using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using Luneraria.Core;
using UnityEngine;

namespace Luneraria.View
{
    /// <summary>
    /// Frame-time benchmark of a player build (U2D). Active only with the command-line argument
    /// "-luneBenchmark &lt;out.json&gt;": runs the match of seed 9 from round 21 (the golden fixture
    /// high_wave_21, the most units) at normal speed, VSync off, and measures two windows once the
    /// armies meet: the whole map (20 s) and a close view of the Mid lane (10 s). Then it quits.
    /// </summary>
    [DefaultExecutionOrder(-100)]
    public sealed class LuneBenchmark : MonoBehaviour
    {
        public LuneMatchDriver Driver;
        public LuneMatchView View;
        public LuneCameraRig Rig;

        sealed class Window
        {
            public string Label;
            public float Seconds;
            public float Zoom;
            public Vec2 Focus;
            public readonly List<double> FrameMs = new List<double>();
            public double Simulation;
            public double Views;
            public int Units;
            public int GcStart;
            public int GcEnd;
            public int SlowFrames;
            public int SlowWithStep;
            public readonly List<double> MainThreadMs = new List<double>();
            public readonly List<double> RenderThreadMs = new List<double>();
            public readonly List<double> GpuMs = new List<double>();
            public readonly List<double> PresentWaitMs = new List<double>();
        }

        readonly FrameTiming[] _timings = new FrameTiming[1];

        string _out;
        readonly List<Window> _windows = new List<Window>();
        int _index = -1;
        float _elapsed;

        void Awake()
        {
            string[] args = Environment.GetCommandLineArgs();
            int at = Array.IndexOf(args, "-luneBenchmark");
            if (at < 0 || at + 1 >= args.Length)
            {
                enabled = false;
                return;
            }
            _out = args[at + 1];
            Running = true;
            // The benchmark runs unattended; it must not pause when its window loses focus.
            Application.runInBackground = true;
            QualitySettings.vSyncCount = 0;
            Application.targetFrameRate = -1;
            _windows.Add(new Window { Label = "overview (zoom 64)", Seconds = 20f, Zoom = 64f, Focus = new Vec2(0, 0) });
            _windows.Add(new Window { Label = "mid lane close (zoom 22)", Seconds = 10f, Zoom = 22f, Focus = new Vec2(0, 0) });
        }

        /// <summary>True in a benchmark run: the game controller keeps the bot match (no human seat).</summary>
        public static bool Running { get; private set; }

        void Start()
        {
            Driver.HumanSlot = -1;
            Driver.Seed = 9;
            Driver.StartRound = 21;
            Driver.ExtraGold = 4000;
            Driver.Speed = 1f;
            Driver.Restart();
            Rig.Interactive = false;
            Rig.Overview(true);
        }

        void Update()
        {
            LuneMatch match = Driver.Runner.Match;
            if (_index < 0)
            {
                if (Driver.Runner.Current == LuneMatchRunner.Stage.Combat && match.Combat.Elapsed >= 10.0)
                    Begin(0);
                return;
            }
            if (_index >= _windows.Count)
                return;
            Window window = _windows[_index];
            double ms = Time.unscaledDeltaTime * 1000.0;
            window.FrameMs.Add(ms);
            // Where the time goes (needs "Frame Timing Stats" in the player settings).
            FrameTimingManager.CaptureFrameTimings();
            if (FrameTimingManager.GetLatestTimings(1, _timings) > 0)
            {
                window.MainThreadMs.Add(_timings[0].cpuMainThreadFrameTime);
                window.RenderThreadMs.Add(_timings[0].cpuRenderThreadFrameTime);
                window.GpuMs.Add(_timings[0].gpuFrameTime);
                window.PresentWaitMs.Add(_timings[0].cpuMainThreadPresentWaitTime);
            }
            // Frames above 1/60 s, and how many of them also ran a simulation step.
            if (ms > 1000.0 / 60.0)
            {
                window.SlowFrames++;
                if (Driver.Runner.StepsThisFrame > 0)
                    window.SlowWithStep++;
            }
            window.Simulation += Driver.LastAdvanceMs;
            window.Views += View.LastSyncMs;
            if (match.Combat != null && window.FrameMs.Count % 30 == 1)
                window.Units = Math.Max(window.Units, CountAlive(match.Combat));
            _elapsed += Time.unscaledDeltaTime;
            if (_elapsed >= window.Seconds)
            {
                window.GcEnd = GC.CollectionCount(0);
                if (_index + 1 < _windows.Count)
                    Begin(_index + 1);
                else
                    Finish();
            }
        }

        static string Describe(List<double> values)
        {
            if (values.Count == 0)
                return "n/a";
            double[] sorted = values.OrderBy(v => v).ToArray();
            return string.Format(CultureInfo.InvariantCulture, "avg {0:0.00} / median {1:0.00} / p95 {2:0.00} ms", sorted.Average(), sorted[sorted.Length / 2], sorted[(int)(sorted.Length * .95)]);
        }

        static int CountAlive(LuneCombat combat)
        {
            int count = 0;
            foreach (LuneUnit unit in combat.Units)
                if (unit.Alive && unit.IsMobile())
                    count++;
            return count;
        }

        void Begin(int index)
        {
            _index = index;
            _elapsed = 0f;
            Window window = _windows[index];
            window.GcStart = GC.CollectionCount(0);
            Rig.LookAt(window.Focus, window.Zoom, true);
        }

        void Finish()
        {
            _index = _windows.Count;
            var text = new System.Text.StringBuilder("{\n");
            text.AppendFormat("  \"build\": \"{0} player, {1}, {2}\",\n", Application.platform, Application.unityVersion, Debug.isDebugBuild ? "development" : "release");
            text.AppendFormat("  \"device\": \"{0}; {1}; {2}\",\n", SystemInfo.deviceModel, SystemInfo.processorType, SystemInfo.graphicsDeviceName);
            text.AppendFormat("  \"graphics_api\": \"{0}\",\n  \"resolution\": \"{1}x{2}\",\n  \"vsync\": {3},\n", SystemInfo.graphicsDeviceType, Screen.width, Screen.height, QualitySettings.vSyncCount);
            text.Append("  \"match\": \"seed 9 from round 21 (fixture high_wave_21), speed 1x, measured after 10 s of combat\",\n  \"windows\": [\n");
            for (int i = 0; i < _windows.Count; i++)
            {
                Window window = _windows[i];
                double[] sorted = window.FrameMs.OrderBy(v => v).ToArray();
                double total = window.FrameMs.Sum();
                text.AppendFormat(CultureInfo.InvariantCulture,
                    "    {{\"view\": \"{0}\", \"frames\": {1}, \"fps\": {2:0.0}, \"frame_ms_avg\": {3:0.00}, \"frame_ms_median\": {4:0.00}, \"frame_ms_p95\": {5:0.00}, \"frame_ms_p99\": {6:0.00}, \"frame_ms_max\": {7:0.00}, \"frames_over_16_7_ms\": {8}, \"of_them_with_simulation_step\": {9}, \"gc_collections\": {10}, \"simulation_ms_per_frame\": {11:0.000}, \"views_ms_per_frame\": {12:0.000}, \"units_alive_max\": {13}}}{14}\n",
                    window.Label, sorted.Length, sorted.Length / (total / 1000.0), total / sorted.Length, sorted[sorted.Length / 2], sorted[(int)(sorted.Length * .95)], sorted[(int)(sorted.Length * .99)], sorted[sorted.Length - 1],
                    window.SlowFrames, window.SlowWithStep, window.GcEnd - window.GcStart, window.Simulation / sorted.Length, window.Views / sorted.Length, window.Units, i < _windows.Count - 1 ? "," : "");
                text.AppendFormat(CultureInfo.InvariantCulture, "    // timings {0}: main thread {1}, render thread {2}, gpu {3}, present wait {4}\n", window.Label,
                    Describe(window.MainThreadMs), Describe(window.RenderThreadMs), Describe(window.GpuMs), Describe(window.PresentWaitMs));
            }
            text.Append("  ]\n}\n");
            Directory.CreateDirectory(Path.GetDirectoryName(_out));
            File.WriteAllText(_out, text.ToString());
            Application.Quit();
        }
    }
}