/* =========================STYLE-GUIDELINES===========================
 * All comments use MD-Syntax;
 * Formulas are written in KaTeX/TeX Syntax.
 * We adhere by the `kernel.org` style-guidelines.
 * See: https://www.kernel.org/doc/html/v4.10/process/coding-style.html
 * =============================AUTHORS================================
 * Created by Frederik Beimgraben, Minh Dan Cam and Lea Hornberger in
 * the winter term of 2024/25 at the faculty of computer science at
 * Reutlingen University.
 * After grading the full source code will be available at:
 * https://git.beimgraben.net/MMS-2024-25/MMS-Loesung-2024-25.git
 */

#include "MMS24-25.h"
#include "math.h"
#include <stdio.h>
#include <stdlib.h>
#include "MMS24-25.h"
#include <stdio.h>

// NULL Pointer
#ifndef NULL
#define NULL 0
#endif

double interpolateLine(
        double dX1,
        double dY1,
        double dX2,
        double dY2,
        double dXq
    ) {
    double y = (
        (dY2 - dY1) / (dX2 - dX1)
    ) * (dXq + dX1);

    #ifdef _DEBUG_
        // DEBUG: print the parameters and result
        printf("interpolateLine(%lf, %lf, %lf, %lf, %lf) -> %lf\n",
           dX1,dY1,dX2,dY2,dXq,y);
    #endif

    return y;
}

void rescaleDoubleArray(
        double *pdIn,
        int iLen,
        double dMin,
        double dFactor,
        double *pdOut
    ) {
    /* Rescale an array of double values, so that the following rules apply:
     * Given $ |pdIn| = |pdOut| = iLen $ it should be, that:
     * $ min(pdIn) > dMin $, as well as
     * \[ \forall i, j \in (0,\dots,iLen-1):
     *        (pdOut_i - pdOut_j) = (pdIn_i - pdIn_j) * dFactor \],
     * which naturally results from:
     * $ pdOut_i = pdIn_i * dFactor + dMin $
     */
    for (int i = 0; i < iLen; i++) {
        pdOut[i] = pdIn[i] * dFactor + dMin;
    }
}

double *generateSineValues(
        int iNumValues,
        int iNumSamplesPerPeriod,
        double dAmp
    ) {
    /* Generate an array of `iNumValues` double value, so that the values
     * represent the Y-coordinates of a sine curve of which one full period
     * occupies `iNumSamplesPerPeriod` values
     */

    // Initialize the output array
    double* sineArray = NULL;
    sineArray = (double*) malloc(sizeof(double) * iNumValues);

    if (sineArray == NULL) {
        printf("Failed to allocate memory for SineArray\n");
        exit(-1);
    }

    for (int i=0; i<iNumValues;i++){
        sineArray[i] = dAmp*sin(((2*M_PI)/iNumSamplesPerPeriod) * i);
    }

    return sineArray;
}

void writeDoubleArray(double *pdOut, int iLen, char *pcOutName) {
    /* Write a list of double values to a file
     */

    FILE* datei = fopen(pcOutName, "w");
    if (datei == NULL) {
        printf("Error while opening file '%s'.\n", pcOutName);
        exit(-1);
    }

    for (int i = 0; i < iLen; i++) {
        fprintf(datei, "%f\n", pdOut[i]);
    }

    fclose(datei);
}