# mudlib

Telnet MUD engine built on telnetlib3. Python 3.12+, managed with uv.

## Commands

- `just check` - lint (ruff --fix + format), typecheck (ty), test (pytest)
- `just lint` / `just typecheck` / `just test` - individual steps
- `just run` - start the server (`python -m mudlib`)
- `just debug` - start with debug logging
- `just render` - generate full world map HTML in `build/`

## Project Layout

- `src/mudlib/` - the engine (commands, world, combat, render, store)
- `tests/` - pytest tests
- `content/` - content definitions (commands, combat moves) loaded at runtime
- `worlds/` - world definition files (yaml/toml, version controlled)
- `docs/` - project knowledge (see below)
- `DREAMBOOK.md` - the vision, philosophy, wild ideas. not a spec
- `scripts/` - standalone tools (map renderer, etc)
- `build/` - generated output (gitignored)
- `repos/` - symlinked reference repos, gitignored, not our code. includes:
  - `repos/viola/` - DFillmore/viola z-machine interpreter (working, global state)
  - `repos/zvm/` - sussman/zvm z-machine interpreter (clean architecture, half-built)
  - `repos/telnetlib3/`, `repos/miniboa/` - telnet libraries

## Docs

Consult `docs/index.rst` when starting unfamiliar work to find relevant docs.

Three categories in `docs/`. Plain text or rst, not markdown.

- `docs/how/` - how things work. write one when you build something non-obvious.
  terrain generation, command system, etc. aimed at someone reading the code
  who wants the "why did we do it this way" context.
- `docs/why/` - design philosophy. telnet-first, text worlds, etc. the reasoning
  behind big decisions. doesn't change often.
- `docs/lessons/` - things we learned the hard way. write one when you hit a
  real bug or gotcha that cost time. charset-vs-mtts, etc. include the fix so
  we don't repeat it.

Update docs when:
- you build a new system (add a how/)
- you make a design decision worth explaining (add a why/)
- you debug something painful (add a lessons/)
- existing docs become wrong (update them)

## Architecture

- telnetlib3 is a **dependency**, not vendored. contribute fixes upstream
- telnetlib3 gives us: GMCP, MSDP, NAWS, async server, reader/writer streams
- game loop is tick-based (async task alongside telnet server)
- world is toroidal (wraps in both axes). terrain noise tiles seamlessly
- world definitions live in data files, runtime state lives in memory
- SQLite for persistence (player accounts, progress)
- session mode stack filters what events reach the player (normal/combat/editor)
- combat system: state machine with TOML-defined moves (attacks, defends, counters). see `docs/how/combat.rst`
  - moves with directional variants (punch left/right) use a single TOML with `[variants]` sections
  - commands are always single words; direction is an argument, not part of the command name
- content loading: TOML definitions for commands and combat moves, loaded at startup
- entity model: Entity base class, Player and Mob subclasses sharing common interface
- editor mode: in-world text editor with syntax highlighting and search/replace
- IF mode: interactive fiction via dfrotz subprocess, mode stack integration, spectator broadcasting. see `docs/how/if-terminal.txt`

## Style

- simple > clever
- no mock implementations
- match existing patterns in each file