LuaScript/src/main/java/org/openautonomousconnection/luascript/tables/ObserversTable.java

package org.openautonomousconnection.luascript.tables;

import org.luaj.vm2.LuaFunction;
import org.luaj.vm2.LuaValue;
import org.luaj.vm2.Varargs;
import org.luaj.vm2.lib.*;
import org.openautonomousconnection.luascript.events.JavaToLua;
import org.openautonomousconnection.luascript.hosts.HostServices;
import org.openautonomousconnection.luascript.hosts.ObserverHost;
import org.openautonomousconnection.luascript.utils.ScriptTable;

import java.util.Map;

/**
 * Lua table: observers
 *
 * <p>Functions:</p>
 * <ul>
 *   <li>observers.on(fn(type, targetId, dataTable))</li>
 *   <li>observers.mutationObserve(id, subtree, attributes, childList, characterData)</li>
 *   <li>observers.mutationUnobserve(id)</li>
 *   <li>observers.resizeObserve(id)</li>
 *   <li>observers.resizeUnobserve(id)</li>
 *   <li>observers.intersectionObserve(id, threshold)</li>
 *   <li>observers.intersectionUnobserve(id)</li>
 * </ul>
 */
public final class ObserversTable extends ScriptTable {

    public ObserversTable() {
        super("observers");
    }

    @Override
    protected void define(HostServices services) {
        ObserverHost host = services.observers().orElseThrow(() -> new IllegalStateException("ObserverHost not provided"));

        table().set("on", new OneArgFunction() {
            @Override
            public LuaValue call(LuaValue fn) {
                LuaFunction cb = fn.checkfunction();
                host.setCallback((type, targetId, data) -> {
                    LuaValue luaData = JavaToLua.coerce(data);
                    cb.call(LuaValue.valueOf(type), LuaValue.valueOf(targetId), luaData);
                });
                return LuaValue.NIL;
            }
        });

        table().set("mutationObserve", new VarArgFunction() {
            @Override
            public Varargs invoke(Varargs args) {
                String id = args.arg(1).checkjstring();
                boolean subtree = args.arg(2).optboolean(false);
                boolean attributes = args.arg(3).optboolean(true);
                boolean childList = args.arg(4).optboolean(true);
                boolean characterData = args.arg(5).optboolean(false);
                host.observeMutations(id, subtree, attributes, childList, characterData);
                return LuaValue.NIL;
            }
        });

        table().set("mutationUnobserve", new OneArgFunction() {
            @Override
            public LuaValue call(LuaValue id) {
                host.unobserveMutations(id.checkjstring());
                return LuaValue.NIL;
            }
        });

        table().set("resizeObserve", new OneArgFunction() {
            @Override
            public LuaValue call(LuaValue id) {
                host.observeResize(id.checkjstring());
                return LuaValue.NIL;
            }
        });

        table().set("resizeUnobserve", new OneArgFunction() {
            @Override
            public LuaValue call(LuaValue id) {
                host.unobserveResize(id.checkjstring());
                return LuaValue.NIL;
            }
        });

        table().set("intersectionObserve", new TwoArgFunction() {
            @Override
            public LuaValue call(LuaValue id, LuaValue threshold) {
                host.observeIntersection(id.checkjstring(), threshold.checkdouble());
                return LuaValue.NIL;
            }
        });

        table().set("intersectionUnobserve", new OneArgFunction() {
            @Override
            public LuaValue call(LuaValue id) {
                host.unobserveIntersection(id.checkjstring());
                return LuaValue.NIL;
            }
        });
    }
}