Add change tracking and history display to Option 5

- Initialize change tracking before applying optimizations
- Log each change made during optimization process
- Track before/after values for all modifications
- Display detailed change log after optimization completes
- Show recent change history from change tracker
- Provides auditability and visibility into what changed

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

modules/performance/php-optimizer.sh

@@ -926,11 +926,118 @@ optimize_all_domains() {
             ;;
     esac
 
+    # ========================================================================
+    # STEP 3: PREVIEW CHANGES BEFORE APPLYING
+    # ========================================================================
+
+    show_banner
+    cecho "${WHITE}${BOLD}PREVIEW: Changes that will be applied${NC}"
+    cecho "${CYAN}─────────────────────────────────────────────────────────────────────${NC}"
+    echo ""
+
+    local preview_count=0
+    local preview_total_impact=0
+
+    # Get all users for preview
+    local preview_users
+    preview_users=$(list_all_users)
+
+    while IFS= read -r username; do
+        [ -z "$username" ] && continue
+
+        local user_domains
+        user_domains=$(get_user_domains "$username")
+
+        while IFS= read -r domain; do
+            [ -z "$domain" ] && continue
+
+            # Check if this domain/user was selected
+            local should_preview=false
+            if [ "$SYS_CONTROL_PANEL" = "cpanel" ]; then
+                [ "${domains_to_apply[$domain]}" = "true" ] && should_preview=true
+            else
+                [ "${domains_to_apply[$username]}" = "true" ] && should_preview=true
+            fi
+
+            if [ "$should_preview" = "false" ]; then
+                continue
+            fi
+
+            preview_count=$((preview_count + 1))
+
+            # Get current pool config
+            local pool_config
+            pool_config=$(find_fpm_pool_config "$username" "$domain" 2>/dev/null)
+
+            if [ -z "$pool_config" ] || [ ! -f "$pool_config" ]; then
+                continue
+            fi
+
+            # Get current and recommended values
+            local current_max recommended_max
+            current_max=$(grep "^pm.max_children" "$pool_config" 2>/dev/null | awk -F'=' '{print $2}' | tr -d ' ')
+
+            if [ "$SYS_CONTROL_PANEL" = "cpanel" ]; then
+                recommended_max="${recommended_values[$domain]}"
+            else
+                recommended_max="${recommended_values[$username]}"
+            fi
+
+            if [ -z "$current_max" ] || [ -z "$recommended_max" ]; then
+                continue
+            fi
+
+            # Calculate memory impact (assume 20MB per process on average)
+            local memory_freed=$((( current_max - recommended_max ) * 20))
+
+            if [ "$current_max" -ne "$recommended_max" ]; then
+                cecho "  ${CYAN}[$preview_count]${NC} $domain"
+                cecho "      Current: pm.max_children = ${YELLOW}$current_max${NC}"
+                cecho "      Change to: pm.max_children = ${GREEN}$recommended_max${NC}"
+
+                if [ "$memory_freed" -gt 0 ]; then
+                    cecho "      Memory freed: ${GREEN}+${memory_freed}MB${NC}"
+                    preview_total_impact=$((preview_total_impact + memory_freed))
+                elif [ "$memory_freed" -lt 0 ]; then
+                    cecho "      Memory allocated: ${YELLOW}$((-memory_freed))MB${NC} (growth)"
+                fi
+                echo ""
+            fi
+        done <<< "$user_domains"
+    done <<< "$preview_users"
+
+    if [ "$preview_count" -eq 0 ]; then
+        cecho "${YELLOW}No changes to preview${NC}"
+        echo ""
+        read -p "Press Enter to continue..."
+        return
+    fi
+
+    echo ""
+    cecho "${CYAN}═══════════════════════════════════════════════════════════════════${NC}"
+    cecho "${WHITE}${BOLD}PREVIEW SUMMARY${NC}"
+    cecho "  Total changes: ${WHITE}$preview_count${NC}"
+    if [ "$preview_total_impact" -gt 0 ]; then
+        cecho "  Total memory that could be freed: ${GREEN}+${preview_total_impact}MB${NC}"
+    fi
+    echo ""
+    cecho "${CYAN}─────────────────────────────────────────────────────────────────────${NC}"
+
+    # Ask for final confirmation before applying
+    if ! confirm "Apply these changes?"; then
+        cecho "${YELLOW}Optimization cancelled${NC}"
+        read -p "Press Enter to continue..."
+        return
+    fi
+
     show_banner
     cecho "${WHITE}${BOLD}Applying optimizations...${NC}"
     cecho "${CYAN}Selected: ${#domains_to_apply[@]} domain(s)/user(s)${NC}"
     echo ""
 
+    # Initialize change tracking
+    init_change_tracking 2>/dev/null || true
+
     # Get all users
     local users
     users=$(list_all_users)
@@ -946,6 +1053,7 @@ optimize_all_domains() {
     local optimized_count=0
     local skipped_count=0
     declare -A optimization_summary
+    declare -a changes_made_list
 
     # Process each user
     while IFS= read -r username; do
@@ -1046,6 +1154,10 @@ optimize_all_domains() {
             if [ "$changes_made" -gt 0 ]; then
                 cecho "    ${GREEN}✓${NC} Optimized ($changes_made changes): $changes_list"
                 optimized_count=$((optimized_count + 1))
+
+                # Log the change
+                log_change "$domain|$username" "pm.max_children" "$current_max_children" "$recommended_max_children" "Server-wide optimization" 2>/dev/null || true
+                changes_made_list+=("$domain: $current_max_children → $recommended_max_children (freed ~$((( current_max_children - recommended_max_children ) * 20))MB)")
             else
                 if [ -n "$changes_list" ]; then
                     cecho "    ${YELLOW}⊙${NC} Detected: $changes_list (manual intervention needed)"
@@ -1095,7 +1207,35 @@ optimize_all_domains() {
     fi
 
     echo ""
-    cecho "${CYAN}═══════════════════════════════════════════════════════════════════${NC}"
+
+    # Display change history
+    if [ "${#changes_made_list[@]}" -gt 0 ]; then
+        cecho "${CYAN}─────────────────────────────────────────────────────────────────────${NC}"
+        cecho "${WHITE}${BOLD}DETAILED CHANGES${NC}"
+        cecho "${CYAN}─────────────────────────────────────────────────────────────────────${NC}"
+        echo ""
+
+        for change in "${changes_made_list[@]}"; do
+            cecho "  ${GREEN}✓${NC} $change"
+        done
+
+        echo ""
+
+        # Get recent change history from tracker
+        local recent_changes
+        recent_changes=$(get_change_history 2>/dev/null || echo "")
+
+        if [ -n "$recent_changes" ]; then
+            cecho "${CYAN}─────────────────────────────────────────────────────────────────────${NC}"
+            cecho "${WHITE}${BOLD}CHANGE HISTORY${NC}"
+            cecho "${CYAN}─────────────────────────────────────────────────────────────────────${NC}"
+            echo ""
+            cecho "$recent_changes" | head -20  # Show last 20 changes
+            echo ""
+        fi
+    fi
+
+    cecho "${CYAN}═════════════════════════════════════════════════════════════════════${NC}"
     echo ""
     read -p "Press Enter to continue..."
 }