using System;

namespace SpectacleTransformer {
    public abstract class TranslationRequest {
        public readonly Uri InstanceUri;
        public readonly Language Source;
        public readonly Language Target;
        public readonly string Text;

        /// <summary>
        /// Create a new translation request.
        /// </summary>
        /// <param name="InstanceUri">URI pointing to the server instance to use.</param>
        /// <param name="Source">The source language.</param>
        /// <param name="Target">The target language.</param>
        /// <param name="Text">The text to translate.</param>
        public TranslationRequest(Uri InstanceUri, Language Source, Language Target, string Text) {
            if (Source.Equals(Target)) throw new ArgumentException("The source and target languages cannot be the same.");
            this.InstanceUri = InstanceUri;
            this.Source = Source;
            this.Target = Target;
            this.Text = Text;
        }

        /// <summary>
        /// Determines if this TranslationRequest can be instanciated with an instance URI.
        /// </summary>
        /// <param name="InstanceUri">The instance URI to check.</param>
        /// <returns>Whether this translation request can be performed on this instance URI.</returns>
        public static bool MatchesInstance(Uri InstanceUri) {
            return true;
        }

        /// <summary>
        /// Perform a translation request.
        /// </summary>
        /// <returns>The translated text, or null if the translation failed.</returns>
        public abstract string Run();

        /// <summary>
        /// Called in the main thread with UI controls to allow further post-processing that could require them.
        /// </summary>
        /// <param name="response">The response returned by Run().</param>
        /// <returns>A processed response.</returns>
        public virtual string PostProcess(string response) {
            return response;
        }
    }
}