using NUnit.Framework;
using System.Linq;

namespace Rubjerg.Graphviz.Test;

#nullable enable

[TestFixture()]
public class Tutorial
{
    public const string PointPattern = @"{X=[\d.]+, Y=[\d.]+}";
    public const string RectPattern = @"{X=[\d.]+, Y=[\d.]+, Width=[\d.]+, Height=[\d.]+}";
    public const string SplinePattern =
        @"{X=[\d.]+, Y=[\d.]+}, {X=[\d.]+, Y=[\d.]+}, {X=[\d.]+, Y=[\d.]+}, {X=[\d.]+, Y=[\d.]+}";

    [Test, Order(1)]
    public void GraphConstruction()
    {
        // You can programmatically construct graphs as follows
        RootGraph root = RootGraph.CreateNew(GraphType.Directed, "Some Unique Identifier");
        // The graph name is optional, and can be omitted. The name is not interpreted by Graphviz,
        // except it is recorded and preserved when the graph is written as a file.

        // The node names are unique identifiers within a graph in Graphviz
        Node nodeA = root.GetOrAddNode("A");
        Node nodeB = root.GetOrAddNode("B");
        Node nodeC = root.GetOrAddNode("C");

        // The edge name is only unique between two nodes
        Edge edgeAB = root.GetOrAddEdge(nodeA, nodeB, "Some edge name");
        Edge edgeBC = root.GetOrAddEdge(nodeB, nodeC, "Some edge name");
        Edge anotherEdgeBC = root.GetOrAddEdge(nodeB, nodeC, "Another edge name");

        // An edge name is optional and omitting it will result in a new nameless edge.
        // There can be multiple nameless edges between any two nodes.
        Edge edgeAB1 = root.GetOrAddEdge(nodeA, nodeB);
        Edge edgeAB2 = root.GetOrAddEdge(nodeA, nodeB);
        Assert.AreNotEqual(edgeAB1, edgeAB2);

        // We can attach attributes to nodes, edges and graphs to store information and instruct
        // Graphviz by specifying layout parameters. At the moment we only support string
        // attributes. Cgraph assumes that all objects of a given kind (graphs/subgraphs, nodes,
        // or edges) have the same attributes. An attribute has to be introduced with a default value
        // first for a certain kind, before we can use it.
        Node.IntroduceAttribute(root, "my attribute", "defaultvalue");
        nodeA.SetAttribute("my attribute", "othervalue");

        // Attributes are introduced per kind (Node, Edge, Graph) per root graph.
        // So to be able to use "my attribute" on edges, we first have to introduce it as well.
        Edge.IntroduceAttribute(root, "my attribute", "defaultvalue");
        edgeAB.SetAttribute("my attribute", "othervalue");

        // To introduce and set an attribute at the same time, there are convenience wrappers
        edgeBC.SafeSetAttribute("arrowsize", "2.0", "1.0");
        // If we set an unintroduced attribute, the attribute will be introduced with an empty default value.
        edgeBC.SetAttribute("new attr", "value");

        // Some attributes - like "label" - accept HTML strings as value
        // To tell Graphviz that a string should be interpreted as HTML use the designated methods
        Node.IntroduceAttribute(root, "label", "defaultlabel");
        nodeB.SetAttributeHtml("label", "<b>Some HTML string</b>");

        // We can simply export this graph to a text file in dot format
        root.ToDotFile(TestContext.CurrentContext.TestDirectory + "/out.dot");

        // A word of advice, Graphviz doesn't play very well with empty strings.
        // Try to avoid them when possible. (https://gitlab.com/graphviz/graphviz/-/issues/1887)
    }

    [Test, Order(2)]
    public void Layouting()
    {
        // If we have a given dot file (in this case the one we generated above), we can also read it back in
        RootGraph root = RootGraph.FromDotFile(TestContext.CurrentContext.TestDirectory + "/out.dot");

        // We can ask Graphviz to compute a layout and render it to svg
        root.ToSvgFile(TestContext.CurrentContext.TestDirectory + "/dot_out.svg");

        // We can use layout engines other than dot by explicitly passing the engine we want
        root.ToSvgFile(TestContext.CurrentContext.TestDirectory + "/neato_out.svg", LayoutEngines.Neato);

        // Or we can ask Graphviz to compute the layout and programatically read out the layout attributes
        // This will create a copy of our original graph with layout information attached to it in the form
        // of attributes. Graphviz outputs coordinates in a bottom-left originated coordinate system.
        // But since many applications require rendering in a top-left originated coordinate system,
        // we provide a way to translate the coordinates.
        RootGraph layout = root.CreateLayout(coordinateSystem: CoordinateSystem.TopLeft);

        // There are convenience methods available that parse these attributes for us and give
        // back the layout information in an accessible form.
        Node nodeA = layout.GetNode("A")!;
        PointD position = nodeA.GetPosition();
        Utils.AssertPattern(PointPattern, position.ToString());

        RectangleD nodeboundingbox = nodeA.GetBoundingBox();
        Utils.AssertPattern(RectPattern, nodeboundingbox.ToString());

        // Or splines between nodes
        Node nodeB = layout.GetNode("B")!;
        Edge edge = layout.GetEdge(nodeA, nodeB, "Some edge name")!;
        PointD[] spline = edge.GetFirstSpline();
        string splineString = string.Join(", ", spline.Select(p => p.ToString()));
        Utils.AssertPattern(SplinePattern, splineString);

        // If we require detailed drawing information for any object, we can retrieve the so called "xdot"
        // operations. See https://graphviz.org/docs/outputs/canon/#xdot for a specification.
        var activeFillColor = System.Drawing.Color.Black;
        foreach (var op in nodeA.GetDrawing())
        {
            if (op is XDotOp.FillColor { Value: Color.Uniform { HtmlColor: var htmlColor } })
            {
                activeFillColor = System.Drawing.ColorTranslator.FromHtml(htmlColor);
            }
            else if (op is XDotOp.FilledEllipse { Value: var boundingBox })
            {
                Utils.AssertPattern(RectPattern, boundingBox.ToString());
            }
            // Handle any xdot operation you require
        }

        foreach (var op in nodeA.GetLabelDrawing())
        {
            if (op is XDotOp.Text { Value: var text })
            {
                Utils.AssertPattern(PointPattern, text.Anchor.ToString());
                var boundingBox = text.TextBoundingBoxEstimate();
                Utils.AssertPattern(RectPattern, boundingBox.ToString());
                Assert.AreEqual(text.Text, "A");
                Assert.AreEqual(text.Font.Name, "Times-Roman");
            }
            // Handle any xdot operation you require
        }

        // These are just simple examples to showcase the structure of xdot operations.
        // In reality the information can be much richer and more complex.
    }

    [Test, Order(3)]
    public void Clusters()
    {
        RootGraph root = RootGraph.CreateNew(GraphType.Directed, "Graph with clusters");
        Node nodeA = root.GetOrAddNode("A");
        Node nodeB = root.GetOrAddNode("B");
        Node nodeC = root.GetOrAddNode("C");
        Node nodeD = root.GetOrAddNode("D");

        // When a subgraph name is prefixed with cluster,
        // the dot layout engine will render it as a box around the containing nodes.
        SubGraph cluster1 = root.GetOrAddSubgraph("cluster_1");
        cluster1.AddExisting(nodeB);
        cluster1.AddExisting(nodeC);
        SubGraph cluster2 = root.GetOrAddSubgraph("cluster_2");
        cluster2.AddExisting(nodeD);

        // COMPOUND EDGES
        // Graphviz does not really support edges from and to clusters. However, by adding an
        // invisible dummynode and setting the ltail or lhead attributes of an edge this
        // behavior can be faked. Graphviz will then draw an edge to the dummy node but clip it
        // at the border of the cluster. We provide convenience methods for this.
        // To enable this feature, Graphviz requires us to set the "compound" attribute to "true".
        Graph.IntroduceAttribute(root, "compound", "true"); // Allow lhead/ltail
        // The boolean indicates whether the dummy node should take up any space. When you pass
        // false and you have a lot of edges, the edges may start to overlap a lot.
        _ = root.GetOrAddEdge(nodeA, cluster1, false, "edge to a cluster");
        _ = root.GetOrAddEdge(cluster1, nodeD, false, "edge from a cluster");
        _ = root.GetOrAddEdge(cluster1, cluster1, false, "edge between clusters");

        var layout = root.CreateLayout();

        SubGraph cluster = layout.GetSubgraph("cluster_1")!;
        RectangleD clusterbox = cluster.GetBoundingBox();
        RectangleD rootgraphbox = layout.GetBoundingBox();
        Utils.AssertPattern(RectPattern, clusterbox.ToString());
        Utils.AssertPattern(RectPattern, rootgraphbox.ToString());
    }

    [Test, Order(4)]
    public void Records()
    {
        RootGraph root = RootGraph.CreateNew(GraphType.Directed, "Graph with records");
        Node nodeA = root.GetOrAddNode("A");
        nodeA.SetAttribute("shape", "record");
        // New line characters are not supported by record labels, and will be ignored by Graphviz
        nodeA.SetAttribute("label", "1|2|3|{4|5}|6|{7|8|9}");

        var layout = root.CreateLayout();

        // The order of the list matches the order in which the labels occur in the label string above.
        var rects = layout.GetNode("A")!.GetRecordRectangles().ToList();
        var rectLabels = layout.GetNode("A")!.GetRecordRectangleLabels().Select(l => l.Text).ToList();
        Assert.AreEqual(9, rects.Count);
        Assert.AreEqual(new[] { "1", "2", "3", "4", "5", "6", "7", "8", "9" }, rectLabels);
    }

    [Test, Order(5)]
    public void StringEscaping()
    {
        RootGraph root = RootGraph.CreateNew(GraphType.Directed, "Graph with escaped strings");
        Node.IntroduceAttribute(root, "label", "\\N");
        Node nodeA = root.GetOrAddNode("A");

        // Several characters and character sequences can have special meanings in labels, like \N.
        // When you want to have a literal string in a label, we provide a convenience function for you to do just that.
        nodeA.SetAttribute("label", CGraphThing.EscapeLabel("Some string literal \\N \\n |}>"));

        // When defining portnames, some characters, like ':' and '|', are not allowed and they can't be escaped either.
        // This can be troubling if you have an externally defined ID for such a port.
        // We provide a function that maps strings to valid portnames.
        var somePortId = "port id with :| special characters";
        var validPortName = Edge.ConvertUidToPortName(somePortId);
        Node nodeB = root.GetOrAddNode("B");
        nodeB.SetAttribute("shape", "record");
        nodeB.SetAttribute("label", $"<{validPortName}>1|2");

        // The conversion function makes sure different strings don't accidentally map onto the same portname
        Assert.AreNotEqual(Edge.ConvertUidToPortName(":"), Edge.ConvertUidToPortName("|"));
    }
}