using System;
using System.Net;
using GitCommands;
using GitUIPluginInterfaces;

namespace ResourceManager.CommitDataRenders
{
    /// <summary>
    /// Provides the ability to render the body of a commit message.
    /// </summary>
    public interface ICommitDataBodyRenderer
    {
        /// <summary>
        /// Render the body of a commit message.
        /// </summary>
        string Render(CommitData commitData, bool showRevisionsAsLinks);
    }

    /// <summary>
    /// Renders the body of a commit message.
    /// </summary>
    public sealed class CommitDataBodyRenderer : ICommitDataBodyRenderer
    {
        private readonly Func<IGitModule> _getModule;
        private readonly ILinkFactory _linkFactory;

        public CommitDataBodyRenderer(Func<IGitModule> getModule, ILinkFactory linkFactory)
        {
            _getModule = getModule;
            _linkFactory = linkFactory;
        }

        /// <summary>
        /// Render the body of a commit message.
        /// </summary>
        public string Render(CommitData commitData, bool showRevisionsAsLinks)
        {
            if (commitData == null)
            {
                throw new ArgumentNullException(nameof(commitData));
            }

            var body = "\n" + WebUtility.HtmlEncode((commitData.Body ?? "").Trim());

            if (showRevisionsAsLinks)
            {
                body = GitRevision.Sha1HashShortRegex.Replace(body, match => ProcessHashCandidate(match.Value));
            }

            return body;
        }

        private string ProcessHashCandidate(string hash)
        {
            var module = _getModule();

            if (module == null)
            {
                return hash;
            }

            if (!module.TryResolvePartialCommitId(hash, out var fullHash))
            {
                return hash;
            }

            return _linkFactory.CreateCommitLink(fullHash, hash, true);
        }
    }
}