package com.reactlibrary.io;

/**
 * Created by MJX  on 2018/9/28 18:13.
 */
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.Iterator;
import java.util.NoSuchElementException;

public class LineIterator implements Iterator<String> {
    private final BufferedReader bufferedReader;
    private String cachedLine;
    private boolean finished = false;

    public LineIterator(Reader reader) throws IllegalArgumentException {
        if(reader == null) {
            throw new IllegalArgumentException("Reader must not be null");
        } else {
            if(reader instanceof BufferedReader) {
                this.bufferedReader = (BufferedReader)reader;
            } else {
                this.bufferedReader = new BufferedReader(reader);
            }

        }
    }

    public boolean hasNext() {
        if(this.cachedLine != null) {
            return true;
        } else if(this.finished) {
            return false;
        } else {
            try {
                String ioe;
                do {
                    ioe = this.bufferedReader.readLine();
                    if(ioe == null) {
                        this.finished = true;
                        return false;
                    }
                } while(!this.isValidLine(ioe));

                this.cachedLine = ioe;
                return true;
            } catch (IOException var2) {
                this.close();
                throw new IllegalStateException(var2);
            }
        }
    }

    protected boolean isValidLine(String line) {
        return true;
    }

    public String next() {
        return this.nextLine();
    }

    public String nextLine() {
        if(!this.hasNext()) {
            throw new NoSuchElementException("No more lines");
        } else {
            String currentLine = this.cachedLine;
            this.cachedLine = null;
            return currentLine;
        }
    }

    public void close() {
        this.finished = true;
        IOUtils.closeQuietly(this.bufferedReader);
        this.cachedLine = null;
    }

    public void remove() {
        throw new UnsupportedOperationException("Remove unsupported on LineIterator");
    }

    public static void closeQuietly(LineIterator iterator) {
        if(iterator != null) {
            iterator.close();
        }

    }
}