/*

 * Copyright 2023 Google LLC

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#include "fuzz/Fuzz.h"

#include "include/private/base/SkAssert.h"

#include "include/private/base/SkFloatingPoint.h"

#include "src/base/SkCubics.h"

#include "src/base/SkQuads.h"

#include "src/base/SkUtils.h"

#include <cmath>

static void fuzz_quad_real_roots(double A, double B, double C) {

    double roots[2];

    const int numSolutions = SkQuads::RootsReal(A, B, C, roots);

    SkASSERT_RELEASE(numSolutions >= 0 && numSolutions <= 2);

    for (int i = 0; i < numSolutions; i++) {

        SkASSERT_RELEASE(std::isfinite(roots[i]));

        // You may be tempted to add assertions that plug the provided solutions into

        // the quadratic equation and verify that the result is zero. Be advised

        // that the fuzzer is very good at finding float values that result in

        // seemingly arbitrarily large errors, due to the imprecision of floating

        // point math. Unless the input range is sufficiently small, such an

        // effort seems fruitless.

    }

    if (numSolutions == 2) {

        // Roots should not be duplicated

        SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[1]));

    }

}

DEF_FUZZ(QuadRoots, fuzz) {

    double A, B, C;

    fuzz->next(&A);

    fuzz->next(&B);

    fuzz->next(&C);

    // Uncomment for easy test case creation

//    SkDebugf("A %16e (0x%lx) B %16e (0x%lx) C %16e (0x%lx)\n",

//             A, sk_bit_cast<uint64_t>(A), B, sk_bit_cast<uint64_t>(B),

//             C, sk_bit_cast<uint64_t>(C));

    fuzz_quad_real_roots(A, B, C);

}