using System.Collections;
using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

/// <summary>
/// Contains all game logic for the JustSign game
/// </summary>
public class JustSignController : MonoBehaviour
{   
    /// <summary>
    /// The canvas containing all components
    /// </summary>
    public Canvas canvas;

    /// <summary>
    /// The input field where the user can type his or her answer
    /// </summary>
    public TMP_InputField answerField;

    /// <summary>
    /// All of the words that can be used in this session
    /// </summary>
    private string[] words;

    /// <summary>
    /// All of the available themes
    /// </summary>
    private ThemeList themeList;

    /// <summary>
    /// The theme we are currently using
    /// </summary>
    private Theme currentTheme;

    /// <summary>
    /// List of strings representing all words on the track
    /// </summary>
    private List<string> activeWords = new List<string>();

    /// <summary>
    /// List of objects representing all symbols on the track
    /// </summary>
    private List<GameObject> activeSymbols = new List<GameObject>();

    /// <summary>
    /// Width and height of the symbols
    /// </summary>
    private int symbolSize = 280;

    /// <summary>
    /// Controls movement speed of symbols (higher -> faster)
    /// </summary>
    private int moveSpeed = 200;
    
    /// <summary>
    /// Starting X-coordinate of a symbol = (-1920 - symbolsize) / 2
    /// </summary>
    private int trackX = -1100;

    /// <summary>
    /// Starting Y-coordinate of a symbol
    /// </summary>
    private int trackY = -200;

    /// <summary>
    /// Time at which the last symbol was spawned
    /// </summary>
    private float lastSpawn;

    /// <summary>
    /// Start is called before the first frame update
    /// </summary>
    void Start()
    {   
        themeList = ThemeLoader.LoadJson();
        currentTheme = FindThemeByName(PlayerPrefs.GetString("themeName"));
        words = currentTheme.words;
        lastSpawn = Time.time;
        
        SpawnNewSymbol();
    }

    /// <summary>
    /// Update is called once per frame
    /// </summary>
    void Update()
    {   
        if (answerField.text.ToLower() == activeWords[0]) {
            DestroyRightmostSymbol();
            answerField.text = "";
        }

        if (activeSymbols[0].GetComponent<RectTransform>().localPosition.x > -trackX) {
            DestroyRightmostSymbol();
        }

        float currentTime = Time.time;
        if (currentTime - lastSpawn > 1) {
            lastSpawn = currentTime;
            SpawnNewSymbol();
        }

        foreach (GameObject symbol in activeSymbols) {
            RectTransform rectTransform = symbol.GetComponent<RectTransform>();
            rectTransform.localPosition = new Vector3(rectTransform.localPosition.x + Time.deltaTime * moveSpeed, trackY, 0);
        }
    }

    /// <summary>
    /// Destroy the oldest symbol on the track
    /// </summary>
    void DestroyRightmostSymbol() {
        activeWords.RemoveAt(0);
        GameObject symbol = activeSymbols[0];
        activeSymbols.RemoveAt(0);
        Destroy(symbol);
    }

    /// <summary>
    /// Find the chosen theme by its name
    /// </summary>
    /// <param name="themeName">The name of the theme to find</param>
    /// <returns>The requested theme</returns>
    private Theme FindThemeByName(string themeName)
    {
        int themeIndex = 0;

        while (themeIndex < themeList.themes.Length)
        {
            Theme theme = themeList.themes[themeIndex];
            if (theme.name == themeName)
            {
                return theme;
            }
            themeIndex++;
        }

        Debug.Log("Requested theme not found");
        return null;
    }

    /// <summary>
    /// Create a new symbol at the start of the track
    /// </summary>
    void SpawnNewSymbol() {
        string nextSymbol = words[UnityEngine.Random.Range(0, words.Length)];

        GameObject newSymbolObject = new GameObject("Symbol");
        Image newImage = newSymbolObject.AddComponent<Image>();
        RectTransform rectTransform = newSymbolObject.GetComponent<RectTransform>();
        rectTransform.SetParent(canvas.transform, false); // Set the parent to the Canvas
        rectTransform.localPosition = new Vector3(trackX, trackY, 0);
        rectTransform.sizeDelta = new Vector2(symbolSize, symbolSize);

        Sprite sprite = Resources.Load<Sprite>("Common/Images/" + nextSymbol);

        // Set the new sprite as the Image component's source image
        newImage.sprite = sprite;

        activeWords.Add(nextSymbol);
        activeSymbols.Add(newSymbolObject);
    }
}