package com.sprintstack;

import java.nio.file.Files;

import java.nio.file.FileSystem;

import java.nio.file.FileSystems;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.net.URI;

import java.util.HashMap;

import java.io.IOException;

import org.json.simple.JSONObject;

import com.sprintstack.util.JSON;

public class ModuleLoader {

private static FileSystem jar;

private static Path resolve(String name) {

return resolve(name, null);

}

private static Path resolve(String name, String ext) {

// Test if we're referring to a core module

Path resource = getJarPath().getParent().resolve("../resources/" + name + ".js").normalize();

if (Files.exists(resource)) {

return resource;

} else {

// Failing that, check if we're looking for a

// local file

Path localPath = Paths.get(name);

if (Files.exists(localPath)) {

// Is localPath a file or folder?

if (Files.isRegularFile(localPath)) {

return localPath;

} else {

// Look for package.json

Path packageJson = localPath.resolve("package.json");

if (Files.exists(packageJson)) {

String mainPath = parsePackage(packageJson);

return resolve(localPath.resolve(mainPath).toString());

}

}

}

}

try {

return bouncePath(name, ext);

} catch (IOException e) {

return null;

}

}

private static Path bouncePath(String name, String ext) throws IOException {

if (ext == null) {

return resolve(name.concat(".js"), "js");

} else if (ext == "js") {

String prefix = name.substring(0, (name.length()-2));

return resolve(prefix.concat("json"), "json");

} else {

throw new IOException();

}

}

public static String resolveParent(String id) {

return resolve(id).getParent().toString();

}

public static String resolveDirect(String id) {

return resolve(id).toString();

}

private static String parsePackage(Path path) {

String json = loadFile(path);

JSONObject parsed = JSON.decode(json);

String main = (String)parsed.get("main");

return main;

}

private static Path getJarPath() {

return Paths.get(SprintStack.class.getProtectionDomain().getCodeSource().getLocation().getPath());

}

public static String loadFile(String location) {

Path path = Paths.get(location);

return loadFile(path);

}

private static String loadFile(Path path) {

try {

byte[] bytes = Files.readAllBytes(path);

return new String(bytes);

} catch (IOException e) { return null; }

}

public static String require(String name) {

Path module = resolve(name);

if (module == null) return null;

return loadFile(module.toString());

}

}