Minecraft implementation (#6)

* Initial minecraft support

* Made previews_chat an option

* Better error handling and removed version structure

* Minecraft Server types

* Fixed compilation and renamed stuff

* 'extract till you drop!' extracted sockets

* extracted java version and fixed socket udp receive

* Legacy 1.4 and 1.6 implementation (incomplete)

* Furter implementation

* Implementations work

* Protocol beta v1.8+ implemented

* Removed bedrock support

* Added auto query

* Renamed minecraft to mc and added to md's

* Docs, renames and small optimization changes

* Changed java version to be able to return None on players sample

src/protocols/minecraft/protocol/legacy_v1_6.rs

@@ -0,0 +1,103 @@
+use crate::{GDError, GDResult};
+use crate::protocols::minecraft::{LegacyGroup, Response, Server};
+use crate::protocols::types::TimeoutSettings;
+use crate::socket::{Socket, TcpSocket};
+use crate::utils::buffer::{get_string_utf16_be, get_u16_be, get_u8};
+
+pub struct LegacyV1_6 {
+    socket: TcpSocket
+}
+
+impl LegacyV1_6 {
+    fn new(address: &str, port: u16, timeout_settings: Option<TimeoutSettings>) -> GDResult<Self> {
+        let socket = TcpSocket::new(address, port)?;
+        socket.apply_timeout(timeout_settings)?;
+
+        Ok(Self {
+            socket
+        })
+    }
+
+    fn send_initial_request(&mut self) -> GDResult<()> {
+        self.socket.send(&[
+            // Packet ID (FE)
+            0xfe,
+            // Ping payload (01)
+            0x01,
+            // Packet identifier for plugin message
+            0xfa,
+            // Length of 'GameDig' string (7) as unsigned short
+            0x00, 0x07,
+            // 'GameDig' string as UTF-16BE
+            0x00, 0x47, 0x00, 0x61, 0x00, 0x6D, 0x00, 0x65, 0x00, 0x44, 0x00, 0x69, 0x00, 0x67])?;
+
+        Ok(())
+    }
+
+    pub fn is_protocol(buf: &[u8], pos: &mut usize) -> GDResult<bool> {
+        let state = buf[*pos..].starts_with(&[0x00, 0xA7, 0x00, 0x31, 0x00, 0x00]);
+
+        if state {
+            *pos += 6;
+        }
+
+        Ok(state)
+    }
+
+    pub fn get_response(buf: &[u8], pos: &mut usize) -> GDResult<Response> {
+        let packet_string = get_string_utf16_be(&buf, pos)?;
+
+        let split: Vec<&str> = packet_string.split("\x00").collect();
+        if split.len() != 5 {
+            return Err(GDError::PacketBad("Not right split size".to_string()));
+        }
+
+        let version_protocol = split[0].parse()
+            .map_err(|_| GDError::PacketBad("Expected int".to_string()))?;
+        let version_name = split[1].to_string();
+        let description = split[2].to_string();
+        let max_players = split[3].parse()
+            .map_err(|_| GDError::PacketBad("Expected int".to_string()))?;
+        let online_players = split[4].parse()
+            .map_err(|_| GDError::PacketBad("Expected int".to_string()))?;
+
+        Ok(Response {
+            version_name,
+            version_protocol,
+            max_players,
+            online_players,
+            sample_players: None,
+            description,
+            favicon: None,
+            previews_chat: None,
+            enforces_secure_chat: None,
+            server_type: Server::Legacy(LegacyGroup::V1_6)
+        })
+    }
+
+    fn get_info(&mut self) -> GDResult<Response> {
+        self.send_initial_request()?;
+
+        let buf = self.socket.receive(None)?;
+        let mut pos = 0;
+
+        if get_u8(&buf, &mut pos)? != 0xFF {
+            return Err(GDError::PacketBad("Expected 0xFF".to_string()));
+        }
+
+        let length = get_u16_be(&buf, &mut pos)? * 2;
+        if buf.len() != (length + 3) as usize { //+ 3 because of the first byte and the u16
+            return Err(GDError::PacketBad("Not right size".to_string()));
+        }
+
+        if !LegacyV1_6::is_protocol(&buf, &mut pos)? {
+            return Err(GDError::PacketBad("Not good".to_string()));
+        }
+
+        LegacyV1_6::get_response(&buf, &mut pos)
+    }
+
+    pub fn query(address: &str, port: u16, timeout_settings: Option<TimeoutSettings>) -> GDResult<Response> {
+        LegacyV1_6::new(address, port, timeout_settings)?.get_info()
+    }
+}