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

/// <summary>
/// Class to handle panel with multiple choice options
/// </summary>
public class PanelMultipleChoice : MonoBehaviour
{
    /// <summary>
    /// Reference to the webcam screen
    /// </summary>
    public RawImage webcamScreen;

    /// <summary>
    /// Video 'play' sprite
    /// </summary>
    public Sprite playSprite;

    /// <summary>
    /// Video 'pause' sprite
    /// </summary>
    public Sprite pauseSprite;

    /// <summary>
    /// Reference to its course controller to be able to go to call NextSignMultipleChoice to go to the next panel
    /// </summary>
    public CoursesController courseController;

    /// <summary>
    /// Reference to instructional video player
    /// </summary>
    public VideoPlayer videoPlayer;

    /// <summary>
    /// Refrence to the video play/pause button
    /// </summary>
    public Image playButton;

    /// <summary>
    /// Reference to the image for displaying the current words sprite
    /// </summary>
    public Transform optionContainer;

    /// <summary>
    /// Reference to the image for displaying the current words sprite, for a fingerspelling courses
    /// </summary>
    public Transform optionFingerspellingContainer;

    /// <summary>
    /// Reference to the option prefab
    /// </summary>
    public GameObject optionPrefab;

    /// <summary>
    /// Reference to the option prefab, for a fingerspelling course
    /// </summary>
    public GameObject optionFingerspellingPrefab;

    /// <summary>
    /// Reference to the saved progress
    /// </summary>
    public PersistentDataController.SavedCourseProgress progress;

    /// <summary>
    /// The current sign that will be displayed
    /// </summary>
    private Learnable currentSign;

    /// <summary>
    /// Reference to all signs in this course
    /// </summary>
    public List<Learnable> signs;

    /// <summary>
    /// Index of the current sign
    /// </summary>
    public int currentSignIndex;

    /// <summary>
    /// Boolean used to check whether the current course is a fingerspelling course
    /// </summary>
    public bool isFingerSpelling;

    /// <summary>
    /// Boolean used to check whether the user has already answered the question
    /// </summary>
    private bool hasAnswered = false;

    /// <summary>
    /// Get a list of wrongs answers
    /// </summary>
    /// <param name="notThisIndex">The index of the correct sign</param>
    /// <returns></returns>
    public List<Learnable> GetWrongOptions(int notThisIndex)
    {
        var test = progress.learnables.FindAll((l) => l.index != notThisIndex && l.inUse);

        for (int i = test.Count - 1; i > 0; i--)
        {
            // Generate a random index between 0 and i (inclusive)
            int j = UnityEngine.Random.Range(0, i + 1);

            // Swap the values at indices i and j
            (test[j], test[i]) = (test[i], test[j]);
        }

        List<Learnable> randomSigns = new List<Learnable>();
        foreach (var sign in test.Take(3))
        {
            randomSigns.Add(signs[sign.index]);
        }

        return randomSigns;
    }

    /// <summary>
    /// Update the display of this panel
    /// </summary>
    public void Display()
    {
        currentSign = signs[currentSignIndex];
        videoPlayer.aspectRatio = VideoAspectRatio.FitInside;
        videoPlayer.clip = currentSign.clip;
        videoPlayer.Play();
        // Gets three random selected signs from the list signs which are not equal to currentSign
        List<Learnable> allOptions = GetWrongOptions(currentSignIndex);

        // Add the correct sign at a random position in the list of all options
        int randomIndex = UnityEngine.Random.Range(0, allOptions.Count + 1);
        allOptions.Insert(randomIndex, currentSign);

        var prefab = isFingerSpelling ? optionFingerspellingPrefab : optionPrefab;
        var container = isFingerSpelling ? optionFingerspellingContainer : optionContainer;
        foreach (Learnable option in allOptions)
        {
            GameObject multipleChoiceOption = GameObject.Instantiate(prefab, container);
            if (!isFingerSpelling)
                multipleChoiceOption.transform.Find("TextOption").GetComponent<TMP_Text>().text = option.name;
            multipleChoiceOption.transform.Find("ImageOption").GetComponent<Image>().sprite = option.image;

            Button button = multipleChoiceOption.GetComponent<Button>();
            button.onClick.AddListener(() =>
            {
                if (!hasAnswered)
                {
                    courseController.NextSignMultipleChoice(currentSign.name, option.name);
                    ShowAnswers(option.name);
                    hasAnswered = true;
                }
            });
        }
    }

    /// <summary>
    /// Show the asnwers
    /// </summary>
    /// <param name="answerName">The name of the clicked sign</param>
    public void ShowAnswers(string answerName)
    {
        if (answerName == currentSign.name)
        {
            courseController.courseTitle.text = "Correct!";
        }
        else
        {
            courseController.courseTitle.text = "Spijtig, fout";
        }

        var container = isFingerSpelling ? optionFingerspellingContainer : optionContainer;
        for (int i = 0; i < container.childCount; i++)
        {
            // Get the i-th child object
            Transform childTransform = container.GetChild(i);

            // Change the background color of the Button
            Color col = new Color(0xf5 / 255.0f, 0x49 / 255.0f, 0x3d / 255.0f);
            if (childTransform.Find("ImageOption").GetComponent<Image>().sprite == currentSign.image)
            {
                col = new Color(0x8b / 255.0f, 0xd4 / 255.0f, 0x5e / 255.0f);
            }
            childTransform.GetComponent<Image>().color = col;
        }
        StartCoroutine(GoToNextScreen());
    }

    /// <summary>
    /// Wait and go to the next sign
    /// </summary>
    /// <returns></returns>
    private IEnumerator GoToNextScreen()
    {
        // Wait for 5 seconds
        yield return new WaitForSeconds(1.5f);
        courseController.NextSign();
    }

    /// <summary>
    /// This function is called when the pause-button is pressed on the video.
    /// It switches between playing and pausing the video.
    /// It then makes the button invisible when the video is playing, or visible when it's paused.
    /// </summary>
    public void TogglePlayPause()
    {
        if (!videoPlayer.isPlaying)
        {
            // Play video and switch sprite of button
            playButton.sprite = pauseSprite;
            videoPlayer.Play();
        }
        else
        {
            // Pause video and and switch sprite of button
            playButton.sprite = playSprite;
            videoPlayer.Pause();
        }
    }
}