/// <summary>
/// Initializes a new <see cref="GameLevel"/> instance with the specified lists of vertices
/// and line segments, and resets the vertices' positions if requested.
/// </summary>
/// <param name="vertices">An enumeration of vertices.</param>
/// <param name="lineSegments">An enumeration of line segments.</param>
/// <param name="resetPositions">Specifies whether the vertices' positions should be reset,
/// arranging all vertices in a circle in random order.</param>
private GameLevel(
IEnumerable<Vertex> vertices,
IEnumerable<LineSegment> lineSegments,
bool resetPositions)
{
_vertices = vertices.ToArray();
_lineSegments = lineSegments.ToArray();
_intersections = new Dictionary<LineSegment, HashSet<LineSegment>>();
foreach (LineSegment lineSegment in _lineSegments)
{
_intersections[lineSegment] = new HashSet<LineSegment>();
}
_draggedVertex = null;
_intersectionCount = 0;
if (resetPositions)
{
while (_intersectionCount == 0)
{
ResetVertexPositions();
CalculateAllIntersections();
}
}
else
CalculateAllIntersections();
}
/// <summary>
/// Changes the current state of a vertex and possibly the states of vertices which are
/// directly connected to it and line segments which are attached to it.
/// </summary>
/// <param name="vertex">The vertex whose state should be changed.</param>
/// <param name="state">The new state of the vertex.</param>
private void ChangeVertexState(Vertex vertex, VertexState state)
{
VertexState oldState = vertex.State;
vertex.State = state;
if (state == VertexState.Dragged || state == VertexState.UnderMouse)
{
if (oldState != VertexState.Dragged && oldState != VertexState.UnderMouse)
{
// The vertex was neither under the mouse, nor was it being dragged by the
// user, but now either of those events has occurred
foreach (Vertex connectedVertex in vertex.ConnectedVertices)
{
connectedVertex.State = VertexState.ConnectedToHighlighted;
}
foreach (LineSegment lineSegment in vertex.LineSegments)
{
lineSegment.State = LineSegmentState.Highlighted;
}
}
}
else if (oldState == VertexState.Dragged || oldState == VertexState.UnderMouse)
{
// The vertex was under the mouse or was being dragged by the user, but
// that is no longer the case
foreach (Vertex connectedVertex in vertex.ConnectedVertices)
{
connectedVertex.State = VertexState.Normal;
}
foreach (LineSegment lineSegment in vertex.LineSegments)
{
lineSegment.State = (_intersections[lineSegment].Count > 0
? LineSegmentState.Intersected
: LineSegmentState.Normal);
}
}
}
/// <summary>
/// Identifies any changes in the intersections between line segments attached to a
/// specific vertex and any line segments in the game level, after that vertex has been
/// dragged to a new position.
/// </summary>
/// <param name="vertex">The vertex which has been dragged to a new position.</param>
/// <remarks>
/// <para>The a single vertex has been dragged to a new position, only the intersections
/// of the line segments attached to it might have changed, so it is unnecessary to
/// recalculate all intersections in the game level.</para>
/// </remarks>
private void RecalculateIntersectionsForVertex(Vertex vertex)
{
foreach (LineSegment lineSegment in vertex.LineSegments)
{
HashSet<LineSegment> intersectingSegments = _intersections[lineSegment];
foreach (LineSegment otherSegment in _lineSegments)
{
if (otherSegment == lineSegment)
continue;
if (CalculationHelper.CheckLinesIntersect(
lineSegment.Point1,
lineSegment.Point2,
otherSegment.Point1,
otherSegment.Point2))
{
if (!intersectingSegments.Contains(otherSegment))
AddIntersection(lineSegment, otherSegment);
}
else if (intersectingSegments.Contains(otherSegment))
RemoveIntersection(lineSegment, otherSegment);
}
}
}
/// <summary>
/// Sets the vertex which is currently under the mouse cursor.
/// </summary>
/// <param name="vertex">The vertex which is currently under the mouse cursor.</param>
public void SetVertexUnderMouse(Vertex vertex)
{
if (_vertexUnderMouse == vertex)
return;
if (_vertexUnderMouse != null && !IsDragging)
ChangeVertexState(_vertexUnderMouse, VertexState.Normal);
_vertexUnderMouse = vertex;
if (_vertexUnderMouse != null && !IsDragging)
ChangeVertexState(_vertexUnderMouse, VertexState.UnderMouse);
}
/// <summary>
/// Initiates the dragging of a specified vertex requested by the user.
/// </summary>
/// <param name="draggedVertex">The vertex which should be dragged.</param>
public void StartDrag(Vertex draggedVertex)
{
_draggedVertex = draggedVertex;
_draggedVertex.State = VertexState.Dragged;
}
/// <summary>
/// Completes the dragging of the vertex which is currently being dragged, and
/// recalculates all current and potential intersections which might have been affected by
/// the dragging.
/// </summary>
public void FinishDrag()
{
ChangeVertexState(_draggedVertex, VertexState.Normal);
RecalculateIntersectionsForVertex(_draggedVertex);
_draggedVertex = null;
if (_vertexUnderMouse != null)
ChangeVertexState(_vertexUnderMouse, VertexState.UnderMouse);
if (_intersectionCount == 0)
OnLevelSolved();
}
/// <summary>
/// Creates a new <see cref="GameLevel"/> instance from an enumeration of vertices
/// generated by a <see cref="Generation.LevelGenerator"/> instance.
/// </summary>
/// <param name="generatedVertices">An enumeration of vertices generated by the game level
/// generator.</param>
/// <returns>The created game level instance.</returns>
/// <remarks>
/// <para>The generated vertices are automatically arranged in a circle in random order
/// during the game level's initialization.</para>
/// </remarks>
public static GameLevel Create(IEnumerable<Generation.Vertex> generatedVertices)
{
var vertexMappings = new Dictionary<Generation.Vertex, Vertex>();
var lineSegments = new List<LineSegment>();
foreach (Generation.Vertex generatedVertex in generatedVertices)
{
var vertex = new Vertex();
vertexMappings[generatedVertex] = vertex;
foreach (Generation.Vertex connectedGeneratedVertex in generatedVertex.ConnectedVertices)
{
if (!vertexMappings.ContainsKey(connectedGeneratedVertex))
{
// The connected vertex has not been mapped to a vertex view model yet;
// skip this line segment for now, it will be added when the other vertex
// is enumerated
continue;
}
Vertex otherVertex = vertexMappings[connectedGeneratedVertex];
LineSegment lineSegment = vertex.ConnectToVertex(otherVertex);
lineSegments.Add(lineSegment);
}
}
return new GameLevel(vertexMappings.Values, lineSegments, true);
}
/// <summary>
/// Creates a new <see cref="GameLevel"/> instance from an enumeration of vertices loaded
/// from a saved game file.
/// </summary>
/// <param name="savedVertices">An enumeration of vertices loaded from the saved game file.
/// </param>
/// <returns>The created game level instance.</returns>
/// <remarks>
/// <para>The loaded vertices' positions are preserved during the game level's
/// initialization.</para>
/// </remarks>
public static GameLevel Create(IEnumerable<Saves.Vertex> savedVertices)
{
var vertexMappings = new Dictionary<int, Vertex>();
var lineSegments = new List<LineSegment>();
foreach (Saves.Vertex savedVertex in savedVertices)
{
var vertex = new Vertex();
vertex.SetPosition(new Point(savedVertex.X, savedVertex.Y));
vertexMappings[savedVertex.Id] = vertex;
foreach (int connectedVertexId in savedVertex.ConnectedVertexIds)
{
if (!vertexMappings.ContainsKey(connectedVertexId))
{
// The connected vertex has not been mapped to a vertex view model yet;
// skip this line segment for now, it will be added when the other vertex
// is enumerated
continue;
}
Vertex otherVertex = vertexMappings[connectedVertexId];
LineSegment lineSegment = vertex.ConnectToVertex(otherVertex);
lineSegments.Add(lineSegment);
}
}
return new GameLevel(vertexMappings.Values, lineSegments, false);
}
/// <summary>
/// Connects the vertex to another vertex with a line segment and returns it.
/// </summary>
/// <param name="otherVertex">The vertex which should be connected to the current one.
/// </param>
/// <returns>The created line segment between the two vertices.</returns>
/// <exception cref="InvalidOperationException">
/// An attempt is made to connect the vertex to itself.
///
/// -or-
/// A line segment between the two vertices already exists.
/// </exception>
public LineSegment ConnectToVertex(Vertex otherVertex)
{
if (this == otherVertex)
throw new InvalidOperationException("A vertex cannot be connected to itself.");
if (_lineSegmentsMap.ContainsKey(otherVertex))
{
throw new InvalidOperationException(
"A line segment between the two vertices already exists.");
}
var lineSegment = new LineSegment(this, otherVertex);
_lineSegmentsMap[otherVertex] = lineSegment;
otherVertex._lineSegmentsMap[this] = lineSegment;
return lineSegment;
}
/// <summary>
/// Initializes a new <see cref="LineSegment"/> instance with the specified two endpoint
/// vertices.
/// </summary>
/// <param name="vertex1">The vertex at the first endpoint of the line segment.</param>
/// <param name="vertex2">The vertex at the second endpoint of the line segment.</param>
public LineSegment(Vertex vertex1, Vertex vertex2)
{
_vertex1 = vertex1;
_vertex2 = vertex2;
}
