Refactor: Improve UI rendering and address code review comments

This commit addresses several code review comments primarily focused on improving the rendering and stability of the CLI UI.

Key changes include:
- Passing `isPending` and `availableTerminalHeight` props to `MarkdownDisplay` to enable more intelligent rendering of content, especially for pending messages and code blocks.
- Adjusting height calculations in `ToolGroupMessage` and `ToolMessage` to more accurately reflect available space.
- Refining the logic in `App.tsx` for measuring and utilizing terminal height, including renaming `footerRef` to `mainControlsRef` for clarity.
- Ensuring consistent prop drilling for `isPending` and `availableTerminalHeight` through `HistoryItemDisplay`, `GeminiMessage`, and `GeminiMessageContent`.
- In `MarkdownDisplay`, when `isPending` is true and content exceeds `availableTerminalHeight`, the code block will now be truncated with a "... generating more ..." message. If there's insufficient space even for the
message, a simpler "... code is being written ..." will be shown.

packages/cli/src/ui/components/HistoryItemDisplay.tsx

@@ -17,18 +17,30 @@ import { Box } from 'ink';
 interface HistoryItemDisplayProps {
   item: HistoryItem;
   availableTerminalHeight: number;
+  isPending: boolean;
 }
 
 export const HistoryItemDisplay: React.FC<HistoryItemDisplayProps> = ({
   item,
   availableTerminalHeight,
+  isPending,
 }) => (
   <Box flexDirection="column" key={item.id}>
     {/* Render standard message types */}
     {item.type === 'user' && <UserMessage text={item.text} />}
-    {item.type === 'gemini' && <GeminiMessage text={item.text} />}
+    {item.type === 'gemini' && (
+      <GeminiMessage
+        text={item.text}
+        isPending={isPending}
+        availableTerminalHeight={availableTerminalHeight}
+      />
+    )}
     {item.type === 'gemini_content' && (
-      <GeminiMessageContent text={item.text} />
+      <GeminiMessageContent
+        text={item.text}
+        isPending={isPending}
+        availableTerminalHeight={availableTerminalHeight}
+      />
     )}
     {item.type === 'info' && <InfoMessage text={item.text} />}
     {item.type === 'error' && <ErrorMessage text={item.text} />}

packages/cli/src/ui/components/messages/GeminiMessage.tsx

@@ -11,9 +11,15 @@ import { Colors } from '../../colors.js';
 
 interface GeminiMessageProps {
   text: string;
+  isPending: boolean;
+  availableTerminalHeight: number;
 }
 
-export const GeminiMessage: React.FC<GeminiMessageProps> = ({ text }) => {
+export const GeminiMessage: React.FC<GeminiMessageProps> = ({
+  text,
+  isPending,
+  availableTerminalHeight,
+}) => {
   const prefix = '✦ ';
   const prefixWidth = prefix.length;
 
@@ -23,7 +29,11 @@ export const GeminiMessage: React.FC<GeminiMessageProps> = ({ text }) => {
         <Text color={Colors.AccentPurple}>{prefix}</Text>
       </Box>
       <Box flexGrow={1} flexDirection="column">
-        <MarkdownDisplay text={text} />
+        <MarkdownDisplay
+          text={text}
+          isPending={isPending}
+          availableTerminalHeight={availableTerminalHeight}
+        />
       </Box>
     </Box>
   );

packages/cli/src/ui/components/messages/GeminiMessageContent.tsx

@@ -10,6 +10,8 @@ import { MarkdownDisplay } from '../../utils/MarkdownDisplay.js';
 
 interface GeminiMessageContentProps {
   text: string;
+  isPending: boolean;
+  availableTerminalHeight: number;
 }
 
 /*
@@ -20,13 +22,19 @@ interface GeminiMessageContentProps {
  */
 export const GeminiMessageContent: React.FC<GeminiMessageContentProps> = ({
   text,
+  isPending,
+  availableTerminalHeight,
 }) => {
   const originalPrefix = '✦ ';
   const prefixWidth = originalPrefix.length;
 
   return (
     <Box flexDirection="column" paddingLeft={prefixWidth}>
-      <MarkdownDisplay text={text} />
+      <MarkdownDisplay
+        text={text}
+        isPending={isPending}
+        availableTerminalHeight={availableTerminalHeight}
+      />
     </Box>
   );
 };

packages/cli/src/ui/components/messages/ToolGroupMessage.tsx

@@ -29,7 +29,6 @@ export const ToolGroupMessage: React.FC<ToolGroupMessageProps> = ({
   const borderColor = hasPending ? Colors.AccentYellow : Colors.SubtleComment;
 
   const staticHeight = /* border */ 2 + /* marginBottom */ 1;
-  availableTerminalHeight -= staticHeight;
 
   return (
     <Box
@@ -58,7 +57,7 @@ export const ToolGroupMessage: React.FC<ToolGroupMessageProps> = ({
             resultDisplay={tool.resultDisplay}
             status={tool.status}
             confirmationDetails={tool.confirmationDetails}
-            availableTerminalHeight={availableTerminalHeight}
+            availableTerminalHeight={availableTerminalHeight - staticHeight}
           />
           {tool.status === ToolCallStatus.Confirming &&
             tool.confirmationDetails && (

packages/cli/src/ui/components/messages/ToolMessage.tsx

@@ -26,7 +26,6 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
   const statusIndicatorWidth = 3;
   const hasResult = resultDisplay && resultDisplay.toString().trim().length > 0;
   const staticHeight = /* Header */ 1;
-  availableTerminalHeight -= staticHeight;
 
   let displayableResult = resultDisplay;
   let hiddenLines = 0;
@@ -37,7 +36,7 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
     const lines = resultDisplay.split('\n');
     // Estimate available height for this specific tool message content area
     // This is a rough estimate; ideally, we'd have a more precise measurement.
-    const contentHeightEstimate = availableTerminalHeight - 5; // Subtracting lines for tool name, status, padding etc.
+    const contentHeightEstimate = availableTerminalHeight - staticHeight - 5; // Subtracting lines for tool name, status, padding etc.
     if (lines.length > contentHeightEstimate && contentHeightEstimate > 0) {
       displayableResult = lines.slice(0, contentHeightEstimate).join('\n');
       hiddenLines = lines.length - contentHeightEstimate;
@@ -83,7 +82,11 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
           <Box flexDirection="column">
             {typeof displayableResult === 'string' && (
               <Box flexDirection="column">
-                <MarkdownDisplay text={displayableResult} />
+                <MarkdownDisplay
+                  text={displayableResult}
+                  isPending={false}
+                  availableTerminalHeight={availableTerminalHeight}
+                />
               </Box>
             )}
             {typeof displayableResult === 'object' && (