#include "inputHandling.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>


char formulaBuffer[1000];
calc_op* resultCalc = NULL;
calc_op* currentCalc = NULL;

void processInput(char* formStr, int len) {
    deleteWhitespace(formStr, len);
    if (resultCalc != NULL){
        free(resultCalc);
    }
    resultCalc = malloc(sizeof(calc_op));
    memset(resultCalc, 0, sizeof(calc_op));
    resultCalc->functionsType = opResult;
    memcpy(formulaBuffer, formStr, len);
    calc_op * nextCalc = NULL;
    nextCalc= malloc(sizeof(calc_op));
    memset(nextCalc, 0, sizeof(calc_op));
    nextCalc->formular = formStr;
    nextCalc->parent = (void*) resultCalc;
    nextCalc->functionsType = detectFunctionOperator(formulaBuffer, 10);
    if (getNumbers(formulaBuffer, len, nextCalc) == NULL){
        resultCalc->children[0] = (void*) nextCalc;
        showStruct(nextCalc);
    } else {
        printf("Formular %s not supported", resultCalc->formular);
    }
}

calc_op* getNextCalc(){
    calc_op* newCalc = NULL;
    if (currentCalc != NULL){
        newCalc = (calc_op*) currentCalc->parent;
        if (newCalc == NULL) {
            return NULL;
        }
        newCalc->inputNumbers[0]= currentCalc->result;
        free(currentCalc);
    } else {
        newCalc = (calc_op*) resultCalc->children[0];
    }
    if (newCalc==NULL){
        return NULL;
    }
    currentCalc = newCalc; // get ext calculation
    showStruct(currentCalc);
    return currentCalc;
}

//Leerzeichen löschen
void deleteWhitespace(char* formStr, int len){
    for(int stringPos=0; stringPos < len; stringPos++){
        if((formStr[stringPos] == ' ') || (formStr[stringPos] == '\n') || (formStr[stringPos] == '\r')){
            for (int j=stringPos; j < len; j++){
                formStr[j]=formStr[j + 1];
            }
            stringPos--;
        }
    }
}

//Einfachste Rechenoperationen lesen
op detectFunctionOperator(char* formStr, int len){
    for(int stringCount=0; stringCount < len; stringCount++){
        switch (formStr[stringCount]){
            case '+': return opAdd;
            case '-': return opSub;
            case '/':case ':': return opDiv;
            case '*': return opMult;
            case '^': return opExp;
            case '\0': return opEmpty;
        }
    }
    return opNotSupported;
}

//Zahlen auslesen (+)
char* getNumbers(char* formStr, int len, calc_op* formRef){ //processInput sind: string, länge vom String, berechnungsstruct
    // char tmp[len];
    char* splitPnt;
    int numPos = 0;
    char delimiter;
    switch (formRef->functionsType) {
        case opAdd:
            delimiter = '+';
            break;
        case opSub:
            delimiter = '-';
            break;
        case opDiv:
            delimiter = '/';
            break;
        case opMult:
            delimiter = '*';
            break;
        default: return NULL;
    }
    // memcpy(tmp, formStr, len);     //string kopiert
    char *token = strtok(formStr, &delimiter); //An der Stelle von dem ersten Plus wird ein NULL (Stringende) gesetzt
    while (token != NULL) {
        formRef->inputNumbers[numPos] = atof(token);  // String zu double konvertiert
        numPos++;
        splitPnt = token;
        token = strtok(NULL, "+"); //Sucht von der letzten Plus-Stelle an weiter
    }
    formRef->arrayLength=numPos; //Länge des Arrays (also zu berechnende Zahlen) gespeichert
    op type = detectFunctionOperator(splitPnt, strlen(splitPnt) + 1);
    if (type != opNotSupported && type != opEmpty){
        return splitPnt;
    } else {
        return NULL;
    }
}

void showStruct(calc_op* formRef){
    printf("\nBerechnung: %s\n", formRef->formular);
    switch (formRef->functionsType) {
        case opAdd:
            printf("Rechenoperation: Addition\n"); break;
        case opSub:
            printf("Rechenoperation: Subtraktion\n"); break;
        case opMult:
            printf("Rechenoperation: Multiplikation\n"); break;
        case opDiv:
            printf("Rechenoperation: Division\n"); break;
        default:
            printf("Fehler bei Auswahl der Rechenoperationen \n");
    }
    printf("Calculation Variables:\n");
    for (int arrayCount = 0; arrayCount < formRef->arrayLength; ++arrayCount) {
        printf("Array[%i] = %f\n", arrayCount, formRef->inputNumbers[arrayCount]);
    }
    printf("Result: %f\n", formRef->result);
}