using AppKit;
using Foundation;

namespace Cauldron.Macos.SourceWriter;

public class FormatDescriptor : NSObject
{
	#region Computed Properties

	/// <summary>Gets or sets the <c>FormatDescriptorType</c> for this format descriptor.</summary>
	/// <value>The <c>FormatDescriptorType</c>.</value>
	public FormatDescriptorType Type { get; set; } = FormatDescriptorType.Prefix;

	/// <summary>
	/// Gets or sets the forground color that text matching this format will be set to.
	/// </summary>
	/// <value>The <c>NSColor</c>.</value>
	public NSColor Color { get; set; } = NSColor.Gray;

	/// <summary>Gets or sets the character sequence that this format starts with.</summary>
	/// <value>The starting <c>string</c> sequence.</value>
	public string StartsWith { get; set; } = "";

	/// <summary>
	/// Gets or sets the character sequence that text matching this format ends with.
	/// </summary>
	/// <value>The ending <c>string</c> sequence.</value>
	/// <remarks>
	/// This value will be an empty string ("") if the <c>Type</c> is a <c>Prefix</c> format.
	/// </remarks>
	public string EndsWith { get; set; } = "";

	/// <summary>
	/// Gets or sets the index of the last matching character within either the <c>StartsWith</c> or
	/// <c>EndsWith</c> based on the state of the <c>Active</c> property.
	/// </summary>
	/// <value>The index of the char.</value>
	/// <remarks>
	/// This value should ONLY be changed by the <see cref="\LanguageFormatter"/>.
	/// </remarks>
	public int CharIndex { get; set; } = 0;

	/// <summary>
	/// Gets or sets if this format has been "activated" (if the matching <c>StartsWith</c> character sequence
	/// has been found).
	/// </summary>
	/// <value><c>true</c> if the matching <c>StartsWith</c> character sequence
	/// has been found; otherwise, <c>false</c>.</value>
	/// <remarks>
	/// This value should ONLY be changed by the <see cref="LanguageFormatter"/>.
	/// </remarks>
	public bool Active { get; set; } = false;

	/// <summary>
	/// Gets a value indicating whether this <see cref="FormatDescriptor"/> is "triggered"
	/// (all of the <c>StartsWith</c> or <c>EndsWith</c> characters have been found based on the
	/// <c>Active</c> property).
	/// </summary>
	/// <value><c>true</c> if triggered; otherwise, <c>false</c>.</value>
	public bool Triggered
	{
		get
		{
			if (Active)
			{
				return CharIndex > (EndsWith.Length - 1);
			}
			else
			{
				return CharIndex > (StartsWith.Length - 1);
			}
		}
	}

	#endregion

	#region Constructors

	/// <summary>Initializes a new instance of the <see cref="FormatDescriptor"/> class.</summary>
	/// <param name="startsWith">The starting character sequence for this format.</param>
	/// <param name="color">The <c>NSColor</c> that text in this sequence will be set too.</param>
	/// <remarks>The <c>type</c> will automatically be set to <c>Prefix</c>.</remarks>
	public FormatDescriptor(string startsWith, NSColor color)
	{
		this.Type = FormatDescriptorType.Prefix;
		this.StartsWith = startsWith;
		this.Color = color;
	}

	/// <summary>Initializes a new instance of the <see cref="FormatDescriptor"/> class.</summary>
	/// <param name="startsWith">The starting character sequence for this format.</param>
	/// <param name="endsWith">The ending character sequence for this format.</param>
	/// <param name="color">The <c>NSColor</c> that text in this sequence will be set too.</param>
	/// <remarks>The <c>type</c> will automatically be set to <c>Enclosure</c>.</remarks>
	public FormatDescriptor(string startsWith, string endsWith, NSColor color)
	{
		this.Type = FormatDescriptorType.Enclosure;
		this.StartsWith = startsWith;
		this.EndsWith = endsWith;
		this.Color = color;
	}
	#endregion

	#region Public Methods

	/// <summary>
	/// Tests to see if the passed in character matches the character at <c>CharIndex</c> of
	/// either the <c>StartsWith</c> or <c>EndsWith</c> character sequence based on the state
	/// of the <c>Active</c> property.
	/// </summary>
	/// <returns><c>true</c>, if character was matched, <c>false</c> otherwise.</returns>
	/// <param name="c">The character being tested.</param>
	public bool MatchesCharacter(char c)
	{
		bool matches;

		// Is this format currently active?
		if (Active)
		{
			matches = c == EndsWith[CharIndex];
		}
		else
		{
			matches = (c == StartsWith[CharIndex]);
		}

		// Increment
		if (matches)
		{
			++CharIndex;
		}

		return matches;
	}

	#endregion
}