using System;
using System.Collections.Generic;
using System.Linq;

namespace Spectre.Console.Cli
{
    /// <summary>
    /// An attribute representing a command option.
    /// </summary>
    /// <seealso cref="Attribute" />
    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
    public sealed class CommandOptionAttribute : Attribute
    {
        /// <summary>
        /// Gets the long names of the option.
        /// </summary>
        /// <value>The option's long names.</value>
        public IReadOnlyList<string> LongNames { get; }

        /// <summary>
        /// Gets the short names of the option.
        /// </summary>
        /// <value>The option's short names.</value>
        public IReadOnlyList<string> ShortNames { get; }

        /// <summary>
        /// Gets the value name of the option.
        /// </summary>
        /// <value>The option's value name.</value>
        public string? ValueName { get; }

        /// <summary>
        /// Gets a value indicating whether the value is optional.
        /// </summary>
        public bool ValueIsOptional { get; }

        /// <summary>
        /// Initializes a new instance of the <see cref="CommandOptionAttribute"/> class.
        /// </summary>
        /// <param name="template">The option template.</param>
        public CommandOptionAttribute(string template)
        {
            if (template == null)
            {
                throw new ArgumentNullException(nameof(template));
            }

            // Parse the option template.
            var result = TemplateParser.ParseOptionTemplate(template);

            // Assign the result.
            LongNames = result.LongNames;
            ShortNames = result.ShortNames;
            ValueName = result.Value;
            ValueIsOptional = result.ValueIsOptional;
        }

        internal bool IsMatch(string name)
        {
            return
                ShortNames.Contains(name, StringComparer.Ordinal) ||
                LongNames.Contains(name, StringComparer.Ordinal);
        }
    }
}