package Lect29Library;

/**
 * This class implements the data component of the MVC associated
 * with a textEditor.  The text area is represented as a two-dimensional
 * array of characters.
 */
public class TextEditorCorrect {
	private int numLines;
	private char[][] textArea;
	
	public TextEditorCorrect() {
		// no lines to start
		textArea = new char[0][];
		numLines = 0;
	}
	
	public void deleteLine(int lineNum) {
		int row;

		// shift elements up
		for (row=lineNum; row<numLines-1; row++) {
			textArea[row] = textArea[row+1];
		}
		textArea[row] = null;
		numLines--;
	}

	public void appendLine(String line) {
		insertLine(line.toCharArray(), numLines);
	}

	// public method uses convenient type for caller
	public void insertLine(String line, int lineNum) {
		insertLine(line.toCharArray(), lineNum);
	}
	
	// private implementation uses convenient type for implementation
	private void insertLine(char[] line, int lineNum) {
		if (numLines < textArea.length) {
			// shift elements down
			for (int row=numLines; row>lineNum; row--){
				textArea[row] = textArea[row-1];
			}
			// insert line
			textArea[lineNum] = line;
		} else {
			// no space therefore we expand array
			
			// new array to fit the new line
			char[][] newTextArea;
			newTextArea = new char[textArea.length + 1][];
			
			// copy current lines to new array and insert line
			for (int row=0,newRow=0; row<textArea.length; row++) {
				if (row == lineNum) {
					newTextArea[newRow++] = line;
					newTextArea[newRow++] = textArea[row];
				} else {
					newTextArea[newRow++] = textArea[row]; 
				}
			}
			// special check for inserting at end
			if (lineNum == textArea.length) {
				newTextArea[lineNum] = line;
			}
			
			textArea = newTextArea;
		}
		
		numLines++;
	}
	
	public String toString() {
		String result = "";
		for (int row=0; row<numLines; row++) {
			for (int col=0; col<textArea[row].length; col++) {
				result += textArea[row][col];
			}
			result += "\n";
		}
		
		return result;
	}
	
	
	public static void main(String[] args) {
		TextEditorCorrect textEditor = new TextEditorCorrect();
		
		textEditor.appendLine("The homework required a");
		textEditor.appendLine("lot of work but");
		textEditor.appendLine("it was fun");
		
		System.out.println("*** Original Document ***");
		System.out.println(textEditor);
		
		textEditor.deleteLine(1);
		System.out.println("*** After Deleting Line ***");
		System.out.println(textEditor);
		
		textEditor.insertLine("lot of dedication but", 1);
		System.out.println("*** After inserting ***");
		System.out.println(textEditor);
		
		System.out.println("*** After clearing the document***");
		textEditor.deleteLine(0);
		textEditor.deleteLine(0);
		textEditor.deleteLine(0);
		textEditor.appendLine("A new document");
		textEditor.insertLine("related to the topic", 1);
		textEditor.appendLine("is now in progress");
		System.out.println(textEditor);
	}
}