chore: Replace atuin-ai rendering with component-oriented system (#3288)

4 files changed, 716 insertions, 497 deletions

diff --git a/crates/atuin-ai/src/tui/component.rs b/crates/atuin-ai/src/tui/component.rs
new file mode 100644
index 00000000..ff20f195
--- /dev/null
+++ b/crates/atuin-ai/src/tui/component.rs
@@ -0,0 +1,186 @@
+//! Component-oriented rendering primitives for the TUI.
+//!
+//! Defines the `Component` trait and container types (`VStack`, `SymbolRow`, etc.)
+//! that enable declarative, composable UI layout.
+
+use atuin_client::theme::{Meaning, Theme};
+use ratatui::{
+    Frame, backend::FromCrossterm, layout::Rect, style::Style, text::Span, widgets::Paragraph,
+};
+use tui_textarea::TextArea;
+
+/// Context passed through the component tree during rendering.
+pub struct RenderContext<'a> {
+    pub theme: &'a Theme,
+    pub anchor_col: u16,
+    pub textarea: Option<&'a TextArea<'static>>,
+    /// Maximum viewport height (for scroll calculations)
+    pub max_height: u16,
+    /// When true, the viewport is a fixed rect already positioned for the card.
+    /// The card fills the entire viewport instead of positioning via anchor_col.
+    pub popup_mode: bool,
+    /// When true, blocks are rendered in reverse order so that the input field
+    /// appears at the bottom of the card (close to the prompt when the popup
+    /// is above the cursor).
+    pub render_above: bool,
+}
+
+/// A renderable component with intrinsic sizing.
+pub trait Component {
+    /// Calculate the intrinsic height at the given width.
+    fn height(&self, width: u16) -> u16;
+
+    /// Render into the given area.
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext);
+}
+
+/// Vertical stack of components.
+///
+/// Children are laid out top-to-bottom with optional spacing between them.
+/// When `scroll_offset > 0`, content is scrolled so that only the visible
+/// portion is rendered.
+pub struct VStack {
+    pub children: Vec<Box<dyn Component>>,
+    pub spacing: u16,
+    pub scroll_offset: u16,
+}
+
+impl VStack {
+    pub fn new(children: Vec<Box<dyn Component>>) -> Self {
+        Self {
+            children,
+            spacing: 0,
+            scroll_offset: 0,
+        }
+    }
+}
+
+impl Component for VStack {
+    fn height(&self, width: u16) -> u16 {
+        if self.children.is_empty() {
+            return 0;
+        }
+        let content: u16 = self.children.iter().map(|c| c.height(width)).sum();
+        let gaps = (self.children.len() as u16 - 1) * self.spacing;
+        content + gaps
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        if self.children.is_empty() {
+            return;
+        }
+
+        let heights: Vec<u16> = self.children.iter().map(|c| c.height(area.width)).collect();
+
+        let viewport_start = self.scroll_offset;
+        let viewport_end = self.scroll_offset + area.height;
+
+        let mut cum: u16 = 0;
+        for (i, (child, &h)) in self.children.iter().zip(heights.iter()).enumerate() {
+            let child_start = cum;
+            let child_end = cum + h;
+
+            // Render if any part of the child is within the viewport
+            if child_end > viewport_start && child_start < viewport_end {
+                let visible_start = child_start.max(viewport_start);
+                let visible_end = child_end.min(viewport_end);
+
+                let child_area = Rect {
+                    x: area.x,
+                    y: area.y + visible_start - viewport_start,
+                    width: area.width,
+                    height: visible_end - visible_start,
+                };
+
+                child.render(frame, child_area, ctx);
+            }
+
+            cum = child_end;
+            if i < self.children.len() - 1 {
+                cum += self.spacing;
+            }
+        }
+    }
+}
+
+/// Fixed-height empty space.
+pub struct Spacer(pub u16);
+
+impl Component for Spacer {
+    fn height(&self, _width: u16) -> u16 {
+        self.0
+    }
+
+    fn render(&self, _frame: &mut Frame, _area: Rect, _ctx: &RenderContext) {}
+}
+
+/// A row with a symbol in column 0 and content in columns 2+.
+///
+/// This is the horizontal layout primitive used by all content types that
+/// display a prefix symbol (>, $, !, ?, etc.) followed by text.
+pub struct SymbolRow {
+    pub symbol: String,
+    pub symbol_meaning: Meaning,
+    pub inner: Box<dyn Component>,
+}
+
+impl Component for SymbolRow {
+    fn height(&self, width: u16) -> u16 {
+        self.inner.height(width.saturating_sub(2))
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        // Render symbol at column 0, first row only
+        let style = Style::from_crossterm(ctx.theme.as_style(self.symbol_meaning));
+        let symbol_area = Rect {
+            x: area.x,
+            y: area.y,
+            width: 1,
+            height: 1,
+        };
+        frame.render_widget(
+            Paragraph::new(self.symbol.as_str()).style(style),
+            symbol_area,
+        );
+
+        // Render inner content at column 2+
+        let content_area = Rect {
+            x: area.x.saturating_add(2),
+            y: area.y,
+            width: area.width.saturating_sub(2),
+            height: area.height,
+        };
+        self.inner.render(frame, content_area, ctx);
+    }
+}
+
+/// Horizontal separator spanning the full card width (├───┤).
+///
+/// Extends beyond its content area to overlap the card's left and right borders.
+pub struct Separator {
+    pub card_width: u16,
+}
+
+impl Component for Separator {
+    fn height(&self, _width: u16) -> u16 {
+        1
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
+        let inner_width = self.card_width.saturating_sub(2) as usize;
+        let separator = format!(
+            "\u{251c}{}\u{2524}",           // ├ ... ┤
+            "\u{2500}".repeat(inner_width)  // ─
+        );
+
+        // Extend left to overlap the card border (content area is inset by border + padding)
+        let sep_area = Rect {
+            x: area.x.saturating_sub(2),
+            y: area.y,
+            width: self.card_width,
+            height: 1,
+        };
+        frame.render_widget(Paragraph::new(Span::styled(separator, style)), sep_area);
+    }
+}
diff --git a/crates/atuin-ai/src/tui/components.rs b/crates/atuin-ai/src/tui/components.rs
new file mode 100644
index 00000000..50abd8c1
--- /dev/null
+++ b/crates/atuin-ai/src/tui/components.rs
@@ -0,0 +1,510 @@
+//! Leaf components for each content type and factory functions for building
+//! the component tree from the view model.
+
+use atuin_client::theme::{Meaning, Theme};
+use ratatui::{
+    Frame,
+    backend::FromCrossterm,
+    layout::Rect,
+    style::{Modifier, Style},
+    text::{Line, Span},
+    widgets::{Paragraph, Wrap},
+};
+
+use super::component::{Component, RenderContext, Separator, Spacer, SymbolRow, VStack};
+use super::spinner::active_frame;
+use super::view_model::{Block, Content, WarningKind};
+
+// ---------------------------------------------------------------------------
+// Text measurement utilities
+// ---------------------------------------------------------------------------
+
+/// Count lines when text is wrapped at given width.
+/// Uses ratatui's Paragraph::line_count for accurate wrapping calculation.
+pub(crate) fn line_count_wrapped(text: &str, width: usize) -> u16 {
+    if width == 0 {
+        return 1;
+    }
+    let paragraph = Paragraph::new(text).wrap(Wrap { trim: false });
+    paragraph.line_count(width as u16).max(1) as u16
+}
+
+/// Count lines using word-wrap algorithm (matches TextArea's WrapMode::Word).
+/// Words won't be broken mid-word, so this may produce more lines than character wrapping.
+/// Returns (line_count, last_line_width) so caller can determine if cursor needs extra space.
+pub(crate) fn word_wrap_line_count_with_last_width(text: &str, width: usize) -> (u16, usize) {
+    if width == 0 || text.is_empty() {
+        return (1, 0);
+    }
+
+    let mut line_count = 0u16;
+    let mut current_line_width = 0usize;
+
+    for line in text.lines() {
+        if line.is_empty() {
+            line_count += 1;
+            current_line_width = 0;
+            continue;
+        }
+
+        let mut line_started = false;
+
+        for word in line.split_whitespace() {
+            let word_width = unicode_width::UnicodeWidthStr::width(word);
+
+            if !line_started {
+                if word_width > width {
+                    line_count += word_width.div_ceil(width) as u16;
+                    current_line_width = word_width % width;
+                    if current_line_width == 0 {
+                        current_line_width = 0;
+                        line_started = false;
+                    } else {
+                        line_started = true;
+                    }
+                } else {
+                    current_line_width = word_width;
+                    line_started = true;
+                }
+            } else {
+                let needed = current_line_width + 1 + word_width;
+                if needed > width {
+                    line_count += 1;
+                    if word_width > width {
+                        line_count += word_width.div_ceil(width) as u16;
+                        current_line_width = word_width % width;
+                        if current_line_width == 0 {
+                            line_started = false;
+                        }
+                    } else {
+                        current_line_width = word_width;
+                    }
+                } else {
+                    current_line_width = needed;
+                }
+            }
+        }
+
+        if line_started {
+            line_count += 1;
+        }
+    }
+
+    if line_count == 0 {
+        line_count = 1;
+        current_line_width = 0;
+    }
+
+    (line_count, current_line_width)
+}
+
+// ---------------------------------------------------------------------------
+// Inline markdown formatting
+// ---------------------------------------------------------------------------
+
+/// Parse inline markdown formatting (**bold** and `code`) into styled spans.
+/// Preserves all other text — list prefixes, indentation, and line structure
+/// are left exactly as-is.
+fn style_inline_markdown(text: &str, theme: &Theme) -> Vec<Line<'static>> {
+    let base_style = Style::from_crossterm(theme.as_style(Meaning::Base));
+    let code_style = Style::from_crossterm(theme.as_style(Meaning::Guidance));
+    let bold_style = base_style.add_modifier(Modifier::BOLD);
+
+    text.lines()
+        .map(|line| {
+            Line::from(parse_inline_formatting(
+                line, base_style, bold_style, code_style,
+            ))
+        })
+        .collect()
+}
+
+/// Parse a single line for `code` and **bold** markers, returning styled spans.
+fn parse_inline_formatting(
+    line: &str,
+    base: Style,
+    bold: Style,
+    code: Style,
+) -> Vec<Span<'static>> {
+    let mut spans = Vec::new();
+    let mut current = String::new();
+    let mut chars = line.chars().peekable();
+
+    while let Some(ch) = chars.next() {
+        if ch == '`' {
+            // Flush accumulated plain text
+            if !current.is_empty() {
+                spans.push(Span::styled(std::mem::take(&mut current), base));
+            }
+            // Collect until closing backtick
+            let mut code_text = String::new();
+            let mut closed = false;
+            for next in chars.by_ref() {
+                if next == '`' {
+                    closed = true;
+                    break;
+                }
+                code_text.push(next);
+            }
+            if closed {
+                spans.push(Span::styled(code_text, code));
+            } else {
+                // Unclosed backtick — render as-is
+                current.push('`');
+                current.push_str(&code_text);
+            }
+        } else if ch == '*' && chars.peek() == Some(&'*') {
+            chars.next(); // consume second *
+            // Flush accumulated plain text
+            if !current.is_empty() {
+                spans.push(Span::styled(std::mem::take(&mut current), base));
+            }
+            // Collect until closing **
+            let mut bold_text = String::new();
+            let mut closed = false;
+            while let Some(next) = chars.next() {
+                if next == '*' && chars.peek() == Some(&'*') {
+                    chars.next();
+                    closed = true;
+                    break;
+                }
+                bold_text.push(next);
+            }
+            if closed {
+                spans.push(Span::styled(bold_text, bold));
+            } else {
+                // Unclosed ** — render as-is
+                current.push_str("**");
+                current.push_str(&bold_text);
+            }
+        } else {
+            current.push(ch);
+        }
+    }
+
+    if !current.is_empty() {
+        spans.push(Span::styled(current, base));
+    }
+
+    spans
+}
+
+// ---------------------------------------------------------------------------
+// Leaf components
+// ---------------------------------------------------------------------------
+
+/// User input display (active textarea or static text).
+pub struct InputContent {
+    pub text: String,
+    pub active: bool,
+}
+
+impl Component for InputContent {
+    fn height(&self, width: u16) -> u16 {
+        let w = width as usize;
+        if self.active {
+            let (lines, last_width) = word_wrap_line_count_with_last_width(&self.text, w);
+            if last_width >= w {
+                lines.saturating_add(1)
+            } else {
+                lines
+            }
+        } else {
+            line_count_wrapped(&self.text, w)
+        }
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        if self.active {
+            if let Some(textarea) = ctx.textarea {
+                frame.render_widget(textarea, area);
+            }
+        } else {
+            let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
+            frame.render_widget(
+                Paragraph::new(self.text.as_str())
+                    .style(style)
+                    .wrap(Wrap { trim: false }),
+                area,
+            );
+        }
+    }
+}
+
+/// Command suggestion ($ prefix).
+pub struct CommandContent {
+    pub text: String,
+    pub faded: bool,
+}
+
+impl Component for CommandContent {
+    fn height(&self, width: u16) -> u16 {
+        line_count_wrapped(&self.text, width as usize)
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        let mut style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
+        if self.faded {
+            style = style.add_modifier(Modifier::DIM);
+        }
+        frame.render_widget(
+            Paragraph::new(self.text.as_str())
+                .style(style)
+                .wrap(Wrap { trim: false }),
+            area,
+        );
+    }
+}
+
+/// Markdown text content (indented, no symbol).
+pub struct TextContent {
+    pub markdown: String,
+}
+
+impl Component for TextContent {
+    fn height(&self, width: u16) -> u16 {
+        // Height uses raw text — slightly overestimates since markdown syntax
+        // characters (**, `) are stripped in rendering, but this is harmless
+        // (allocates equal or more space than needed, never less).
+        line_count_wrapped(&self.markdown, width as usize)
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        let lines = style_inline_markdown(&self.markdown, ctx.theme);
+        let paragraph = Paragraph::new(lines).wrap(Wrap { trim: false });
+        frame.render_widget(paragraph, area);
+    }
+}
+
+/// Error message (! prefix).
+pub struct ErrorContent {
+    pub message: String,
+}
+
+impl Component for ErrorContent {
+    fn height(&self, width: u16) -> u16 {
+        line_count_wrapped(&self.message, width as usize)
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
+        frame.render_widget(
+            Paragraph::new(self.message.as_str())
+                .style(style)
+                .wrap(Wrap { trim: false }),
+            area,
+        );
+    }
+}
+
+/// Warning for dangerous or low-confidence commands.
+pub struct WarningContent {
+    pub kind: WarningKind,
+    pub text: String,
+    pub pending_confirm: bool,
+}
+
+impl Component for WarningContent {
+    fn height(&self, width: u16) -> u16 {
+        let display_text = if self.pending_confirm {
+            "Press Enter again to run this dangerous command"
+        } else {
+            self.text.as_str()
+        };
+        line_count_wrapped(display_text, width as usize)
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
+        let display_text = if self.pending_confirm {
+            "Press Enter again to run this dangerous command"
+        } else {
+            self.text.as_str()
+        };
+        frame.render_widget(
+            Paragraph::new(display_text)
+                .style(style)
+                .wrap(Wrap { trim: false }),
+            area,
+        );
+    }
+}
+
+/// Animated spinner with status text.
+pub struct SpinnerContent {
+    pub status_text: String,
+}
+
+impl Component for SpinnerContent {
+    fn height(&self, _width: u16) -> u16 {
+        1
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Annotation));
+        frame.render_widget(Paragraph::new(self.status_text.as_str()).style(style), area);
+    }
+}
+
+/// Tool call progress (in-flight spinner or completed checkmark).
+pub struct ToolStatusContent {
+    pub completed_count: usize,
+    pub current_label: Option<String>,
+    pub frame: usize,
+}
+
+impl Component for ToolStatusContent {
+    fn height(&self, _width: u16) -> u16 {
+        1
+    }
+
+    fn render(&self, frame: &mut Frame, area: Rect, ctx: &RenderContext) {
+        let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Annotation));
+        let text = if let Some(ref label) = self.current_label {
+            if self.completed_count > 0 {
+                format!(
+                    "{} (used {} tool{})",
+                    label,
+                    self.completed_count,
+                    if self.completed_count == 1 { "" } else { "s" }
+                )
+            } else {
+                label.clone()
+            }
+        } else {
+            format!(
+                "Used {} tool{}",
+                self.completed_count,
+                if self.completed_count == 1 { "" } else { "s" }
+            )
+        };
+        frame.render_widget(Paragraph::new(text).style(style), area);
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Factory functions
+// ---------------------------------------------------------------------------
+
+/// Convert a view model `Content` item into a `SymbolRow`-wrapped component.
+fn content_to_component(content: &Content) -> Box<dyn Component> {
+    match content {
+        Content::Input { text, active, .. } => Box::new(SymbolRow {
+            symbol: ">".to_string(),
+            symbol_meaning: Meaning::Guidance,
+            inner: Box::new(InputContent {
+                text: text.clone(),
+                active: *active,
+            }),
+        }),
+
+        Content::Command { text, faded } => Box::new(SymbolRow {
+            symbol: "$".to_string(),
+            symbol_meaning: Meaning::Important,
+            inner: Box::new(CommandContent {
+                text: text.clone(),
+                faded: *faded,
+            }),
+        }),
+
+        Content::Text { markdown } => Box::new(SymbolRow {
+            symbol: " ".to_string(),
+            symbol_meaning: Meaning::Base,
+            inner: Box::new(TextContent {
+                markdown: markdown.clone(),
+            }),
+        }),
+
+        Content::Error { message } => Box::new(SymbolRow {
+            symbol: "!".to_string(),
+            symbol_meaning: Meaning::AlertError,
+            inner: Box::new(ErrorContent {
+                message: message.clone(),
+            }),
+        }),
+
+        Content::Warning {
+            kind,
+            text,
+            pending_confirm,
+        } => {
+            let (symbol, meaning) = match kind {
+                WarningKind::Danger => ("!", Meaning::AlertError),
+                WarningKind::LowConfidence => ("?", Meaning::AlertWarn),
+            };
+            Box::new(SymbolRow {
+                symbol: symbol.to_string(),
+                symbol_meaning: meaning,
+                inner: Box::new(WarningContent {
+                    kind: *kind,
+                    text: text.clone(),
+                    pending_confirm: *pending_confirm,
+                }),
+            })
+        }
+
+        Content::Spinner { frame, status_text } => Box::new(SymbolRow {
+            symbol: active_frame(*frame).to_string(),
+            symbol_meaning: Meaning::Annotation,
+            inner: Box::new(SpinnerContent {
+                status_text: status_text.clone(),
+            }),
+        }),
+
+        Content::ToolStatus {
+            completed_count,
+            current_label,
+            frame,
+        } => {
+            let symbol = if current_label.is_some() {
+                active_frame(*frame).to_string()
+            } else {
+                "\u{2713}".to_string() // ✓
+            };
+            Box::new(SymbolRow {
+                symbol,
+                symbol_meaning: Meaning::Annotation,
+                inner: Box::new(ToolStatusContent {
+                    completed_count: *completed_count,
+                    current_label: current_label.clone(),
+                    frame: *frame,
+                }),
+            })
+        }
+    }
+}
+
+/// Convert a view model `Block` into a `VStack` of content components.
+fn build_block_component(block: &Block) -> Box<dyn Component> {
+    let mut children: Vec<Box<dyn Component>> = Vec::new();
+
+    for (idx, content) in block.content.iter().enumerate() {
+        if idx > 0 {
+            children.push(Box::new(Spacer(1))); // blank line between items
+        }
+        children.push(content_to_component(content));
+    }
+
+    // Trailing blank line (padding after content)
+    children.push(Box::new(Spacer(1)));
+
+    Box::new(VStack::new(children))
+}
+
+/// Build the full component tree from an ordered list of view model blocks.
+///
+/// The tree is a `VStack` with blocks separated by `Separator` + `Spacer` pairs.
+/// The caller sets `scroll_offset` on the returned `VStack` before rendering.
+pub fn build_component_tree(items: &[&Block], card_width: u16) -> VStack {
+    let mut children: Vec<Box<dyn Component>> = Vec::new();
+
+    for (idx, block) in items.iter().enumerate() {
+        if idx > 0 {
+            children.push(Box::new(Separator { card_width }));
+            children.push(Box::new(Spacer(1))); // leading blank after separator
+        }
+        children.push(build_block_component(block));
+    }
+
+    VStack::new(children)
+}
diff --git a/crates/atuin-ai/src/tui/mod.rs b/crates/atuin-ai/src/tui/mod.rs
index 03a9c007..6df3d08f 100644
--- a/crates/atuin-ai/src/tui/mod.rs
+++ b/crates/atuin-ai/src/tui/mod.rs
@@ -1,4 +1,6 @@
 pub mod app;
+pub mod component;
+pub mod components;
 pub mod event;
 #[cfg(unix)]
 pub mod popup;
diff --git a/crates/atuin-ai/src/tui/render.rs b/crates/atuin-ai/src/tui/render.rs
index 9326b0df..9b514ccf 100644
--- a/crates/atuin-ai/src/tui/render.rs
+++ b/crates/atuin-ai/src/tui/render.rs
@@ -3,35 +3,22 @@ use pulldown_cmark::{Event, Parser, Tag, TagEnd};
 use ratatui::{
     Frame,
     backend::FromCrossterm,
-    layout::{Alignment, Constraint, Direction, Layout, Rect},
+    layout::{Alignment, Rect},
     style::{Modifier, Style},
     text::{Line, Span},
-    widgets::{Block as RatatuiBlock, Borders, Padding, Paragraph, Wrap},
+    widgets::{Block as RatatuiBlock, Borders, Padding},
 };
-use tui_textarea::TextArea;
 
+use super::component::Component;
+pub use super::component::RenderContext;
+use super::components::build_component_tree;
 use super::spinner::active_frame;
 use super::state::AppState;
-use super::view_model::{Blocks, Content, WarningKind};
+use super::view_model::Blocks;
 
 /// Fixed card width for the TUI
 pub(crate) const CARD_WIDTH: u16 = 64;
 
-pub struct RenderContext<'a> {
-    pub theme: &'a Theme,
-    pub anchor_col: u16,
-    pub textarea: Option<&'a TextArea<'static>>,
-    /// Maximum viewport height (for scroll calculations)
-    pub max_height: u16,
-    /// When true, the viewport is a fixed rect already positioned for the card.
-    /// The card fills the entire viewport instead of positioning via anchor_col.
-    pub popup_mode: bool,
-    /// When true, blocks are rendered in reverse order so that the input field
-    /// appears at the bottom of the card (close to the prompt when the popup
-    /// is above the cursor).
-    pub render_above: bool,
-}
-
 /// Calculate the height needed to render the current state.
 /// Used to dynamically resize the viewport before rendering.
 /// `card_width` is the outer card width (including borders); pass 0 to use CARD_WIDTH default.
@@ -42,20 +29,13 @@ pub fn calculate_needed_height(state: &AppState, card_width: u16) -> u16 {
     } else {
         CARD_WIDTH
     };
-    let content_width = usize::from(w.saturating_sub(4)).max(1);
+    let content_width = w.saturating_sub(4).max(1);
 
-    let mut total_height = 0u16;
-    for (idx, block) in view.items.iter().enumerate() {
-        if idx > 0 {
-            total_height = total_height.saturating_add(1); // separator
-            total_height = total_height.saturating_add(1); // leading blank after separator
-        }
-        total_height =
-            total_height.saturating_add(calculate_block_height(&block.content, content_width));
-    }
+    let items: Vec<_> = view.items.iter().collect();
+    let tree = build_component_tree(&items, w);
 
     // Add borders (2) + top padding (1), minimum 5
-    total_height.saturating_add(3).max(5)
+    tree.height(content_width).saturating_add(3).max(5)
 }
 
 /// Main render function: derives view model from state, then renders it
@@ -89,7 +69,6 @@ fn render_view(frame: &mut Frame, view: &Blocks, ctx: &RenderContext) {
         let preferred_x = full_area.x + ctx.anchor_col.saturating_sub(2);
         (full_area, preferred_x.min(max_x), dw)
     };
-    let content_width = usize::from(desired_width.saturating_sub(4)).max(1);
 
     // Build ordered items list — the active content (input/LLM response)
     // should always be closest to the cursor/prompt:
@@ -102,20 +81,11 @@ fn render_view(frame: &mut Frame, view: &Blocks, ctx: &RenderContext) {
         view.items.iter().collect()
     };
 
-    // Calculate height from view model
-    let mut total_height = 0u16;
-    for (idx, block) in items.iter().enumerate() {
-        if idx > 0 {
-            total_height = total_height.saturating_add(1); // separator
-            total_height = total_height.saturating_add(1); // leading blank after separator
-        }
-        total_height =
-            total_height.saturating_add(calculate_block_height(&block.content, content_width));
-    }
+    // Build component tree from view model
+    let mut tree = build_component_tree(&items, desired_width);
+    let content_width = desired_width.saturating_sub(4).max(1);
 
-    let desired_height = total_height
-        .saturating_add(3) // borders (2) + top padding (1), no bottom padding
-        .max(5);
+    let desired_height = tree.height(content_width).saturating_add(3).max(5);
 
     // Cap card height at viewport height to prevent overflow
     let actual_height = desired_height.min(area.height);
@@ -124,7 +94,7 @@ fn render_view(frame: &mut Frame, view: &Blocks, ctx: &RenderContext) {
     // When render_above=false (popup below cursor), items are reversed so the active
     // content (input/spinner) is at the top — scroll_offset stays 0 to show the top.
     // Otherwise, scroll to show the bottom where the active content lives.
-    let scroll_offset = if ctx.popup_mode && !ctx.render_above {
+    tree.scroll_offset = if ctx.popup_mode && !ctx.render_above {
         0
     } else {
         desired_height.saturating_sub(actual_height)
@@ -164,460 +134,11 @@ fn render_view(frame: &mut Frame, view: &Blocks, ctx: &RenderContext) {
     let inner_area = outer_block.inner(card);
     frame.render_widget(outer_block, card);
 
-    // Render blocks (with scroll offset for overflowing content)
-    render_blocks_content(frame, &items, ctx, inner_area, card.width, scroll_offset);
-}
-
-fn render_blocks_content(
-    frame: &mut Frame,
-    items: &[&super::view_model::Block],
-    ctx: &RenderContext,
-    area: Rect,
-    card_width: u16,
-    scroll_offset: u16,
-) {
-    let content_width = usize::from(area.width).max(1);
-
-    // Build layout constraints for full content
-    let mut constraints = Vec::new();
-    let mut block_heights = Vec::new();
-    for (idx, block) in items.iter().enumerate() {
-        if idx > 0 {
-            constraints.push(Constraint::Length(1)); // separator
-            constraints.push(Constraint::Length(1)); // leading blank after separator
-            block_heights.push(1);
-            block_heights.push(1);
-        }
-        let height = calculate_block_height(&block.content, content_width);
-        constraints.push(Constraint::Length(height));
-        block_heights.push(height);
-    }
-
-    if constraints.is_empty() {
-        return;
-    }
-
-    // Calculate cumulative heights to find which blocks are visible after scrolling
-    let mut cumulative: Vec<u16> = Vec::with_capacity(block_heights.len() + 1);
-    cumulative.push(0);
-    for h in &block_heights {
-        cumulative.push(cumulative.last().unwrap() + h);
-    }
-
-    // Render each chunk, offsetting by scroll_offset and clipping to visible area
-    let chunks = Layout::default()
-        .direction(Direction::Vertical)
-        .constraints(constraints)
-        .split(area);
-
-    let mut chunk_idx = 0;
-    for (idx, block) in items.iter().enumerate() {
-        if idx > 0 {
-            // Check if separator is visible (its position minus scroll_offset)
-            let sep_start = cumulative[chunk_idx];
-            if sep_start >= scroll_offset && sep_start < scroll_offset + area.height {
-                let adjusted_chunk = Rect {
-                    y: area.y + sep_start - scroll_offset,
-                    ..chunks[chunk_idx]
-                };
-                render_separator(frame, adjusted_chunk, ctx, card_width);
-            }
-            chunk_idx += 1;
-            chunk_idx += 1; // skip leading blank
-        }
-
-        // Check if this block is at least partially visible
-        let block_start = cumulative[chunk_idx];
-        let block_end = cumulative[chunk_idx + 1];
-
-        // Block is visible if it starts before viewport end and ends after viewport start
-        if block_start < scroll_offset + area.height && block_end > scroll_offset {
-            // Calculate visible portion
-            let visible_start = block_start.max(scroll_offset);
-            let visible_end = block_end.min(scroll_offset + area.height);
-
-            let adjusted_chunk = Rect {
-                x: area.x,
-                y: area.y + visible_start - scroll_offset,
-                width: area.width,
-                height: visible_end - visible_start,
-            };
-
-            render_block_content(frame, &block.content, adjusted_chunk, ctx);
-        }
-
-        chunk_idx += 1;
-    }
-}
-
-/// Render all content items in a block
-fn render_block_content(frame: &mut Frame, content: &[Content], area: Rect, ctx: &RenderContext) {
-    if content.is_empty() {
-        return;
-    }
-
-    let content_width = usize::from(area.width).max(1);
-
-    // Build layout constraints for each content item WITH spacing between items
-    let mut constraints = Vec::new();
-    for (idx, c) in content.iter().enumerate() {
-        if idx > 0 {
-            constraints.push(Constraint::Length(1)); // blank line between items
-        }
-        constraints.push(Constraint::Length(calculate_single_content_height(
-            c,
-            content_width,
-        )));
-    }
-
-    let chunks = Layout::default()
-        .direction(Direction::Vertical)
-        .constraints(constraints)
-        .split(area);
-
-    let mut chunk_idx = 0;
-    for (idx, item) in content.iter().enumerate() {
-        if idx > 0 {
-            chunk_idx += 1; // skip the blank line chunk
-        }
-        render_single_content(frame, item, chunks[chunk_idx], ctx);
-        chunk_idx += 1;
-    }
-}
-
-/// Render a single content item using ratatui's native wrapping.
-/// Symbol is rendered at column 0, text wraps in columns 2+ (offset area).
-fn render_single_content(frame: &mut Frame, content: &Content, area: Rect, ctx: &RenderContext) {
-    // Helper to create offset text area (2 chars for symbol column)
-    let text_area = Rect {
-        x: area.x.saturating_add(2),
-        y: area.y,
-        width: area.width.saturating_sub(2),
-        height: area.height,
-    };
-
-    match content {
-        Content::Input { text, active, .. } => {
-            let symbol_style = Style::from_crossterm(ctx.theme.as_style(Meaning::Guidance));
-            let text_style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
-
-            // Render ">" symbol at column 0
-            render_symbol(frame, ">", symbol_style, area);
-
-            if *active {
-                // Active input: render TextArea widget (handles cursor display)
-                if let Some(textarea) = ctx.textarea {
-                    frame.render_widget(textarea, text_area);
-                }
-            } else {
-                // Inactive input: render as plain paragraph
-                let paragraph = Paragraph::new(text.as_str())
-                    .style(text_style)
-                    .wrap(Wrap { trim: false });
-                frame.render_widget(paragraph, text_area);
-            }
-        }
-
-        Content::Command { text, faded } => {
-            let symbol_style = Style::from_crossterm(ctx.theme.as_style(Meaning::Important));
-            let mut text_style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
-            if *faded {
-                text_style = text_style.add_modifier(Modifier::DIM);
-            }
-
-            render_symbol(frame, "$", symbol_style, area);
-
-            let paragraph = Paragraph::new(text.as_str())
-                .style(text_style)
-                .wrap(Wrap { trim: false });
-            frame.render_widget(paragraph, text_area);
-        }
-
-        Content::Text { markdown } => {
-            // No symbol, just indent - render directly in offset area
-            let text_style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
-
-            let paragraph = Paragraph::new(markdown.as_str())
-                .style(text_style)
-                .wrap(Wrap { trim: false });
-            frame.render_widget(paragraph, text_area);
-        }
-
-        Content::Error { message } => {
-            let symbol_style = Style::from_crossterm(ctx.theme.as_style(Meaning::AlertError));
-            let text_style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
-
-            render_symbol(frame, "!", symbol_style, area);
-
-            let paragraph = Paragraph::new(message.as_str())
-                .style(text_style)
-                .wrap(Wrap { trim: false });
-            frame.render_widget(paragraph, text_area);
-        }
-
-        Content::Warning {
-            kind,
-            text,
-            pending_confirm,
-        } => {
-            let (symbol, meaning) = match kind {
-                WarningKind::Danger => ("!", Meaning::AlertError),
-                WarningKind::LowConfidence => ("?", Meaning::AlertWarn),
-            };
-            let symbol_style = Style::from_crossterm(ctx.theme.as_style(meaning));
-            let text_style = Style::from_crossterm(ctx.theme.as_style(Meaning::Base));
-
-            let display_text = if *pending_confirm {
-                "Press Enter again to run this dangerous command"
-            } else {
-                text.as_str()
-            };
-
-            render_symbol(frame, symbol, symbol_style, area);
-
-            let paragraph = Paragraph::new(display_text)
-                .style(text_style)
-                .wrap(Wrap { trim: false });
-            frame.render_widget(paragraph, text_area);
-        }
-
-        Content::Spinner {
-            frame: spinner_frame,
-            status_text,
-        } => {
-            let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Annotation));
-            let symbol = active_frame(*spinner_frame);
-
-            render_symbol(frame, symbol, style, area);
-
-            let paragraph = Paragraph::new(status_text.as_str()).style(style);
-            frame.render_widget(paragraph, text_area);
-        }
-
-        Content::ToolStatus {
-            completed_count,
-            current_label,
-            frame: spinner_frame,
-        } => {
-            let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Annotation));
-
-            let (symbol, text) = if let Some(label) = current_label {
-                let spinner = active_frame(*spinner_frame);
-                let text = if *completed_count > 0 {
-                    format!(
-                        "{} (used {} tool{})",
-                        label,
-                        completed_count,
-                        if *completed_count == 1 { "" } else { "s" }
-                    )
-                } else {
-                    label.clone()
-                };
-                (spinner, text)
-            } else {
-                (
-                    "\u{2713}",
-                    format!(
-                        "Used {} tool{}",
-                        completed_count,
-                        if *completed_count == 1 { "" } else { "s" }
-                    ),
-                )
-            };
-
-            render_symbol(frame, symbol, style, area);
-
-            let paragraph = Paragraph::new(text).style(style);
-            frame.render_widget(paragraph, text_area);
-        }
-    }
-}
-
-/// Render a single-character symbol at the start of an area
-fn render_symbol(frame: &mut Frame, symbol: &str, style: Style, area: Rect) {
-    let symbol_area = Rect {
-        x: area.x,
-        y: area.y,
-        width: 1,
-        height: 1,
-    };
-    frame.render_widget(Paragraph::new(symbol).style(style), symbol_area);
-}
-
-fn render_separator(frame: &mut Frame, area: Rect, ctx: &RenderContext, card_width: u16) {
-    let style = Style::from_crossterm(ctx.theme.as_style(Meaning::Muted));
-
-    // Build separator: ├ + ─ repeated + ┤ spanning the full card width
-    // -2 for the ├ and ┤ characters themselves
-    let inner_width = card_width.saturating_sub(2) as usize;
-    let separator = format!(
-        "\u{251c}{}\u{2524}",           // ├ ... ┤
-        "\u{2500}".repeat(inner_width)  // ─
-    );
-
-    let paragraph = Paragraph::new(Span::styled(separator, style));
-
-    // Render at x offset to overlap the border (area is inside padding, border is 2 chars left)
-    let sep_area = Rect {
-        x: area.x.saturating_sub(2), // move left to overlap left border
-        y: area.y,
-        width: card_width,
-        height: 1,
-    };
-    frame.render_widget(paragraph, sep_area);
-}
-
-/// Calculate total height for all content items in a block
-fn calculate_block_height(content: &[Content], width: usize) -> u16 {
-    let content_height: u16 = content
-        .iter()
-        .map(|c| calculate_single_content_height(c, width))
-        .sum();
-
-    // Add spacing between items (n-1 blank lines for n items)
-    let spacing = if content.len() > 1 {
-        (content.len() - 1) as u16
-    } else {
-        0
-    };
-
-    // Add 1 for trailing blank line (padding after content)
-    content_height.saturating_add(spacing).saturating_add(1)
-}
-
-/// Calculate height for a single content item.
-/// Uses ratatui's Paragraph::line_count for consistency with rendering.
-fn calculate_single_content_height(content: &Content, width: usize) -> u16 {
-    // Text area is offset by 2 for symbol column
-    let text_width = width.saturating_sub(2);
-
-    match content {
-        // Input uses word wrapping (WrapMode::Word) in TextArea, which can produce
-        // more lines than character wrapping since it won't break words mid-word
-        Content::Input { text, active, .. } => {
-            if *active {
-                // For active input, use word-wrap line counting to match TextArea behavior
-                let (lines, last_line_width) =
-                    word_wrap_line_count_with_last_width(text, text_width);
-                // Only add extra line for cursor if the last line is full
-                if last_line_width >= text_width {
-                    lines.saturating_add(1)
-                } else {
-                    lines
-                }
-            } else {
-                line_count_wrapped(text, text_width)
-            }
-        }
-        Content::Command { text, .. } => line_count_wrapped(text, text_width),
-        Content::Text { markdown } => line_count_wrapped(markdown, text_width),
-        Content::Error { message } => line_count_wrapped(message, text_width),
-        Content::Warning {
-            text,
-            pending_confirm,
-            ..
-        } => {
-            let display_text = if *pending_confirm {
-                "Press Enter again to run this dangerous command"
-            } else {
-                text.as_str()
-            };
-            line_count_wrapped(display_text, text_width)
-        }
-        Content::Spinner { .. } => 1,
-        Content::ToolStatus { .. } => 1,
-    }
-}
-
-/// Count lines when text is wrapped at given width.
-/// Uses ratatui's Paragraph::line_count for accurate wrapping calculation.
-fn line_count_wrapped(text: &str, width: usize) -> u16 {
-    if width == 0 {
-        return 1;
-    }
-
-    let paragraph = Paragraph::new(text).wrap(Wrap { trim: false });
-    paragraph.line_count(width as u16).max(1) as u16
-}
-
-/// Count lines using word-wrap algorithm (matches TextArea's WrapMode::Word).
-/// Words won't be broken mid-word, so this may produce more lines than character wrapping.
-/// Returns (line_count, last_line_width) so caller can determine if cursor needs extra space.
-fn word_wrap_line_count_with_last_width(text: &str, width: usize) -> (u16, usize) {
-    if width == 0 || text.is_empty() {
-        return (1, 0);
-    }
-
-    let mut line_count = 0u16;
-    let mut current_line_width = 0usize;
-
-    for line in text.lines() {
-        if line.is_empty() {
-            line_count += 1;
-            current_line_width = 0;
-            continue;
-        }
-
-        let mut line_started = false;
-
-        for word in line.split_whitespace() {
-            let word_width = unicode_width::UnicodeWidthStr::width(word);
-
-            if !line_started {
-                // First word on line
-                if word_width > width {
-                    // Word is longer than width, it will be split by character
-                    // Count how many lines it takes
-                    line_count += word_width.div_ceil(width) as u16;
-                    current_line_width = word_width % width;
-                    if current_line_width == 0 {
-                        current_line_width = 0;
-                        line_started = false;
-                    } else {
-                        line_started = true;
-                    }
-                } else {
-                    current_line_width = word_width;
-                    line_started = true;
-                }
-            } else {
-                // Subsequent word - need space before it
-                let needed = current_line_width + 1 + word_width;
-                if needed > width {
-                    // Word doesn't fit, start new line
-                    line_count += 1;
-                    if word_width > width {
-                        // Word itself is too long, will be split
-                        line_count += word_width.div_ceil(width) as u16;
-                        current_line_width = word_width % width;
-                        if current_line_width == 0 {
-                            line_started = false;
-                        }
-                    } else {
-                        current_line_width = word_width;
-                    }
-                } else {
-                    current_line_width = needed;
-                }
-            }
-        }
-
-        // Count the last line of this logical line
-        if line_started {
-            line_count += 1;
-        }
-    }
-
-    // Handle case where text has no lines() output (empty or just whitespace)
-    if line_count == 0 {
-        line_count = 1;
-        current_line_width = 0;
-    }
-
-    (line_count, current_line_width)
+    // Render the component tree
+    tree.render(frame, inner_area, ctx);
 }
 
-/// Convert markdown to styled spans (existing function, kept as-is)
+/// Convert markdown to styled spans
 pub fn markdown_to_spans<'a>(text: &'a str, theme: &'a Theme) -> Vec<Line<'a>> {
     let parser = Parser::new(text);
     let mut lines: Vec<Vec<Span<'a>>> = vec![Vec::new()];