private CommandResponse ExecuteCreateComment(CreateCommentCommand command)
{
var comment = new Comment
{
Id = Guid.NewGuid(),
Timestamp = DateTime.Now,
Author = command.IssuedBy,
Text = command.Text
};
foreach (var q in Questions)
{
if (q.Id == command.QuestionOrAnswerId)
{
q.Comments.Add(comment);
return(CommandResponse.Success(comment));
}
foreach (var a in q.Answers)
{
if (a.Id == command.QuestionOrAnswerId)
{
a.Comments.Add(comment);
return(CommandResponse.Success(comment));
}
}
}
return(CommandResponse.Failure($"Question or answer with id {command.QuestionOrAnswerId} does not exist."));
}
private CommandResponse ExecuteDeleteQuestion(DeleteQuestionCommand command)
{
var existingQuestion = Questions.FirstOrDefault(q => q.Id == command.QuestionId);
if (existingQuestion == null)
{
return(CommandResponse.Failure($"Question {command.QuestionId} doesn't exist."));
}
Questions.Remove(existingQuestion);
return(CommandResponse.Success());
}
private CommandResponse ExecuteAcceptAnswerCommand(AcceptAnswerCommand command)
{
foreach (var q in Questions)
{
var answer = q.Answers.SingleOrDefault(a => a.Id == command.AnswerId);
if (answer != null)
{
q.AcceptedAnswerId = answer.Id;
return(CommandResponse.Success(answer));
}
}
return(CommandResponse.Failure($"Answer {command.AnswerId} doesn't exist."));
}
private CommandResponse ExecuteEditComment(EditCommentCommand command)
{
var existingComment = Questions.SelectMany(q => q.Comments).Concat(Questions.SelectMany(q => q.Answers.SelectMany(a => a.Comments)))
.SingleOrDefault(c => c.Id == command.CommentId);
if (existingComment == null)
{
return(CommandResponse.Failure($"Comment with id {command.CommentId} does not exist."));
}
existingComment.Text = command.Text;
return(CommandResponse.Success(existingComment));
}
private CommandResponse ExecuteEditAnswer(EditAnswerCommand command)
{
var existingAnswer = Questions.SelectMany(q => q.Answers).SingleOrDefault(a => a.Id == command.AnswerId);
if (existingAnswer == null)
{
return(CommandResponse.Failure($"Answer {command.AnswerId} doesn't exist."));
}
existingAnswer.History.Add(new PostHistoryItem
{
Author = existingAnswer.Author,
Text = existingAnswer.Text
});
existingAnswer.Text = command.Text;
return(CommandResponse.Success(existingAnswer));
}
private CommandResponse ExecuteVoteQuestionCommand(VoteQuestionCommand command)
{
var existingQuestion = Questions.FirstOrDefault(q => q.Id == command.QuestionId);
if (existingQuestion == null)
{
return(CommandResponse.Failure($"Question {command.QuestionId} doesn't exist."));
}
existingQuestion.Votes.Add(new Vote
{
Author = command.IssuedBy,
Id = Guid.NewGuid(),
Timestamp = DateTime.Now,
Direction = command.VoteDirection
});
return(CommandResponse.Success(existingQuestion));
}
private CommandResponse ExecuteVoteAnswer(VoteAnswerCommand command)
{
var existingAnswer = Questions.SelectMany(q => q.Answers).SingleOrDefault(a => a.Id == command.AnswerId);
if (existingAnswer == null)
{
return(CommandResponse.Failure($"Answer {command.AnswerId} doesn't exist."));
}
existingAnswer.Votes.Add(new Vote
{
Author = command.IssuedBy,
Id = Guid.NewGuid(),
Timestamp = DateTime.Now,
Direction = command.VoteDirection
});
return(CommandResponse.Success(existingAnswer));
}
private CommandResponse ExecuteEditQuestion(EditQuestionCommand command)
{
var existingQuestion = Questions.FirstOrDefault(q => q.Id == command.QuestionId);
if (existingQuestion == null)
{
return(CommandResponse.Failure($"Question {command.QuestionId} doesn't exist."));
}
existingQuestion.History.Add(new PostHistoryItem
{
Author = existingQuestion.Author,
Text = existingQuestion.Text
});
existingQuestion.Title = command.Title;
existingQuestion.Text = command.Text;
return(CommandResponse.Success(existingQuestion));
}
public CommandResponse Execute(CommandBase command)
{
switch (command)
{
case EditQuestionCommand editQuestion:
return(ExecuteEditQuestion(editQuestion));
case CreateQuestionCommand createQuestion:
return(ExecuteCreateQuestion(createQuestion));
case DeleteQuestionCommand deleteQuestion:
return(ExecuteDeleteQuestion(deleteQuestion));
case VoteQuestionCommand voteQuestion:
return(ExecuteVoteQuestionCommand(voteQuestion));
case CreateAnswerCommand createAnswer:
return(ExecuteCreateAnswer(createAnswer));
case EditAnswerCommand editAnswer:
return(ExecuteEditAnswer(editAnswer));
case DeleteAnswerCommand deleteAnswer:
return(ExecuteDeleteAnswer(deleteAnswer));
case VoteAnswerCommand voteAnswer:
return(ExecuteVoteAnswer(voteAnswer));
case AcceptAnswerCommand acceptAnswer:
return(ExecuteAcceptAnswerCommand(acceptAnswer));
case CreateCommentCommand createComment:
return(ExecuteCreateComment(createComment));
case EditCommentCommand editComment:
return(ExecuteEditComment(editComment));
case DeleteCommentCommand deleteComment:
return(ExecuteDeleteComment(deleteComment));
}
return(CommandResponse.Failure($"Command {command.GetType().Name} has no handlers"));
}
private CommandResponse ExecuteCreateAnswer(CreateAnswerCommand command)
{
var existingQuestion = Questions.FirstOrDefault(q => q.Id == command.QuestionId);
if (existingQuestion == null)
{
return(CommandResponse.Failure($"Question {command.QuestionId} doesn't exist."));
}
var answer = new Answer
{
Author = command.IssuedBy,
Id = Guid.NewGuid(),
Timestamp = DateTime.Now,
Text = command.Text
};
existingQuestion.Answers.Add(answer);
return(CommandResponse.Success(answer));
}
private CommandResponse ExecuteDeleteComment(DeleteCommentCommand command)
{
foreach (var q in Questions)
{
var existingComment = q.Comments.SingleOrDefault(c => c.Id == command.CommentId);
if (existingComment != null)
{
q.Comments.Remove(existingComment);
return(CommandResponse.Success());
}
foreach (var a in q.Answers)
{
existingComment = a.Comments.SingleOrDefault(c => c.Id == command.CommentId);
if (existingComment != null)
{
a.Comments.Remove(existingComment);
return(CommandResponse.Success());
}
}
}
return(CommandResponse.Failure($"Comment with id {command.CommentId} does not exist."));
}
