#include <stdio.h>

#define N 5 // Number of taps (filter coefficients)

// Example filter coefficients (simple low-pass averaging filter)
float coeffs[N] = {
    0.2, 0.2, 0.2, 0.2, 0.2 // Equal weights → moving average filter
};

float buffer[N] = {0}; // Circular buffer to store recent inputs
int   bufIndex = 0;

float fir_filter(float input) {
    buffer[bufIndex] = input;

    float output = 0.0;
    int   index = bufIndex;

    // Apply the convolution (dot product of input buffer and coefficients)
    for (int i = 0; i < N; ++i) {
        output += coeffs[i] * buffer[index];
        if (--index < 0)
            index = N - 1; // Wrap around circular buffer
    }

    bufIndex = (bufIndex + 1) % N;
    return output;
}

int main() {
    float noisy_signal[] = {1,   2, 3, 2,
                            100, 3, 2, 1}; // A spike in the middle (100)
    int   len = sizeof(noisy_signal) / sizeof(float);

    printf("Filtered output:\n");
    for (int i = 0; i < len; ++i) {
        float filtered = fir_filter(noisy_signal[i]);
        printf("%.2f\n", filtered);
    }

    return 0;
}