/// <summary>
/// Writes a text to the console with word wrap.
/// </summary>
/// <param name="message">the message to write</param>
/// <param name="maxLineWidth">the maximum length of a line before line break.</param>
/// <param name="writeToNewLine">write the message to a separated line (otherwise continue to output on the same line)</param>
/// <param name="indentation">Apply indentation when writing on a new line.</param>
/// <param name="prefixForNewLines">The text to put at the beginning of each new line that need to be created because of word wrap.</param>
public void Write(string message, int maxLineWidth, bool writeToNewLine, int indentation = 0, string prefixForNewLines = null)
{
// handle null message
if (message == null)
{
// write a new line
if (writeToNewLine && HasWroteToOuput)
{
WriteLine();
}
HasWroteToOuput = true;
return;
}
// check indentation
if (maxLineWidth > 0 && indentation >= maxLineWidth - 10)
{
indentation = maxLineWidth - 10;
}
indentation = Math.Max(indentation, 0);
// write without word wrap
if (maxLineWidth <= 0)
{
// write a new line
if (writeToNewLine && HasWroteToOuput)
{
WriteLine();
_currentLineSpaceTaken = 0;
}
message = _currentLineSpaceTaken == 0 && indentation > 0 ? message.PadLeft(message.Length + indentation) : message;
UnderLyingWriter.Write(message);
_currentLineSpaceTaken += message.Length;
HasWroteToOuput = true;
return;
}
// for each line of text
int lineStartPos, nextLineStartPos;
for (lineStartPos = 0; lineStartPos < message.Length; lineStartPos = nextLineStartPos)
{
int eolPosition = message.IndexOf('\n', lineStartPos);
if (eolPosition == -1)
{
nextLineStartPos = eolPosition = message.Length;
}
else
{
nextLineStartPos = eolPosition + 1;
if (eolPosition == lineStartPos)
{
// found a new line
WriteLine();
continue;
}
}
// an input line can have indentation; if we split this input line into several lines (because it is too long),
// we need to keep the same indentation for each new line
bool newInputLineStarting = true;
int paragraphIndent = 0;
if (eolPosition > lineStartPos)
{
do
{
// write a new line
if (writeToNewLine && HasWroteToOuput || _currentLineSpaceTaken >= maxLineWidth)
{
if (newInputLineStarting || string.IsNullOrEmpty(prefixForNewLines))
{
WriteLine();
}
else
{
var newLinePrefix = prefixForNewLines.PadRight(Math.Max(0, indentation + paragraphIndent));
WriteLine($"{UnderLyingWriter.NewLine}{newLinePrefix}");
_currentLineSpaceTaken += newLinePrefix.Length;
}
}
int lineLength = eolPosition - lineStartPos;
int totalIndent = _currentLineSpaceTaken > 0 ? 0 : indentation + paragraphIndent;
int currentConsoleLineSpaceLeft = maxLineWidth - _currentLineSpaceTaken - totalIndent;
if (lineLength > currentConsoleLineSpaceLeft)
{
lineLength = GetLineLengthToKeep(message, lineStartPos, currentConsoleLineSpaceLeft, !writeToNewLine && message.Length <= maxLineWidth - totalIndent);
}
if (lineLength > 0)
{
var line = message.Substring(lineStartPos, lineLength);
line = _currentLineSpaceTaken > 0 ? line : line.PadLeft(lineLength + indentation + paragraphIndent, ' ');
UnderLyingWriter.Write(line);
_currentLineSpaceTaken += line.Length;
HasWroteToOuput = true;
}
if (newInputLineStarting && writeToNewLine)
{
while (lineStartPos + paragraphIndent < message.Length && char.IsWhiteSpace(message[lineStartPos + paragraphIndent]))
{
paragraphIndent++;
}
if (indentation + paragraphIndent >= maxLineWidth)
{
paragraphIndent = maxLineWidth - indentation - 10;
}
}
newInputLineStarting = false;
writeToNewLine = true;
// trim the whitespaces following a word break
lineStartPos += lineLength;
while (lineStartPos < eolPosition && message[lineStartPos] != '\n' && char.IsWhiteSpace(message[lineStartPos]))
{
lineStartPos++;
}
} while (eolPosition > lineStartPos);
}
}
}
/// <summary>
/// Write a new line char into the text writer
/// </summary>
/// <param name="newLine"></param>
public void WriteLine(string newLine = null)
{
UnderLyingWriter.Write(newLine ?? UnderLyingWriter.NewLine);
_currentLineSpaceTaken = 0;
HasWroteToOuput = true;
}
