using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;

namespace MSCO
{
    /// <summary>
    /// Laufzeit-Statistik: wie viele ms pro Bild jeder MSCO-Teil braucht, FPS und Garbage-Collections. Konsole (F7):
    /// "perf" bzw. "perf reset". Mit der Startoption -msco-perf wird alle 30 s eine Zeile in MSCO\MSCO_Loader.txt
    /// geschrieben (zum Messen ohne Konsole).
    /// </summary>
    public static class PerfStats
    {
        static readonly Dictionary<string, double> totals = new Dictionary<string, double>();
        /// <summary>Aufrufe der Harmony-Haken (Fsm.SwitchState, Fsm.Event, cInput) - zum Abschätzen ihrer Kosten.</summary>
        public static int SwitchStateCalls, EventCalls, InputCalls;
        static int frames, gcStart = -1;
        static double frameSeconds, worstFrame;
        static float started = -1f;
        static readonly bool autoLog = Array.IndexOf(Environment.GetCommandLineArgs(), "-msco-perf") >= 0;

        public static void Add(string part, double ms)
        {
            double t;
            totals.TryGetValue(part, out t);
            totals[part] = t + ms;
        }

        /// <summary>Einmal pro Bild (Update).</summary>
        public static void Frame(float dt)
        {
            if (started < 0f) Reset();
            frames++;
            frameSeconds += dt;
            if (dt > worstFrame) worstFrame = dt;
            // Mit -msco-perf alle 30 s, sonst im Spiel alle 5 Minuten ein Bericht in MSCO_Loader.txt - so lässt sich bei
            // "wenig FPS" nachsehen, ob MSCO, eine Mod oder das Spiel selbst die Zeit braucht
            float every = autoLog ? 30f : 300f;
            if ((autoLog || MenuHelper.InGame) && Time.realtimeSinceStartup - started >= every)
            {
                Bootstrap.Log(Report());
                Reset();
            }
        }

        public static void Reset()
        {
            totals.Clear();
            frames = 0;
            frameSeconds = 0;
            worstFrame = 0;
            started = Time.realtimeSinceStartup;
            gcStart = GC.CollectionCount(0);
            SwitchStateCalls = EventCalls = InputCalls = 0;
        }

        public static string Report()
        {
            if (frames == 0) return "PERF: no frames measured yet";
            double seconds = Math.Max(0.001, Time.realtimeSinceStartup - started);
            double msco = 0;
            foreach (double v in totals.Values) msco += v;
            var parts = new List<KeyValuePair<string, double>>(totals);
            parts.Sort((a, b) => b.Value.CompareTo(a.Value));
            var sb = new StringBuilder();
            sb.Append("PERF ").Append(seconds.ToString("0")).Append(" s (").Append(MenuHelper.Scene).Append("): ")
              .Append((frames / frameSeconds).ToString("0")).Append(" fps, ")
              .Append((frameSeconds * 1000.0 / frames).ToString("0.0")).Append(" ms/frame (worst ")
              .Append((worstFrame * 1000.0).ToString("0")).Append(" ms), MSCO ")
              .Append((msco / frames).ToString("0.00")).Append(" ms/frame, GC ")
              .Append(((GC.CollectionCount(0) - gcStart) * 60.0 / seconds).ToString("0.0")).Append("/min")
              .Append(", hooks/frame: state ").Append((SwitchStateCalls / (double)frames).ToString("0"))
              .Append(" event ").Append((EventCalls / (double)frames).ToString("0"))
              .Append(" input ").Append((InputCalls / (double)frames).ToString("0"));
            for (int i = 0; i < parts.Count && i < 8; i++)
                sb.Append(i == 0 ? " | " : ", ").Append(parts[i].Key).Append(' ').Append((parts[i].Value / frames).ToString("0.000"));
            return sb.ToString();
        }
    }
}