using System.Collections.Generic;
using System.Linq;
using System.Text;
using LibGit2Sharp.Core;

namespace LibGit2Sharp
{
    /// <summary>
    /// Provides methods to manage the rules ensuring that some specific
    /// untracked files are ignored.
    /// </summary>
    public class Ignore
    {
        private readonly Repository repo;

        /// <summary>
        /// Needed for mocking purposes.
        /// </summary>
        protected Ignore()
        { }

        internal Ignore(Repository repo)
        {
            this.repo = repo;
        }

        /// <summary>
        /// Adds a custom .gitignore rule that will be applied to futher operations to the Index. This is in addition
        /// to the standard .gitignore rules that would apply as a result of the system/user/repo .gitignore
        /// </summary>
        /// <param name="rules">The content of a .gitignore file that will be applied.</param>
        public virtual void AddTemporaryRules(IEnumerable<string> rules)
        {
            Ensure.ArgumentNotNull(rules, "rules");

            var allRules = rules.Aggregate(new StringBuilder(), (acc, x) =>
            {
                acc.Append(x);
                acc.Append("\n");
                return acc;
            });

            Proxy.git_ignore_add_rule(repo.Handle, allRules.ToString());
        }

        /// <summary>
        /// Resets all custom rules that were applied via calls to
        /// <see cref="AddTemporaryRules"/> - note that this will not affect
        /// the application of the user/repo .gitignores.
        /// </summary>
        public virtual void ResetAllTemporaryRules()
        {
            Proxy.git_ignore_clear_internal_rules(repo.Handle);
        }

        /// <summary>
        ///  Given a relative path, this method determines whether a path should be ignored, checking
        ///  both the custom ignore rules as well as the "normal" .gitignores.
        /// </summary>
        /// <param name="relativePath">A path relative to the repository</param>
        /// <returns>true if the path should be ignored.</returns>
        public virtual bool IsPathIgnored(string relativePath)
        {
            Ensure.ArgumentNotNullOrEmptyString(relativePath, "relativePath");

            return Proxy.git_ignore_path_is_ignored(repo.Handle, relativePath);
        }
    }
}