first textarea implementation

canvas/src/textarea/widget.rs

@@ -0,0 +1,106 @@
+// src/textarea/widget.rs
+#[cfg(feature = "gui")]
+use ratatui::{
+    buffer::Buffer,
+    layout::{Alignment, Rect},
+    style::Style,
+    text::{Line, Span},
+    widgets::{
+        Block, BorderType, Borders, Paragraph, StatefulWidget, Widget, Wrap,
+    },
+};
+
+#[cfg(feature = "gui")]
+use crate::data_provider::DataProvider; // bring trait into scope
+
+#[cfg(feature = "gui")]
+use crate::textarea::state::TextAreaState;
+
+#[cfg(feature = "gui")]
+#[derive(Debug, Clone)]
+pub struct TextArea<'a> {
+    pub(crate) block: Option<Block<'a>>,
+    pub(crate) style: Style,
+    pub(crate) border_type: BorderType,
+}
+
+#[cfg(feature = "gui")]
+impl<'a> Default for TextArea<'a> {
+    fn default() -> Self {
+        Self {
+            block: Some(
+                Block::default()
+                    .borders(Borders::ALL)
+                    .border_type(BorderType::Rounded),
+            ),
+            style: Style::default(),
+            border_type: BorderType::Rounded,
+        }
+    }
+}
+
+#[cfg(feature = "gui")]
+impl<'a> TextArea<'a> {
+    pub fn block(mut self, block: Block<'a>) -> Self {
+        self.block = Some(block);
+        self
+    }
+
+    pub fn style(mut self, style: Style) -> Self {
+        self.style = style;
+        self
+    }
+
+    pub fn border_type(mut self, ty: BorderType) -> Self {
+        self.border_type = ty;
+        if let Some(b) = &mut self.block {
+            *b = b.clone().border_type(ty);
+        }
+        self
+    }
+}
+
+#[cfg(feature = "gui")]
+impl<'a> StatefulWidget for TextArea<'a> {
+    type State = TextAreaState;
+
+    fn render(self, area: Rect, buf: &mut Buffer, state: &mut Self::State) {
+        state.ensure_visible(area, self.block.as_ref());
+
+        let inner = if let Some(b) = &self.block {
+            b.clone().render(area, buf);
+            b.inner(area)
+        } else {
+            area
+        };
+
+        let total = state.editor.data_provider().line_count();
+        let start = state.scroll_y as usize;
+        let end = start
+            .saturating_add(inner.height as usize)
+            .min(total);
+
+        let mut display_lines: Vec<Line> = Vec::with_capacity(end - start);
+
+        if start >= end {
+            if let Some(ph) = &state.placeholder {
+                display_lines.push(Line::from(Span::raw(ph.clone())));
+            }
+        } else {
+            for i in start..end {
+                let s = state.editor.data_provider().field_value(i);
+                display_lines.push(Line::from(Span::raw(s.to_string())));
+            }
+        }
+
+        let mut p = Paragraph::new(display_lines)
+            .alignment(Alignment::Left)
+            .style(self.style);
+
+        if state.wrap {
+            p = p.wrap(Wrap { trim: false });
+        }
+
+        p.render(inner, buf);
+    }
+}