#define DEBUG_MAT_GEN

using UnityEngine;

namespace UnityEditor.MaterialGraph
{
    class MaterialWindow : EditorWindow
    {
        [MenuItem("Window/Material")]
        public static void OpenMenu()
        {
            GetWindow<MaterialWindow>();
        }

        private MaterialGraph m_MaterialGraph;
        private MaterialGraphGUI m_MaterialGraphGUI;
        private MaterialSubGraph m_MaterialSubGraph;
        private MaterialSubGraphGUI m_MaterialSubGraphGUI;

        private BaseMaterialGraphGUI m_ActiveGUI;
        private ScriptableObject m_ActiveGraph;

        private bool shouldRepaint
        {
            get
            {
                return m_MaterialGraph != null && m_MaterialGraph.currentGraph != null && m_MaterialGraph.currentGraph.requiresRepaint
                       || m_MaterialSubGraph != null && m_MaterialSubGraph.requiresRepaint;
            }
        }

        void Update()
        {
            if (shouldRepaint)
                Repaint();
        }

        void OnSelectionChange()
        {
            MaterialWindow.DebugMaterialGraph("Got OnSelection Change: " + Selection.activeObject);

            if (Selection.activeObject == null || !EditorUtility.IsPersistent(Selection.activeObject))
                return;

            if (Selection.activeObject is MaterialSubGraph)
            {
                var selection = Selection.activeObject as MaterialSubGraph;
                if (selection != m_MaterialSubGraph)
                {
                    m_MaterialSubGraph = selection;
                    m_MaterialSubGraphGUI = null;
                    m_MaterialGraph = null;
                    m_MaterialSubGraph.GeneratePreviewShaders();
                }

                if (m_MaterialSubGraphGUI == null)
                {
                    m_MaterialSubGraphGUI = CreateInstance<MaterialSubGraphGUI>();
                    m_MaterialSubGraphGUI.hideFlags = HideFlags.HideAndDontSave;
                    m_MaterialSubGraphGUI.graph = m_MaterialSubGraph;
                }

                m_ActiveGUI = m_MaterialSubGraphGUI;
                m_ActiveGraph = m_MaterialSubGraph;
            }
            else if (Selection.activeObject is MaterialGraph)
            {
                var selection = Selection.activeObject as MaterialGraph;
                MaterialWindow.DebugMaterialGraph("Selection: " + selection);
                MaterialWindow.DebugMaterialGraph("Existing: " + m_MaterialGraph);
                if (selection != m_MaterialGraph)
                {
                    m_MaterialGraph = selection;
                    m_MaterialSubGraph = null;
                    m_MaterialGraphGUI = null;
                    m_MaterialGraph.currentGraph.GeneratePreviewShaders();
                }

                if (m_MaterialGraphGUI == null)
                {
                    m_MaterialGraphGUI = CreateInstance<MaterialGraphGUI>();
                    m_MaterialGraphGUI.hideFlags = HideFlags.HideAndDontSave;
                    m_MaterialGraphGUI.graph = m_MaterialGraph.currentGraph;
                    m_MaterialGraphGUI.materialGraph = m_MaterialGraph;
                }

                m_ActiveGUI = m_MaterialGraphGUI;
                m_ActiveGraph = m_MaterialGraph;
            }

            Repaint();
        }

        void OnGUI()
        {
            if (m_ActiveGraph == null || m_ActiveGUI == null)
            {
                GUILayout.Label("No Graph selected");
                return;
            }

            if (m_ActiveGUI == m_MaterialGraphGUI)
            {
                m_MaterialGraphGUI.graph = m_MaterialGraph.currentGraph;
                m_MaterialGraphGUI.materialGraph = m_MaterialGraph;
            }
            else if (m_ActiveGUI == m_MaterialSubGraphGUI)
            {
                m_MaterialSubGraphGUI.graph = m_MaterialSubGraph;
            }

            m_ActiveGUI.BeginGraphGUI(this, new Rect(0, 0, position.width - 300, position.height));
            m_ActiveGUI.OnGraphGUI();
            m_ActiveGUI.EndGraphGUI();
            if (m_ActiveGUI == m_MaterialGraphGUI)
                m_MaterialGraphGUI.RenderOptions(new Rect(position.width - 300, 0, 300, position.height), m_MaterialGraph);
        }

        public static void DebugMaterialGraph(string s)
        {
#if DEBUG_MAT_GEN
            Debug.Log(s);
#endif
        }
    }
}