// Copyright (C) Stichting Deltares 2020. All rights reserved.
//
// This file is part of the Dam Engine.
//
// The Dam Engine is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// All names, logos, and references to "Deltares" are registered trademarks of
// Stichting Deltares and remain full property of Stichting Deltares at all times.
// All rights reserved.

using System;
using System.Collections.Generic;

namespace Deltares.LayerOnSlopeTool.Data
{
    /// <summary>
    /// Defines the surface line
    /// </summary>
    public class SurfaceLine
    {
        private readonly List<SurfaceLinePoint> surfaceLinePoints = new List<SurfaceLinePoint>();

        public string SurfaceLineId { get; set; }

        /// <summary>
        /// Gets the surface line points.
        /// </summary>
        /// <value>
        /// The surface line points.
        /// </value>
        public List<SurfaceLinePoint> SurfaceLinePoints
        {
            get { return surfaceLinePoints; }
        }

        /// <summary>
        /// Gets the surface line point by location.
        /// </summary>
        /// <param name="x">The x.</param>
        /// <param name="z">The z.</param>
        /// <returns></returns>
        public SurfaceLinePoint GetSurfaceLinePointByLocation(double x, double z)
        {
            var index = 0;
            var searchPoint = new SurfaceLinePoint {XCoordinate = x, ZCoordinate = z};
            SurfaceLinePoint surfaceLinePoint = null;
            while (surfaceLinePoint == null && index < surfaceLinePoints.Count)
            {
                if (surfaceLinePoints[index].LocationEquals(searchPoint))
                {
                    surfaceLinePoint = surfaceLinePoints[index];
                }

                index++;
            }
            return surfaceLinePoint;
        }

        /// <summary>
        /// Gets the type of the surface line point by.
        /// </summary>
        /// <param name="pointType">Type of the point.</param>
        /// <returns></returns>
        public SurfaceLinePoint GetSurfaceLinePointByType(CharacteristicPointType pointType)
        {
            var index = 0;
            SurfaceLinePoint surfaceLinePoint = null;
            while (surfaceLinePoint == null && index < surfaceLinePoints.Count)
            {
                if (surfaceLinePoints[index].PointType == pointType)
                {
                    surfaceLinePoint = surfaceLinePoints[index];
                }

                index++;
            }
            return surfaceLinePoint;
        }

        /// <summary>
        /// Creates the lowered surface line for given layer thickness.
        /// </summary>
        /// <param name="layerThickness">The layer thickness.</param>
        /// <returns></returns>
        public SurfaceLine CreateLoweredSurfaceLineForGivenLayerThickness(double layerThickness)
        {
            const double tolerance = 1e-4;
            const double horizontalOffset = 0.01;
            var loweredSurfaceLine = new SurfaceLine();
            var dikeTopPolder = GetSurfaceLinePointByType(CharacteristicPointType.DikeTopAtPolder);
            var dikeToePolder = GetSurfaceLinePointByType(CharacteristicPointType.DikeToeAtPolder);
            foreach (var point in SurfaceLinePoints)
            {
                if (point.XCoordinate <= dikeTopPolder.XCoordinate)
                {
                    HandlePointsUpToAndIncludingDikeTopPolder(layerThickness, point, loweredSurfaceLine, dikeTopPolder, tolerance, horizontalOffset);
                }
                else
                {
                    // Handle all points between dike top polder and dike toe polder (taking into account the horizontal offset).
                    if (point.XCoordinate > dikeTopPolder.XCoordinate + horizontalOffset && point.XCoordinate < dikeToePolder.XCoordinate - horizontalOffset)
                    {
                        var newPointLowered = new SurfaceLinePoint
                        {
                            XCoordinate = point.XCoordinate,
                            ZCoordinate = point.ZCoordinate - layerThickness,
                            PointType = point.PointType
                        };
                        loweredSurfaceLine.SurfaceLinePoints.Add(newPointLowered);
                    }
                    else
                    {
                        HandlePointsAtDikeToePolderAndBeyond(layerThickness, point, dikeToePolder, tolerance, horizontalOffset, loweredSurfaceLine);
                    }
                }
            }
            return loweredSurfaceLine;
        }

        private static void HandlePointsAtDikeToePolderAndBeyond(double layerThickness, SurfaceLinePoint point,
            SurfaceLinePoint dikeToePolder, double tolerance, double horizontalOffset, SurfaceLine loweredSurfaceLine)
        {
            if (Math.Abs(point.XCoordinate - dikeToePolder.XCoordinate) < tolerance)
            {
                var newPointAtDikeToe = new SurfaceLinePoint
                {
                    XCoordinate = point.XCoordinate - horizontalOffset,
                    ZCoordinate = point.ZCoordinate - layerThickness,
                    PointType = CharacteristicPointType.None
                };
                loweredSurfaceLine.SurfaceLinePoints.Add(newPointAtDikeToe);
            }

            if (point.XCoordinate >= dikeToePolder.XCoordinate)
            {
                var newPointBeyondDikeToe = new SurfaceLinePoint
                {
                    XCoordinate = point.XCoordinate,
                    ZCoordinate = point.ZCoordinate,
                    PointType = point.PointType
                };
                loweredSurfaceLine.SurfaceLinePoints.Add(newPointBeyondDikeToe);
            }
        }

        private static void HandlePointsUpToAndIncludingDikeTopPolder(double layerThickness, SurfaceLinePoint point,
            SurfaceLine loweredSurfaceLine, SurfaceLinePoint dikeTopPolder, double tolerance, double horizontalOffset)
        {
            var newPointUpToDikeTop = new SurfaceLinePoint
            {
                XCoordinate = point.XCoordinate,
                ZCoordinate = point.ZCoordinate,
                PointType = point.PointType
            };
            loweredSurfaceLine.SurfaceLinePoints.Add(newPointUpToDikeTop);
            if (Math.Abs(point.XCoordinate - dikeTopPolder.XCoordinate) < tolerance)
            {
                var newPointAtDikeTop = new SurfaceLinePoint
                {
                    XCoordinate = point.XCoordinate + horizontalOffset,
                    ZCoordinate = point.ZCoordinate - layerThickness,
                    PointType = CharacteristicPointType.None
                };
                loweredSurfaceLine.SurfaceLinePoints.Add(newPointAtDikeTop);
            }
        }
    }
}