using UnityEngine;
using System.Collections;

public class MainMenu : MonoBehaviour {

    public GUISkin menuSkin;
    public GUIStyle versionStyle;
    public Texture background;

    Vector2 versionSize;
    Vector2 versionPlacement;

    Vector2 titleSize;
    Vector2 titlePlacement;

    Vector2 menuButtonSize;
    Vector2 menuButtonPlacement;

    string version;

    bool isMainMenu;
    bool isNewGameMenu;
    bool isLoadGameMenu;
    bool isOptionsMenu;
    bool isCreditsMenu;
    bool isQuitDialog;

    void Start () {

        isMainMenu = true;

        menuButtonSize = new Vector2 (160f, 40f);
        versionSize    = new Vector2 (100f, 20f);
        titleSize      = new Vector2 (400f, 80f);

        menuButtonPlacement = new Vector2 ((Screen.width / 2f) - (menuButtonSize.x / 2f), (Screen.height / 2f) - (menuButtonSize.y / 2f));
        versionPlacement    = new Vector2 (Screen.width - versionSize.x, Screen.height - versionSize.y);
        titlePlacement      = new Vector2 ((Screen.width / 2f) - (titleSize.x / 2f), 80f);

        version = "null";

    }

    void OnGUI () {

        GUI.skin = menuSkin;
        GUI.DrawTexture (new Rect (0f, 0f, Screen.width, Screen.height), background, ScaleMode.StretchToFill, false);
        GUI.Label (new Rect (versionPlacement.x, versionPlacement.y, versionSize.x, versionSize.y), "Version: " + version, versionStyle);

        // Main Menu
        if (isMainMenu) {
            GUI.Label (new Rect (titlePlacement.x, titlePlacement.y, titleSize.x, titleSize.y), "Game Title");
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y - 100f, menuButtonSize.x, menuButtonSize.y), "New Game")) {isNewGameMenu = true; isMainMenu = false;}
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y - 50f , menuButtonSize.x, menuButtonSize.y), "Load Game")) {isLoadGameMenu = true; isMainMenu = false;}
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y       , menuButtonSize.x, menuButtonSize.y), "Options")) {isOptionsMenu = true; isMainMenu = false;}
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y + 50f , menuButtonSize.x, menuButtonSize.y), "Credits")) {isCreditsMenu = true; isMainMenu = false;}
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y + 100f, menuButtonSize.x, menuButtonSize.y), "Quit")) {isQuitDialog = true; isMainMenu = false;}
        }

        // New Game
        if (isNewGameMenu) {
            GUI.Label (new Rect (titlePlacement.x, titlePlacement.y, titleSize.x, titleSize.y), "New Game");
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y + 100f, menuButtonSize.x, menuButtonSize.y), "Back")) {isNewGameMenu = false; isMainMenu = true;}
        }

        // Load Game
        if (isLoadGameMenu) {
            GUI.Label (new Rect (titlePlacement.x, titlePlacement.y, titleSize.x, titleSize.y), "Load Game");
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y + 100f, menuButtonSize.x, menuButtonSize.y), "Back")) {isLoadGameMenu = false; isMainMenu = true;}
        }

        // Options
        if (isOptionsMenu) {
            GUI.Label (new Rect (titlePlacement.x, titlePlacement.y, titleSize.x, titleSize.y), "Options");
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y + 100f, menuButtonSize.x, menuButtonSize.y), "Back")) {isOptionsMenu = false; isMainMenu = true;}
        }

        // Credits
        if (isCreditsMenu) {
            GUI.Label (new Rect (titlePlacement.x, titlePlacement.y, titleSize.x, titleSize.y), "Credits");
            if (GUI.Button (new Rect (menuButtonPlacement.x, menuButtonPlacement.y + 100f, menuButtonSize.x, menuButtonSize.y), "Back")) {isCreditsMenu = false; isMainMenu = true;}
        }

        //Quit Dialog
        if (isQuitDialog) {
            GUI.Label (new Rect (titlePlacement.x, titlePlacement.y, titleSize.x, titleSize.y), "Quit Game?");
            if (GUI.Button (new Rect ((Screen.width / 2f) - 90f, (Screen.height / 2f), 80f, 30f), "Yes")) {Application.Quit();}
            if (GUI.Button (new Rect ((Screen.width / 2f) + 10f, (Screen.height / 2f), 80f, 30f), "No")) {isQuitDialog = false; isMainMenu = true;}
        }
    }
}