using NodeDev.Core.Connections;

using NodeDev.Core.Types;

using System.Linq.Expressions;

namespace NodeDev.Core.Nodes.Flow;

public class TryCatchNode : FlowNode

{

public override bool IsFlowNode => true;

public TryCatchNode(Graph graph, string? id = null) : base(graph, id)

{

Name = "TryCatch";

Inputs.Add(new("Exec", this, TypeFactory.ExecType));

Outputs.Add(new("Try", this, TypeFactory.ExecType));

Outputs.Add(new("Catch", this, TypeFactory.ExecType));

Outputs.Add(new("Finally", this, TypeFactory.ExecType));

Outputs.Add(new("Exception", this, new UndefinedGenericType("T"), linkedExec: Outputs[1]));

}

public override string GetExecOutputPathId(string pathId, Connection execOutput)

{

return pathId + "-" + execOutput.Id;

}

// We're allowed to have 'nothing' in the blocks, ex an empty "finally" or an empty "catch"

public override bool DoesOutputPathAllowDeadEnd(Connection execOutput)

{

return execOutput.Connections.Count == 0;

}

/// <summary>

/// We allow merging back together at the end. Technically all paths could continue, such as :

/// Try { } catch( Exception ex) {} finally { } ...

/// </summary>

public override bool DoesOutputPathAllowMerge(Connection execOutput) => true;

internal override Expression BuildExpression(Dictionary<Connection, Graph.NodePathChunks>? subChunks, BuildExpressionInfo info)

{

ArgumentNullException.ThrowIfNull(subChunks);

var tryBlock = Expression.Block(Graph.BuildExpression(subChunks[Outputs[0]], info));

var catchBlock = Expression.Block(Graph.BuildExpression(subChunks[Outputs[1]], info));

var finallyBlock = Expression.Block(Graph.BuildExpression(subChunks[Outputs[2]], info));

//var exceptionVariable = Expression.Variable(Outputs[3].Type.MakeRealType(), "ex");

//info.LocalVariables[Outputs[3]] = exceptionVariable; // Make sure other pieces of code use the right variable for that exception

var catchClause = Expression.Catch(Outputs[3].Type.MakeRealType(), catchBlock);

return Expression.Block(Expression.TryCatchFinally(tryBlock, Outputs[2].Connections.Count == 0 ? null : finallyBlock, catchClause));

}

}