using System;
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>
    /// The feedback on the timing
    /// </summary>
    public TMP_Text feedBack;

    /// <summary>
    /// The current score
    /// </summary>
    public TMP_Text scoreDisplay;

    /// <summary>
    /// The zone that the player should be hitting with his or her inputs
    /// </summary>
    public GameObject hitZone;

    /// <summary>
    /// Symbol prefab
    /// </summary>
    public GameObject symbolPrefab;

    /// <summary>
    /// Reference to symbol prefab
    /// </summary>
    public Transform symbolContainer;

    /// <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>
    /// The current score
    /// </summary>
    private int score;

    /// <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>
    /// Max distance from hit zone to get perfect score
    /// </summary>
    private int perfectBoundary = 10;

    /// <summary>
    /// Score obtained when getting a perfect hit
    /// </summary>
    private int perfectScore = 5;

    /// <summary>
    /// Max distance from hit zone to get good score
    /// </summary>
    private int goodBoundary = 120;

    /// <summary>
    /// Score obtained when getting a good hit
    /// </summary>
    private int goodScore = 3;

    /// <summary>
    /// Max distance from hit zone to get meh score
    /// </summary>
    private int mehBoundary = 200;

    /// <summary>
    /// Score obtained when getting a meh hit
    /// </summary>
    private int mehScore = 1;

    /// <summary>
    /// Score obtained when getting a terrible hit
    /// </summary>
    private int terribleScore = -3;

    /// <summary>
    /// Score obtained when symbol goes offscreen
    /// </summary>
    private int offscreenScore = -5;

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

    /// <summary>
    /// Determines every how many seconds a symbol should spawn (will become music-dependent later on)
    /// </summary>
    private float spawnPeriod = 3.0f;

    /// <summary>
    /// Start is called before the first frame update
    /// </summary>
    void Start()
    {   
        scoreDisplay.text = "Score: " + score.ToString();
        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()
    {    
        int matchedSymbolIndex = -1;
        for (int i = 0; i < activeWords.Count; i++) {
            if (activeWords[i] == answerField.text.ToLower()) {
                matchedSymbolIndex = i;
            }
        }

        // Destroy the oldest symbol if the current input matches it
        if (matchedSymbolIndex >= 0) {
            int difference = Math.Abs((int) (activeSymbols[matchedSymbolIndex].transform.position.x - hitZone.transform.position.x));
            if (difference < perfectBoundary) {
                feedBack.text = "Perfect!";
                score += perfectScore;
            } else if (difference < goodBoundary) {
                feedBack.text = "Good!";
                score += goodScore;
            } else if (difference < mehBoundary) {
                feedBack.text = "Meh...";
                score += mehScore;
            } else {
                feedBack.text = "Terrible!";
                score += terribleScore;
            }

            DestroySymbolAt(matchedSymbolIndex);
            answerField.text = "";
        }

        // Destroy the oldest symbol if it leaves the screen
        if (activeSymbols.Count > 0) {
            if (activeSymbols[0].GetComponent<RectTransform>().localPosition.x > -trackX) {
                DestroySymbolAt(0);
                score += offscreenScore;
            }
        }

        // Spawn new symbol every spawn period
        float currentTime = Time.time;
        if (currentTime - lastSpawn > spawnPeriod) {
            lastSpawn = currentTime;
            SpawnNewSymbol();
        }

        // Move all active symbols to the right
        foreach (GameObject symbol in activeSymbols) {
            RectTransform rectTransform = symbol.GetComponent<RectTransform>();
            rectTransform.localPosition = new Vector3(rectTransform.localPosition.x + Time.deltaTime * moveSpeed, trackY, 0);
        }

        scoreDisplay.text = "Score: " + score.ToString();
    }

    /// <summary>
    /// Destroy the symbol at the given index
    /// </summary>
    /// <param name="index">The index of the symbol to destroy</param>
    void DestroySymbolAt(int index) {
        activeWords.RemoveAt(index);
        GameObject symbol = activeSymbols[index];
        activeSymbols.RemoveAt(index);
        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() {
        // Pick a word that isn't in use yet
        List<int> unusedWordIndices = new List<int>();

        for (int i = 0; i < words.Length; i++) {
            if (!activeWords.Contains(words[i])) {
                unusedWordIndices.Add(i);
            }
        }

        string nextSymbol = words[unusedWordIndices[UnityEngine.Random.Range(0, unusedWordIndices.Count)]];

        GameObject newSymbolObject = GameObject.Instantiate(symbolPrefab, symbolContainer);

        // Dynamically load appearance
        Image image = newSymbolObject.GetComponent<Image>();
        Sprite sprite = Resources.Load<Sprite>("Common/Images/" + nextSymbol);
        image.sprite = sprite;
        image.rectTransform.sizeDelta = new Vector2(symbolSize, symbolSize);

        // Place the word that the symbol represents under the image
        TMP_Text text = newSymbolObject.GetComponentInChildren<TMP_Text>();
        text.text = nextSymbol;
        text.color = Color.black;
        text.rectTransform.localPosition = new Vector3(0, -160, 0);

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