package com.juick.www;

import org.springframework.cache.annotation.Cacheable;
import org.springframework.core.io.ClassPathResource;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.regex.Pattern;

/**
 * Created by aalexeev on 12/11/16.
 */
public class HelpService {
    private static final Pattern LANG_PATTERN = Pattern.compile("[a-z]{2}");

    private static final Pattern PAGE_PATTERN = Pattern.compile("[a-zA-Z0-9\\-_]+");

    private final String helpPath;


    public HelpService(String helpPath) {
        this.helpPath = helpPath;
    }

    @Cacheable("help")
    public String getHelp(final String page, final String lang) {
        if (canPage(page) && canLang(lang)) {
            try {
                Path file = Paths.get(helpPath, lang, page);
                String path = file.toString();
                file = Paths.get(new ClassPathResource(path).getURI());

                if (Files.isReadable(file))
                    return new String(Files.readAllBytes(file));
            } catch (IOException e) {
            }
        }

        return null;
    }

    public boolean canPage(final String anything) {
        return anything != null && PAGE_PATTERN.matcher(anything).matches();
    }

    public boolean canLang(final String anything) {
        return anything != null && LANG_PATTERN.matcher(anything).matches();
    }
}