using System.Linq;
using Content.Shared.Administration.Logs;
using Content.Shared.Alert;
using Content.Shared.CCVar;
using Content.Shared.CombatMode;
using Content.Shared.Damage.Components;
using Content.Shared.Damage.Events;
using Content.Shared.Database;
using Content.Shared.Effects;
using Content.Shared.FixedPoint;
using Content.Shared.Movement.Components;
using Content.Shared.Movement.Systems;
using Content.Shared.Projectiles;
using Content.Shared.Rejuvenate;
using Content.Shared.Rounding;
using Content.Shared.StatusEffectNew;
using Content.Shared.Stunnable;
using Content.Shared.Throwing;
using Content.Shared.Weapons.Melee.Events;
using JetBrains.Annotations;
using Robust.Shared.Audio;
using Robust.Shared.Audio.Systems;
using Robust.Shared.Configuration;
using Robust.Shared.Network;
using Robust.Shared.Player;
using Robust.Shared.Prototypes;
using Robust.Shared.Serialization;
using Robust.Shared.Timing;

namespace Content.Shared.Damage.Systems;

public abstract partial class SharedStaminaSystem : EntitySystem
{
    public static readonly EntProtoId StaminaLow = "StatusEffectStaminaLow";

    [Dependency] private readonly IConfigurationManager _config = default!;
    [Dependency] protected readonly IGameTiming Timing = default!;
    [Dependency] private readonly INetManager _net = default!;
    [Dependency] private readonly ISharedAdminLogManager _adminLogger = default!;
    [Dependency] private readonly AlertsSystem _alerts = default!;
    [Dependency] private readonly MetaDataSystem _metadata = default!;
    [Dependency] private readonly MovementModStatusSystem _movementMod = default!;
    [Dependency] private readonly SharedAudioSystem _audio = default!;
    [Dependency] private readonly SharedColorFlashEffectSystem _color = default!;
    [Dependency] private readonly StatusEffectsSystem _status = default!;
    [Dependency] protected readonly SharedStunSystem StunSystem = default!;

    /// <summary>
    /// How much of a buffer is there between the stun duration and when stuns can be re-applied.
    /// </summary>
    protected static readonly TimeSpan StamCritBufferTime = TimeSpan.FromSeconds(3f);

    public float UniversalStaminaDamageModifier { get; private set; } = 1f;

    public override void Initialize()
    {
        base.Initialize();

        InitializeModifier();
        InitializeResistance();

        SubscribeLocalEvent<StaminaComponent, ComponentStartup>(OnStartup);
        SubscribeLocalEvent<StaminaComponent, ComponentShutdown>(OnShutdown);
        SubscribeLocalEvent<StaminaComponent, AfterAutoHandleStateEvent>(OnStamHandleState);
        SubscribeLocalEvent<StaminaComponent, DisarmedEvent>(OnDisarmed);
        SubscribeLocalEvent<StaminaComponent, RejuvenateEvent>(OnRejuvenate);

        SubscribeLocalEvent<StaminaDamageOnEmbedComponent, EmbedEvent>(OnProjectileEmbed);

        SubscribeLocalEvent<StaminaDamageOnCollideComponent, ProjectileHitEvent>(OnProjectileHit);
        SubscribeLocalEvent<StaminaDamageOnCollideComponent, ThrowDoHitEvent>(OnThrowHit);

        SubscribeLocalEvent<StaminaDamageOnHitComponent, MeleeHitEvent>(OnMeleeHit);

        Subs.CVar(_config, CCVars.PlaytestStaminaDamageModifier, value => UniversalStaminaDamageModifier = value, true);
    }

    protected virtual void OnStamHandleState(Entity<StaminaComponent> entity, ref AfterAutoHandleStateEvent args)
    {
        if (entity.Comp.Critical)
            EnterStamCrit(entity);
        else
        {
            if (entity.Comp.StaminaDamage > 0f)
                EnsureComp<ActiveStaminaComponent>(entity);

            ExitStamCrit(entity);
        }
    }

    protected virtual void OnShutdown(Entity<StaminaComponent> entity, ref ComponentShutdown args)
    {
        if (MetaData(entity).EntityLifeStage < EntityLifeStage.Terminating)
        {
            RemCompDeferred<ActiveStaminaComponent>(entity);
        }
        _alerts.ClearAlert(entity.Owner, entity.Comp.StaminaAlert);
    }

    private void OnStartup(Entity<StaminaComponent> entity, ref ComponentStartup args)
    {
        UpdateStaminaVisuals(entity);
    }

    [PublicAPI]
    public float GetStaminaDamage(EntityUid uid, StaminaComponent? component = null)
    {
        if (!Resolve(uid, ref component))
            return 0f;

        var curTime = Timing.CurTime;
        var pauseTime = _metadata.GetPauseTime(uid);
        return MathF.Max(0f, component.StaminaDamage - MathF.Max(0f, (float) (curTime - (component.NextUpdate + pauseTime)).TotalSeconds * component.Decay));
    }

    private void OnRejuvenate(Entity<StaminaComponent> entity, ref RejuvenateEvent args)
    {
        if (entity.Comp.StaminaDamage >= entity.Comp.CritThreshold)
        {
            ExitStamCrit(entity, entity.Comp);
        }

        entity.Comp.StaminaDamage = 0;
        AdjustStatus(entity.Owner);
        RemComp<ActiveStaminaComponent>(entity);
        _status.TryRemoveStatusEffect(entity, StaminaLow);
        UpdateStaminaVisuals(entity);
        Dirty(entity);
    }

    private void OnDisarmed(EntityUid uid, StaminaComponent component, ref DisarmedEvent args)
    {
        if (args.Handled)
            return;

        if (component.Critical)
            return;

        var damage = args.PushProbability * component.CritThreshold;
        TakeStaminaDamage(uid, damage, component, source: args.Source);

        args.PopupPrefix = "disarm-action-shove-";
        args.IsStunned = component.Critical;

        args.Handled = true;
    }

    private void OnMeleeHit(EntityUid uid, StaminaDamageOnHitComponent component, MeleeHitEvent args)
    {
        if (!args.IsHit ||
            !args.HitEntities.Any() ||
            component.Damage <= 0f)
        {
            return;
        }

        var ev = new StaminaDamageOnHitAttemptEvent();
        RaiseLocalEvent(uid, ref ev);
        if (ev.Cancelled)
            return;

        var stamQuery = GetEntityQuery<StaminaComponent>();
        var toHit = new List<(EntityUid Entity, StaminaComponent Component)>();

        // Split stamina damage between all eligible targets.
        foreach (var ent in args.HitEntities)
        {
            if (!stamQuery.TryGetComponent(ent, out var stam))
                continue;

            toHit.Add((ent, stam));
        }

        var hitEvent = new StaminaMeleeHitEvent(toHit);
        RaiseLocalEvent(uid, hitEvent);

        if (hitEvent.Handled)
            return;

        var damage = component.Damage;

        damage *= hitEvent.Multiplier;

        damage += hitEvent.FlatModifier;

        foreach (var (ent, comp) in toHit)
        {
            TakeStaminaDamage(ent, damage / toHit.Count, comp, source: args.User, with: args.Weapon, sound: component.Sound);
        }
    }

    private void OnProjectileHit(EntityUid uid, StaminaDamageOnCollideComponent component, ref ProjectileHitEvent args)
    {
        OnCollide(uid, component, args.Target);
    }

    private void OnProjectileEmbed(EntityUid uid, StaminaDamageOnEmbedComponent component, ref EmbedEvent args)
    {
        if (!TryComp<StaminaComponent>(args.Embedded, out var stamina))
            return;

        TakeStaminaDamage(args.Embedded, component.Damage, stamina, source: uid);
    }

    private void OnThrowHit(EntityUid uid, StaminaDamageOnCollideComponent component, ThrowDoHitEvent args)
    {
        OnCollide(uid, component, args.Target);
    }

    private void OnCollide(EntityUid uid, StaminaDamageOnCollideComponent component, EntityUid target)
    {
        // you can't inflict stamina damage on things with no stamina component
        // this prevents stun batons from using up charges when throwing it at lockers or lights
        if (!HasComp<StaminaComponent>(target))
            return;

        var ev = new StaminaDamageOnHitAttemptEvent();
        RaiseLocalEvent(uid, ref ev);
        if (ev.Cancelled)
            return;

        TakeStaminaDamage(target, component.Damage, source: uid, sound: component.Sound);
    }

    private void UpdateStaminaVisuals(Entity<StaminaComponent> entity)
    {
        SetStaminaAlert(entity, entity.Comp);
        SetStaminaAnimation(entity);
    }

    // Here so server can properly tell all clients in PVS range to start the animation
    protected virtual void SetStaminaAnimation(Entity<StaminaComponent> entity){}

    private void SetStaminaAlert(EntityUid uid, StaminaComponent? component = null)
    {
        if (!Resolve(uid, ref component, false) || component.Deleted)
            return;

        var severity = ContentHelpers.RoundToLevels(MathF.Max(0f, component.CritThreshold - component.StaminaDamage), component.CritThreshold, 7);
        _alerts.ShowAlert(uid, component.StaminaAlert, (short) severity);
    }

    /// <summary>
    /// Tries to take stamina damage without raising the entity over the crit threshold.
    /// </summary>
    public bool TryTakeStamina(EntityUid uid, float value, StaminaComponent? component = null, EntityUid? source = null, EntityUid? with = null, bool visual = false)
    {
        // Something that has no Stamina component automatically passes stamina checks
        if (!Resolve(uid, ref component, false))
            return true;

        var oldStam = component.StaminaDamage;

        if (oldStam + value >= component.CritThreshold || component.Critical)
            return false;

        TakeStaminaDamage(uid, value, component, source, with, visual: visual);
        return true;
    }

    public void TakeStaminaDamage(EntityUid uid, float value, StaminaComponent? component = null,
        EntityUid? source = null, EntityUid? with = null, bool visual = true, SoundSpecifier? sound = null, bool ignoreResist = false)
    {
        if (!Resolve(uid, ref component, false))
            return;

        var ev = new BeforeStaminaDamageEvent(value);
        RaiseLocalEvent(uid, ref ev);
        if (ev.Cancelled)
            return;

        // Allow stamina resistance to be applied.
        if (!ignoreResist)
        {
            value = ev.Value;
        }

        value = UniversalStaminaDamageModifier * value;

        // Have we already reached the point of max stamina damage?
        if (component.Critical)
            return;

        var oldDamage = component.StaminaDamage;
        component.StaminaDamage = MathF.Max(0f, component.StaminaDamage + value);

        // Reset the decay cooldown upon taking damage.
        if (oldDamage < component.StaminaDamage)
        {
            var nextUpdate = Timing.CurTime + TimeSpan.FromSeconds(component.Cooldown);

            if (component.NextUpdate < nextUpdate)
                component.NextUpdate = nextUpdate;
        }

        AdjustStatus(uid);

        UpdateStaminaVisuals((uid, component));

        // Checking if the stamina damage has decreased to zero after exiting the stamcrit
        if (component.AfterCritical && oldDamage > component.StaminaDamage && component.StaminaDamage <= 0f)
        {
            component.AfterCritical = false; // Since the recovery from the crit has been completed, we are no longer 'after crit'
            _status.TryRemoveStatusEffect(uid, StaminaLow);
        }

        if (!component.Critical)
        {
            if (component.StaminaDamage >= component.CritThreshold)
            {
                EnterStamCrit(uid, component);
            }
        }
        else
        {
            if (component.StaminaDamage < component.CritThreshold)
            {
                ExitStamCrit(uid, component);
            }
        }

        EnsureComp<ActiveStaminaComponent>(uid);
        Dirty(uid, component);

        if (value <= 0)
            return;
        if (source != null)
        {
            _adminLogger.Add(LogType.Stamina, $"{ToPrettyString(source.Value):user} caused {value} stamina damage to {ToPrettyString(uid):target}{(with != null ? $" using {ToPrettyString(with.Value):using}" : "")}");
        }
        else
        {
            _adminLogger.Add(LogType.Stamina, $"{ToPrettyString(uid):target} took {value} stamina damage");
        }

        if (visual)
        {
            _color.RaiseEffect(Color.Aqua, new List<EntityUid>() { uid }, Filter.Pvs(uid, entityManager: EntityManager));
        }

        if (_net.IsServer)
        {
            _audio.PlayPvs(sound, uid);
        }
    }

    public override void Update(float frameTime)
    {
        base.Update(frameTime);

        var stamQuery = GetEntityQuery<StaminaComponent>();
        var query = EntityQueryEnumerator<ActiveStaminaComponent>();
        var curTime = Timing.CurTime;

        while (query.MoveNext(out var uid, out _))
        {
            // Just in case we have active but not stamina we'll check and account for it.
            if (!stamQuery.TryGetComponent(uid, out var comp) ||
                comp.StaminaDamage <= 0f && !comp.Critical)
            {
                RemComp<ActiveStaminaComponent>(uid);
                continue;
            }

            // Shouldn't need to consider paused time as we're only iterating non-paused stamina components.
            var nextUpdate = comp.NextUpdate;

            if (nextUpdate > curTime)
                continue;

            // Handle exiting critical condition and restoring stamina damage
            if (comp.Critical)
                ExitStamCrit(uid, comp);

            comp.NextUpdate += TimeSpan.FromSeconds(1f);

            TakeStaminaDamage(
                uid,
                comp.AfterCritical ? -comp.Decay * comp.AfterCritDecayMultiplier : -comp.Decay, // Recover faster after crit
                comp);

            Dirty(uid, comp);
        }
    }

    private void EnterStamCrit(EntityUid uid, StaminaComponent? component = null)
    {
        if (!Resolve(uid, ref component) ||
            component.Critical)
        {
            return;
        }

        component.Critical = true;
        component.StaminaDamage = component.CritThreshold;

        if (StunSystem.TryUpdateParalyzeDuration(uid, component.StunTime))
            StunSystem.TrySeeingStars(uid);

        // Give them buffer before being able to be re-stunned
        component.NextUpdate = Timing.CurTime + component.StunTime + StamCritBufferTime;
        EnsureComp<ActiveStaminaComponent>(uid);
        Dirty(uid, component);
        _adminLogger.Add(LogType.Stamina, LogImpact.Medium, $"{ToPrettyString(uid):user} entered stamina crit");
    }

    private void ExitStamCrit(EntityUid uid, StaminaComponent? component = null)
    {
        if (!Resolve(uid, ref component) ||
            !component.Critical)
        {
            return;
        }

        component.Critical = false;
        component.AfterCritical = true;  // Set to true to indicate that stamina will be restored after exiting stamcrit
        component.NextUpdate = Timing.CurTime;

        UpdateStaminaVisuals((uid, component));
        Dirty(uid, component);
        _adminLogger.Add(LogType.Stamina, LogImpact.Low, $"{ToPrettyString(uid):user} recovered from stamina crit");
    }

    /// <summary>
    /// Adjusts the modifiers of the <see cref="StaminaLow"/> status effect entity and applies relevant statuses.
    /// System iterates through the <see cref="StaminaComponent.StunModifierThresholds"/> to find correct movement modifer.
    /// This modifier is saved to the Stamina Low Status Effect entity's <see cref="MovementModStatusEffectComponent"/>.
    /// </summary>
    /// <param name="ent">Entity to update</param>
    private void AdjustStatus(Entity<StaminaComponent?> ent)
    {
        if (!Resolve(ent, ref ent.Comp))
            return;

        if (!_status.TrySetStatusEffectDuration(ent, StaminaLow, out var status))
            return;

        var closest = FixedPoint2.Zero;

        // Iterate through the dictionary in the similar way as in Damage.SlowOnDamageSystem.OnRefreshMovespeed
        foreach (var thres in ent.Comp.StunModifierThresholds)
        {
            var key = thres.Key.Float();

            if (ent.Comp.StaminaDamage >= key && key > closest && closest < ent.Comp.CritThreshold)
                closest = thres.Key;
        }

        _movementMod.TryUpdateMovementStatus(ent.Owner, status.Value, ent.Comp.StunModifierThresholds[closest]);
    }

    [Serializable, NetSerializable]
    public sealed class StaminaAnimationEvent(NetEntity entity) : EntityEventArgs
    {
        public NetEntity Entity = entity;
    }
}