docs: document usage, api and floor format in readme

readme.md

@@ -1,31 +1,169 @@
 # Python Dungeon Generator
-This is a simple dungeon generator.
-It uses a simple algorithm to generate a random dungeon. 
-The algorithm is based of the generator from the game "The Binding of Isaac"
+
+A small generator for 2D dungeon floors.
+The algorithm is based on the floor generation of the game "The Binding of Isaac",
 which is described in this [article](https://www.boristhebrave.com/2020/09/12/dungeon-generation-in-binding-of-isaac/).
 
-## Usage
-The dungeon generator can be used with an ui or without.
-The ui is a simple tkinter window which shows the generated dungeon.
-It also can be used as a rest endpoint.
-
-## Generated Dungeon
-The dungeon gets generated as a json file.
-The json file contains the following information:
-- The seed the dungeon was generated with
-- Width and height of the dungeon
-- The floor layout
-  - A list of all rooms
-  - Each room contains the following information
-    - The room id
-    - The room type
-    - x and y position
-    - a list of all door positions
-
-### Room Types
-- 0: Normal Room
-- 1: Dead End
-- 2: Item Room
-- 3: Shop
-- 4: Start Room
-- 5: Teleport Room
+A floor is a grid of 9 × 8 cells with a start room, normal rooms, dead ends and a boss room.
+Depending on the layout it also contains an item room, a shop and secret rooms.
+The same seed and floor id always produce the same floor.
+
+The generator can be used in three ways:
+
+- as a [command line tool](#command-line) that writes the floor to a JSON file
+- with a [Tkinter UI](#user-interface) that draws the floors
+- as a [REST API](#rest-api) that returns the floor as JSON
+
+## Installation
+
+Requires Python 3.12 or newer. The UI additionally needs Tkinter
+(on Debian/Ubuntu: `apt install python3-tk`).
+
+```bash
+pip install -r requirements.txt
+```
+
+## Command line
+
+```bash
+python src/main.py -s my-seed -f 3 -o my-floor
+```
+
+| Option | Description | Default |
+|---|---|---|
+| `-s`, `--seed` | Seed for the random number generator | random seed |
+| `-f`, `--floor` | Floor id, must be 0 or greater. Higher floor ids get more rooms (at most 15) | `2` |
+| `-o`, `--output` | Name of the output file | `floor` |
+| `-u`, `--ui` | Opens the UI instead of writing a file | disabled |
+| `-h`, `--help` | Shows the help | |
+
+The floor is saved in the `generation` folder in the project root.
+A number based on the current time is appended to the file name, e.g. `generation/my-floor123456.json`.
+
+## User interface
+
+```bash
+python src/main.py --ui
+```
+
+The UI draws a generated floor room by room. Every generated floor is kept,
+so you can switch between them.
+
+| Key | Action |
+|---|---|
+| `Space` | Generate a new floor with the seed from the "Next seed" field |
+| `Enter` in "Next seed" | Generate a new floor with the entered seed |
+| `←` / `→` | Switch to the previous / next floor |
+| `Ctrl+O` | Open a floor from a JSON file |
+| `Ctrl+S` | Save the current floor |
+| `Ctrl+Shift+S` | Save the current floor as a new file |
+| `Ctrl+T` | Switch between light and dark theme |
+| `F1` | Show the legend of the room colors |
+| `Ctrl+Q` | Quit |
+
+## REST API
+
+```bash
+pip install -r requirements.txt
+python -m uvicorn controller:app --app-dir src --port 8000
+```
+
+Or with Docker:
+
+```bash
+docker build -t dungeon-python .
+docker run -p 8000:8000 dungeon-python
+```
+
+| Endpoint | Description |
+|---|---|
+| `GET /gen` | Floor with id 0 and a random seed |
+| `GET /gen/{floor_id}` | Floor with the given id and a random seed |
+| `GET /gen/{floor_id}/{seed}` | Floor with the given id and seed |
+
+All endpoints return the floor as `application/json` with the file name `floor.json`.
+A negative floor id returns `422`.
+
+## Floor format
+
+```json
+{
+  "_width": 9,
+  "_height": 8,
+  "_floor": {
+    "_seed": "2",
+    "_rooms": [
+      {
+        "_doors": [2],
+        "_id": 0,
+        "_type": 4,
+        "_x": 3,
+        "_y": 0
+      },
+      {
+        "_doors": [3, 2],
+        "_id": 12,
+        "_type": 5,
+        "_x": 8,
+        "_y": 1,
+        "_connected_room_id": 3
+      }
+    ]
+  },
+  "_generated_by": "python"
+}
+```
+
+| Field | Description |
+|---|---|
+| `_width`, `_height` | Size of the floor in rooms |
+| `_floor._seed` | Seed the floor was generated with |
+| `_floor._rooms` | List of all rooms |
+| `_id` | Id of the room, unique within the floor |
+| `_type` | [Room type](#room-types) |
+| `_x`, `_y` | Position of the room. `0, 0` is the top left corner, `y` grows downwards |
+| `_doors` | [Doors](#doors) of the room |
+| `_connected_room_id` | Only for teleport rooms: id of the room the teleport leads to |
+
+### Room types
+
+| Value | Type |
+|---|---|
+| 0 | Normal room |
+| 1 | Dead end |
+| 2 | Item room |
+| 3 | Shop |
+| 4 | Start room |
+| 5 | Teleport room |
+| 6 | Boss room |
+| 7 | Secret room |
+
+A boss room can span up to 2 × 2 cells, every cell is stored as its own room.
+On some floors the boss room is moved to a free cell away from the other rooms
+and can only be reached through a teleport room.
+
+### Doors
+
+| Value | Door |
+|---|---|
+| 0 | Top |
+| 1 | Right |
+| 2 | Bottom |
+| 3 | Left |
+
+## Development
+
+```bash
+pip install -r requirements-dev.txt
+```
+
+| Check | Command |
+|---|---|
+| Tests | `pytest` |
+| Formatting | `black --check src test` |
+| Linting | `pylint src --rcfile=.pylintrc` and `flake8 src test` |
+| Type checks | `mypy` |
+
+The UI tests are skipped when no display is available. On Linux they can be run with `xvfb-run -a pytest`.
+
+Pull requests target the `dev` branch.