using System;
using System.Collections.Generic;
using UnityEngine;

namespace AibisDream.UI.Terminal
{
    public enum TerminalPage
    {
        None,
        Start,
        Setting,
        Chapter,
        Record
    }

    public enum TerminalOpenSource
    {
        None,
        MainMenu,
        InGame
    }

    public class TerminalPanel : MonoBehaviour, IUIPanel
    {
        [SerializeField] private TerminalHeaderView header;
        [SerializeField] private TerminalStartPanel startPage;
        [SerializeField] private TerminalSettingPanel settingPage;
        [SerializeField] private TerminalChapterPanel chapterPage;
        [SerializeField] private TerminalRecordPanel recordPage;

        private readonly Stack<TerminalPage> _backStack = new();
        private TerminalPage _currentPage = TerminalPage.None;
        private TerminalOpenSource _source = TerminalOpenSource.None;
        private bool _pausedByTerminal;

        public bool IsOpen => gameObject.activeSelf && _currentPage != TerminalPage.None;
        public bool IsCloseable => _source == TerminalOpenSource.InGame;
        public TerminalPage CurrentPage => _currentPage;
        public TerminalOpenSource Source => _source;

        public void Initialize(RectTransform searchRoot)
        {
            startPage ??= searchRoot.GetComponentInChildren<TerminalStartPanel>(true);
            settingPage ??= searchRoot.GetComponentInChildren<TerminalSettingPanel>(true);
            chapterPage ??= searchRoot.GetComponentInChildren<TerminalChapterPanel>(true);
            recordPage ??= searchRoot.GetComponentInChildren<TerminalRecordPanel>(true);

            startPage?.SetOwner(this);
            settingPage?.SetOwner(this);
            chapterPage?.SetOwner(this);
            recordPage?.SetOwner(this);
            Close();
        }

        public bool HasRequiredPages()
        {
            return startPage != null && settingPage != null && chapterPage != null && recordPage != null;
        }

        public void Show()
        {
            Open(TerminalPage.Start, TerminalOpenSource.MainMenu);
        }

        public void Hide()
        {
            Close();
        }

        public void Open(TerminalPage page, TerminalOpenSource source)
        {
            if (!HasRequiredPages())
            {
                return;
            }

            if (!IsOpen || _source != source)
            {
                _backStack.Clear();
            }

            gameObject.SetActive(true);
            _source = source;
            PauseIfNeeded(page, source);
            SwitchTo(page, pushCurrent: false);
        }

        public void SwitchTo(TerminalPage page, bool pushCurrent = true)
        {
            if (page == TerminalPage.None || page == _currentPage)
            {
                return;
            }

            if (pushCurrent && _currentPage != TerminalPage.None)
            {
                _backStack.Push(_currentPage);
            }

            HidePage(_currentPage);
            _currentPage = page;
            ShowPage(_currentPage);
        }

        public void Back()
        {
            if (_source == TerminalOpenSource.InGame)
            {
                Close();
                return;
            }

            if (_backStack.Count > 0)
            {
                var previous = _backStack.Pop();
                HidePage(_currentPage);
                _currentPage = previous;
                ShowPage(_currentPage);
                return;
            }

            if (_currentPage != TerminalPage.Start)
            {
                SwitchTo(TerminalPage.Start, pushCurrent: false);
            }
        }

        public bool HandleEscape()
        {
            if (!IsOpen)
            {
                return false;
            }

            if (_currentPage == TerminalPage.Start)
            {
                return true;
            }

            Back();
            return true;
        }

        public void CloseThen(Action action)
        {
            Close();
            action?.Invoke();
        }

        public void Close()
        {
            HideAllPages();
            _backStack.Clear();
            _currentPage = TerminalPage.None;
            _source = TerminalOpenSource.None;
            ContinueIfPaused();
            gameObject.SetActive(false);
        }

        public void CloseToMainMenu()
        {
            Close();
            GameManager.Instance.QuitGame();
        }

        public void AppendDialogLine(LineInfo lineInfo)
        {
            recordPage?.AppendDialogLine(lineInfo);
        }

        public void ClearDialog()
        {
            recordPage?.ClearDialog();
        }

        public void SetHeader(string title, string status = "")
        {
            header?.SetText(title, status);
        }

        private void PauseIfNeeded(TerminalPage page, TerminalOpenSource source)
        {
            if (source != TerminalOpenSource.InGame || page is not (TerminalPage.Setting or TerminalPage.Record))
            {
                return;
            }

            if (!_pausedByTerminal)
            {
                GameManager.Instance.PauseGame();
                _pausedByTerminal = true;
            }
        }

        private void ContinueIfPaused()
        {
            if (!_pausedByTerminal)
            {
                return;
            }

            GameManager.Instance.ContinueGame();
            _pausedByTerminal = false;
        }

        private void ShowPage(TerminalPage page)
        {
            switch (page)
            {
                case TerminalPage.Start:
                    startPage?.Show();
                    break;
                case TerminalPage.Setting:
                    settingPage?.Show();
                    break;
                case TerminalPage.Chapter:
                    chapterPage?.Show();
                    break;
                case TerminalPage.Record:
                    recordPage?.Show();
                    break;
            }
        }

        private void HidePage(TerminalPage page)
        {
            switch (page)
            {
                case TerminalPage.Start:
                    startPage?.Hide();
                    break;
                case TerminalPage.Setting:
                    settingPage?.Hide();
                    break;
                case TerminalPage.Chapter:
                    chapterPage?.Hide();
                    break;
                case TerminalPage.Record:
                    recordPage?.Hide();
                    break;
            }
        }

        private void HideAllPages()
        {
            startPage?.Hide();
            settingPage?.Hide();
            chapterPage?.Hide();
            recordPage?.Hide();
        }
    }
}