the-forest/server/interpreter.js

const { LuaFactory } = require('wasmoon');

const sqlite = require('better-sqlite3');
const db = new sqlite('the_big_db.db', { verbose: console.log });

const factory = new LuaFactory();

let lua;

async function makeLua() {
	lua = await factory.createEngine();
	lua.global.set('executeVerb', executeVerb);
	lua.global.set('getAttribute', luaSafe(getAttribute));
	lua.global.set('setAttribute', luaSafe(setAttribute));
	lua.global.set('deleteAttribute', luaSafe(deleteAttribute));
	lua.global.set('hasOwnAttribute', luaSafe(hasOwnAttribute));
	lua.global.set('verifyObjectReference', luaSafe(verifyObjectReference));
	lua.global.set('lookUpObject', luaSafe(lookUpObject));
	lua.global.set('lookUpObjectAttributes', luaSafe(lookUpObjectAttributes));
	lua.global.set('interpret', interpret);
}

makeLua();

var sockets = new Map();

function interpret(context, player, command) {
	// interpret and execute a command entered by a player.
	//
	// context: the location the player has entered the command in from. 
	//		may be null if it's executing from a script?
	// player: the id of the player object who typed in the command. 
	//		may? be null if it's executing from a script? used for output.
	//		so arguably 
	// command: the full string typed in by the player

	const socket = sockets.get(player)
	const wordsAndQuotes = tokenizeQuotes(command.trim());

	try {
		//for the moment we'll only allow statements of the form "go north" with implicit subject: the player
		
		const verb = findVerb(wordsAndQuotes[0], context, player);

		if (verb) {
			let prepositions = getAttribute(verb, "prepositions");
			
			const wordsAndPreps = tokenizePrepositions(wordsAndQuotes, prepositions || []);
			let words = wordsAndPreps.filter((x) => typeof(x) == "string");
			let preps = wordsAndPreps.filter((x) => typeof(x) == "object");
			let prepMap = {};
			for (const obj of preps) {
				prepMap[obj.preposition] = obj.contents;
			}

			const [first, second, third, ...rest] = words;

			executeVerb(command, player, verb, prepMap, player, second, third, ...rest)
		} else {
			interpret(1,1, `system_send_message '{"error": "verb ${verbId} not found in ${fullCommand}"}' to ${player}`);
		}
	} catch (error) {
		interpret(1,1, `system_send_message '{"error": "error found: ${error}"}' to ${player}`);
	}

	/*
	// if the second word is a verb, but the first word is also a verb, what do we do?
	if (second in verbs) {
		// for now, assume that if the second word is a verb, it's the verb we want.
		executeVerb(player, verbs.get(second), first, third, ...rest);
	} else {
		// if the second word is not a verb, then the first word is the verb, and the player is the implied subject.
		executeVerb(player, verbs.get(first), player, second, third, ...rest)
	}
	*/
}

async function executeVerb(fullCommand, outputObject, verbId, prepositions, subject, object, ...rest) {
	if (verbId == 2) {
		// todo: make this more intelligently get the rright thing to send
		let theObject;
		try {
			theObject = verifyObjectReference(object);
		} catch (error) {
			theObject = verifyObjectReference(outputObject);
		}
		if (prepositions["to"]) {
			let destination = verifyObjectReference(prepositions["to"])
			return sockets.get(destination)?.send(object);
		}
		return sockets
			.get(theObject)
			?.send(`full command: ${fullCommand}. verb id: ${verbId}. subject: ${subject} object: ${object}`); 
	}

	const fullVerb = lookUpObject(verbId);
	if (!fullVerb) {
		return interpret(1, 1, `system_send_message '{"error": "verb ${verbId} not found in ${fullCommand}"}' to ${outputObject}`);
	}

	// generate a temp name for this verb, then define it and execute.
	const verbName = "verb" + Math.random().toString(36).substring(2);
	const body = fullVerb.description.replace(/ /g, " ");
	const verbDeclaration = `
		function ${verbName} (fullCommand, outputObject, prepositionMap, subject, object, ...)
			${body}
		end`;
	console.log("verb we're running:");
	console.log(verbDeclaration);
	await lua.doString(verbDeclaration);
	
	
	let returnValue = await lua.global.get(verbName)(fullCommand, outputObject, prepositions, subject, object, ...rest);
	// maybe unset it so we dno't have an ever-growing set of functions cluttering up the space?
	//lua.global.set(verbName, null); 
	
	return returnValue;
}

const objectQuery = db.prepare('select * from pages where number=? order by time desc');
function lookUpObject(number) {
	return objectQuery.get(number);
}

const attributeQuery = db.prepare(`select * from attributes where number=?`);
function lookUpObjectAttributes(number) {
	return JSON.parse(attributeQuery.get(number).contents);
}

function findVerb(word, location, actor) {
	// returns the number of a verb which matches the requested word.
	// check for verbs on actor
	let verb = [];

	if (verifyObjectReference(word)) {
		return verifyObjectReference(word);
	}

	if (actor) {
		verb = findVerbOnObject(word, actor);
		if (verb) return verb;

		let actorContents = getAttribute(actor, "contents");
		for (const obj of (actorContents || [])) {
			verb = findVerbOnObject(word, obj);
			if (verb) return verb;
		}
	}

	if (location) {
		const locationContents = getAttribute(location, "contents");
		for (const obj of (locationContents || [])) {
			verb = findVerbOnObject(word, obj);
			if (verb) return verb;
		}

		verb = findVerbOnObject(word, location);
		if (verb) return verb;
	}

	return undefined;
}

function findVerbOnObject(word, object) {
	// check for verbs on a single object, and its chain of parents. return a matching verbId, or undefined
	if (!word) return undefined;

	let focus = object;
	while (focus) {
		const focusVerbs = getAttribute(focus, "verbs");
		for (const verbId of (focusVerbs || [])) {
			const fullVerb = lookUpObject(verbId);

			if (!fullVerb) continue;

			// test our word against 
			if (word.toLowerCase() == fullVerb.title.toLowerCase()) {
				return verbId;
			}
		}
		focus = getAttribute(focus, "parent");
	}

	return undefined;
}

function findAllVerbsOnObject(object) {
	let verbs = [];
	let focus = object;

	while (focus) {
		const newVerbs = (getAttribute(focus, "verbs") || []).filter((verb) => !(verb in verbs));
		verbs = verbs.concat(newVerbs);

		focus = getAttribute(focus, "parent");
	}

	return verbs;
}

function findAllVerbsInArea(location, actor) {
	// returns all verb ids in an area or on an actor
	let verbs = findAllVerbsOnObject(actor);

	const actorContents = getAttribute(actor, "contents");
	for (const obj of (actorContents || [])) {
		verbs = concatWithoutDuplicates(verbs, findAllVerbsOnObject(obj));
	}

	if (location) {
		const locationContents = getAttribute(location, "contents");
		for (const obj of (locationContents || [])) {
			verbs = concatWithoutDuplicates(verbs, findAllVerbsOnObject(obj));
		}

		verbs = concatWithoutDuplicates(verbs, findAllVerbsOnObject(location));
	}

	return verbs;
}

const pullAttribute = db.prepare(`select * from attributes where number=?`);
function getAttribute(obj, attributeName) {
	if (!verifyObjectReference(obj)) return undefined;

	let attributeStore = pullAttribute.get(verifyObjectReference(obj));

	let contents = JSON.parse(attributeStore.contents);

	if (contents.hasOwnProperty(attributeName)) {
		return contents[attributeName];
	}

	if (contents.hasOwnProperty("parent")) {
		if (contents["parent"]) {
			return getAttribute(verifyObjectReference(contents["parent"]), attributeName);
		}
	}

	return undefined;
}

function hasOwnAttribute(obj, attributeName) {
	if (!verifyObjectReference(obj)) return undefined;

	const attributeStore = pullAttribute.get(verifyObjectReference(obj));
	const contents = JSON.parse(attributeStore.contents);
	
	return contents.hasOwnProperty(attributeName);
}

const insertAttribute = db.prepare(`update or replace attributes set contents=:contents where number=:number`);
function setAttribute(obj, attributeName, value) {
	if (!verifyObjectReference(obj)) return undefined;

	const attributeStore = pullAttribute.get(verifyObjectReference(obj));
	const contents = JSON.parse(attributeStore.contents);

	contents[attributeName] = value;
	
	insertAttribute.run({...attributeStore, contents: JSON.stringify(contents)});
}

function deleteAttribute(obj, attributeName) {
	if (!verifyObjectReference(obj)) return undefined;

	const attributeStore = pullAttribute.get(verifyObjectReference(obj));
	const contents = JSON.parse(attributeStore.contents);
	
	delete contents[attributeName];
	
	insertAttribute.run({...attributeStore, contents: JSON.stringify(contents)});
}

function verifyObjectReference(obj) {
	try {
		if (typeof(obj) === "string") {
			return Number(obj.replace("#", ""));
		} else if (typeof(obj) === "number") {
			return obj;
		} else if (typeof(obj.number) == "number") {
			return obj.number;
		}
		return undefined;
	} catch (error) {
		throw new Error(`Tried to get an attribute from something which wasn't an object: ${obj}`);
	}
}

function concatWithoutDuplicates(a, b) {
	let b2 = b.filter((x) => !(x in a));
	return a.concat(b2);
}
function luaSafe(func) {
	return (...all) => {
		let value = func(...all);
		if (value == null) {
			return undefined;
		}
		return value;
	};
}

function tokenizeQuotes(string) {
	let arr = string.split("'");
	let out = [];
	let inQuotes = false;
	for (const bit of arr) {
		if (inQuotes) {
			out.push(bit);
		}	else {
			if (bit != '') {
				out = out.concat(bit.trim().split(" ").filter((x) => x != ''));
			}
		}
		inQuotes = !inQuotes;
	}
	return out;
}

function tokenizePrepositions(sequence, prepositions) {
	let out = [];

	let current = {};

	let inPreposition = false;

	for (const bit of sequence) {
		if (inPreposition) {
			current.contents = bit;
			out.push(current);
			current = {};
			inPreposition = false;
		} else if (prepositions.includes(bit)) {
			current.preposition = bit;
			inPreposition = true;
		} else {
			out.push(bit);
		}
	}

	return out;
}

module.exports = { interpret, sockets, 
	lookUpObject, 
	getAttribute, setAttribute, deleteAttribute, hasOwnAttribute, 
	findVerbOnObject, findAllVerbsOnObject, findAllVerbsInArea };