using System;

using ColdMint.scripts.camp;
using ColdMint.scripts.character;
using ColdMint.scripts.damage;

using Godot;

namespace ColdMint.scripts.item.weapon;

/// <summary>
/// <para>WeaponTemplate</para>
/// <para>武器模板</para>
/// </summary>
public abstract partial class WeaponTemplate : RigidBody2D, IItem
{
    private float _gravity = ProjectSettings.GetSetting("physics/2d/default_gravity").AsSingle();

    //Implements IItem
    [Export] public virtual string Id { get; private set; } = "ID";

    protected Texture2D? UniqueIcon { get; set; }
    public Texture2D Icon => UniqueIcon ?? ItemTypeManager.DefaultIconOf(Id);

    protected string? UniqueName { get; set; }
    public new string Name => UniqueName ?? ItemTypeManager.DefaultNameOf(Id);

    protected string? UniqueDescription { get; set; }
    public string? Description => UniqueDescription ?? ItemTypeManager.DefaultDescriptionOf(Id);


    public void Use(Node2D? owner, Vector2 targetGlobalPosition)
    {
        Fire(owner, targetGlobalPosition);
    }

    public virtual void Destroy()
    {
        QueueFree();
    }

    public bool CanStackWith(IItem item) => false;


    /// <summary>
    /// <para>Whether the weapon is currently picked up</para>
    /// <para>当前武器是否被捡起了</para>
    /// </summary>
    public bool Picked { get; set; }

    /// <summary>
    /// <para>Owner</para>
    /// <para>主人</para>
    /// </summary>
    public new Node2D? Owner { get; set; }


    /// <summary>
    /// <para>Enabled contact injury</para>
    /// <para>启用接触伤害</para>
    /// </summary>
    public bool EnableContactInjury;

    [Export] private int _minContactInjury = 1;
    [Export] private int _maxContactInjury = 2;

    private DateTime? _lastFiringTime;

    /// <summary>
    /// <para>Firing interval</para>
    /// <para>开火间隔</para>
    /// </summary>
    private TimeSpan _firingInterval;
    private long _firingIntervalAsMillisecond = 100;
    [Export] protected long FiringIntervalAsMillisecond
    {
        get => _firingIntervalAsMillisecond;
        set
        {
            _firingIntervalAsMillisecond = value;
            _firingInterval = TimeSpan.FromMilliseconds(_firingIntervalAsMillisecond);
        }
    }


    /// <summary>
    /// <para>The recoil of the weapon</para>
    /// <para>武器的后坐力</para>
    /// </summary>
    /// <remarks>
    ///<para>When the weapon is fired, how much recoil is applied to the user, in units: the number of cells, and the X direction of the force is automatically inferred.</para>
    ///<para>武器开火，要对使用者施加多大的后坐力，单位：格数，力的X方向是自动推断的。</para>
    /// </remarks>
    [Export] private Vector2 _recoil;

    /// <summary>
    /// <para>This area represents the collision range of the weapon, and when other nodes enter this area, they will deal damage.</para>
    /// <para>这个区域表示武器的碰撞范围，当其他节点进入此区域时，会造成伤害。</para>
    /// </summary>
    private Area2D? _damageArea2D;

    /// <summary>
    /// <para>The number of tile maps in contact with this weapon</para>
    /// <para>与此武器接触的瓦片地图数量</para>
    /// </summary>
    private int _tileMapNumber;


    public override void _Ready()
    {
        _damageArea2D = GetNode<Area2D>("DamageArea2D");
        _damageArea2D.BodyEntered += OnBodyEnter;
        _damageArea2D.BodyExited += OnBodyExited;
    }

    private void OnBodyExited(Node node)
    {
        if (Picked)
        {
            return;
        }

        //If it leaves the ground or walls.
        //如果离开了地面或墙壁。
        if (node is TileMap)
        {
            _tileMapNumber--;
            if (_tileMapNumber == 0)
            {
                //No longer in contact with any shingles can cause injury
                //不再与任何瓦片接触后，可以造成伤害
                EnableContactInjury = true;
                SetCollisionMaskValue(Config.LayerNumber.Player, false);
            }
        }
    }

    /// <summary>
    /// <para>Use weapons against the enemy</para>
    /// <para>使用武器砸敌人</para>
    /// </summary>
    /// <param name="node"></param>
    private void OnBodyEnter(Node node)
    {
        if (Picked)
        {
            return;
        }

        if (node is TileMap)
        {
            _tileMapNumber++;
            EnableContactInjury = false;
            //Items can be pushed by the player when they are on the ground
            //当物品在地面上时，可被玩家推动
            SetCollisionMaskValue(Config.LayerNumber.Player, true);
        }
        else if (node is CharacterTemplate characterTemplate)
        {
            if (!EnableContactInjury)
            {
                return;
            }


            if (Owner is not CharacterTemplate ownerCharacterTemplate)
            {
                return;
            }

            //Determine if your side can cause damage
            //判断所属的阵营是否可以造成伤害
            var canCauseHarm = CampManager.CanCauseHarm(CampManager.GetCamp(ownerCharacterTemplate.CampId),
                                                        CampManager.GetCamp(characterTemplate.CampId));
            if (!canCauseHarm)
            {
                return;
            }

            //If allowed to cause harm
            //如果允许造成伤害
            var damage = new Damage
            {
                MaxDamage = Math.Abs(_maxContactInjury),
                MinDamage = Math.Abs(_minContactInjury),
                Attacker = ownerCharacterTemplate
            };
            damage.CreateDamage();
            damage.MoveLeft = LinearVelocity.X < 0;
            damage.Type = Config.DamageType.Physical;
            characterTemplate.Damage(damage);
            //Reduce speed after hitting enemies.
            //击中敌人后减少速度。
            LinearVelocity *= 1 - Config.ThrownItemsHitEnemiesReduceSpeedByPercentage;
        }
    }

    /// <summary>
    /// <para>翻转武器</para>
    /// </summary>
    /// <param name="facingLeft"></param>
    public void Flip(bool facingLeft) { }


    /// <summary>
    /// <para>Discharge of the weapon</para>
    /// <para>武器开火</para>
    /// </summary>
    /// <remarks>
    ///<param name="owner">
    ///<para>owner</para>
    ///<para>武器所有者</para>
    /// </param>
    /// <param name="enemyGlobalPosition">
    ///<para>enemyGlobalPosition</para>
    ///<para>敌人所在位置</para>
    /// </param>
    /// </remarks>
    public void Fire(Node2D? owner, Vector2 enemyGlobalPosition)
    {
        var nowTime = DateTime.Now;
        //If the present time minus the time of the last fire is less than the interval between fires, it means that the fire cannot be fired yet.
        //如果现在时间减去上次开火时间小于开火间隔，说明还不能开火。
        if (_lastFiringTime != null && nowTime - _lastFiringTime < _firingInterval)
        {
            return;
        }

        if (owner is CharacterTemplate characterTemplate)
        {
            //We check the recoil of the weapon before each firing.
            //我们在每次开火之前，检查武器的后坐力。
            if (_recoil != Vector2.Zero)
            {
                var force = new Vector2();
                var forceX = Math.Abs(_recoil.X);
                if (Math.Abs(RotationDegrees) < 90)
                {
                    //The weapon goes to the right and we apply a recoil to the left
                    //武器朝向右边我们向左施加后坐力
                    forceX = -forceX;
                }

                force.X = forceX * Config.CellSize;
                force.Y = _recoil.Y * Config.CellSize;
                characterTemplate.AddForce(force);
            }
        }

        DoFire(owner, enemyGlobalPosition);
        _lastFiringTime = nowTime;
    }

    /// <summary>
    /// <para>Execute fire</para>
    /// <para>执行开火</para>
    /// </summary>
    protected abstract void DoFire(Node2D? owner, Vector2 enemyGlobalPosition);
}