using System;
using UnityEngine;

namespace GamecraftModdingAPI.Interface.IMGUI
{
    /// <summary>
    /// A text input field.
    /// This wraps Unity's IMGUI TextField and TextArea.
    /// </summary>
    public class Text : UIElement
    {
        private bool automaticLayout;

        /// <summary>
        /// Whether the text input field is multiline (true -> TextArea) or not (false -> TextField).
        /// </summary>
        public bool Multiline { get; set; }

        private string text;
        
        /// <summary>
        /// The rectangular area that the text field can use.
        /// </summary>
        public Rect Box { get; set; } = Rect.zero;

        /// <summary>
        /// An event that fires whenever the text input is edited.
        /// </summary>
        public event EventHandler<string> OnEdit;
        
        public void OnGUI()
        {
            string editedText = null;
            if (automaticLayout)
            {
                if (Multiline)
                {
                    editedText = GUILayout.TextArea(text, Constants.Default.textArea);
                }
                else
                {
                    editedText = GUILayout.TextField(text, Constants.Default.textField);
                }
            }
            else
            {
                if (Multiline)
                {
                    editedText = GUI.TextArea(Box, text, Constants.Default.textArea);
                }
                else
                {
                    editedText = GUI.TextField(Box, text, Constants.Default.textField);
                }
            }

            if (editedText != null && editedText != text)
            {
                OnEdit?.Invoke(this, editedText);
                text = editedText;
            }
        }

        /// <summary>
        /// The text field's unique name.
        /// </summary>
        public string Name { get; }
        
        /// <summary>
        /// Whether to display the text field.
        /// </summary>
        public bool Enabled { set; get; } = true;

        /// <summary>
        /// Initialize the text input field with automatic layout.
        /// </summary>
        /// <param name="initialText">Initial text in the input field.</param>
        /// <param name="name">The text field's name.</param>
        /// <param name="multiline">Allow multiple lines?</param>
        public Text(string initialText = null, string name = null, bool multiline = false)
        {
            this.Multiline = multiline;
            automaticLayout = true;
            text = initialText ?? "";
            if (name == null)
            {
                this.Name = typeof(Text).FullName + "::" + text;
            }
            else
            {
                this.Name = name;
            }
            IMGUIManager.AddElement(this);
        }

        /// <summary>
        /// Initialize the text input field.
        /// </summary>
        /// <param name="box">Rectangular area for the text field.</param>
        /// <param name="initialText">Initial text in the input field.</param>
        /// <param name="name">The text field's name.</param>
        /// <param name="multiline">Allow multiple lines?</param>
        public Text(Rect box, string initialText = null, string name = null, bool multiline = false) : this(initialText, name, multiline)
        {
            this.Box = box;
            automaticLayout = false;
        }
    }
}