using Cysharp.Threading.Tasks;
using System;
using System.Collections.Generic;
using System.Threading;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

public class Instruction : MonoBehaviour
{
    [Header("Exit progress")]
    [SerializeField] private CanvasGroup progressGroup;
    [SerializeField] private Image bar;
    private bool groupVisible = false;
    private float progress;
    private CancellationTokenSource exitBarCts;

    [Header("Instruction")]
    [SerializeField] TextMeshProUGUI instructionLabel;
    [SerializeField] CanvasGroup UpLeft, UpRight, DownLeft, DownRight, LabelCG;
    [SerializeField] List<InstructionBlock> instructions;
    private CancellationTokenSource instructionCts;
    private Dictionary<InSignal, CanvasGroup> buttons;

    public void SetProgress(float percent) => progress = percent;

    public void Init()
    {
        buttons = new()
        {
            [InSignal.UpLeft] = UpLeft,
            [InSignal.UpRight] = UpRight,
            [InSignal.DownLeft] = DownLeft,
            [InSignal.DownRight] = DownRight
        };

        instructionCts = new();
        StartInstructionsSequence(instructionCts.Token).Forget();

        SetProgress(0);
    }

    private void Update()
    {
        ProgressBarProcess();
    }

    private void OnDestroy()
    {
        instructionCts?.Cancel();
        instructionCts?.Dispose();

        exitBarCts?.Cancel();
        exitBarCts?.Dispose();
    }

    private void ProgressBarProcess()
    {
        if (!groupVisible && progress > 0)
        {
            exitBarCts?.Cancel();
            exitBarCts?.Dispose();
            exitBarCts = new();

            SetVisibility(true, exitBarCts.Token).Forget();
        }
        if (groupVisible && progress == 0)
        {
            exitBarCts?.Cancel();
            exitBarCts?.Dispose();
            exitBarCts = new();

            SetVisibility(false, exitBarCts.Token).Forget();
        }

        bar.fillAmount = progress;
    }

    private async UniTask SetVisibility(bool visible, CancellationToken token)
    {
        float targetAlpha = visible ? 1 : 0;
        groupVisible = visible;

        while (progressGroup.alpha != targetAlpha && !token.IsCancellationRequested)
        {
            progressGroup.alpha = Mathf.MoveTowards(progressGroup.alpha, targetAlpha, Time.deltaTime);
            await UniTask.Yield(PlayerLoopTiming.Update, token);
        }
    }

    private async UniTask StartInstructionsSequence(CancellationToken token)
    {
        if (instructions == null) return;
        if (instructions.Count == 0) return;

        int instructionIndex = 0;
        while (!token.IsCancellationRequested)
        {
            await ShowInstruction(instructions[instructionIndex], token);
            instructionIndex = (instructionIndex + 1) % instructions.Count;
        }
    }

    private async UniTask ShowInstruction(InstructionBlock instruction, CancellationToken token)
    {
        HideInstruction();
        instructionLabel.text = instruction.text;


        float t = 0;
        //Зажигаем
        while (!token.IsCancellationRequested && t < 1)
        {
            t += Time.deltaTime;
            t = Mathf.Min(t, 1);

            foreach (var signal in instruction.signals)
                buttons[signal].alpha = t;
            LabelCG.alpha = t;

            await UniTask.Yield(token);
        }

        await UniTask.Delay(1000, cancellationToken: token);
        t = 0;

        //Тушим
        while (!token.IsCancellationRequested && t < 1)
        {
            t += Time.deltaTime;
            t = Mathf.Min(t, 1);

            float oneMinus = 1 - t;
            foreach (var signal in instruction.signals)
                buttons[signal].alpha = oneMinus;
            LabelCG.alpha = oneMinus;

            await UniTask.Yield(token);
        }
    }

    private void HideInstruction()
    {
        UpLeft.alpha = 0;
        UpRight.alpha = 0;
        DownLeft.alpha = 0;
        DownRight.alpha = 0;

        LabelCG.alpha = 0;
    }

    [Serializable]
    private class InstructionBlock
    {
        public List<InSignal> signals;
        [TextArea] public string text;
    }
}