using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.IO;
using UnityEngine;
using UnityEngine.Video;
using TMPro;

public static class CollectionExtension
{
    private static System.Random _rng = new System.Random();

    public static T RandomElement<T>(this IList<T> list)
    {
        return list[_rng.Next(list.Count)];
    }

    public static T RandomElement<T>(this T[] array)
    {
        return array[_rng.Next(array.Length)];
    }
}

class DialogueState
{
    string _text, _flag;
    DialogueState _parent;
    private Dictionary<KeyCode, List<DialogueState>> _next;

    public void SetText(string newText)
    {
        _text = newText;
    }

    public void SetFlag(string newFlag)
    {
        _flag = newFlag;
    }

    public string GetText()
    {
        return _text;
    }

    public string GetFlag()
    {
        return _flag;
    }

    public DialogueState()
    {
        _next = new Dictionary<KeyCode, List<DialogueState>>();
        SetFlag("None");
    }

    public DialogueState(string newText)
    {
        _next = new Dictionary<KeyCode, List<DialogueState>>();
        SetText(newText);
        SetFlag("None");
    }

    public DialogueState(string newText, string newFlag)
    {
        _next = new Dictionary<KeyCode, List<DialogueState>>();
        SetText(newText);
        SetFlag(newFlag);
    }

    public void SetNextState(KeyCode key, DialogueState nextState)
    {
        if (!_next.ContainsKey(key))
            _next.Add(key, new List<DialogueState>());
        _next[key].Add(nextState);
        nextState._parent = this;
    }
    
    public DialogueState GetNextState(KeyCode key)
    {
        if (_next.ContainsKey(key))
            return _next[key].RandomElement();
        return this;
    }
}

public class TVScript : MonoBehaviour
{
	public TextMeshPro textMeshPro;
    public GameObject player;
    public GameObject cinemaPlane;
    Dictionary<int, DialogueState> _dialogueStates = new Dictionary<int, DialogueState>();
    private DialogueState _currState;

    private float _delayTimeBeforeNextInput = 0f;
    private bool _videoPlayedAtLeastOnce;

    private void ConnectStates(KeyCode key, int i, int j)
    {
        _dialogueStates[i].SetNextState(key, _dialogueStates[j]);
    }
    private void Start()
    {
        // Player
        player = GameObject.FindGameObjectsWithTag("Player")[0];

        // Initialise dialogue states
        using (StreamReader streamReader = new StreamReader("Assets/Texts/dialogues.txt"))
        {
            string line;
            for (int i = 0; (line = streamReader.ReadLine()) != null; i++)
            {
                _dialogueStates[i] = new DialogueState(line);
            }
        }
        _dialogueStates[29].SetFlag("PlayVideo");
        _dialogueStates[49].SetFlag("PlayVideoAgain");

        // Connect dialogue states
        ConnectStates(KeyCode.B, 0, 1);
        ConnectStates(KeyCode.B, 1, 2);
        
        for (int i = 2; i < 6; i++)
        {
            ConnectStates(KeyCode.Y, i, i + 1);
            ConnectStates(KeyCode.N, i, i + 1);
        }
        
        ConnectStates(KeyCode.Y, 6, 10);
        ConnectStates(KeyCode.N, 6, 7);
        
        ConnectStates(KeyCode.Y, 7, 8);
        ConnectStates(KeyCode.N, 7, 8);
        
        ConnectStates(KeyCode.Y, 8, 9);
        ConnectStates(KeyCode.N, 8, 9);
        
        ConnectStates(KeyCode.Y, 9, 6);
        ConnectStates(KeyCode.N, 9, 7);
        
        for (int i = 10; i < 29; i++)
        {
            ConnectStates(KeyCode.Y, i, i + 1);
            ConnectStates(KeyCode.N, i, i + 1);
        }
        
        ConnectStates(KeyCode.Y, 29, 35);
        ConnectStates(KeyCode.N, 33, 34);

        for (int i = 30; i < 46; i += 2)
        {
            ConnectStates(KeyCode.Y, 29, i);
            ConnectStates(KeyCode.N, 29, i);
            ConnectStates(KeyCode.Y, i, i + 1);
            ConnectStates(KeyCode.N, i, i + 1);
            ConnectStates(KeyCode.Y, i + 1, 29);
            ConnectStates(KeyCode.N, i + 1, 29);
        }

        ConnectStates(KeyCode.Y, 29, 46);
        ConnectStates(KeyCode.N, 29, 46);
        
        ConnectStates(KeyCode.Y, 46, 48);
        ConnectStates(KeyCode.N, 46, 47);
        
        ConnectStates(KeyCode.Y, 47, 29);
        ConnectStates(KeyCode.N, 47, 29);
        
        ConnectStates(KeyCode.Y, 48, 49);
        ConnectStates(KeyCode.N, 48, 47);
        
        ConnectStates(KeyCode.Y, 49, 29);
        ConnectStates(KeyCode.N, 49, 29);

        _currState = _dialogueStates[0];
        
        textMeshPro.SetText(_currState.GetText());
    }

    private void Update()
    {
        if (_currState.GetFlag() == "PlayVideoAgain")
        {
            _videoPlayedAtLeastOnce = false;
        }
        
        if (_currState.GetFlag() == "PlayVideo" && !_videoPlayedAtLeastOnce)
        {
            cinemaPlane.GetComponent<VideoPlayer>().Play();
            _videoPlayedAtLeastOnce = true;
        }

        if (cinemaPlane.GetComponent<VideoPlayer>().isPlaying)
        {
            return;
        }

        float distanceToPlayer = Vector3.Distance(player.transform.position, transform.position);
        if (distanceToPlayer > 5)
        {
            textMeshPro.SetText("...");
            return;
        }

        textMeshPro.SetText(_currState.GetText());

        if (_delayTimeBeforeNextInput > 0f)
        {
            _delayTimeBeforeNextInput -= Time.deltaTime;
            return;
        }

        if (!Input.anyKeyDown) return;

        if (!Regex.IsMatch(Input.inputString, @"^[a-zA-Z]+$")) return;

        if (Input.inputString.Length > 1) return;

        KeyCode key = (KeyCode)System.Enum.Parse(typeof(KeyCode), Input.inputString, true);
        _currState = _currState.GetNextState(key);
        textMeshPro.SetText(_currState.GetText());

        _delayTimeBeforeNextInput = 0.5f;
    }
}