using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using ImGuiNET;
using skyscraper5.Skyscraper.Scraper;

namespace SDL2Demo.Forms
{
    internal class LogWindow : IRenderable, ISkyscraperEventLogger
    {
        public LogWindow()
        {
            logEntries = new LinkedList<string>();
            clipperMemory = Marshal.AllocHGlobal(1024);
            flags = Int32.MaxValue;
        }

        private string GetFullLogAsString()
        {
            StringWriter sw = new StringWriter();
            LinkedListNode<string> logEntriesFirst = logEntries.First;
            while (true)
            {
                if (logEntriesFirst.Next == null)
                    break;
                sw.WriteLine(logEntriesFirst.Value);
                logEntriesFirst = logEntriesFirst.Next;
            }
            return sw.ToString();
        }

        private IntPtr clipperMemory;
        private Vector2 zero;
        private LinkedList<string> logEntries;
        private int flags;
        private Vector2 windowSize;
        private bool isOpen;
        public bool IsOpen
        {
            get => isOpen;
            set
            {
                logEntries = new LinkedList<string>();
                isOpen = value;
            } 
        }
        public void Render()
        {
            if (!IsOpen)
                return;

            if (windowSize == Vector2.Zero)
                windowSize = new Vector2(0.0f, ImGui.GetFontSize() * 12.0f);

            ImGui.SetNextWindowSize(windowSize, ImGuiCond.FirstUseEver);
            
            if (!ImGui.Begin("skyscraper5 Debug Log", ref isOpen))
            {
                ImGui.End();
                return;
            }

            ImGui.AlignTextToFramePadding();
            ImGui.Text("Log events:");
            ImGui.SameLine();
            ImGui.CheckboxFlags("All", ref flags, Int32.MaxValue);
            ImGui.SameLine(); ImGui.CheckboxFlags("UI", ref flags, 1);
            ImGui.SameLine(); ImGui.CheckboxFlags("Scraper", ref flags, 2);
            ImGui.SameLine(); ImGui.CheckboxFlags("Seconds", ref flags, 4);
            ImGui.SameLine(); ImGui.CheckboxFlags("Job", ref flags, 8);
            //ImGui.SameLine(); ImGui.CheckboxFlags("???16", ref flags, 16);
            //ImGui.SameLine(); ImGui.CheckboxFlags("???32", ref flags, 32);
            //ImGui.SameLine(); ImGui.CheckboxFlags("???32", ref flags, 64);
            //ImGui.SameLine(); ImGui.CheckboxFlags("???32", ref flags, 128);
            //ImGui.SameLine(); ImGui.CheckboxFlags("???32", ref flags, 256);
            
            if (ImGui.SmallButton("Clear"))
            {
                logEntries = new LinkedList<string>();
            }
            ImGui.SameLine();
            if (ImGui.SmallButton("Copy"))
                ImGui.SetClipboardText(GetFullLogAsString());
            ImGui.BeginChild("##log", zero, true, ImGuiWindowFlags.AlwaysVerticalScrollbar | ImGuiWindowFlags.AlwaysHorizontalScrollbar);

            ImGuiListClipperPtr clipper = new ImGuiListClipperPtr(clipperMemory);
            clipper.Begin(logEntries.Count);
            while (clipper.Step())
                for (int line_no = clipper.DisplayStart; line_no < clipper.DisplayEnd; line_no++)
                {
                    string line = GetLine(line_no);
                    ImGui.TextUnformatted(line);
                }
            if (ImGui.GetScrollY() >= ImGui.GetScrollMaxY())
                ImGui.SetScrollHereY(1.0f);
            ImGui.EndChild();

        ImGui.End();

    }

        private string GetLine(int lineNo)
        {
            LinkedListNode<string> logEntriesFirst = logEntries.First;
            if (lineNo == 0)
                return logEntriesFirst.Value;
            try
            {
	            for (int i = 1; i < lineNo; i++)
	            {
		            if (logEntriesFirst == null)
			            return "";
		            if (logEntriesFirst.Next == null)
			            return "";
		            logEntriesFirst = logEntriesFirst.Next;
	            }
			}
            catch (NullReferenceException e)
            {
	            return "";
            }
            return logEntriesFirst.Value;
        }

        private const bool LOG_TO_CONSOLE = true;
        private const bool LOG_TO_DEBUG = false;
        private const bool LOG_TO_TRACE = false;
        public void Log(string toString, int flags = 1)
        {
            lock (logEntries)
            {
                while (logEntries.Count > 9000)
                {
                    logEntries.RemoveFirst();
                }
                if (isOpen)
                {
                    if (((this.flags) & (flags)) != 0)
                    {
                        logEntries.AddLast(toString);
                        if (LOG_TO_CONSOLE)
                            Console.WriteLine(toString);
                        if (LOG_TO_DEBUG)
                            Debug.WriteLine(toString);
                        if (LOG_TO_TRACE)
                            Trace.WriteLine(toString);
                    }
                }
            }
        }

        public void Log(TimeSpan duration, DateTime eventTimestamp, SkyscraperContextEvent eventType, string name = null)
        {
            StringBuilder sb = new StringBuilder();
            sb.AppendFormat("[{0} {1}] ", eventTimestamp.ToShortDateString(), eventTimestamp.ToShortTimeString());
            sb.AppendFormat("{0}", eventType.ToString());

            if (!string.IsNullOrEmpty(name) && !string.IsNullOrWhiteSpace(name))
            {
                sb.AppendFormat(" ({0}) ", name);
            }


            if (eventType != SkyscraperContextEvent.StartPacketProcessing && eventType != SkyscraperContextEvent.TdtTime && eventType != SkyscraperContextEvent.TotTime)
            {
                sb.AppendFormat(" ({0} ms)", duration.TotalMilliseconds);
            }

            Log(sb.ToString(),2);
        }

        public ulong NumEvents => (uint)logEntries.Count;
    }
}