using System;
using System.Linq;
using System.Xml.Linq;

namespace Unosquare.Swan.Components
{
    /// <summary>
    /// Represents a CsProj metadata abstract class
    /// to use with <c>CsProjFile</c> parser.
    /// </summary>
    public abstract class CsProjMetadataBase
    {
        private XDocument _xmlDocument;

        /// <summary>
        /// Gets the package identifier.
        /// </summary>
        /// <value>
        /// The package identifier.
        /// </value>
        public String PackageId => this.FindElement(nameof(this.PackageId))?.Value;

        /// <summary>
        /// Gets the name of the assembly.
        /// </summary>
        /// <value>
        /// The name of the assembly.
        /// </value>
        public String AssemblyName => this.FindElement(nameof(this.AssemblyName))?.Value;

        /// <summary>
        /// Gets the target frameworks.
        /// </summary>
        /// <value>
        /// The target frameworks.
        /// </value>
        public String TargetFrameworks => this.FindElement(nameof(this.TargetFrameworks))?.Value;

        /// <summary>
        /// Gets the target framework.
        /// </summary>
        /// <value>
        /// The target framework.
        /// </value>
        public String TargetFramework => this.FindElement(nameof(this.TargetFramework))?.Value;

        /// <summary>
        /// Gets the version.
        /// </summary>
        /// <value>
        /// The version.
        /// </value>
        public String Version => this.FindElement(nameof(this.Version))?.Value;

        /// <summary>
        /// Parses the cs proj tags.
        /// </summary>
        /// <param name="args">The arguments.</param>
        public abstract void ParseCsProjTags(ref String[] args);

        /// <summary>
        /// Sets the data.
        /// </summary>
        /// <param name="xmlDocument">The XML document.</param>
        public void SetData(XDocument xmlDocument) => this._xmlDocument = xmlDocument;

        /// <summary>
        /// Finds the element.
        /// </summary>
        /// <param name="elementName">Name of the element.</param>
        /// <returns>A XElement.</returns>
        protected XElement FindElement(String elementName) => this._xmlDocument.Descendants(elementName).FirstOrDefault();
    }
}