feat: enhance DiffViewer with asking agent for comment functionality and mobile support (#153)

packages/ui/src/components/views/PierreDiffViewer.tsx

@@ -1,12 +1,22 @@
-import React, { useMemo, useRef } from 'react';
+import React, { useMemo, useRef, useState, useCallback, useEffect } from 'react';
+import { createPortal } from 'react-dom';
 import { FileDiff } from '@pierre/diffs/react';
-import { parseDiffFromFile, type FileContents, type FileDiffMetadata } from '@pierre/diffs';
+import { parseDiffFromFile, type FileContents, type FileDiffMetadata, type SelectedLineRange } from '@pierre/diffs';
+import { RiSendPlane2Line } from '@remixicon/react';
 
 import { useOptionalThemeSystem } from '@/contexts/useThemeSystem';
 import { ScrollableOverlay } from '@/components/ui/ScrollableOverlay';
 import { ensureFlexokiThemesRegistered } from '@/lib/shiki/registerFlexokiThemes';
 import { flexokiThemeNames } from '@/lib/shiki/flexokiThemes';
 
+import { Textarea } from '@/components/ui/textarea';
+import { useSessionStore } from '@/stores/useSessionStore';
+import { useConfigStore } from '@/stores/useConfigStore';
+import { useUIStore } from '@/stores/useUIStore';
+import { useDeviceInfo } from '@/lib/device';
+import { cn, getModifierLabel } from '@/lib/utils';
+
+
 interface PierreDiffViewerProps {
   original: string;
   modified: string;
@@ -40,6 +50,18 @@ const WEBKIT_SCROLL_FIX_CSS = `
   [data-code] {
     -webkit-overflow-scrolling: touch;
   }
+  
+  /* Mobile touch selection support */
+  [data-line-number] {
+    touch-action: manipulation;
+    -webkit-tap-highlight-color: transparent;
+    cursor: pointer;
+  }
+  
+  /* Ensure interactive line numbers work on touch */
+  pre[data-interactive-line-numbers] [data-line-number] {
+    touch-action: manipulation;
+  }
   /* Reduce hunk separator height */
   [data-separator-content] {
     height: 24px !important;
@@ -83,6 +105,21 @@ function getCacheKey(fileName: string, original: string, modified: string): stri
   return `${fileName}:${original.length}:${modified.length}:${sampleOriginal.length}:${sampleModified.length}`;
 }
 
+const extractSelectedCode = (original: string, modified: string, range: SelectedLineRange): string => {
+  // Default to modified if side is ambiguous, as users mostly comment on new code
+  const isOriginal = range.side === 'deletions';
+  const content = isOriginal ? original : modified;
+  const lines = content.split('\n');
+  
+  // Ensure bounds
+  const startLine = Math.max(1, range.start);
+  const endLine = Math.min(lines.length, range.end);
+  
+  if (startLine > endLine) return '';
+  
+  return lines.slice(startLine - 1, endLine).join('\n');
+};
+
 export const PierreDiffViewer: React.FC<PierreDiffViewerProps> = ({
   original,
   modified,
@@ -92,9 +129,149 @@ export const PierreDiffViewer: React.FC<PierreDiffViewerProps> = ({
   wrapLines = false,
   layout = 'fill',
 }) => {
+  const isInlineLayout = layout === 'inline';
+  const { isMobile } = useDeviceInfo();
+  const { inputBarOffset, isKeyboardOpen } = useUIStore();
+  
   const themeSystem = useOptionalThemeSystem();
   const isDark = themeSystem?.currentTheme?.metadata?.variant === 'dark';
 
+  const setActiveMainTab = useUIStore(state => state.setActiveMainTab);
+
+  const [selection, setSelection] = useState<SelectedLineRange | null>(null);
+  const [commentText, setCommentText] = useState('');
+
+  
+  // Calculate initial center synchronously to avoid flicker
+  const getMainContentCenter = useCallback(() => {
+    if (isMobile) return '50%';
+    const mainContent = document.querySelector('main.flex-1');
+    if (mainContent) {
+      const rect = mainContent.getBoundingClientRect();
+      return `${rect.left + rect.width / 2}px`;
+    }
+    return '50%';
+  }, [isMobile]);
+  
+  const [mainContentCenter, setMainContentCenter] = useState<string>(getMainContentCenter);
+  
+  const sendMessage = useSessionStore(state => state.sendMessage);
+  const currentSessionId = useSessionStore(state => state.currentSessionId);
+  const { currentProviderId, currentModelId, currentAgentName, currentVariant } = useConfigStore();
+  
+  // Update main content center on resize
+  useEffect(() => {
+    if (isMobile) return;
+    
+    const updateCenter = () => {
+      setMainContentCenter(getMainContentCenter());
+    };
+    
+    window.addEventListener('resize', updateCenter);
+    return () => window.removeEventListener('resize', updateCenter);
+  }, [isMobile, getMainContentCenter]);
+
+  const handleSelectionChange = useCallback((range: SelectedLineRange | null) => {
+    // On mobile: implement "tap to extend" behavior
+    // If user taps a new single line while we have an existing selection, extend the range
+    if (isMobile && range && selection && range.start === range.end) {
+      const tappedLine = range.start;
+      const existingStart = selection.start;
+      const existingEnd = selection.end;
+      
+      // Extend the selection to include the tapped line
+      const newStart = Math.min(existingStart, existingEnd, tappedLine);
+      const newEnd = Math.max(existingStart, existingEnd, tappedLine);
+      
+      // Only extend if tapping outside current selection
+      if (tappedLine < existingStart || tappedLine > existingEnd) {
+        setSelection({
+          ...range,
+          start: newStart,
+          end: newEnd,
+        });
+        return;
+      }
+    }
+    
+    setSelection(range);
+    if (!range) {
+      setCommentText('');
+    }
+  }, [isMobile, selection]);
+
+  // Dismiss selection when clicking outside line numbers (desktop behavior)
+  useEffect(() => {
+    if (!selection) return;
+    
+    const handleClickOutside = (e: MouseEvent) => {
+      const target = e.target as HTMLElement;
+      
+      // Check if click is inside the comment UI portal
+      const commentUI = document.querySelector('[data-comment-ui]');
+      if (commentUI?.contains(target)) return;
+      
+      // Check if click is on a line number (inside shadow DOM)
+      const path = e.composedPath();
+      const isLineNumber = path.some((el) => {
+        if (el instanceof HTMLElement) {
+          return el.hasAttribute('data-line-number') || el.closest?.('[data-line-number]');
+        }
+        return false;
+      });
+      
+      if (!isLineNumber) {
+        setSelection(null);
+        setCommentText('');
+      }
+    };
+    
+    // Use timeout to avoid immediate dismissal from the same click that selected
+    const timeoutId = setTimeout(() => {
+      document.addEventListener('click', handleClickOutside);
+    }, 100);
+    
+    return () => {
+      clearTimeout(timeoutId);
+      document.removeEventListener('click', handleClickOutside);
+    };
+  }, [selection]);
+
+  const handleSendComment = useCallback(async () => {
+    if (!selection || !commentText.trim()) return;
+    if (!currentSessionId || !currentProviderId || !currentModelId) {
+      console.warn('Cannot send comment: no active session or model not selected');
+      return;
+    }
+    
+    const code = extractSelectedCode(original, modified, selection);
+    const startLine = selection.start;
+    const endLine = selection.end;
+    const side = selection.side === 'deletions' ? 'original' : 'modified';
+    
+    const message = `Comment on \`${fileName}\` lines ${startLine}-${endLine} (${side}):\n\`\`\`${language}\n${code}\n\`\`\`\n\n${commentText}`;
+    
+    // Clear state and switch tab immediately for responsive UX
+    setCommentText('');
+    setSelection(null);
+    setActiveMainTab('chat');
+    
+    try {
+      await sendMessage(
+        message,
+        currentProviderId,
+        currentModelId,
+        currentAgentName,
+        undefined,
+        undefined,
+        undefined,
+        currentVariant
+      );
+    } catch (e) {
+      console.error("Failed to send comment", e);
+    }
+  }, [selection, commentText, original, modified, fileName, language, sendMessage, currentSessionId, currentProviderId, currentModelId, currentAgentName, currentVariant, setActiveMainTab]);
+
   ensureFlexokiThemesRegistered();
 
   // Cache the last computed diff to avoid recomputing on every render
@@ -146,27 +323,186 @@ export const PierreDiffViewer: React.FC<PierreDiffViewerProps> = ({
     lineDiffType: 'word-alt' as const,
     overflow: wrapLines ? ('wrap' as const) : ('scroll' as const),
     disableFileHeader: true,
-    enableLineSelection: false,
+    enableLineSelection: true,
     enableHoverUtility: false,
+    onLineSelected: handleSelectionChange,
     unsafeCSS: WEBKIT_SCROLL_FIX_CSS,
-  }), [isDark, renderSideBySide, wrapLines]);
-
-  const isInlineLayout = layout === 'inline';
+  }), [isDark, renderSideBySide, wrapLines, handleSelectionChange]);
  
   if (typeof window === 'undefined') {
     return null;
   }
  
+  // Extracted Comment Interface Content for reuse in Portal or In-Flow
+  const renderCommentContent = () => {
+    if (!selection) return null;
+    return (
+      <div 
+        className="flex flex-col items-center gap-2 px-4"
+        style={{ width: 'min(100vw - 2rem, 42rem)' }}
+      >
+        <div className="w-full rounded-xl border bg-sidebar flex flex-col relative shadow-lg" style={{ borderColor: 'var(--primary)' }}>
+          {/* Textarea - auto-grows from 1 line to max 5 lines */}
+          <Textarea
+            value={commentText}
+            onChange={(e) => {
+              setCommentText(e.target.value);
+              // Auto-resize textarea
+              const textarea = e.target;
+              textarea.style.height = 'auto';
+              const lineHeight = 20; // approx line height
+              const maxHeight = lineHeight * 5 + 8; // 5 lines + padding
+              textarea.style.height = `${Math.min(textarea.scrollHeight, maxHeight)}px`;
+            }}
+            placeholder="Type your comment..."
+            className="min-h-[28px] max-h-[108px] resize-none border-0 px-3 pt-2 pb-1 shadow-none rounded-none appearance-none focus:shadow-none focus-visible:shadow-none focus-visible:border-transparent focus-visible:ring-0 focus-visible:ring-transparent hover:border-transparent bg-transparent dark:bg-transparent focus-visible:outline-none overflow-y-auto"
+            autoFocus={!isMobile}
+            rows={1}
+            onKeyDown={(e) => {
+              if (e.key === 'Enter' && (e.metaKey || e.ctrlKey)) {
+                e.preventDefault();
+                handleSendComment();
+              }
+              if (e.key === 'Escape') {
+                e.preventDefault();
+                setSelection(null);
+                setCommentText('');
+              }
+            }}
+          />
+          {/* Footer */}
+          <div className="px-2.5 py-1 flex items-center justify-between gap-x-1.5">
+            <span className="text-xs text-muted-foreground">
+              {fileName.split('/').pop()}:{selection.start}-{selection.end}
+            </span>
+            <div className="flex items-center gap-x-1.5">
+              {!isMobile && (
+                <span className="text-xs text-muted-foreground">
+                  {getModifierLabel()}+⏎
+                </span>
+              )}
+              <button
+                type="button"
+                onTouchEnd={(e) => {
+                  // On mobile, handle send via touchend to avoid race with selection clearing
+                  if (commentText.trim()) {
+                    e.preventDefault();
+                    handleSendComment();
+                  }
+                }}
+                onClick={() => {
+                  // Desktop click handler
+                  if (!isMobile) {
+                    handleSendComment();
+                  }
+                }}
+                disabled={!commentText.trim()}
+                className={cn(
+                  "h-7 w-7 flex items-center justify-center text-muted-foreground transition-none outline-none focus:outline-none flex-shrink-0",
+                  commentText.trim() ? "text-primary hover:text-primary" : "opacity-30"
+                )}
+                aria-label="Send comment"
+              >
+                <RiSendPlane2Line className="h-[18px] w-[18px]" />
+              </button>
+            </div>
+          </div>
+        </div>
+      </div>
+    );
+  };
+
+  const commentContent = renderCommentContent();
+
+  // If we're in the main diff view ('fill' layout), render In-Flow (like ChatInput).
+  // If we're in an inline diff ('inline' layout), render via Portal (fixed over content).
+  if (layout === 'fill') {
+    return (
+      <div 
+        className={cn("flex flex-col relative", "size-full")}
+        style={{
+          // Apply keyboard padding to the main container, just like ChatContainer
+          paddingBottom: isMobile ? 'var(--oc-keyboard-inset, 0px)' : undefined
+        }}
+      >
+        <div className="flex-1 relative min-h-0">
+          <ScrollableOverlay
+            outerClassName="pierre-diff-wrapper size-full"
+            disableHorizontal={false}
+            fillContainer={true}
+          >
+            <FileDiff
+              fileDiff={fileDiff}
+              options={options}
+              selectedLines={selection}
+            />
+          </ScrollableOverlay>
+        </div>
+        
+        {/* Render Input In-Flow at the bottom */}
+        {selection && (
+          <div 
+            className={cn(
+              "pointer-events-auto relative pb-2 transition-none z-50 flex justify-center",
+              isMobile && isKeyboardOpen ? "ios-keyboard-safe-area" : "bottom-safe-area"
+            )}
+            style={{
+              marginBottom: isMobile 
+                ? (!isKeyboardOpen && inputBarOffset > 0 ? `${inputBarOffset}px` : '16px')
+                : '16px'
+            }}
+            data-keyboard-avoid="true"
+          >
+            {commentContent}
+          </div>
+        )}
+      </div>
+    );
+  }
+
+  // Fallback for 'inline' layout: use Portal behavior
   return (
-    <ScrollableOverlay
-      outerClassName={isInlineLayout ? "pierre-diff-wrapper w-full" : "pierre-diff-wrapper size-full"}
-      disableHorizontal={false}
-      fillContainer={!isInlineLayout}
-    >
-      <FileDiff
-        fileDiff={fileDiff}
-        options={options}
-      />
-    </ScrollableOverlay>
+    <div className={cn("relative", "w-full")}>
+      <ScrollableOverlay
+        outerClassName="pierre-diff-wrapper w-full"
+        disableHorizontal={false}
+        fillContainer={false}
+      >
+        <FileDiff
+          fileDiff={fileDiff}
+          options={options}
+          selectedLines={selection}
+        />
+      </ScrollableOverlay>
+      
+      {selection && createPortal(
+        <div 
+          className="fixed inset-0 z-50 flex flex-col justify-end items-start pointer-events-none transition-none transform-gpu"
+          style={{ 
+            paddingBottom: isMobile ? 'var(--oc-keyboard-inset, 0px)' : '0px',
+            isolation: 'isolate'
+          }}
+        >
+          <div 
+            className={cn(
+              "pointer-events-auto relative pb-2 transition-none",
+              isMobile && isKeyboardOpen ? "ios-keyboard-safe-area" : "bottom-safe-area"
+            )}
+            style={{ 
+              marginLeft: mainContentCenter,
+              transform: 'translateX(-50%)',
+              marginBottom: isMobile 
+                ? (!isKeyboardOpen && inputBarOffset > 0 ? `${inputBarOffset}px` : '16px')
+                : '16px'
+            }}
+            data-keyboard-avoid="true"
+            data-comment-ui="true"
+          >
+            {commentContent}
+          </div>
+        </div>,
+        document.body
+      )}
+    </div>
   );
 };