# Clojure TUI

A terminal user interface framework for Clojure, inspired by [Bubbletea](https://github.com/charmbracelet/bubbletea) (Go). Build interactive CLI applications using the Elm Architecture with Hiccup-style views.

![Counter Example](assets/counter.gif)

## Features

- **Elm Architecture** - Predictable state management with `init`, `update`, and `view`
- **Hiccup Views** - Declarative UI with familiar Clojure syntax
- **Async Commands** - Timers, batched operations, and custom async functions
- **Rich Styling** - Colors (16, 256, true color), bold, italic, underline, and more
- **Layout System** - Rows, columns, and boxes with borders
- **Input Handling** - Full keyboard support including arrows, function keys, and modifiers
- **Babashka Compatible** - Fast startup with Babashka or full Clojure

## Quick Start

### Installation

Add to your `deps.edn`:

```clojure
{:deps {io.github.yourname/clojure-tui {:git/tag "v0.1.0" :git/sha "..."}}}
```

### Hello World

```clojure
(ns myapp.core
  (:require [tui.core :as tui]))

(defn update-fn [model msg]
  (if (tui/key= msg "q")
    [model tui/quit]
    [model nil]))

(defn view [model _size]
  [:col
   [:text {:fg :cyan :bold true} "Hello, TUI!"]
   [:text {:fg :gray} "Press q to quit"]])

(tui/run {:init {}
          :update update-fn
          :view view})
```

Output:
```
Hello, TUI!
Press q to quit
```

### Counter Example

```clojure
(ns myapp.counter
  (:require [tui.core :as tui]))

(defn update-fn [model msg]
  (cond
    (tui/key= msg "q")     [model tui/quit]
    (tui/key= msg "k")     [(inc model) nil]
    (tui/key= msg "j")     [(dec model) nil]
    (tui/key= msg "r")     [0 nil]
    :else                  [model nil]))

(defn view [model _size]
  [:col
   [:box {:border :rounded :padding [0 2]}
    [:text {:fg :yellow :bold true} (str "Count: " model)]]
   [:text {:fg :gray} "j/k: change  r: reset  q: quit"]])

(tui/run {:init 0
          :update update-fn
          :view view})
```

Output:
```
╭──────────────╮
│  Count: 0    │
╰──────────────╯
j/k: change  r: reset  q: quit
```

## Examples

### Counter
Simple counter demonstrating basic Elm Architecture.

![Counter](assets/counter.gif)

```bash
bb counter
```

### Timer
Countdown timer with pause/resume - demonstrates async commands.

![Timer](assets/timer.gif)

```bash
bb timer
```

### List Selection
Multi-select list with cursor navigation.

![List Selection](assets/list.gif)

```bash
bb list
```

### Spinner
Animated loading spinners with multiple styles.

![Spinner](assets/spinner.gif)

```bash
bb spinner
```

### Views
State machine pattern with multiple views and navigation.

![Views](assets/views.gif)

```bash
bb views
```

### HTTP
Async HTTP requests with loading states.

![HTTP](assets/http.gif)

```bash
bb http
```

### Running Examples

Run examples with Babashka (recommended for fast startup):

```bash
bb counter
bb timer
```

Or with full Clojure:

```bash
clojure -A:dev -M -m examples.counter
```

## Documentation

- [Getting Started](docs/getting-started.md) - Installation, first app, core concepts
- [Hiccup Views](docs/hiccup-views.md) - View elements, styling, and layout
- [API Reference](docs/api-reference.md) - Complete API documentation
- [Examples](docs/examples.md) - Annotated example applications

## Architecture

```
View (hiccup) → Render (ANSI string) → Terminal (raw mode I/O)
     ↑                                        │
     │                                        v
   Model  ←──────── Update ←─────────── Input (key parsing)
```

The application follows the Elm Architecture:

1. **Model** - Your application state (any Clojure data structure)
2. **Update** - A pure function `(fn [model msg] [new-model cmd])` that handles messages
3. **View** - A pure function `(fn [model size] hiccup)` that renders the UI, where `size` is `{:width w :height h}`

## Hiccup View Elements

| Element | Description | Example |
|---------|-------------|---------|
| `:text` | Styled text | `[:text {:fg :red :bold true} "Error"]` |
| `:row` | Horizontal layout | `[:row "Left" "Right"]` |
| `:col` | Vertical layout | `[:col "Line 1" "Line 2"]` |
| `:box` | Bordered container | `[:box {:border :rounded} "Content"]` |
| `:space` | Empty space | `[:space {:width 5}]` |

## Commands

Commands are returned from your `update` function to trigger side effects:

| Command | Description |
|---------|-------------|
| `tui/quit` | Exit the application |
| `(tui/tick ms)` | Send `:tick` after ms milliseconds |
| `(tui/batch c1 c2)` | Run commands in parallel |
| `(tui/sequentially c1 c2)` | Run commands sequentially |
| `(fn [] msg)` | Custom async function returning a message |

## Key Matching

```clojure
(tui/key= msg "q")        ;; Character
(tui/key= msg :enter)     ;; Special key
(tui/key= msg :up)        ;; Arrow
(tui/key= msg [:ctrl \c]) ;; Control combo
(tui/key= msg [:alt \x])  ;; Alt combo
```

## Project Structure

```
src/
  tui/
    core.clj      # Main runtime (Elm architecture + async commands)
    render.clj    # Hiccup → ANSI
    terminal.clj  # Raw mode, input/output
    input.clj     # Key parsing
    ansi.clj      # ANSI codes, colors
examples/
    counter.clj
    timer.clj
    list_selection.clj
    spinner.clj
    views.clj
    http.clj
```

## License

MIT