package org.bukkit.craftbukkit.updater;

import com.google.gson.FieldNamingPolicy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import org.bukkit.Bukkit;

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Type;
import java.net.URL;
import java.net.URLConnection;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.logging.Level;

public class BukkitDLUpdaterService
{
	private static final String API_PREFIX_ARTIFACT = "/api/1.0/downloads/projects/craftbukkit/view/";
	private static final String API_PREFIX_CHANNEL = "/api/1.0/downloads/channels/";
	private static final DateDeserializer dateDeserializer = new DateDeserializer();
	private final String host;

	public BukkitDLUpdaterService(String host)
	{
		this.host = host;
	}

	public ArtifactDetails getArtifact(String slug, String name)
	{
		try
		{
			return fetchArtifact(slug);
		} catch(UnsupportedEncodingException ex)
		{
			Bukkit.getLogger().log(Level.WARNING, "Could not get " + name + ": " + ex.getClass().getSimpleName());
		} catch(IOException ex)
		{
			Bukkit.getLogger().log(Level.WARNING, "Could not get " + name + ": " + ex.getClass().getSimpleName());
		}

		return null;
	}

	private String getUserAgent()
	{
		return "CraftBukkit/" + BukkitDLUpdaterService.class.getPackage().getImplementationVersion() + "/" + System.getProperty("java.version");
	}

	public ArtifactDetails fetchArtifact(String slug) throws IOException
	{
		URL url = new URL("http", host, API_PREFIX_ARTIFACT + slug + "/");
		InputStreamReader reader = null;

		try
		{
			URLConnection connection = url.openConnection();
			connection.setRequestProperty("User-Agent", getUserAgent());
			reader = new InputStreamReader(connection.getInputStream());
			Gson gson = new GsonBuilder().registerTypeAdapter(Date.class, dateDeserializer).setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES).create();
			return gson.fromJson(reader, ArtifactDetails.class);
		} finally
		{
			if(reader != null)
			{
				reader.close();
			}
		}
	}

	public ArtifactDetails.ChannelDetails getChannel(String slug, String name)
	{
		try
		{
			return fetchChannel(slug);
		} catch(UnsupportedEncodingException ex)
		{
			Bukkit.getLogger().log(Level.WARNING, "Could not get " + name + ": " + ex.getClass().getSimpleName());
		} catch(IOException ex)
		{
			Bukkit.getLogger().log(Level.WARNING, "Could not get " + name + ": " + ex.getClass().getSimpleName());
		}

		return null;
	}

	public ArtifactDetails.ChannelDetails fetchChannel(String slug) throws IOException
	{
		URL url = new URL("http", host, API_PREFIX_CHANNEL + slug + "/");
		InputStreamReader reader = null;

		try
		{
			URLConnection connection = url.openConnection();
			connection.setRequestProperty("User-Agent", getUserAgent());
			reader = new InputStreamReader(connection.getInputStream());
			Gson gson = new GsonBuilder().registerTypeAdapter(Date.class, dateDeserializer).setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES).create();

			return gson.fromJson(reader, ArtifactDetails.ChannelDetails.class);
		} finally
		{
			if(reader != null)
			{
				reader.close();
			}
		}
	}

	static class DateDeserializer implements JsonDeserializer<Date>
	{
		private static final SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

		public Date deserialize(JsonElement je, Type type, JsonDeserializationContext jdc) throws JsonParseException
		{
			try
			{
				return format.parse(je.getAsString());
			} catch(ParseException ex)
			{
				throw new JsonParseException("Date is not formatted correctly", ex);
			}
		}
	}
}