package mightypork.utils.config;


import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import mightypork.utils.files.FileUtils;
import mightypork.utils.logging.Log;


/**
 * Utility for parsing simple config files<br>
 * # and // mark a comment<br>
 * empty lines and lines without "=" are ignored<br>
 * lines with "=" must have "key = value" format, or a warning is logged.<br>
 * use "NULL" to create empty value.
 * 
 * @author Ondřej Hruška (MightyPork)
 */
public class SimpleConfig {
	
	/**
	 * Load list from file
	 * 
	 * @param file file
	 * @return map of keys and values
	 * @throws IOException
	 */
	public static List<String> listFromFile(File file) throws IOException
	{
		final String fileText = FileUtils.fileToString(file);
		
		return listFromString(fileText);
	}
	
	
	/**
	 * Load map from file
	 * 
	 * @param file file
	 * @return map of keys and values
	 * @throws IOException
	 */
	public static Map<String, String> mapFromFile(File file) throws IOException
	{
		final String fileText = FileUtils.fileToString(file);
		
		return mapFromString(fileText);
	}
	
	
	/**
	 * Load list from string
	 * 
	 * @param text text of the file
	 * @return map of keys and values
	 */
	public static List<String> listFromString(String text)
	{
		final List<String> list = new ArrayList<>();
		
		final String[] groupsLines = text.split("\n");
		
		for (String s : groupsLines) {
			// ignore invalid lines
			if (s.length() == 0) continue;
			if (s.startsWith("#") || s.startsWith("//")) continue;
			
			// NULL value
			if (s.equalsIgnoreCase("NULL")) s = null;
			
			if (s != null) s = s.replace("\\n", "\n");
			
			// save extracted key-value pair
			list.add(s);
		}
		
		return list;
	}
	
	
	/**
	 * Load map from string
	 * 
	 * @param text text of the file
	 * @return map of keys and values
	 */
	public static Map<String, String> mapFromString(String text)
	{
		final LinkedHashMap<String, String> pairs = new LinkedHashMap<>();
		
		final String[] groupsLines = text.split("\n");
		
		for (final String s : groupsLines) {
			// ignore invalid lines
			if (s.length() == 0) continue;
			if (s.startsWith("#") || s.startsWith("//")) continue;
			if (!s.contains("=")) continue;
			
			// split and trim
			String[] parts = s.split("=");
			for (int i = 0; i < parts.length; i++) {
				parts[i] = parts[i].trim();
			}
			
			// check if both parts are valid
			if (parts.length == 0) {
				Log.w("Bad line in config file: " + s);
				continue;
			}
			
			if (parts.length == 1) {
				parts = new String[] { parts[0], "" };
			}
			
			if (parts.length != 2) {
				Log.w("Bad line in config file: " + s);
				continue;
			}
			
			// NULL value
			if (parts[0].equalsIgnoreCase("NULL")) parts[0] = null;
			if (parts[1].equalsIgnoreCase("NULL")) parts[1] = null;
			
			if (parts[0] != null) parts[0] = parts[0].replace("\\n", "\n");
			if (parts[1] != null) parts[1] = parts[1].replace("\\n", "\n");
			
			// save extracted key-value pair
			pairs.put(parts[0], parts[1]);
		}
		
		return pairs;
	}
	
	
	/**
	 * Save map to file
	 * 
	 * @param target
	 * @param data
	 * @param allowNulls allow nulls.
	 * @throws IOException
	 */
	public static void mapToFile(File target, Map<String, String> data, boolean allowNulls) throws IOException
	{
		final List<String> lines = new ArrayList<>();
		
		for (final Entry<String, String> e : data.entrySet()) {
			String key = e.getKey();
			String value = e.getValue();
			
			if (!allowNulls && (key == null || value == null || key.length() == 0 || value.length() == 0)) continue;
			
			if (key == null) key = "NULL";
			if (value == null) value = "NULL";
			
			key = key.replace("\n", "\\n");
			value = value.replace("\n", "\\n");
			
			lines.add(key + " = " + value);
		}
		
		String text = ""; // # File written by SimpleConfig
		
		for (final String s : lines) {
			if (text.length() > 0) text += "\n";
			
			text += s;
		}
		
		FileUtils.stringToFile(target, text);
		
	}
	
	
	/**
	 * Save list to file
	 * 
	 * @param target
	 * @param data
	 * @throws IOException
	 */
	public static void listToFile(File target, List<String> data) throws IOException
	{
		String text = ""; // # File written by SimpleConfig
		
		for (String s : data) {
			if (text.length() > 0) text += "\n";
			
			if (s == null) s = "NULL";
			
			s = s.replace("\n", "\\n");
			
			text += s;
		}
		
		FileUtils.stringToFile(target, text);
		
	}
}