using System.Collections.Generic;
using Luneraria.Core;
using UnityEngine;

namespace Luneraria.View
{
    /// <summary>
    /// Hosts a match in the scene (U2C/U2D; human seat and tempo since U3). Update only hands frame
    /// time (times the speed) to the runner's fixed clock; it never decides anything in combat.
    /// Seed, start round and extra gold are the public fixtures of the golden scenarios. With
    /// HumanSlot &gt;= 0 the HUD plans that seat and planning waits for its Ready; tempo steps
    /// (1×, 2×, 4×) and pause act only in combat, as in Godot (lune_game.gd).
    /// </summary>
    public sealed class LuneMatchDriver : MonoBehaviour
    {
        /// <summary>Tempo steps of the HUD's tempo button.</summary>
        public static readonly int[] SpeedSteps = { 1, 2, 4 };

        /// <summary>
        /// True: the scene's match starts at once, without the start screen, as before U4. Tests
        /// set it before they load the scene; the benchmark (-luneBenchmark) skips the start screen
        /// by itself. False (the game): the start screen (Luneraria.UI.LuneNetPlay) starts matches.
        /// </summary>
        public static bool DirectStart;

        public int Seed = 2;
        public int StartRound = 1;
        public int ExtraGold;
        public string Profile = "";
        /// <summary>Optional Bünde of the six seats (fixtures like Godot's start option "bunds"); empty seats follow the seed.</summary>
        [System.NonSerialized] public string[] Bunds;
        /// <summary>The seat a human plays through the HUD; -1 for a bot match (U2 tests, benchmark).</summary>
        public int HumanSlot = -1;
        /// <summary>Match speed: simulated seconds per real second (tests run faster than 1).</summary>
        public float Speed = 1f;
        /// <summary>Index into SpeedSteps (the player's tempo, on top of Speed).</summary>
        public int SpeedIndex;
        public bool Paused;
        public bool RecordTrace = true;
        /// <summary>S1: extended rules for matches the driver starts itself (tests, benchmark); the start screen decides for the game.</summary>
        public bool Extended;

        public LuneMatchRunner Runner { get; private set; }
        /// <summary>Main-thread cost of the last frame's simulation (milliseconds).</summary>
        public double LastAdvanceMs { get; private set; }
        /// <summary>Bound network session (U4); null offline.</summary>
        public LuneSession Session;
        /// <summary>True on a guest: the host simulates, this side only shows snapshots.</summary>
        public bool IsClient;
        readonly System.Diagnostics.Stopwatch _clock = new System.Diagnostics.Stopwatch();

        public int Tempo { get { return SpeedSteps[Mathf.Clamp(SpeedIndex, 0, SpeedSteps.Length - 1)]; } }

        public void Restart()
        {
            var options = new MatchOptions { Seed = Seed, HumanSlot = HumanSlot, Bunds = Bunds != null ? new List<string>(Bunds) : new List<string>(), Extended = Extended };
            Runner = new LuneMatchRunner(options, StartRound, ExtraGold, Profile);
            if (RecordTrace)
                Runner.Trace = new LuneTrace();
            SpeedIndex = 0;
            Paused = false;
            Session = null;
            IsClient = false;
        }

        /// <summary>
        /// Adopts the session's match (U4). The host still advances combat and ticks snapshots;
        /// a guest never advances — its match is a display mirror of the host's snapshots.
        /// </summary>
        public void Adopt(LuneMatch match, int humanSlot, bool isClient, LuneSession session)
        {
            Session = session;
            IsClient = isClient;
            Runner = new LuneMatchRunner(match, humanSlot, session);
            SpeedIndex = 0;
            Paused = false;
        }

        /// <summary>Next tempo step (1× → 2× → 4× → 1×).</summary>
        public void CycleSpeed()
        {
            SpeedIndex = (SpeedIndex + 1) % SpeedSteps.Length;
        }

        /// <summary>Pause exists only in combat; planning waits for the player anyway.</summary>
        public bool TogglePause()
        {
            if (Runner == null || Runner.Current != LuneMatchRunner.Stage.Combat)
                return false;
            Paused = !Paused;
            return true;
        }

        void Awake()
        {
            if (Runner == null)
                Restart();
        }

        void Update()
        {
            if (Runner == null)
                return;
            _clock.Restart();
            // A guest shows the host's snapshots and never advances the match.
            if (IsClient)
            {
                LastAdvanceMs = 0.0;
                return;
            }
            // Pause holds only the combat steps (Godot: a paused game still plans and settles).
            if (!(Paused && Runner.Current == LuneMatchRunner.Stage.Combat))
                Runner.Advance(Time.deltaTime * Speed * Tempo);
            if (Session != null && Session.IsNetworked() && Session.IsAuthority())
                Session.HostTick(Time.deltaTime * Speed * Tempo);
            LastAdvanceMs = _clock.Elapsed.TotalMilliseconds;
        }
    }
}