using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;

namespace Octokit
{
    public class AssigneesClient : ApiClient, IAssigneesClient
    {
        /// <summary>
        /// Instantiates a new GitHub Issue Assignees API client.
        /// </summary>
        /// <param name="apiConnection">An API connection</param>
        public AssigneesClient(IApiConnection apiConnection) : base(apiConnection)
        {
        }

        /// <summary>
        /// Gets all the available assignees (owner + collaborators) to which issues may be assigned.
        /// </summary>
        /// <param name="owner">The owner of the repository</param>
        /// <param name="name">The name of the repository</param>
        /// <returns></returns>
        public Task<IReadOnlyList<User>> GetForRepository(string owner, string name)
        {
            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
            Ensure.ArgumentNotNullOrEmptyString(name, "name");

            return ApiConnection.GetAll<User>(ApiUrls.Assignees(owner, name));
        }

        /// <summary>
        /// Checks to see if a user is an assignee for a repository.
        /// </summary>
        /// <param name="owner">The owner of the repository</param>
        /// <param name="name">The name of the repository</param>
        /// <param name="assignee">Username of the prospective assignee</param>
        /// <returns></returns>
        public async Task<bool> CheckAssignee(string owner, string name, string assignee)
        {
            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
            Ensure.ArgumentNotNullOrEmptyString(name, "name");
            Ensure.ArgumentNotNullOrEmptyString(assignee, "assignee");

            try
            {
                var response = await Connection.GetAsync<object>(ApiUrls.CheckAssignee(owner, name, assignee), null, null)
                                               .ConfigureAwait(false);
                if (response.StatusCode != HttpStatusCode.NotFound && response.StatusCode != HttpStatusCode.NoContent)
                {
                    throw new ApiException("Invalid Status Code returned. Expected a 204 or a 404", response.StatusCode);
                }
                return response.StatusCode == HttpStatusCode.NoContent;
            }
            catch (NotFoundException)
            {
                return false;
            }
        }
    }
}