/*
 * Flotsam.cs
 * Authors: August Zinsser, Adam Nabinger
 * Copyright (c) 2007-2008 Cornell University

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

using System;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Random=Util.Random;

namespace MaritimeDefender
{
	/// <summary>
	/// The items that the friendly ships in Meteor Madness throw to the player
	/// They upgrade the player's weapon and grant him/her a resource when the player's ship collides with this
	/// </summary>
	class Flotsam : UFO
	{
		#region Fields

		// The resource to pick up
		private readonly Pickup mResource;
		
		// The amount of the resource to be collected
		private int mValue;
		
		// Reference to the current Maritime Defender game screen
		private readonly MaritimeDefender m_Game;

		#endregion

		#region Predicate

		/// <summary>
		/// Let's the game know when the collectable can be disposed of
		/// </summary>
		public static readonly Predicate<Flotsam> Destroyed = delegate(Flotsam o)
		{
			return !o.mAlive;
		};

		#endregion

		#region Creation

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="resourceType">Type of resource to award the player for collecting this powerup</param>
		/// <param name="value">Amount of that resource to award</param>
		/// <param name="texturePath">Path name of texture to use for the collectable</param>
		/// <param name="width">The width of the collectable</param>
		/// <param name="height">The height of the collectable</param>
		/// <param name="depth">The layer depth of the collectable</param>
		/// <param name="p_Game">Reference to the currenct Maritime Defender game screen</param>
		public Flotsam(Pickup resourceType, int value, string texturePath, float width, float height, float depth, MaritimeDefender p_Game)
			: base(texturePath, width, height, depth, 10)
		{
			mResource = resourceType;
			mValue = value;

			// Add a bit of rotation for aesthetics
			mAngVel = Random.NextFloat(-5f, 5f);
			mRot = Random.NextFloat(MathHelper.TwoPi);

			m_Game = p_Game;
		}

		#endregion

		#region Update

		/// <summary>
		/// Updates the collectable
		/// </summary>
		/// <param name="gameTime">Time passed in game</param>
		/// <param name="playerShip">The player ship to react with</param>
		public void Update(GameTime gameTime, Entity playerShip)
		{
			base.Update(gameTime);
			if (mResource == Pickup.Credits)
			{
				// Home in on the player
				Vector3 oldTraj = mVel;
				float speed = Math.Max(mVel.Length(), (m_Game.ShooterSpeed * 10f));
				float correctionFactor = 1 - Math.Min(.925f, mPos.Z);
				Vector3 correctiveTraj;
				if (playerShip != null)
				{
					correctiveTraj = playerShip.Position - mPos;
				}
				else
				{
					correctiveTraj = mPos;
				}
				correctiveTraj.Normalize();
				correctiveTraj = Vector3.Multiply(correctiveTraj, correctionFactor);
				oldTraj.Normalize();
				oldTraj = Vector3.Multiply(oldTraj, 1 - correctionFactor);
				mVel = correctiveTraj + oldTraj;
				mVel = Vector3.Multiply(mVel, speed);
			}
		}

		#endregion

		#region Collision

		/// <summary>
		/// Awards the appropriate resources and upgrades the players' weapons
		/// </summary>
		/// <param name="player">The player to be awarded from picking up the collectable</param>
		public override void CollideWithPlayer(Entity player)
		{
			int screenCenterX = m_Game.GraphicsDevice.Viewport.Width >> 1;
			int screenCenterY = m_Game.GraphicsDevice.Viewport.Height >> 1;
			Rectangle proj = Space3D.Project(player.X, player.Y, player.Z, this.Width, this.Height);

			mAlive = false;
			m_Game.Log(EventCode.MD_ShooterPlayerCollectibleCollision, EventCode.MD_ShooterPlayerCollectibleCollision.ToString() + " Collectible=" + mResource.ToString());

			// Gather the resource
			// TODO: Scoring?
			//m_Game.Score.Gather(mResource, mValue);

			if (mResource == Pickup.Weapon && player is CheetahFighter)
			{
				((CheetahFighter)player).UpgradeWeapon();
			}

			if (m_Game.DisplayWaitTimer < 0)
			{
				StringBuilder text = new StringBuilder("+");
				text.Append(mResource);

				m_Game.AddNewMessage(
					text.ToString(),
					null,
					@"Fonts\dialogfont",
					new Vector2(proj.X - screenCenterX, proj.Y - screenCenterY),
					new Vector2(0, -50f),
					(mResource == Pickup.Weapon ? Color.Aqua : Color.LimeGreen),
					1f,
					1f,
					true);

				m_Game.ResetDisplayWaitTimer();
			}
		}

		#endregion

		#region State Modifiers

		/// <summary>
		/// Deals the specified amount of damage to this flotsam, potentially destroying it
		/// </summary>
		/// <param name="damage">Amount of damage to deal to this collectable</param>
		public override void GetHit(int damage)
		{
			mHitPoints -= damage;
			if (mHitPoints < 0)
				Destroy();
		}

		/// <summary>
		/// Flotsam does not react, so this method does nothing
		/// </summary>
		/// <param name="playerShip">The ship to react to</param>
		/// <returns>False always</returns>
		public override bool React(CheetahFighter playerShip)
		{
			return false;
		}

		/// <summary>
		/// Destroys this collectable
		/// </summary>
		public override void Destroy()
		{
			mAlive = false;
		}

		#endregion
	}
}