package nabble.naml.namespaces;

import nabble.naml.compiler.Command;
import nabble.naml.compiler.CommandSpec;
import nabble.naml.compiler.IPrintWriter;
import nabble.naml.compiler.Interpreter;
import nabble.naml.compiler.Namespace;

import java.util.List;


@Namespace (
	name = "list",
	global = true
)
public class ListSequence<T> extends Sequence {
	protected final List<T> elements;
	protected int index = -1;

	public ListSequence(List<T> elements) {
		this.elements = elements;
	}

	protected final T get() {
		return elements.get(index);
	}

	protected final T getPrevious() {
		return index == 0? null : elements.get(index-1);
	}

	public static final CommandSpec has_more_elements = new CommandSpec.Builder()
		.dotParameter("n")
		.optionalParameters("n")
		.build()
	;

	@Command public final void has_more_elements(IPrintWriter out,Interpreter interp) {
		int n = interp.getArgAsInt("n", 1);
		out.print( index+n < elements.size() );
	}

	public static final CommandSpec next_element = new CommandSpec.Builder()
		.optionalParameters("inc")
		.build()
	;

	@Command public void next_element(IPrintWriter out,Interpreter interp) {
		int inc = interp.getArgAsInt("inc", 1);
		index += inc;
		out.print( index < elements.size() );
	}

	@Command public void current_element(IPrintWriter out,Interpreter interp) {
		out.print( get() );
	}

	@Command public void element_count(IPrintWriter out,Interpreter interp) {
		out.print( elements.size() );
	}

	@Command public void is_last_element(IPrintWriter out,Interpreter interp) {
		out.print( index == elements.size()-1);
	}

	@Command public void is_first_element(IPrintWriter out,Interpreter interp) {
		out.print( index == 0);
	}

	@Command public void list_is_empty(IPrintWriter out,Interpreter interp) {
		out.print( elements.isEmpty() );
	}

	public static final CommandSpec remove_current_element = CommandSpec.NO_OUTPUT;

	@Command public void remove_current_element(IPrintWriter out,Interpreter interp) {
		elements.remove(index--);
	}

	public static final CommandSpec reset_list_index = CommandSpec.NO_OUTPUT;

	@Command public void reset_list_index(IPrintWriter out,Interpreter interp) {
		index = -1;
	}

	@Command public void current_index(IPrintWriter out,Interpreter interp) {
		out.print(index);
	}

	public static final CommandSpec has_element_at = new CommandSpec.Builder()
		.parameters("index")
		.build()
	;

	@Command public void has_element_at(IPrintWriter out,Interpreter interp) {
		int index = interp.getArgAsInt("index");
		out.print( index < elements.size() );
	}

	public static final CommandSpec join = new CommandSpec.Builder()
		.dotParameter("do")
		.parameters("separator")
		.build()
	;

	@Command public void join(IPrintWriter out,Interpreter interp) {
		Object todo = interp.getArg("do");
		String separator = interp.getArgString("separator");
		StringBuilder buf = new StringBuilder();
		for( index = 0; index < elements.size(); index++ ) {
			if( index > 0 )
				buf.append( separator );
			buf.append( todo );
		}
		out.print( buf );
	}
}