/*------------------------------------------------------------------------------
 *	Copyright (c) 2023 by Bai Bing (seread@163.com)
 *	See COPYING file for copying and redistribution conditions.
 *
 *  Alians IT Studio.
 *----------------------------------------------------------------------------*/
#pragma once
#include <algorithm>
#include <execution>
#include <list>
#include <utility>
#include <vector>

#include "_Define.h"
#include "ASPoint.h"
#include "ASMatrix.h"
#include "core/Error.h"

namespace ais
{
    /// Enum To describe an axis
    enum class Axis3DType : int
    {
        X = 0,
        Y,
        Z
    };

    //================================================================
    //
    /// get point list for specified axis
    /// @param pointList vector list for ais::Point or ais::PointXYZ
    /// @param axis for target axis, must be Axis3DType::X, Axis3DType::Y, Axis3DType::Z
    ///
    template <class PT = ais::Point>
    AIS_EXPORT std::vector<double> getAxisValues(const std::vector<PT> &pointList, Axis3DType axis)
    {
        std::vector<double> axisValues;
        for (auto &p : pointList)
        {
            if (axis == Axis3DType::Z)
            {
                if constexpr (ais::all_same_v<PT, ais::PointXYZ>)
                {
                    axisValues.push_back(p.z);
                }
                else
                    THROW_INVALID_ARGUMENT("PointList not contains z axis values.");
            }
            else
                axisValues.push_back(axis == Axis3DType::Y ? p.y : p.x);
        }
        return axisValues;
    }

    //================================================================
    //
    /// get min and max values from point list
    /// @param points list of points
    ///
    template <class dt>
    AIS_EXPORT std::pair<dt, dt> getMinMax(const std::vector<dt> &points)
    {
        const auto [minp, maxp] = std::minmax_element(std::execution::par_unseq, points.begin(), points.end());

        return std::pair<dt, dt>(*minp, *maxp);
    }

    //================================================================
    //
    /// get min and max values from point matrix
    /// @param matrix matrix of point values
    ///
    template <class dt = double>
    AIS_EXPORT std::pair<dt, dt> getMinMax(const ais::Matrix<dt> &matrix)
    {
        const auto [minp, maxp] = std::minmax_element(std::execution::par_unseq, matrix.begin(), matrix.end());

        return std::pair<dt, dt>(*minp, *maxp);
    }

    //================================================================
    //
    /// get average values from list
    /// @param matrix matrix of point values
    ///
    template <typename DC>
    AIS_EXPORT double getAverage(const DC &list)
    {
        double ret = INFINITY;
        double sum = 0.0;
        size_t count = 0;

        for (auto &value : list)
        {
            if (!std::isnan(value) && !std::isinf(value))
            {
                count++;
                sum += value;
            }
        }

        ret = count == 0 ? INFINITY : sum / count;

        return ret;
    }

    //================================================================
    //
    /// get inverse distance weighting average values from list
    /// @param matrix matrix of point values
    ///
    template <typename DC>
    AIS_EXPORT double get_idw(const DC &list)
    {
        double ret = INFINITY;
        double sum = 0.0;
        double denominator = 0.0;

        std::pair<double, double> nearestWeight{1e+10, 0};
        for (auto &dv_pair : list)
        {
            if (nearestWeight.first > dv_pair.first)
                nearestWeight = dv_pair;
        }

        for (auto &dv_pair : list)
        {
            auto [distance, value] = dv_pair;
            if (std::abs(distance) < 1e-6)
                return value;

            double weight = 1 / (distance * distance);
            sum += weight * value;
            denominator += weight;
        }

        ret = std::abs(denominator) < 1e-6 ? INFINITY : sum / denominator;

        return ret;
    }

    //================================================================
    //
    /// get mean values from list
    /// @param matrix matrix of point values
    ///
    template <typename DC>
    AIS_EXPORT double get_mean(const DC &list, size_t top = 0)
    {
        double ret = INFINITY;
        double sum = 0.0;
        double denominator = 0.0;

        std::pair<double, double> nearestWeight{1e+10, 0};
        for (auto &dv_pair : list)
        {
            if (nearestWeight.first > dv_pair.first)
                nearestWeight = dv_pair;
        }

        size_t count = 0;
        for (auto &dv_pair : list)
        {
            if (top > 0 && count > top)
                break;

            auto [distance, value] = dv_pair;
            if (std::abs(distance) < 1e-6)
                return value;

            if (std::isnan(value) || std::isinf(value))
                continue;

            sum += value;
            denominator += 1;

            count++;
        }

        ret = std::abs(denominator) < 1e-6 ? INFINITY : sum / denominator;

        return ret;
    }

    //================================================================
    //
    /// get mean values from list
    /// @param matrix matrix of point values
    ///
    template <typename DC>
    AIS_EXPORT double get_weight_mean(const DC &list, size_t top = 0)
    {
        double ret = INFINITY;
        double sum = 0.0;
        double denominator = 0.0;

        size_t count = 0;
        for (auto &dv_pair : list)
        {
            if (top > 0 && count > top)
                break;

            auto [weight, value] = dv_pair;

            if (std::isnan(value) || std::isinf(value))
                continue;

            sum += value * weight;
            denominator += weight;
            count++;
        }

        ret = std::abs(denominator) < 1e-6 ? INFINITY : sum / denominator;

        return ret;
    }

    //================================================================
    //
    /// generate axis values from start to end, point count = grid count + 1
    ///
    AIS_EXPORT std::vector<double> generateAxisPoints(double start, double end, size_t pointCount);

    //================================================================
    //
    /// filter sample points which include in the target area points, out of the range will be erased
    ///
    AIS_EXPORT std::vector<ais::PointXYZ> filter_points(const std::vector<ais::Point> &areaPoints, const std::vector<ais::PointXYZ> &samplePoints);

    //================================================================
    //
    /// filter and copy sample points which include in the target area points
    ///
    AIS_EXPORT void filter_copy_points(const std::pair<double, double> &minPos, const std::pair<double, double> &maxPos,
                                       const std::vector<ais::PointXYZ> &samplePoints,
                                       std::vector<ais::PointXYZ> &outputPoints);
}