#include "svm.h"
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define New(t, n) (t *)malloc((n) * sizeof(t))
#define Size @{size}
#define Bias @{bias}
#define Gama @{gama}
#define Feat @{feat}

static uint8_t okay = 0;
// fill first number of each sv here
static float Scales[Size] = {
    @{scales}
};
// fill element count of each sv here
static uint32_t Elements[Size] = {
    @{elements}
};
// fill the flattened sv weights here
static float Weights[] = {
    @{weights}
};
static Node *Vector[Size];

void svm_init() {
    int i, j, idx = 0;
    for (i = 0; i < Size; ++i) {
        Vector[i] = New(Node, Elements[i] + 1);
        for (j = 0; j < Elements[i]; ++j, ++idx) {
            Vector[i][j].idx = j + 1;
            Vector[i][j].val = Weights[idx];
        }
        Vector[i][j].idx = 0;
    }
    okay = 1;
}

Node *input() {
    Node *x = New(Node, Feat + 1);
    int i;
    for (i = 0; i < Feat; ++i) {
        x[i].idx = i + 1;
        scanf("%f", &x[i].val);  // NOLINT
    }
    x[Feat].idx = 0;
    return x;
}

float rbf_kernel(const Node *x, const Node *y) {
    float sum = 0;

    while (x->idx != 0 && y->idx != 0) {
        if (x->idx == y->idx) {
            float d = x->val - y->val;
            sum += d * d;
            ++x, ++y;
        } else {
            if (x->idx > y->idx) {
                sum += y->val * y->val;
                ++y;
            } else {
                sum += x->val * x->val;
                ++x;
            }
        }
    }

    while (x->idx != 0) {
        sum += x->val * x->val;
        ++x;
    }

    while (y->idx != -0) {
        sum += y->val * y->val;
        ++y;
    }

    return expf(-Gama * sum);
}

int8_t svm_predict(const Node *x) {
    if (okay == 0) {
        printf("you should call `svm_init();` first.");
        return 0;
    }

    float sum = -Bias;
    uint32_t i;
    for (i = 0; i < Size; ++i) sum += Scales[i] * rbf_kernel(x, Vector[i]);
    return sum > 0 ? 1 : -1;
}