using UnityEngine;
using UnityEditor.AssetImporters;
using Unity.GraphToolkit.Editor;
using System;
using System.Collections.Generic;
using System.Linq;
using Dialogue;

namespace Editor.Dialogue
{
    [ScriptedImporter(1, DialogueGraph.AssetExtension)]
    public class DialogueGraphImporter : ScriptedImporter
    {
        public override void OnImportAsset(AssetImportContext ctx)
        {
            DialogueGraph editorGraph = GraphDatabase.LoadGraphForImporter<DialogueGraph>(ctx.assetPath);
            RuntimeDialogueGraph runtimeGraph = ScriptableObject.CreateInstance<RuntimeDialogueGraph>();
            var nodeIDMap = new Dictionary<INode, string>();

            foreach (var node in editorGraph.GetNodes())
            {
                nodeIDMap[node] = Guid.NewGuid().ToString();
            }
            
            // TODO: This could be done in the above loop, but for clarity, I'm keeping it separate for now.
            var startNode = editorGraph.GetNodes().OfType<StartNode>().FirstOrDefault();
            if (startNode != null)
            {
                var entryPoint = startNode.GetOutputPorts().FirstOrDefault()?.firstConnectedPort;
                if (entryPoint != null)
                {
                    runtimeGraph.entryNodeID = nodeIDMap[entryPoint.GetNode()];
                }
                
                runtimeGraph.speakerName = GetPortValue<string>(startNode.GetInputPortByName("SpeakerName"));
            }

            foreach (var iNode in editorGraph.GetNodes())
            {
                if (iNode is StartNode || iNode is EndNode)
                    continue;
                
                var runtimeNode = new RuntimeDialogueNode{ nodeID = nodeIDMap[iNode]};
                if (iNode is DialogueNode dialogueNode)
                {
                    ProcessDialogueNode(dialogueNode, runtimeNode, nodeIDMap);
                }
                
                runtimeGraph.allNodes.Add(runtimeNode);
            }
            
            ctx.AddObjectToAsset("RuntimeData", runtimeGraph);
            ctx.SetMainObject(runtimeGraph);
        }

        private void ProcessDialogueNode(DialogueNode node, RuntimeDialogueNode runtimeNode, Dictionary<INode, string> nodeIDMap)
        {
            runtimeNode.dialogueLine = GetPortValue<string>(node.GetInputPortByName("DialogueLine"));
            
            var nextNodePort = node.GetOutputPortByName("out")?.firstConnectedPort;
            if (nextNodePort != null)
            {
                runtimeNode.nextNodeID = nodeIDMap[nextNodePort.GetNode()];
            }
        }

        private T GetPortValue<T>(IPort port)
        {
            if (port == null) return default(T);

            if (port.isConnected)
            {
                if (port.firstConnectedPort.GetNode() is IVariableNode variableNode)
                {
                    variableNode.variable.TryGetDefaultValue(out T value);
                    return value;
                }
            }
            
            port.TryGetValue(out T fallbackValue);
            return fallbackValue;
        }
    }
}