ISuccessOrErrors.cs

#region licence
// The MIT License (MIT)
// 
// Filename: ISuccessOrErrors.cs
// Date Created: 2014/10/28
// 
// Copyright (c) 2014 Jon Smith (www.selectiveanalytics.com & www.thereformedprogrammer.net)
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#endregion

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

namespace GenericLibsBase
{
    /// <summary>
    /// Interface for handling feedback of success or errors from an operation
    /// </summary>
    public interface ISuccessOrErrors
    {
        /// <summary>
        /// Holds the list of errors. Empty list means no errors. Null means validation has not been done
        /// </summary>
        IReadOnlyList<ValidationResult> Errors { get; }

        /// <summary>
        /// This returns any warning messages
        /// </summary>
        IReadOnlyList<string> Warnings { get; }

        /// <summary>
        /// Returns true if not errors or not validated yet, else false. 
        /// </summary>
        bool IsValid { get; }

        /// <summary>
        /// Returns true if any errors. Note: different to IsValid in that it just checks for errors,
        /// i.e. different to IsValid in that no errors but unset Validity will return false.
        /// Useful for checking inside a method where the status is being manipulated.
        /// </summary>
        bool HasErrors { get; }

        /// <summary>
        /// Returns true if not errors or not validated yet, else false. 
        /// </summary>
        bool HasWarnings { get; }

        /// <summary>
        /// This returns the success message with suffix is nay warning messages
        /// </summary>
        string SuccessMessage { get; }

        /// <summary>
        /// Adds a warning message. It places the test 'Warning: ' before the message
        /// </summary>
        /// <param name="warningformat"></param>
        /// <param name="args"></param>
        void AddWarning(string warningformat, params object[] args);

        /// <summary>
        /// Copies in validation errors found outside into the status
        /// </summary>
        ISuccessOrErrors SetErrors(IEnumerable<ValidationResult> errors);

        /// <summary>
        /// This sets the error list to a series of non property specific error messages
        /// </summary>
        /// <param name="errors"></param>
        /// <returns></returns>
        ISuccessOrErrors SetErrors(IEnumerable<string> errors);

        /// <summary>
        /// Allows a single error to be set.
        /// </summary>
        /// <param name="errorformat"></param>
        /// <param name="args"></param>
        /// <returns></returns>
        ISuccessOrErrors AddSingleError(string errorformat, params object[] args);

        /// <summary>
        /// This adds an error for a specific, named parameter
        /// </summary>
        /// <param name="parameterName"></param>
        /// <param name="errorformat"></param>
        /// <param name="args"></param>
        /// <returns></returns>
        ISuccessOrErrors AddNamedParameterError(string parameterName, string errorformat, params object[] args);

        /// <summary>
        /// This combines any errors or warnings into the current status.
        /// Note: it does NOT copy any success message into the current status
        /// as it is the job of the outer status to set its own success message
        /// </summary>
        /// <param name="status"></param>
        /// <returns></returns>
        ISuccessOrErrors Combine(object status);

        /// <summary>
        /// This sets a success message and sets the IsValid flag to true
        /// </summary>
        /// <param name="successformat"></param>
        /// <param name="args"></param>
        ISuccessOrErrors SetSuccessMessage(string successformat, params object[] args);

        /// <summary>
        /// This returns all the error messages, with parameter name prefix if appropriate, joined together into one long string
        /// </summary>
        /// <param name="joinWith">By default joined using \n, i.e. newline. Can provide different join string </param>
        /// <returns></returns>
        string GetAllErrors(string joinWith = "\n");

        /// <summary>
        /// This returns the errors as:
        /// If only one error then as a html p 
        /// If multiple errors then as an unordered list
        /// </summary>
        /// <returns>simple html data without any classes</returns>
        string ErrorsAsHtml();
    }
}