bobatea 0.0.2

Terminal layout + styling you won't hate.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242

//! Scrollable viewport that crops a larger virtual area into a visible window.
//!
//! ```rust
//! use bobatea::components::viewport::Viewport;
//! let vp = Viewport::new(80, 40); // virtual 80x40
//! ```

use {
    crate::components::{Component, block::BobaBlock, style::BobaStyle},
    crossterm::event::{KeyCode, MouseEvent, MouseEventKind},
    futures_signals::signal::Mutable,
    ratatui::{
        prelude::{Buffer, Frame, Rect},
        widgets::Widget,
    },
};

/// A scrollable viewport into a larger virtual canvas.
pub struct Viewport {
    virtual_width: u16,
    virtual_height: u16,
    scroll_x: Mutable<u16>,
    scroll_y: Mutable<u16>,
    focused: Mutable<bool>,
    show_borders: bool,
    show_scrollbars: bool,
}

impl Viewport {
    pub fn new(vw: u16, vh: u16) -> Self {
        Self {
            virtual_width: vw,
            virtual_height: vh,
            scroll_x: Mutable::new(0),
            scroll_y: Mutable::new(0),
            focused: Mutable::new(false),
            show_borders: true,
            show_scrollbars: true,
        }
    }

    pub fn without_borders(mut self) -> Self {
        self.show_borders = false;
        self
    }

    pub fn without_scrollbars(mut self) -> Self {
        self.show_scrollbars = false;
        self
    }

    pub fn focus(&self) { self.focused.set(true); }

    pub fn blur(&self) { self.focused.set(false); }

    pub fn scroll_to(&self, x: u16, y: u16) {
        self.scroll_x.set(x);
        self.scroll_y.set(y);
    }

    pub fn on_key(&self, code: KeyCode, area: Rect) {
        if !self.focused.get() {
            return;
        }
        let mut sx = self.scroll_x.get();
        let mut sy = self.scroll_y.get();
        let max_x = self.virtual_width.saturating_sub(area.width.saturating_sub(2));
        let max_y = self.virtual_height.saturating_sub(area.height.saturating_sub(2));
        match code {
            KeyCode::Left => sx = sx.saturating_sub(1),
            KeyCode::Right => sx = (sx + 1).min(max_x),
            KeyCode::Up => sy = sy.saturating_sub(1),
            KeyCode::Down => sy = (sy + 1).min(max_y),
            KeyCode::Home => sx = 0,
            KeyCode::End => sx = max_x,
            KeyCode::PageUp => sy = sy.saturating_sub(area.height.saturating_sub(2)),
            KeyCode::PageDown => sy = (sy + area.height.saturating_sub(2)).min(max_y),
            _ => {}
        }
        self.scroll_x.set(sx);
        self.scroll_y.set(sy);
    }

    pub fn on_mouse(&self, area: Rect, ev: &MouseEvent) {
        let inner = Rect {
            x: area.x + 1,
            y: area.y + 1,
            width: area.width.saturating_sub(2),
            height: area.height.saturating_sub(2),
        };
        match ev.kind {
            MouseEventKind::Down(_) | MouseEventKind::Drag(_) => {
                if !is_inside(area, ev) {
                    return;
                }
                // Horizontal scrollbar hit
                if self.virtual_width > inner.width {
                    let bar_y = area.bottom().saturating_sub(1);
                    if ev.row == bar_y {
                        let thumb_w = (inner.width as f64 / self.virtual_width as f64 * inner.width as f64) as u16;
                        let thumb_x = (self.scroll_x.get() as f64 / (self.virtual_width - inner.width) as f64
                            * (inner.width - thumb_w) as f64) as u16;
                        let rel_x = ev.column.saturating_sub(inner.x);
                        if rel_x >= thumb_x && rel_x < thumb_x + thumb_w {
                            // Drag thumb — not fully implemented without drag state
                        } else {
                            let mut sx = ((rel_x as f64 / inner.width as f64) * self.virtual_width as f64) as u16;
                            let max_x = self.virtual_width.saturating_sub(inner.width);
                            sx = sx.min(max_x);
                            self.scroll_x.set(sx);
                        }
                    }
                }
                // Vertical scrollbar hit
                if self.virtual_height > inner.height {
                    let bar_x = area.right().saturating_sub(1);
                    if ev.column == bar_x {
                        let thumb_h = (inner.height as f64 / self.virtual_height as f64 * inner.height as f64) as u16;
                        let thumb_y = (self.scroll_y.get() as f64 / (self.virtual_height - inner.height) as f64
                            * (inner.height - thumb_h) as f64) as u16;
                        let rel_y = ev.row.saturating_sub(inner.y);
                        if rel_y >= thumb_y && rel_y < thumb_y + thumb_h {
                            // Drag thumb
                        } else {
                            let mut sy = ((rel_y as f64 / inner.height as f64) * self.virtual_height as f64) as u16;
                            let max_y = self.virtual_height.saturating_sub(inner.height);
                            sy = sy.min(max_y);
                            self.scroll_y.set(sy);
                        }
                    }
                }
            }
            MouseEventKind::ScrollUp => {
                let mut sy = self.scroll_y.get().saturating_sub(1);
                let max_y = self.virtual_height.saturating_sub(inner.height);
                sy = sy.min(max_y);
                self.scroll_y.set(sy);
            }
            MouseEventKind::ScrollDown => {
                let mut sy = self.scroll_y.get() + 1;
                let max_y = self.virtual_height.saturating_sub(inner.height);
                sy = sy.min(max_y);
                self.scroll_y.set(sy);
            }
            MouseEventKind::ScrollLeft => {
                let mut sx = self.scroll_x.get().saturating_sub(1);
                let max_x = self.virtual_width.saturating_sub(inner.width);
                sx = sx.min(max_x);
                self.scroll_x.set(sx);
            }
            MouseEventKind::ScrollRight => {
                let mut sx = self.scroll_x.get() + 1;
                let max_x = self.virtual_width.saturating_sub(inner.width);
                sx = sx.min(max_x);
                self.scroll_x.set(sx);
            }
            _ => {}
        }
    }

    /// Return the visible sub-rect inside the virtual canvas.
    pub fn visible_area(&self, container: Rect) -> Rect {
        let inner_w = container.width.saturating_sub(if self.show_borders { 2 } else { 0 });
        let inner_h = container.height.saturating_sub(if self.show_borders { 2 } else { 0 });
        Rect {
            x: self.scroll_x.get(),
            y: self.scroll_y.get(),
            width: inner_w.min(self.virtual_width),
            height: inner_h.min(self.virtual_height),
        }
    }

    pub fn render_to_buf<F: FnOnce(Rect, &mut Buffer)>(&self, area: Rect, buf: &mut Buffer, content: F) {
        let focused = self.focused.get();
        let inner = Rect {
            x: area.x + 1,
            y: area.y + 1,
            width: area.width.saturating_sub(2),
            height: area.height.saturating_sub(2),
        };

        // draw content
        let visible = self.visible_area(area);
        let mut scratch = Buffer::empty(inner);
        content(visible, &mut scratch);
        for y in inner.top()..inner.bottom() {
            for x in inner.left()..inner.right() {
                buf[(x, y)] = scratch[(x, y)].clone();
            }
        }

        // borders
        if self.show_borders {
            let style = if focused { BobaStyle::new().accent() } else { BobaStyle::new().rounded() };
            let block: ratatui::widgets::Block<'_> = BobaBlock::new().rounded().border_style(style).into();
            block.render(area, buf);
        }

        // scrollbars
        if self.show_scrollbars {
            if self.virtual_width > inner.width {
                let thumb_w = (inner.width as f64 / self.virtual_width as f64 * inner.width as f64) as u16;
                let thumb_x = (self.scroll_x.get() as f64 / (self.virtual_width - inner.width) as f64
                    * (inner.width - thumb_w) as f64) as u16;
                for x in 0..inner.width {
                    let pos = inner.x + x;
                    let ch = if x >= thumb_x && x < thumb_x + thumb_w { '█' } else { '░' };
                    buf[(pos, area.bottom().saturating_sub(1))].set_char(ch);
                }
            }
            if self.virtual_height > inner.height {
                let thumb_h = (inner.height as f64 / self.virtual_height as f64 * inner.height as f64) as u16;
                let thumb_y = (self.scroll_y.get() as f64 / (self.virtual_height - inner.height) as f64
                    * (inner.height - thumb_h) as f64) as u16;
                for y in 0..inner.height {
                    let pos = inner.y + y;
                    let ch = if y >= thumb_y && y < thumb_y + thumb_h { '█' } else { '░' };
                    buf[(area.right().saturating_sub(1), pos)].set_char(ch);
                }
            }
        }
    }
}

impl Component for Viewport {
    fn render(&mut self, ctx: &mut Frame<'_>, theme: &crate::theme::Theme) {
        let area = ctx.area();
        let buf = ctx.buffer_mut();
        for y in area.top()..area.bottom() {
            for x in area.left()..area.right() {
                buf[(x, y)].set_bg(theme.global_bg);
            }
        }
        self.render_to_buf(area, buf, |_view, _buf| {
            // default no-op; users usually wrap with a closure
        });
    }
}

fn is_inside(area: Rect, ev: &MouseEvent) -> bool {
    ev.column >= area.left() && ev.column < area.right() && ev.row >= area.top() && ev.row < area.bottom()
}