import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
//import java.util.ArrayList;

/**
 * @author gtowell 
 * Written: Jan 29, 2020
 * Modified: Sep 16, 2020
 * Modified: gtowell Feb 24, 2021
 * 
 * A small class that counts the number of uses of each word in a file.
 * This class illustrates ArrayList or ArraList, splitting strings
 * and StringBuffer
 */
public class WordCounter {

	/** An arrayList holding all of the Word and Count objects */
	private List151Impl<KeyValue<String, Integer>> counts = new List151Impl<>();

	/**
	 * Does most of the heavy lifting. Reads a file and fills in the counts
	 * arraylist appropriately
	 * 
	 * @param filename the name of the file to be read.
	 */
	void countFile(String filename) {
		try (BufferedReader br = new BufferedReader(new FileReader(filename));) {
			String line;
			while (null != (line = br.readLine())) { // read line and test if there is a line to read
				String[] ss = line.replace("-", " ").split("\\s+"); // split the line by spaces
				for (String token : ss) {
					// take the token i.e. word, lower case it, then get rid of punctuation
					token = token.toLowerCase().replace(".", "").replace(",", "").replace("?", "").replace("!", "");
					if (token.length() > 0) {
						KeyValue<String, Integer> wordS = findWord(token);
						if (wordS == null) { // if have not already seen the word, add it to the arraylist
							wordS = new KeyValue<>(token, 0);
							try {
								counts.add(wordS);
							} catch (MAxSizeExceededException mex) {
								System.err.println("Stopping reading document, cannot hold more words");
								return;
							}
						}
						wordS.setValue(wordS.getValue() + 1); // increment the number of times the word has been seen
					}
				}
			}
		} catch(FileNotFoundException e) {
			System.err.println("Error in opening the file:" + filename);
			System.exit(1);
		} catch (IOException ioe) {
			System.err.println("Error reading file " + ioe);
			System.exit(1);
		}
	}

/**
	 * Find a word in the list of seen words
	 * 
	 * @param w the word to be found
	 * @return the WordHolder object containing the word. 
	 * Or null if the word has not been seen
	 */
	private KeyValue<String, Integer> findWord(String w) {
		KeyValue<String, Integer> fakeInstance = new KeyValue<>(w, 0);
		return counts.getInstance(fakeInstance);
	}

	
	public String toString() {
		// StringBuffer is a modifiable string. If you are changing a string a lot, it
		// is much more efficient.
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < counts.size(); i++) {
			KeyValue<String, Integer> aWord = counts.get(i);
			sb.append(aWord);
			sb.append("\n");
		}
		sb.append("Distinct words: " + counts.size());
		return sb.toString();
	}


	public static void main(String[] args) {
		WordCounter wc = new WordCounter();
		wc.countFile("ham.txt");
		System.out.println(wc);
	}
}