// TODO - Consider the case where a "cursor" is implemented, allowing deletion / modification at various places in the string and having to keep track of placement
public UserInteraction GetUserInteraction(string userInputString, bool isUpArrowPressed, bool isDownArrowPressed, TerminalState terminalState)
{
// Make sure we actually have a user interaction to deal with this frame - if not, short circuit and just return
var userInteraction = new UserInteraction();
if (string.IsNullOrEmpty(userInputString) && !isUpArrowPressed && !isDownArrowPressed)
{
return(userInteraction);
}
// First, check to see if the user hit the up arrow key to scroll through their last inputs
if (isUpArrowPressed)
{
var previousCommands = terminalState.GetPreviousTerminalCommands();
var currentSelectedCommandNumber = terminalState.GetTerminalCommandSelectedNumber();
var selectedCommand = GetPreviousCommandWithArrowKeys(previousCommands, currentSelectedCommandNumber, isUpArrow: true);
// If, for whatever reason, we could not find the selected command for the user, do not try to change their input or do anything
if (selectedCommand == null)
{
return(userInteraction);
}
// Clear out and modify the user's current input, they want this replaced with a previous submitted input
terminalState.ClearCurrentInput();
var isSetInputSuccess = terminalState.TrySetCurrentInput(selectedCommand.TerminalCommandInput);
if (isSetInputSuccess)
{
userInteraction.IsInputModified = true;
userInteraction.ModifiedInput = selectedCommand.TerminalCommandInput;
terminalState.SetTerminalCommandSelectedNumber(selectedCommand.TerminalCommandNumber);
}
else
{
Debug.Assert(isSetInputSuccess, $"Failed to set current input: {selectedCommand.TerminalCommandInput}");
}
return(userInteraction);
}
// Next, check to see if the user hit the down arrow key to scroll through their last inputs
if (isDownArrowPressed)
{
var previousCommands = terminalState.GetPreviousTerminalCommands();
var currentSelectedCommandNumber = terminalState.GetTerminalCommandSelectedNumber();
var selectedCommand = GetPreviousCommandWithArrowKeys(previousCommands, currentSelectedCommandNumber, isUpArrow: false);
// If, for whatever reason, we could not find the selected command for the user, do not try to change their input or do anything
if (selectedCommand == null)
{
return(userInteraction);
}
// Clear out and modify the user's current input, they want this replaced with a previous submitted input
terminalState.ClearCurrentInput();
var isSetInputSuccess = terminalState.TrySetCurrentInput(selectedCommand.TerminalCommandInput);
if (isSetInputSuccess)
{
userInteraction.IsInputModified = true;
userInteraction.ModifiedInput = selectedCommand.TerminalCommandInput;
terminalState.SetTerminalCommandSelectedNumber(selectedCommand.TerminalCommandNumber);
}
else
{
Debug.Assert(isSetInputSuccess, $"Failed to set current input: {selectedCommand.TerminalCommandInput}");
}
return(userInteraction);
}
// If the user starts typing, we know they did not try to find a previous command (or are modifying a previous one)
// At that point, remove any command that may have been selected and treat this as a brand new input case
terminalState.ClearTerminalCommandSelectedNumber();
// Parse which characters the user's have pressed
foreach (char userInputCharacter in userInputString)
{
// Case of enter or return being pressed to submit the user's input
if (_submitCharacters.Contains(userInputCharacter))
{
// Get the user's full input (not including enter or any prompt characters)
userInteraction.IsInputSubmitted = true;
userInteraction.SubmittedInput = terminalState.GetCurrentInput();
// Clear the user's input since it has been submitted, regardless of its validity
terminalState.ClearCurrentInput();
userInteraction.IsInputModified = true;
userInteraction.ModifiedInput = string.Empty;
}
// Case of backspace or delete bring pressed to delete some of user's input not yet submitted
else if (_deleteCharacters.Contains(userInputCharacter))
{
var currentInput = terminalState.GetCurrentInput();
// If the last character is being deleted, the state should be cleared differently
if (currentInput.Length == 1)
{
terminalState.ClearCurrentInput();
userInteraction.IsInputModified = true;
userInteraction.ModifiedInput = string.Empty;
}
// Otherwise if there is more than one character, delete the last character
else if (currentInput.Length != 0)
{
// If we have characters to delete, remove them and reflect that change back to the user
var updatedInput = currentInput.Remove(currentInput.Length - 1);
var isSetInputSuccess = terminalState.TrySetCurrentInput(updatedInput);
if (isSetInputSuccess)
{
userInteraction.IsInputModified = true;
userInteraction.ModifiedInput = updatedInput;
}
Debug.Assert(isSetInputSuccess, $"Failed to set current input: {updatedInput}");
}
}
// Case of every other key, treated as the text of the key pressed
else
{
var currentInput = terminalState.GetCurrentInput();
var updatedInput = currentInput + userInputCharacter;
var isSetInputSuccess = terminalState.TrySetCurrentInput(updatedInput);
if (isSetInputSuccess)
{
userInteraction.IsInputModified = true;
userInteraction.ModifiedInput = updatedInput;
}
else
{
// We may be over the character limit, so check if the input is valid before asserting that it should have been set
var isValidInput = terminalState.TryValidateInput(updatedInput, out var validInput);
Debug.Assert(!isSetInputSuccess && !isValidInput, $"Failed to set current input with valid input: {validInput}");
}
}
}
return(userInteraction);
}
