/* -------------------------------------------------------------------------
 * This file is part of the MindStudio project.
 * Copyright (c) 2025 Huawei Technologies Co.,Ltd.
 *
 * MindStudio is licensed under Mulan PSL v2.
 * You can use this software according to the terms and conditions of the Mulan PSL v2.
 * You may obtain a copy of Mulan PSL v2 at:
 *
 *          http://license.coscl.org.cn/MulanPSL2
 *
 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
 * See the Mulan PSL v2 for more details.
 * ------------------------------------------------------------------------- */

#include <map>
#include <cstdint>
#include <cmath>
#include <limits>

namespace Mskpp {
double LinearInterpolate(const std::map<uint32_t, double>& curves, uint32_t x)
{
    if (curves.empty()) {
        return 0.0;
    }
    if (x <= curves.begin()->first) {
        return curves.begin()->second;
    } else if (x >= curves.rbegin()->first) {
        return curves.rbegin()->second;
    }
    auto right = curves.upper_bound(x);
    auto left = std::prev(right, 1);
    if (std::fabs(right->first - left->first) <= std::numeric_limits<double>::epsilon()) {
        return 0.0;
    }
    return ((x - left->first) * right->second + (right->first - x) * left->second) /
           (right->first - left->first);
}
}