/*
 * Copyright 2022 Peter Han
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
 * and associated documentation files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

using PeterHan.PLib.Core;
using System;
using System.Collections.Generic;
using UnityEngine;

namespace PeterHan.PLib.UI {
	/// <summary>
	/// A custom UI panel factory which can arrange its children horizontally or vertically.
	/// </summary>
	public class PPanel : PContainer, IDynamicSizable {
		/// <summary>
		/// The alignment position to use for child elements if they are smaller than the
		/// required size.
		/// </summary>
		public TextAnchor Alignment { get; set; }

		/// <summary>
		/// The direction in which components will be laid out.
		/// </summary>
		public PanelDirection Direction { get; set; }

		public bool DynamicSize { get; set; }

		/// <summary>
		/// The spacing between components in pixels.
		/// </summary>
		public int Spacing { get; set; }

		/// <summary>
		/// The children of this panel.
		/// </summary>
		protected readonly ICollection<IUIComponent> children;

		public PPanel() : this(null) { }

		public PPanel(string name) : base(name ?? "Panel") {
			Alignment = TextAnchor.MiddleCenter;
			children = new List<IUIComponent>();
			Direction = PanelDirection.Vertical;
			DynamicSize = true;
			Spacing = 0;
		}

		/// <summary>
		/// Adds a child to this panel.
		/// </summary>
		/// <param name="child">The child to add.</param>
		/// <returns>This panel for call chaining.</returns>
		public PPanel AddChild(IUIComponent child) {
			if (child == null)
				throw new ArgumentNullException(nameof(child));
			children.Add(child);
			return this;
		}

		/// <summary>
		/// Adds a handler when this panel is realized.
		/// </summary>
		/// <param name="onRealize">The handler to invoke on realization.</param>
		/// <returns>This panel for call chaining.</returns>
		public PPanel AddOnRealize(PUIDelegates.OnRealize onRealize) {
			OnRealize += onRealize;
			return this;
		}

		public override GameObject Build() {
			return Build(default, DynamicSize);
		}

		/// <summary>
		/// Builds this panel.
		/// </summary>
		/// <param name="size">The fixed size to use if dynamic is false.</param>
		/// <param name="dynamic">Whether to use dynamic sizing.</param>
		/// <returns>The realized panel.</returns>
		private GameObject Build(Vector2 size, bool dynamic) {
			var panel = PUIElements.CreateUI(null, Name);
			SetImage(panel);
			// Add children
			foreach (var child in children) {
				var obj = child.Build();
				obj.SetParent(panel);
				PUIElements.SetAnchors(obj, PUIAnchoring.Stretch, PUIAnchoring.Stretch);
			}
			var lg = panel.AddComponent<BoxLayoutGroup>();
			lg.Params = new BoxLayoutParams() {
				Direction = Direction, Alignment = Alignment, Spacing = Spacing,
				Margin = Margin
			};
			if (!dynamic) {
				lg.LockLayout();
				panel.SetMinUISize(size);
			}
			lg.flexibleWidth = FlexSize.x;
			lg.flexibleHeight = FlexSize.y;
			InvokeRealize(panel);
			return panel;
		}

		/// <summary>
		/// Builds this panel with a given default size.
		/// </summary>
		/// <param name="size">The fixed size to use.</param>
		/// <returns>The realized panel.</returns>
		public GameObject BuildWithFixedSize(Vector2 size) {
			return Build(size, false);
		}

		/// <summary>
		/// Removes a child from this panel.
		/// </summary>
		/// <param name="child">The child to remove.</param>
		/// <returns>This panel for call chaining.</returns>
		public PPanel RemoveChild(IUIComponent child) {
			if (child == null)
				throw new ArgumentNullException(nameof(child));
			children.Remove(child);
			return this;
		}

		/// <summary>
		/// Sets the background color to the default Klei dialog blue.
		/// </summary>
		/// <returns>This panel for call chaining.</returns>
		public PPanel SetKleiBlueColor() {
			BackColor = PUITuning.Colors.ButtonBlueStyle.inactiveColor;
			return this;
		}

		/// <summary>
		/// Sets the background color to the Klei dialog header pink.
		/// </summary>
		/// <returns>This panel for call chaining.</returns>
		public PPanel SetKleiPinkColor() {
			BackColor = PUITuning.Colors.ButtonPinkStyle.inactiveColor;
			return this;
		}

		public override string ToString() {
			return string.Format("PPanel[Name={0},Direction={1}]", Name, Direction);
		}
	}

	/// <summary>
	/// The direction in which PPanel lays out components.
	/// </summary>
	public enum PanelDirection {
		Horizontal, Vertical
	}
}