package slangc.parser;

//import slang.data.Map;
import slang.data.Mappable;
import slang.vm.Ankh;

/**
 * The sourceFile class is a simple abstraction over a sourceFile file, suitable for easily writing a
 * scanner on top of. The main differences between this and just using a stream or array or string
 * are that it's easier to handle different encodings and access mechanisms this way.
 * 
 * @author Zak
 *
 */
public abstract class Source {
	private final SourceEncoding encoding;
	private final String filename;

	public Source(SourceEncoding encoding, String filename) {
		this.encoding = encoding;
		this.filename = filename;
	}
	
	public Source(String filename) {
		this(new SourceEncoding(), filename);
	}
	
	public Source() {
		this("");
	}
	
	public SourceEncoding getEncoding() {
		return encoding;
	}
	
	public String getFilename() {
		return filename;
	}
	
	public abstract int getIndexLength();
	
	public final boolean isIndexWithinBounds(int index) {
		return index >= 0 && index < getIndexLength();
	}

	public abstract int getCharacter(int index);
	
	public abstract int getNextIndex(int currentIndex);
	
	public String getString(int index, int maximumLength) {
		String result = "";
		
		for (int i = 0; i < maximumLength; i++) {
			if (isIndexWithinBounds(index)) {
				result += getEncoding().getString(getCharacter(index));
				index = getNextIndex(index);
			}
		}
		
		return result;
	}

    private String[][] matchCache = null;
    private int[] matchCheck = new int[1];
    private int lastidx = -1;
    private int lastch = 0;
	
	public boolean matches(int index, String value) {
        if (index != lastidx) {
            lastidx = index;
            lastch = getCharacter(index);
        }
        Ankh.stringToArray(value, "COMPAT32", matchCheck);
        if (matchCheck[0] != lastch) {
            return false;
        }
        
        if (matchCache == null) {
            matchCache = new String[getIndexLength()][];
        }
        if (matchCache[index] == null) {
            matchCache[index] = new String[100];
        }
        int len = value.intsLength();
        String s = matchCache[index][len];
        if (s == null) {
            s = getString(index, len);
            matchCache[index][len] = s;
        }
        return s == value;
		//return getString(index, value.intsLength()) == value;
	}
	
	public boolean matches(int index, String[] values) {
		for (int i = 0; i < values.length; i++) {
			if (matches(index, values[i])) {
				return true;
			}
		}
		return false;
	}
	
	public String match(int index, String[] values) {
		for (int i = 0; i < values.length; i++) {
			if (matches(index, values[i])) {
				return values[i];
			}
		}
		return null;
	}
	
	public boolean matches(int index, String[][] values) {
		for (int i = 0; i < values.length; i++) {
			if (matches(index, values[i][0])) {
				return true;
			}
		}
		return false;
	}
	
	public String match(int index, String[][] values) {
		for (int i = 0; i < values.length; i++) {
			if (matches(index, values[i][0])) {
				return values[i][1];
			}
		}
		return null;
	}
	
	@Override
	public String toString() {
		return Type.of(this).getTypeName() + "(\"" + getFilename() + "\")";
	}
}