// Copyright (C) Stichting Deltares 2023. 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;
using System.Linq;
using Deltares.DamEngine.Data.Geometry;
using Deltares.DamEngine.Data.Properties;
using Deltares.DamEngine.Data.Standard;

namespace Deltares.DamEngine.Data.Geotechnics
{
    /// <summary>
    /// All extension-methods for <see cref="SurfaceLine2"/>.
    /// </summary>
    public static class SurfaceLine2Extensions
    {
        /// <summary>
        /// Returns all <see cref="CharacteristicPoint"/> that require to be sorted on X
        /// ascending.
        /// </summary>
        /// <param name="line">The evaluated surfaceline.</param>
        /// <returns>Collection of characteristic points, ordered by type from the point
        /// expecting the lowest X coordinate in the set through to the one expecting the
        /// highest X coordinate.</returns>
        public static IEnumerable<CharacteristicPoint> GetCharacteristicPointsRequiringAscendingX(this SurfaceLine2 line)
        {
            return line.CharacteristicPoints.Where(p =>
                                                   !double.IsNaN(p.X) && // Note: This probably shall no longer apply to SurfaceLine2
                                                   p.CharacteristicPointType != CharacteristicPointType.None &&
                                                   p.CharacteristicPointType != CharacteristicPointType.TrafficLoadInside &&
                                                   p.CharacteristicPointType != CharacteristicPointType.TrafficLoadOutside).
                        OrderBy(p => p.CharacteristicPointType);
        }

        /// <summary>
        /// Checks whether the specified line has the given annotation.
        /// </summary>
        /// <param name="line">The surface line to be checked.</param>
        /// <param name="type">The type.</param>
        /// <returns></returns>
        /// <seealso cref="IsDefined"/>
        public static bool HasAnnotation(this SurfaceLine2 line, CharacteristicPointType type)
        {
            return line.CharacteristicPoints.GetGeometryPoint(type) != null;
        }

        /// <summary>
        /// Determines whether the specified characteristic point type is defined (has 
        /// the given annotation and its X coordinate is not <see cref="double.NaN"/>).
        /// </summary>
        /// <param name="line">The evaluated surfaceline.</param>
        /// <param name="characteristicPointType">Type of the characteristic point.</param>
        /// <returns>true if input parameter is defined</returns>
        /// <seealso cref="HasAnnotation"/>
        public static bool IsDefined(this SurfaceLine2 line, CharacteristicPointType characteristicPointType)
        {
            // TODO: GRASP: Information Expert -> CharacteristicPoint class should be responsible for this logic.
            return line.HasAnnotation(characteristicPointType) &&
                   !Double.IsNaN(line.CharacteristicPoints.GetGeometryPoint(characteristicPointType).X);
        }

        /// <summary>
        /// Gets the absolute height ([m]) of the dike.
        /// </summary>
        /// <returns>Height of dike, or null if <see cref="CharacteristicPointType.DikeTopAtRiver"/>
        /// is not defined for the surface line.</returns>
        public static double? GetDikeHeight(this SurfaceLine2 line)
        {
            var dikeTopAtRiver = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeTopAtRiver);
            if (dikeTopAtRiver != null)
            {
                return dikeTopAtRiver.Z;
            }
            return null;
        }

        /// <summary>
        /// If shoulder is present then the toe of the shoulder (<see cref="CharacteristicPointType.DikeToeAtPolder"/>) 
        /// is returned, else the toe of the dike (<see cref="CharacteristicPointType.ShoulderBaseInside"/>)
        /// is returned.
        /// </summary>
        /// <returns>Toe of the dike, or null if none of the required characteristic 
        /// annotations can be found.</returns>
        public static GeometryPoint GetDikeToeInward(this SurfaceLine2 line)
        {
            return line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderBaseInside) ??
                   line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtPolder);
        }

        /// <summary>
        /// Gets the length of the dike.
        /// </summary>
        /// <returns>dike length or null in case toe points are null</returns>
        public static double? GetDikeLength(this SurfaceLine2 line)
        {
            var dikeToeAtRiver = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtRiver);
            var dikeToeAtPolder = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtPolder);

            if (dikeToeAtRiver != null && dikeToeAtPolder != null)
            {
                return Math.Abs(dikeToeAtRiver.X - dikeToeAtPolder.X);
            }
            return null;
        }

        /// <summary>
        /// Checks if a surfaceline has all characteristic point types required to describe
        /// a dike.
        /// </summary>
        /// <param name="line">Surfaceline to be checked.</param>
        /// <returns>True if there are characteristic points defined that describe a dike;
        /// False otherwise.</returns>
        public static bool HasDike(this SurfaceLine2 line)
        {
            return IsDefined(line, CharacteristicPointType.DikeToeAtRiver) &&
                   IsDefined(line, CharacteristicPointType.DikeTopAtRiver) &&
                   IsDefined(line, CharacteristicPointType.DikeTopAtPolder) &&
                   IsDefined(line, CharacteristicPointType.DikeToeAtPolder);
        }

        /// <summary>
        /// Add 2D characteristic point without a type
        /// </summary>
        /// <param name="line">The surfaceline to be modified.</param>
        /// <param name="x">The x.</param>
        /// <param name="z">The z.</param>
        public static void EnsurePoint(this SurfaceLine2 line, double x, double z)
        {
            line.EnsurePointOfType(x, z, null);
        }

        /// <summary>
        /// Add characteristic point in X-Z plane
        /// </summary>
        /// <param name="line">The surfaceline to be modified.</param>
        /// <param name="x">The x.</param>
        /// <param name="z">The z.</param>
        /// <param name="type">The type.</param>
        public static void EnsurePointOfType(this SurfaceLine2 line, double x, double z, CharacteristicPointType? type)
        {
            if (!line.CharacteristicPoints.GeometryMustContainPoint)
            {
                throw new NotImplementedException("SurfaceLine specific method, not implemented for 'Ringtoets'-mode.");
            }

            bool movedPointToMatch = false;
            bool addPoint = false;
            GeometryPoint point = null;
            var newPoint = new GeometryPoint()
            {
                X = x,
                Z = z
            };
            if (type.HasValue)
            {
                // Get point of this type..
                point = line.CharacteristicPoints.GetGeometryPoint(type.Value);
                if (point != null)
                {
                    // Characteristic point annotation set, check location...
                    if (point.LocationEquals(newPoint))
                    {
                        // Annotated point is at given location; We're done here! :)
                        return;
                    }
                    else
                    {
                        bool isAssignedToOtherCharacteristicPoints =
                            line.GetCharacteristicPoints(point).Count(cpt => cpt != CharacteristicPointType.None) > 1;
                        if (isAssignedToOtherCharacteristicPoints)
                        {
                            // Other characteristic points exist with the same coordinates so add as new point
                            point = line.Geometry.GetGeometryPointAt(newPoint.X, newPoint.Z); // Get point at specified coords
                            if (point == null)
                            {
                                point = newPoint;
                                addPoint = true;
                            }
                        }
                        else
                        {
                            // Point is unique as characteristic point so set its coords to specified coords
                            point.X = x;
                            point.Z = z;
                            movedPointToMatch = true;
                        }
                    }
                }
            }
            if (point == null)
            {
                point = line.Geometry.GetGeometryPointAt(x, z); // Get point at specified coords
            }
            if (point == null)
            {
                point = new GeometryPoint()
                {
                    X = x,
                    Z = z
                };
                addPoint = true;
            }
            if (addPoint)
            {
                line.Geometry.Points.Add(point);
                line.AddCharacteristicPoint(point, type ?? CharacteristicPointType.None);
            }
            else if (type.HasValue && !movedPointToMatch)
            {
                if (line.CharacteristicPoints.Any(cp => ReferenceEquals(cp.GeometryPoint, point) &&
                                                        cp.CharacteristicPointType != CharacteristicPointType.None))
                {
                    line.AddCharacteristicPoint(point, type.Value);
                }
                else
                {
                    int index = -1;
                    for (int i = 0; i < line.CharacteristicPoints.Count; i++)
                    {
                        if (ReferenceEquals(line.CharacteristicPoints[i].GeometryPoint, point))
                        {
                            index = i;
                            break;
                        }
                    }
                    line.CharacteristicPoints.Annotate(index, type.Value);
                }
            }
            line.Geometry.SyncCalcPoints();
        }

        /// <summary>
        /// Removes the points between the two x values. The start and end points will 
        /// not be removed.
        /// </summary>
        /// <param name="line">Surfaceline being modified.</param>
        /// <param name="startX">The non-inclusive starting X-coordinate.</param>
        /// <param name="endX">The non-inclusive ending X-coordinate.</param>
        /// <seealso cref="RemoveSegmentIncluding"/>
        public static void RemoveSegmentBetween(this SurfaceLine2 line, double startX, double endX)
        {
            RemoveGeometryPointsInRange(line, startX, endX, false);
        }

        /// <summary>
        /// Removes the points between the two x values.
        /// </summary>
        /// <param name="line">Surfaceline being modified.</param>
        /// <param name="startX">The inclusive starting X-Coordinate.</param>
        /// <param name="endX">The inclusive ending X-Coordinate.</param>
        /// <seealso cref="RemoveSegmentBetween"/>
        public static void RemoveSegmentIncluding(this SurfaceLine2 line, double startX, double endX)
        {
            RemoveGeometryPointsInRange(line, startX, endX, true);
        }

        /// <summary>
        /// Removes the points between the two x values.
        /// </summary>
        /// <param name="line">Surfaceline being modified.</param>
        /// <param name="startX">The starting X-Coordinate.</param>
        /// <param name="endX">The ending X-Coordinate.</param>
        /// <param name="isInclusiveRange">Indicates if <paramref name="startX"/> and
        /// <paramref name="endX"/> are inclusive bounds or not.</param>
        private static void RemoveGeometryPointsInRange(SurfaceLine2 line, double startX, double endX, bool isInclusiveRange)
        {
            foreach (var geometryPoint in GetGeometryPointsWithinRange(line, startX, endX, isInclusiveRange).ToArray())
            {
                var characteristicPoints = line.CharacteristicPoints.Where(cp => ReferenceEquals(cp.GeometryPoint, geometryPoint)).ToArray();
                if (characteristicPoints.Length > 0)
                {
                    // CharacteristicPointSet will manage both collections of CharacteristicPoint instances and Geometry
                    foreach (var characteristicPoint in characteristicPoints)
                    {
                        line.CharacteristicPoints.Remove(characteristicPoint);
                    }
                }
                else
                {
                    // Notify change such that CharacteristicPointSet instances observing this
                    // geometry can update if required.
                    line.Geometry.Points.Remove(geometryPoint);
                }
            }
            line.Geometry.SyncCalcPoints();
        }

        /// <summary>
        /// Retrieve all <see cref="CharacteristicPoint"/> instances of a surfaceline that
        /// fall with the range.
        /// </summary>
        /// <param name="line">Surfaceline being evaluated.</param>
        /// <param name="startX">Starting X-coordinate.</param>
        /// <param name="endX">Ending X-coordinate.</param>
        /// <param name="isInclusiveRange">Indicates if <paramref name="startX"/> and
        /// <paramref name="endX"/> are inclusive bounds or not.</param>
        /// <returns>Collection of characteristic points within the given range.</returns>
        private static IEnumerable<GeometryPoint> GetGeometryPointsWithinRange(SurfaceLine2 line,
                                                                               double startX, double endX, bool isInclusiveRange)
        {
            if (isInclusiveRange)
            {
                return line.Geometry.Points.Where(cp => (cp.X >= startX || cp.X.AlmostEquals(startX, GeometryPoint.Precision)) &&
                                                        (cp.X <= endX || cp.X.AlmostEquals(endX, GeometryPoint.Precision)));
            }
            return line.Geometry.Points.Where(cp => cp.X > startX && cp.X < endX);
        }

        /// <summary>
        /// Checks if a surfaceline has all characteristic point types required to describe
        /// an inside shoulder.
        /// </summary>
        /// <param name="line">Surfaceline to be checked.</param>
        /// <returns>True if there are characteristic points defined that described the 
        /// inside shoulder; False otherwise.</returns>
        public static bool HasShoulderInside(this SurfaceLine2 line)
        {
            return IsDefined(line, CharacteristicPointType.ShoulderTopInside) &&
                   IsDefined(line, CharacteristicPointType.ShoulderBaseInside);
        }

        /// <summary>
        /// Checks if a surfaceline has all characteristic point types required to describe
        /// a ditch.
        /// </summary>
        /// <param name="line">Surfaceline to be checked.</param>
        /// <returns>True if there are characteristic points defined that described the 
        /// ditch; False otherwise.</returns>
        public static bool HasDitch(this SurfaceLine2 line)
        {
            return IsDefined(line, CharacteristicPointType.DitchDikeSide) &&
                   IsDefined(line, CharacteristicPointType.DitchPolderSide);
        }

        /// <summary>
        /// Determines whether ditch is correct.
        /// </summary>
        /// <returns><c>true</c> if ditch is correct, otherwise <c>false</c></returns>
        /// <remarks>This methods checks if the following points have their X cooridnates
        /// properly defined:
        /// <list type="bullet">
        /// <item><see cref="CharacteristicPointType.DitchDikeSide"/></item>
        /// <item><see cref="CharacteristicPointType.BottomDitchDikeSide"/></item>
        /// <item><see cref="CharacteristicPointType.BottomDitchPolderSide"/></item>
        /// <item><see cref="CharacteristicPointType.DitchPolderSide"/></item>
        /// </list>
        /// </remarks>
        public static bool IsDitchCorrect(this SurfaceLine2 line)
        {
            // No ditch then always ok
            bool res = !line.HasDitch();
            if (!res)
            {
                // check the unchecked points
                var bottomDitchDikeSide = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.BottomDitchDikeSide);
                var bottomDitchPolderSide = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.BottomDitchPolderSide);
                res = (bottomDitchDikeSide != null && bottomDitchPolderSide != null);

                // check the ditch points describe following shape:
                //     0       0
                //      \     /
                //       0---0
                var ditchPolderSide = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DitchPolderSide);
                var ditchDikeSide = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DitchDikeSide);
                if (res)
                {
                    res = ditchPolderSide.X >= bottomDitchPolderSide.X &&
                          bottomDitchPolderSide.X >= bottomDitchDikeSide.X &&
                          bottomDitchDikeSide.X >= ditchDikeSide.X &&
                          bottomDitchDikeSide.Z <= ditchDikeSide.Z &&
                          bottomDitchPolderSide.Z <= ditchPolderSide.Z;
                }
            }
            return res;
        }

        /// <summary>
        /// Gets the starting point of the surface line.
        /// </summary>
        /// <returns>Starting point, or null if none of the considered points can be found.</returns>
        /// <remarks>
        /// Method looks for the following characteristic points (in this order) and returns
        /// the corresponding geometry point if present:
        /// <list type="number">
        /// <item><see cref="CharacteristicPointType.ShoulderBaseOutside"/></item>
        /// <item><see cref="CharacteristicPointType.ShoulderTopOutside"/></item>
        /// <item><see cref="CharacteristicPointType.DikeToeAtRiver"/></item>
        /// </list>
        /// </remarks>
        public static GeometryPoint GetStartingPoint(this SurfaceLine2 line)
        {
            return line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderBaseOutside) ??
                   line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderTopOutside) ??
                   line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtRiver);
        }

        /// <summary>
        /// Gets the default height of the dike table.
        /// </summary>
        /// <returns>null or height of table</returns>
        public static double? GetDefaultDikeTableHeight(this SurfaceLine2 line)
        {
            // Consulted Erik Vastenburg about this: Use buitenkruinlijn as default DTH
            GeometryPoint point = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeTopAtRiver);
            return point == null ? null : (double?)point.Z;
        }

        /// <summary>
        /// Check whether river level is above the dike toe at river side. If not, throw error
        /// </summary>
        /// <param name="line">The evaluated surfaceline.</param>
        /// <param name="riverLevel">The current river level.</param>
        /// <returns>Bottom of the river if bottomlevel is above riverLevel, else <paramref name="riverLevel"/></returns>
        /// <remarks><paramref name="line"/> is required to have the characteristic point
        /// <see cref="CharacteristicPointType.SurfaceLevelOutside"/> when <paramref name="riverLevel"/>
        /// is not null.
        /// </remarks>
        public static void CheckWaterLevelIsAboveDikeToeRiverSide(this SurfaceLine2 line, double? riverLevel)
        {
            // Waterlevel MUST be above level of dike toe at river side
            if (riverLevel.HasValue)
            {
                double z = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtRiver).Z;
                if (riverLevel < z)
                {
                    ThrowWhenLevelBelowDikeToeDike(z, riverLevel.Value);
                }
            }            
        }

        /// <summary>
        /// Determines the intersection of a horizontal line with the surfaceline, starting
        /// from <see cref="CharacteristicPointType.SurfaceLevelOutside"/> to <see cref="CharacteristicPointType.DikeTopAtRiver"/>.
        /// </summary>
        /// <param name="line">The surfaceline being evaluated.</param>
        /// <param name="level">The height of the horizontal line.</param>
        /// <returns>The GeometryPoint at the intersection, or null if no intersection can
        /// be found.</returns>
        /// <remarks>
        /// <para>Requires that the following characteristic points are defined:</para>
        /// <list type="bullet">
        /// <item><see cref="CharacteristicPointType.SurfaceLevelOutside"/></item>
        /// <item><see cref="CharacteristicPointType.DikeTopAtRiver"/></item>
        /// <item><see cref="CharacteristicPointType.SurfaceLevelInside"/></item>
        /// </list>
        /// <para>This method draws the horizontal line starting from the smallest X available
        /// in the geometry to <see cref="CharacteristicPointType.SurfaceLevelInside"/>.</para>
        /// </remarks>
        /// <exception cref="SurfaceLineException">When <paramref name="level"/> greater than
        /// the height of the characteristic point <see cref="CharacteristicPointType.DikeTopAtRiver"/>.</exception>
        /// <seealso cref="DetermineIntersectionBetweenTaludRiverSideAndWaterLevel"/>
        public static GeometryPoint DetermineIntersectionWithLevel(this SurfaceLine2 line, double level)
        {
            double startXCoordinate = line.Geometry.GetMinX();
            var waterlevelLine = GetWaterlevelLineStartingFrom(line, level, startXCoordinate);

            return DetermineIntersectionWithHorizontalLevel(line, waterlevelLine);
        }

        /// <summary>
        /// Determines the intersection of a horizontal line with the surfaceline, starting
        /// from <see cref="CharacteristicPointType.SurfaceLevelOutside"/> to <see cref="CharacteristicPointType.DikeTopAtRiver"/>.
        /// </summary>
        /// <param name="line">The surfaceline being evaluated.</param>
        /// <param name="level">The height of the horizontal line.</param>
        /// <returns>The GeometryPoint at the intersection, or null if no intersection can
        /// be found.</returns>
        /// <remarks>
        /// <para>Requires that the following characteristic points are defined:</para>
        /// <list type="bullet">
        /// <item><see cref="CharacteristicPointType.SurfaceLevelOutside"/></item>
        /// <item><see cref="CharacteristicPointType.DikeTopAtRiver"/></item>
        /// <item><see cref="CharacteristicPointType.SurfaceLevelInside"/></item>
        /// </list>
        /// <para>This method draws the horizontal line starting from the X coordinate of
        /// <see cref="CharacteristicPointType.SurfaceLevelOutside"/> to <see cref="CharacteristicPointType.SurfaceLevelInside"/>.</para>
        /// </remarks>
        /// <exception cref="SurfaceLineException">When <paramref name="level"/> greater than
        /// the height of the characteristic point <see cref="CharacteristicPointType.DikeTopAtRiver"/>.</exception>
        /// <seealso cref="DetermineIntersectionWithLevel"/>
        public static GeometryPoint DetermineIntersectionBetweenTaludRiverSideAndWaterLevel(this SurfaceLine2 line, double level)
        {
            double startXCoordinate = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.SurfaceLevelOutside).X;
            var waterlevelLine = GetWaterlevelLineStartingFrom(line, level, startXCoordinate);

            return DetermineIntersectionWithHorizontalLevel(line, waterlevelLine);
        }

        /// <summary>
        /// Determines the shoulder length for given shoulder top inside.
        /// </summary>
        /// <param name="line">The line.</param>
        /// <param name="shoulderTopInside">The shoulder top inside.</param>
        /// <returns></returns>
        public static double DetermineShoulderLengthForGivenShoulderTopInside(this SurfaceLine2 line, GeometryPoint shoulderTopInside)
        {
            GeometryPoint geometryPoint1 = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeTopAtPolder);
            GeometryPoint geometryPoint2 = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtPolder);
            GeometryPoint p2 = line.HasShoulderInside() ? line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderBaseInside) : geometryPoint2;
            GeometryPoint geometryPoint3 = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.SurfaceLevelOutside);
            GeometryPoint withExtrapolation = LineHelper.GetIntersectionPointWithExtrapolation(geometryPoint1, p2, shoulderTopInside, new GeometryPoint(geometryPoint3.X, shoulderTopInside.Z));
            return shoulderTopInside.X - withExtrapolation.X;
        }
        /// <summary>
        /// Determines the height of the shoulder.
        /// </summary>
        /// <param name="line">The line.</param>
        /// <returns></returns>
        public static double DetermineShoulderHeight(this SurfaceLine2 line)
        {
            GeometryPoint geometryPoint1 = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderTopInside);
            GeometryPoint geometryPoint2 = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderBaseInside);
            if (geometryPoint1 != null && geometryPoint2 != null)
                return geometryPoint1.Z - line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtPolder).Z;
            return 0.0;
        }

        /// <summary>
        /// Determines the width of the shoulder for this surfaceline.
        /// </summary>
        /// <returns>shoulder length</returns>
        /// <remarks>Method requires the existenc of the following characteristic points when
        /// <see cref="CharacteristicPointType.ShoulderTopInside"/> and 
        /// <see cref="CharacteristicPointType.ShoulderBaseInside"/> are defined:
        /// <list type="bullet">
        /// <item><see cref="CharacteristicPointType.DikeTopAtPolder"/></item>
        /// <item><see cref="CharacteristicPointType.SurfaceLevelOutside"/></item>
        /// <item><see cref="CharacteristicPointType.DikeToeAtPolder"/></item>
        /// </list>
        /// </remarks>
        public static double DetermineShoulderLength(this SurfaceLine2 line)
        {
            var shoulderTopInside = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderTopInside);
            if (shoulderTopInside != null && HasAnnotation(line, CharacteristicPointType.ShoulderBaseInside))
            {
                return line.DetermineShoulderLengthForGivenShoulderTopInside(shoulderTopInside);
            }
            return 0.0;
        }

        /// <summary>
        /// Gets the cotangent of inner slope.
        /// </summary>
        /// <param name="line">The line.</param>
        /// <returns></returns>
        /// <exception cref="System.InvalidOperationException">
        /// GetCotangentOfInnerSlope requires characteristic point DikeTopAtPolder to be defined.
        /// or
        /// GetCotangentOfInnerSlope requires either of characteristic points ShoulderBaseInside or DikeToeAtPolder to be defined.
        /// </exception>
        public static double GetCotangentOfInnerSlope(this SurfaceLine2 line)
        {
            GeometryPoint geometryPoint = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeTopAtPolder);
            if (geometryPoint == null)
                throw new InvalidOperationException(Resources.GetCotangentOfInnerSlopeDikeTopAtPolderRequired);
            GeometryPoint dikeToeInward = line.GetDikeToeInward();
            if (dikeToeInward == null)
                throw new InvalidOperationException(Resources.GetCotangentOfInnerSlopeDikeToeAtPolderRequired);
            return Math.Abs((dikeToeInward.X - geometryPoint.X) / (geometryPoint.Z - dikeToeInward.Z));
        }

        /// <summary>
        /// Gets the limit point for shoulder design.
        /// </summary>
        /// <param name="line">The line.</param>
        /// <returns></returns>
        public static GeometryPoint GetLimitPointForShoulderDesign(this SurfaceLine2 line)
        {
            return line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.ShoulderTopInside) ?? line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeToeAtPolder);
        }
        #region Private methods
        /// <summary>
        /// Create a horizontal line from a given starting X coordinate and ending at the
        /// X coordinate of <see cref="CharacteristicPointType.SurfaceLevelInside"/> defined
        /// in the surfaceline.
        /// </summary>
        /// <param name="line">The referenced surfaceline.</param>
        /// <param name="level">The height level of the horizontal line.</param>
        /// <param name="startXCoordinate">The starting coordinate.</param>
        /// <returns>The line segment.</returns>
        private static Line GetWaterlevelLineStartingFrom(SurfaceLine2 line, double level, double startXCoordinate)
        {
            GeometryPoint pointEndOfprofile = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.SurfaceLevelInside);
            var waterlevelLine = new Line();
            waterlevelLine.CreateHorizontalZLine(startXCoordinate, pointEndOfprofile.X, level);

            return waterlevelLine;
        }

        /// <summary>
        /// Finds the intersection point of a given horizontal line and the river side talud.
        /// </summary>
        /// <param name="line">The evaluated surfaceline.</param>
        /// <param name="waterlevelLine">The horizontal line.</param>
        /// <returns>The intersection point, or null in case no intersection was found.</returns>
        /// <exception cref="SurfaceLineException">When height of the horizontal line is 
        /// greater than the height of the characteristic point <see cref="CharacteristicPointType.DikeTopAtRiver"/>.</exception>
        private static GeometryPoint DetermineIntersectionWithHorizontalLevel(SurfaceLine2 line, Line waterlevelLine)
        {
            ThrowWhenLevelAboveDike(line, waterlevelLine.BeginPoint.Z);

            var list = line.Geometry.Points.Where(point =>
                                                  point.X >= line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.SurfaceLevelOutside).X &&
                                                  point.X <= line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeTopAtRiver).X).ToList();

            for (int i = 1; i < list.Count; i++)
            {
                var surfaceLineSegment = new Line();
                surfaceLineSegment.SetBeginAndEndPoints(
                    new Point2D(list[i - 1].X, list[i - 1].Z), 
                    new Point2D(list[i].X, list[i].Z));

                var intersectPoint = surfaceLineSegment.GetIntersectPointXz(waterlevelLine);
                if (intersectPoint != null)
                {
                    return new GeometryPoint(intersectPoint.X, intersectPoint.Z);
                }
            }

            return null;
        }

        /// <summary>
        /// Throw an <see cref="SurfaceLineException"/> in case the given height level is
        /// higher than the characteristic point <see cref="CharacteristicPointType.DikeTopAtRiver"/>.
        /// </summary>
        private static void ThrowWhenLevelAboveDike(SurfaceLine2 line, double level)
        {
            var dikeTopAtRiver = line.CharacteristicPoints.GetGeometryPoint(CharacteristicPointType.DikeTopAtRiver);
            if (level > dikeTopAtRiver.Z)
            {
                throw new SurfaceLineException(String.Format(
                    "Level ({0:F2} m) should NOT be higher than surface line ({1:F2}))",
                    level, dikeTopAtRiver.Z));
            }
        }

        private static void ThrowWhenLevelBelowDikeToeDike(double levelDikeToeRiverSide, double riverLevel)
        {
            throw new SurfaceLineException(String.Format(
                    "River level ({0:F2} m) should be higher than dike toe at river side ({1:F2}))",
                    riverLevel, levelDikeToeRiverSide));            
        }
        #endregion Private methods
    }
}