using LibGit2Sharp.Core;

namespace LibGit2Sharp
{
    /// <summary>
    /// Provides helper overloads to a <see cref="BranchCollection"/>.
    /// </summary>
    public static class BranchCollectionExtensions
    {
        /// <summary>
        /// Create a new local branch with the specified name, using the default reflog message
        /// </summary>
        /// <param name="name">The name of the branch.</param>
        /// <param name="committish">Revparse spec for the target commit.</param>
        /// <param name="allowOverwrite">True to allow silent overwriting a potentially existing branch, false otherwise.</param>
        /// <param name="branches">The <see cref="BranchCollection"/> being worked with.</param>
        /// <returns>A new <see cref="Branch"/>.</returns>
        public static Branch Add(this BranchCollection branches, string name, string committish, bool allowOverwrite = false)
        {
            return Add(branches, name, committish, null, null, allowOverwrite);
        }

        /// <summary>
        /// Create a new local branch with the specified name
        /// </summary>
        /// <param name="branches">The <see cref="BranchCollection"/> being worked with.</param>
        /// <param name="name">The name of the branch.</param>
        /// <param name="committish">Revparse spec for the target commit.</param>
        /// <param name="signature">The identity used for updating the reflog</param>
        /// <param name="logMessage">The optional message to log in the <see cref="ReflogCollection"/></param>
        /// <param name="allowOverwrite">True to allow silent overwriting a potentially existing branch, false otherwise.</param>
        /// <returns>A new <see cref="Branch"/>.</returns>
        public static Branch Add(this BranchCollection branches, string name, string committish, Signature signature,
            string logMessage = null, bool allowOverwrite = false)
        {
            Ensure.ArgumentNotNullOrEmptyString(name, "name");
            Ensure.ArgumentNotNullOrEmptyString(committish, "committish");

            var commit = branches.repo.LookupCommit(committish);

            if (logMessage == null)
            {
                var createdFrom = committish != "HEAD"
                    ? committish
                    : branches.repo.Info.IsHeadDetached
                        ? commit.Sha
                        : branches.repo.Head.Name;

                logMessage = "branch: Created from " + createdFrom;
            }

            return branches.Add(name, commit, signature, logMessage, allowOverwrite);
        }

        /// <summary>
        /// Deletes the branch with the specified name.
        /// </summary>
        /// <param name="name">The name of the branch to delete.</param>
        /// <param name="isRemote">True if the provided <paramref name="name"/> is the name of a remote branch, false otherwise.</param>
        /// <param name="branches">The <see cref="BranchCollection"/> being worked with.</param>
        public static void Remove(this BranchCollection branches, string name, bool isRemote = false)
        {
            Ensure.ArgumentNotNullOrEmptyString(name, "name");

            string branchName = isRemote ? Reference.RemoteTrackingBranchPrefix + name : name;

            Branch branch = branches[branchName];

            if (branch == null)
            {
                return;
            }

            branches.Remove(branch);
        }

        /// <summary>
        /// Rename an existing local branch, using the default reflog message
        /// </summary>
        /// <param name="currentName">The current branch name.</param>
        /// <param name="newName">The new name the existing branch should bear.</param>
        /// <param name="allowOverwrite">True to allow silent overwriting a potentially existing branch, false otherwise.</param>
        /// <param name="branches">The <see cref="BranchCollection"/> being worked with.</param>
        /// <returns>A new <see cref="Branch"/>.</returns>
        public static Branch Move(this BranchCollection branches, string currentName, string newName, bool allowOverwrite = false)
        {
            Ensure.ArgumentNotNullOrEmptyString(currentName, "currentName");
            Ensure.ArgumentNotNullOrEmptyString(newName, "newName");

            Branch branch = branches[currentName];

            if (branch == null)
            {
                throw new LibGit2SharpException("No branch named '{0}' exists in the repository.");
            }

            return branches.Move(branch, newName, allowOverwrite);
        }
    }
}