeSerialPortDebug(boutRefNum, token);
                    char debugOutput[255];
                    sprintf(debugOutput, "\n'%ld'\n", strlen(token));
                    writeSerialPortDebug(boutRefNum, debugOutput);
                    writeSerialPortDebug(boutRefNum, "\ndone with output\n");
                #endif

                int lengthWithoutControlChars = strlen(token) - 6;

                // writeSerialPortDebug(boutRefNum, "SETTING OUTPUT VARIABLE");
                // char x[2555];
                // sprintf(x, "%s: %d (%.*s)", token, lengthWithoutControlChars, lengthWithoutControlChars, token);
                // writeSerialPortDebug(boutRefNum, x);
                // this seems to be the location where we can sometimes mangle our response data
                sprintf(output, "%.*s", lengthWithoutControlChars, token); // drop the ;;@@&& off the end of the response

                #ifdef DEBUGGING
                    writeSerialPortDebug(boutRefNum, output);
                #endif

                return NULL;

            default:

                break;
        }

        // get the next token. strtokm has some weird syntax
        token = strtokm(NULL, ";;;");
        tokenCounter++;
    }

    return NULL;
}

void writeToCoprocessor(char* operation, char* operand) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: writeToCoprocessor");
    #endif
    
    #ifdef DEBUGGING
        
        writeSerialPortDebug(boutRefNum, "writeToCoprocessor\n");
    #endif

    const char* messageTemplate = "%s;;;%s;;;%s;;;%s;;@@&&"; // see: https://github.com/CamHenlin/coprocessor.js/blob/main/index.js#L25
    char call_id[32];

    // over-allocate by 1kb for the operand (which could be an entire nodejs app) + message template wrapper
    // and other associated info. wasting a tiny bit of memory here, could get more precise if memory becomes a problem.
    char messageToSend[strlen(operand) + 1024];

    sprintf(call_id, "%d", call_counter++);

    // application_id is globally defined for now, how will that work in a library?
    sprintf(messageToSend, messageTemplate, application_id, call_id, operation, operand);

    #ifdef PRINT_ERRORS

        OSErr err = writeSerialPort(messageToSend);

        char errMessage[100];
        sprintf(errMessage, "writeToCoprocessor err:%d\n", err);
        writeSerialPortDebug(boutRefNum, errMessage);
    #else
        writeSerialPort(messageToSend);
    #endif

    return;
}

// must be called after writeToCoprocessor and before other writeToCoprocessor
// operations because we depend on the location of call_counter
void getReturnValueFromResponse(char *response, char *operation, char *output) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: getReturnValueFromResponse");
    #endif

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "getReturnValueFromResponse");
    #endif

    char call_id[32];
    sprintf(call_id, "%d", call_counter - 1);
    
    #ifdef PRINT_ERRORS
        char *err = _getReturnValueFromResponse(response, application_id, call_id, operation, output);

        if (err != NULL) {
            
            writeSerialPortDebug(boutRefNum, "error getting return value from response:");
            writeSerialPortDebug(boutRefNum, err);
    }
    #else
        _getReturnValueFromResponse(response, application_id, call_id, operation, output);
    #endif
}

// TODO: these should all bubble up and return legible errors
void sendProgramToCoprocessor(char* program, char *output) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: sendProgramToCoprocessor");
    #endif

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "sendProgramToCoprocessor");
    #endif

    SetCursor(*GetCursor(watchCursor));

    writeToCoprocessor("PROGRAM", program);

    char serialPortResponse[MAX_RECEIVE_SIZE];
    readSerialPort(serialPortResponse);

    getReturnValueFromResponse(serialPortResponse, "PROGRAM", output);

    SetCursor(&qd.arrow);
    
    return;
}

void callFunctionOnCoprocessor(char* functionName, char* parameters, char* output) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: callFunctionOnCoprocessor");
    #endif
    
    #ifdef DEBUGGING

        writeSerialPortDebug(boutRefNum, "callFunctionOnCoprocessor\n");
    #endif

    const char* functionTemplate = "%s&&&%s";

    // over-allocate by 1kb for the operand (which could be whatever a programmer sends to this function) + message template wrapper
    // and other associated info. wasting a tiny bit of memory here, could get more precise if memory becomes a problem.
    char functionCallMessage[strlen(parameters) + 1024];

    // delimeter for function paramters is &&& - user must do this on their own via sprintf call or other construct - this is easiest for us to deal with
    sprintf(functionCallMessage, functionTemplate, functionName, parameters);

    SetCursor(*GetCursor(watchCursor));

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, functionCallMessage);
    #endif

    writeToCoprocessor("FUNCTION", functionCallMessage);

    char serialPortResponse[MAX_RECEIVE_SIZE];
    readSerialPort(serialPortResponse);

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "Got response from serial port:");
        writeSerialPortDebug(boutRefNum, serialPortResponse);
    #endif

    memset(output, '\0', RECEIVE_WINDOW_SIZE);
    getReturnValueFromResponse(serialPortResponse, "FUNCTION", output);

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "Got return value from response");
        writeSerialPortDebug(boutRefNum, output);
    #endif

    SetCursor(&qd.arrow);
    
    return;
}

void callEvalOnCoprocessor(char* toEval, char* output) {

    #ifdef DEBUG_FUNCTION_CALLS
        writeSerialPortDebug(boutRefNum, "DEBUG_FUNCTION_CALLS: callEvalOnCoprocessor");
    #endif

    #ifdef DEBUGGING
        writeSerialPortDebug(boutRefNum, "callEvalOnCoprocessor\n");
    #endif

    writeToCoprocessor("EVAL", toEval);

    char serialPortResponse[MAX_RECEIVE_SIZE];
    readSerialPort(serialPortResponse);
    getReturnValueFromResponse(serialPortResponse, "EVAL", output);

    return;
}