using System.Collections.Generic;
using System;
using System.Collections;
using UnityEngine;
using UnityEngine.InputSystem;
using UnityEngine.EventSystems;
using NeonTea.Quakeball.Player;
using TMPro;

namespace NeonTea.Quakeball.Interface {
    public class Terminal : MonoBehaviour {

        public RectTransform TerminalPanel;
        public TMP_InputField InputField;
        public TMP_Text TextField;
        public LocalPlayer Player;

        private InputAction ToggleTerminalAction;
        private InputAction SubmitTerminal;
        private float DesiredTerminalPos;
        private bool IsOpen = false;

        private Dictionary<string, Func<string[], bool>> Commands = new Dictionary<string, Func<string[], bool>>();

        private List<string> Messages = new List<string>();
        private string Text = "";
        private List<string> PreviousRuns = new List<string>();
        private int CurrentScroll = -1;
        private bool JustScrolled = false;

        public static string INFO_COLOR = "#FE8";
        public static string ERROR_COLOR = "#F33";

        void Start() {
            ToggleTerminalAction = new InputAction("Toggle Terminal", binding: "<Keyboard>/backquote");
            ToggleTerminalAction.Enable();
            ToggleTerminalAction.performed += ToggleTerminal;
            SubmitTerminal = new InputAction("Terminal Submit", binding: "<Keyboard>/enter");
            SubmitTerminal.Enable();
            SubmitTerminal.performed += Submit;
            SubmitTerminal = new InputAction("Terminal ScrollUp", binding: "<Keyboard>/uparrow");
            SubmitTerminal.Enable();
            SubmitTerminal.performed += _ => { Scroll(1); };
            SubmitTerminal = new InputAction("Terminal ScrollDown", binding: "<Keyboard>/downarrow");
            SubmitTerminal.Enable();
            SubmitTerminal.performed += _ => { Scroll(-1); };

            DesiredTerminalPos = (TerminalPanel.rect.height / 2) * (IsOpen ? -1 : 1);

            InputField.restoreOriginalTextOnEscape = false;
            InputField.onValueChanged.AddListener(_ => {
                if (JustScrolled) {
                    JustScrolled = false;
                    return;
                }
                CurrentScroll = -1;
            });

            AddMessage($"<color={INFO_COLOR}>Welcome to Quakeball!</color>");
        }

        public void ToggleTerminal(InputAction.CallbackContext context) {
            IsOpen = !IsOpen;
            DesiredTerminalPos = (TerminalPanel.rect.height / 2) * (IsOpen ? -1 : 1);
            if (IsOpen) {
                InputField.text = "";
            }
            InputField.readOnly = true;
            if (Player != null) {
                Player.DisableInput = IsOpen;
            }
        }

        void Update() {
            Vector3 pos = TerminalPanel.anchoredPosition;
            pos.y = Mathf.Lerp(pos.y, DesiredTerminalPos, Time.deltaTime * 10);
            TerminalPanel.anchoredPosition = pos;
            if (IsOpened() && EventSystem.current.currentSelectedGameObject != InputField) {
                InputField.Select();
                InputField.ActivateInputField();
                InputField.readOnly = false;
            }
        }

        public bool RegisterCommand(string name, Func<string[], bool> command) {
            if (Commands.ContainsKey(name)) {
                return false;
            }
            Commands.Add(name, command);
            return true;
        }

        public void Run(string command) {
            string[] parts = command.Split(new char[] { ' ' });
            string name = parts[0];
            if (Commands.ContainsKey(name)) {
                Func<string[], bool> func = Commands[name];
                string[] args = new string[parts.Length - 1];
                Array.Copy(parts, 1, args, 0, parts.Length - 1);
                if (func(args)) {
                    AddMessage(command);
                } else {
                    AddMessage($"<color={ERROR_COLOR}>{command}</color>");
                }
            } else {
                AddMessage($"<color={ERROR_COLOR}>{command}</color>");
                AddMessage("No such command exists!");
            }
            PreviousRuns.Insert(0, command);
        }

        public void AddMessage(string message) {
            Messages.Add(message);
            Text = String.Join("\n", Messages.ToArray());
            TextField.text = Text;
        }

        private void Scroll(int amount) {
            if (IsOpened() && PreviousRuns.Count > 0) {
                JustScrolled = true;
                CurrentScroll = Math.Min(Math.Max(0, CurrentScroll + amount), PreviousRuns.Count - 1);
                InputField.text = PreviousRuns[CurrentScroll];
            }
        }

        private void Submit(InputAction.CallbackContext context) {
            if (IsOpened()) {
                Run(InputField.text);
                InputField.text = "";
            }
        }

        private bool IsOpened() {
            return IsOpen && (TerminalPanel.anchoredPosition.y + TerminalPanel.rect.height / 2) < 10;
        }
    }
}