using System;
using UnityEngine;

namespace Arena.Combat
{
	/// <summary>
	/// Fires projectiles from a muzzle, limited by the fire interval and the ammo count.
	/// Placed on the root of the shooter, which the projectiles ignore.
	/// </summary>
	public class ProjectileLauncher : MonoBehaviour
	{
		[System.Serializable]
		public class Settings
		{
			[Tooltip("Weapon data: damage, fire interval, ammo, projectile.")]
			public WeaponData Weapon;
		}

		[System.Serializable]
		public struct References
		{
			[Tooltip("Spawn point of the projectiles. Its forward axis gives the direction.")]
			public Transform Muzzle;
		}

		[System.Serializable]
		public class StateContainer
		{
			public int Ammo;
		}

		#region Fields

		[SerializeField] private Settings _settings;
		[SerializeField] private References _references;
		[SerializeField] private StateContainer _state;

		/// <summary>
		/// Raised with the current and max ammo each time the ammo changes.
		/// </summary>
		public event Action<int, int> OnAmmoChange;

		public StateContainer State => _state;
		public int MaxAmmo => _settings.Weapon.MaxAmmo;

		private float _nextFireTime;

		#endregion

		#region Unity Lifecycle

		private void Awake()
		{
			_state.Ammo = MaxAmmo;
		}

		#endregion

		#region Public Methods

		/// <summary>
		/// Fires one projectile if the weapon is ready and has ammo. Returns true if a shot was fired.
		/// </summary>
		public bool TryFire()
		{
			if (Time.time < _nextFireTime || _state.Ammo <= 0)
				return false;

			_nextFireTime = Time.time + _settings.Weapon.FireInterval;
			SetAmmo(_state.Ammo - 1);

			Transform muzzle = _references.Muzzle;
			Projectile projectile = Instantiate(_settings.Weapon.ProjectilePrefab, muzzle.position, muzzle.rotation);
			projectile.Launch(_settings.Weapon.Damage, gameObject);
			return true;
		}

		/// <summary>
		/// Adds ammo without exceeding the weapon maximum.
		/// </summary>
		public void AddAmmo(int amount)
		{
			if (amount <= 0)
				return;

			SetAmmo(Mathf.Min(_state.Ammo + amount, MaxAmmo));
		}

		#endregion

		#region Private Methods

		private void SetAmmo(int value)
		{
			_state.Ammo = value;
			OnAmmoChange?.Invoke(_state.Ammo, MaxAmmo);
		}

		[ContextMenu("Debug/Try Fire")]
		private void DebugTryFire()
		{
			TryFire();
		}

		#endregion
	}
}