package cn.glycol.t18n;

import java.io.File;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.util.List;

import com.google.common.collect.Lists;

public class LanguageMapBuilder {

	public static LanguageMap fromFile(File langFile) {
		return fromFile(langFile, LanguageMapConfiguration.DEFAULT);
	}
	
	public static LanguageMap fromFile(File langFile, LanguageMapConfiguration config) {
		
		List<String> lines = getLinesFromFile(langFile);
		return getLanguageMapFromLines(config, lines);
	}
	
	private static List<String> getLinesFromFile(File file) {
		if(file.isFile()) {
			try {
				return Files.readAllLines(file.toPath(), Charset.forName("UTF-8"));
			} catch (Exception e) {
				
			}
		}
		return Lists.<String>newArrayList();
	}
	
	private static LanguageMap getLanguageMapFromLines(LanguageMapConfiguration config, List<String> lines) {
		
		final LanguageMap map = new LanguageMap();
		
		for(String s : lines) {
			String[] pair = getLanguageMapFromLine(config, s);
			if(!isUnreadable(pair)) {
				map.put(pair[0], pair[1]);
			}
		}
		
		return map;
		
	}
	
	private static final String[] UNREADABLE = new String[] {null, null};
	
	private static String[] getLanguageMapFromLine(LanguageMapConfiguration config, String s) {
		
		/* Empty Line */
		if(s == null || s.length() == 0) {
			return UNREADABLE;
		}
		
		/* Annotation */
		if(config.isAnnotation(s)) {
			return UNREADABLE;
		}
		
		String[] parts = s.split(config.getSplitter(s), 2);
		
		/* The Key is Null */
		if(parts[0] == null || parts[0].length() == 0) {
			return UNREADABLE;
		}
		
		/* The Value is Null */
		if(parts[1] == null) {
			parts[1] = "null";
		}
		
		return parts;
		
	}
	
	private static boolean isUnreadable(String[] s) {
		return s[0] == null;
	}
	
}