using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;

/** 
 * @package Fungus An open source library for Unity 3D for creating graphic interactive fiction games.
 */
namespace Fungus
{
	/** 
	 * Manages global game state and movement between rooms.
	 */
	[RequireComponent(typeof(Dialog))]
	[RequireComponent(typeof(CommandQueue))]
	[RequireComponent(typeof(CameraController))]
	[RequireComponent(typeof(PageController))]
	public class Game : GameController 
	{
		/**
		 * The currently active Room.
		 * Only one Room may be active at a time.
		 */
		public Room activeRoom;

		/**
		 * Automatically display links between connected Rooms.
		 */
		public bool showLinks = true;

		/**
		 * Time for fade transition to complete when moving to a different Room.
		 */
		public float roomFadeDuration = 1f;

		/**
		 * Time for fade transition to complete when hiding/showing buttons.
		 */
		public float buttonFadeDuration = 0.25f;

		/**
		 * Time which must elapse before buttons will automatically hide.
		 */
		public float autoHideButtonDuration = 5f;

		/**
		 * Currently active Dialog object used to display character text and menus.
		 */
		public Dialog dialog;

		/**
		 * Global dictionary of integer values for storing game state.
		 */
		[HideInInspector]
		static public Dictionary<string, int> values = new Dictionary<string, int>();

		[HideInInspector]
		static public StringTable stringTable = new StringTable();
		
		[HideInInspector]
		public CommandQueue commandQueue;
		
		[HideInInspector]
		public CameraController cameraController;
	
		[HideInInspector]
		public PageController pageController;

		/**
		 * True when executing a Wait() or WaitForTap() command
		 */
		[HideInInspector]
		public bool waiting; 

		float autoHideButtonTimer;

		static Game instance;

		/**
		 * Returns the singleton instance for the Game class
		 */
		public static Game GetInstance()
		{
			if (!instance)
			{
				instance = GameObject.FindObjectOfType(typeof(Game)) as Game;
				if (!instance)
				{
					Debug.LogError("There must be one active Game object in your scene.");
				}
			}
			
			return instance;
		}

		public virtual void Start()
		{
			// Acquire references to required components

			commandQueue = gameObject.GetComponent<CommandQueue>();
			cameraController = gameObject.GetComponent<CameraController>();
			pageController = gameObject.GetComponent<PageController>();

			// Auto-hide buttons should be visible at start of game
			autoHideButtonTimer = autoHideButtonDuration;

			if (activeRoom == null)
			{
				// Pick first room found if none is specified
				activeRoom = GameObject.FindObjectOfType(typeof(Room)) as Room;
			}

			if (activeRoom != null)
			{
				// Move to the active room
				commandQueue.Clear();
				commandQueue.AddCommand(new Command.MoveToRoom(activeRoom));
				commandQueue.Execute();
			}
		}

		public virtual void Update()
		{
			autoHideButtonTimer -= Time.deltaTime;
			autoHideButtonTimer = Mathf.Max(autoHideButtonTimer, 0f);

			if (Input.GetMouseButtonDown(0))
			{
				autoHideButtonTimer = autoHideButtonDuration;
			}
		}

		public IDialog GetDialog()
		{
			if (dialog != null)
			{
				return dialog as IDialog;
			}
			
			return pageController as IDialog;
		}

		/**
		 * Returns true if the game should display 'auto hide' buttons.
		 * Buttons will be displayed if the game is not currently displaying story text/options, and no Wait command is in progress.
		 */
		public bool GetShowAutoButtons()
		{
			if (waiting)
			{
				return false;
			}

			if (pageController == null ||
			    pageController.mode == PageController.Mode.Idle)
			{
				return (autoHideButtonTimer > 0f);
			}

			return false;
		}

		/**
		 * Sets a globally accessible game state value.
		 * @param key The key of the value.
		 * @param value The integer value to store.
		 */
		public void SetGameValue(string key, int value)
		{
			values[key] = value;
		}

		/**
		 * Gets a globally accessible game state value.
		 * @param key The key of the value.
		 * @return The integer value for the specified key, or 0 if the key does not exist.
		 */
		public int GetGameValue(string key)
		{
			if (values.ContainsKey(key))
			{
				return values[key];
			}
			return 0;
		}

		/**
		 * Returns a parallax offset vector based on the camera position relative to the active Room.
		 * Higher values for the parallaxFactor yield a larger offset (appears closer to camera).
		 * Suggested range for good parallax effect is [0.1..0.5].
		 * @param parallaxFactor Horizontal and vertical scale factors to apply to camera offset vector.
		 * @return A parallax offset vector based on camera positon relative to current room and the parallaxFactor.
		 */
		public Vector3 GetParallaxOffset(Vector2 parallaxFactor)
		{
			if (activeRoom == null)
			{
				return Vector3.zero;
			}

			Vector3 a = activeRoom.transform.position;
			Vector3 b = cameraController.GetCameraPosition();
			Vector3 offset = (a - b);
			offset.x *= parallaxFactor.x;
			offset.y *= parallaxFactor.y;

			return offset;
		}

		/**
		 * Loads a new scene.
		 * This is useful for splitting a large Fungus game across multiple scene files to reduce peak memory usage.
		 * All previously loaded assets (including textures) will be released.
		 * @param sceneName The filename of the scene to load.
		 * @param saveGame Automatically save the current game state as a checkpoint.
		 */
		public void LoadScene(string sceneName, bool saveGame)
		{
			Application.LoadLevel(sceneName);

			if (saveGame)
			{
				SaveGame("Fungus.Save");
			}

			// Free up memory used by textures in previous scene
			Resources.UnloadUnusedAssets();
		}

		/**
		 * Save the current game state to persistant storage.
		 * Only the values, string table and current scene are stored.
		 * @param saveName The name of the saved game data.
		 */
		public void SaveGame(string saveName)
		{
			// Store loaded scene name in save data
			SetString("Fungus.Scene", Application.loadedLevelName);

			var b = new BinaryFormatter();
			var m = new MemoryStream();

			// Save values
			{
				b.Serialize(m, values);
				string s = Convert.ToBase64String(m.GetBuffer());
				PlayerPrefs.SetString(saveName + ".values", s);
			}

			// Save string table
			{
				b.Serialize(m, stringTable.stringDict);
				string s = Convert.ToBase64String(m.GetBuffer());
				PlayerPrefs.SetString(saveName + ".stringTable", s);
			}
		}

		/**
		 * Loads the current game state from persistant storage.
		 * This will cause the scene specified in the "Fungus.Scene" string to be loaded.
		 * Each scene in your game should contain the necessary code to restore the current game state based on saved data.
		 * @param saveName The name of the saved game data.
		 */
		public void LoadGame(string saveName)
		{
			// Load values
			{
				var data = PlayerPrefs.GetString(saveName + ".values");
				if (!string.IsNullOrEmpty(data))
				{
					var b = new BinaryFormatter();
					var m = new MemoryStream(Convert.FromBase64String(data));
					values = (Dictionary<string, int>)b.Deserialize(m);
				}
			}

			// Load string table
			{
				var data = PlayerPrefs.GetString(saveName + ".stringTable");
				if (!string.IsNullOrEmpty(data))
				{
					var b = new BinaryFormatter();
					var m = new MemoryStream(Convert.FromBase64String(data));
					stringTable.stringDict = b.Deserialize(m) as Dictionary<string, string>;
				}
			}

			string sceneName = GetString("Fungus.Scene");
			if (sceneName.Length > 0)
			{
				LoadScene(sceneName, true);
			}
		}
	}
}