# Siege durak/Podkidnoy (Throw-in) durak

<img src="durak.png" />

## Description
This is a network-based console version of the classic Russian card game
"Podkidnoy Durak" (Throw-in Fool). Both the client and server are written in
pure C.

TCP/IP sockets are used for network communication, enabling reliable data
transfer via `read` and `write` system calls. The client and server follow an
event-driven programming model using `select()` for I/O multiplexing.

## Gameplay
- Card suits: `%`, `#`, `v`, `^`
- Card ranks: `2`, `3`, `4`, `5`, `6`, `7`, `8`, `9`, `10`, `J`, `Q`, `K`, `A`
- Game phases: attack, defense, and throw-in

The game supports dynamic throw-ins based on real-time player reactions —
whoever throws first, their card is accepted.

## Hint system

Players receive visual hints based on their role:

- Attacker: all cards of matching rank
- Defender: cards that beat the attacking one (higher of same suit or trump)
- Thrower: cards of the same rank as those already on the table

Players may press `Enter` to either surrender the defense or skip the throw-in phase.

The server analyzes each phase:

- Determines whether the defender can beat the attack
- If defense fails, transitions to the throw-in phase
- If no throw-in is possible, moves to the next attack phase

During defense, the defender sees only one attacking card at a time (others see all cards).

## Game State Machine (ASCII Diagram)

```text
+-----------------+
|     ATTACK      |
| (attacker plays)|
+--------+--------+
         |
         v
+-----------------+
|     DEFENSE     |
| (defender tries |
|   to beat cards)|
+--------+--------+
         |
         v
+----------------------------+
| CAN OTHERS THROW-IN?       |
| (same rank as on table)    |
+------+---------------------+
       |YES (NO -- DEFENSE RESULT?)
       v
+----------------------------+
| THROW-IN QUEUE              |
| - If defender already       |
|   failed 1+ cards → put all |
|   queued cards on table     |
| - If still defending well → |
|   throw 1 queued card       |
+------+---------------------+
       |
       v
   (recheck throw-in)
       |
       v
+----------------------------+
| END OF THROW-IN             |
+------+---------------------+
       |
       v
+----------------------------+
| DEFENSE RESULT?             |
| - SUCCESS: defender becomes |
|   next attacker             |
| - FAIL: player after        |
|   defender attacks next     |
+----------------------------+
```

## Features & Technologies

### Technologies

- C programming language — for both client and server
- POSIX sockets — TCP/IP networking
- `select()` system call — event-driven I/O
- Cross-platform — Linux, Windows, Android (via Termux)
- Finite State Machine (FSM) for game phase control**
- Session tracking for each connected client
- Separate adapted Windows client derived from the Linux version

### Gameplay Features
- Full support for "Podkidnoy Durak" rules: attack, defense, throw-in
- Real-time interaction: whoever throws a card first wins the throw-in
- Turn-based logic, respecting the rules of defending, beating, or taking cards
- Hint system based on player role:
    - Attacker — cards of matching rank
    - Defender — suitable beating cards
    - Thrower — cards matching any on the table
- Game logic transparency — only defender sees current attack card; others see all
- Supports multiple clients connected to the same server in real time
- Automatic phase switching based on server logic without client-side decision delays

## Building

### On Linux (MacOS, FreeBSD, Android)

```
git clone https://git.scratko.xyz/durak
cd durak/linux_client
make
./client
```

Note: On Android, use a terminal like `Termux`, and install packages: `clang`, `make`, `git`.

### On Windows

You can download a prebuilt Windows version with the server IP preset:
Windows version: <a href="https://scratko.xyz/games/durak.exe" target="_blank">Download</a>

### Hosting Your Own Server

1. Build and run the server:  
    ```
    ./server 1025
    ```
    Choose a free port (≥1024).

2. Configure the client:  
    Open `linux_client/client.c` or `windows_client/client.c`:
    - Line 14: set your server IP address (e.g., 127.0.0.1 for local)
    - Line 15: set the same port used above

3. Build and run the client (no arguments required).

---

Questions? Contact: m@scratko.xyz