Add proper growth chart visualization

- Created generate_growth_chart.py script with matplotlib
- Replaced emoji sparkline with actual time-series chart
- Chart shows dates (X-axis) vs prompt count (Y-axis)
- Updated README stats script to use proper chart
- Added markers to protect manual README edits from automation
- Chart saved as images/growth_chart.png

Author: danielrosehill

.gitignore

@@ -17,3 +17,4 @@ Thumbs.db
 # Temporary files
 *.tmp
 *.bak
+.chart-env

README.md

@@ -6,14 +6,15 @@
 
 ![alt text](images/banner.webp)
 
-
+<!-- BEGIN_STATS_SECTION -->
 ## 📊 Library Statistics
 
-📈 ▁█▅▅
+![Growth Chart](images/growth_chart.png)
 
 **Total System Prompts:** 922 | **Last Updated:** 2025-08-27
 
 *This library has grown from 892 to 922 prompts since tracking began*
+<!-- END_STATS_SECTION -->
 
 ## Table of Contents
 

images/growth_chart.png

@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+"""
+Generate a proper time-series chart showing System Prompt Library growth over time.
+
+Creates a line chart with:
+- X-axis: Time (dates)
+- Y-axis: Number of system prompts
+- Saves as PNG image for embedding in README
+"""
+
+import json
+import matplotlib.pyplot as plt
+import matplotlib.dates as mdates
+from datetime import datetime
+from pathlib import Path
+import pandas as pd
+
+
+def generate_growth_chart(repo_root: Path, output_file: str = "images/growth_chart.png"):
+    """Generate and save a growth chart from growth_history.json."""
+    
+    growth_file = repo_root / "growth_history.json"
+    output_path = repo_root / output_file
+    
+    # Ensure output directory exists
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+    
+    if not growth_file.exists():
+        print("❌ growth_history.json not found")
+        return False
+    
+    # Load growth data
+    with open(growth_file, 'r') as f:
+        growth_data = json.load(f)
+    
+    entries = growth_data.get("entries", [])
+    if len(entries) < 2:
+        print("❌ Need at least 2 data points to create a meaningful chart")
+        return False
+    
+    # Extract dates and counts
+    dates = []
+    counts = []
+    
+    for entry in entries:
+        # Try different date field names
+        date_str = entry.get("date") or entry.get("updated") or entry.get("created")
+        if date_str:
+            # Parse date (handle both date-only and ISO timestamp formats)
+            try:
+                if 'T' in date_str:
+                    # ISO timestamp format
+                    date_obj = datetime.fromisoformat(date_str.replace('Z', '+00:00'))
+                else:
+                    # Date-only format
+                    date_obj = datetime.strptime(date_str, '%Y-%m-%d')
+                
+                dates.append(date_obj)
+                counts.append(entry["count"])
+            except ValueError as e:
+                print(f"⚠️ Skipping invalid date: {date_str} - {e}")
+                continue
+    
+    if len(dates) < 2:
+        print("❌ Not enough valid date entries found")
+        return False
+    
+    # Create the chart
+    plt.style.use('default')
+    fig, ax = plt.subplots(figsize=(12, 6))
+    
+    # Plot the line chart
+    ax.plot(dates, counts, marker='o', linewidth=2.5, markersize=6, 
+            color='#2E86AB', markerfacecolor='#A23B72', markeredgecolor='white', markeredgewidth=1.5)
+    
+    # Customize the chart
+    ax.set_title('System Prompt Library Growth Over Time', fontsize=16, fontweight='bold', pad=20)
+    ax.set_xlabel('Date', fontsize=12, fontweight='bold')
+    ax.set_ylabel('Number of System Prompts', fontsize=12, fontweight='bold')
+    
+    # Format dates on x-axis
+    ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d'))
+    ax.xaxis.set_major_locator(mdates.DayLocator(interval=max(1, len(dates)//6)))  # Show ~6 date labels
+    plt.xticks(rotation=45)
+    
+    # Add grid
+    ax.grid(True, alpha=0.3, linestyle='--')
+    
+    # Set y-axis to start from a reasonable minimum
+    min_count = min(counts)
+    max_count = max(counts)
+    padding = (max_count - min_count) * 0.1
+    ax.set_ylim(min_count - padding, max_count + padding)
+    
+    # Add value labels on data points
+    for date, count in zip(dates, counts):
+        ax.annotate(f'{count}', (date, count), textcoords="offset points", 
+                   xytext=(0,10), ha='center', fontsize=9, fontweight='bold')
+    
+    # Improve layout
+    plt.tight_layout()
+    
+    # Save the chart
+    plt.savefig(output_path, dpi=300, bbox_inches='tight', facecolor='white', edgecolor='none')
+    plt.close()
+    
+    print(f"✅ Growth chart saved to {output_file}")
+    print(f"📊 Chart shows {len(dates)} data points from {dates[0].strftime('%Y-%m-%d')} to {dates[-1].strftime('%Y-%m-%d')}")
+    print(f"📈 Growth: {min_count} → {max_count} prompts ({max_count - min_count:+d})")
+    
+    return True
+
+
+def main():
+    """Main function."""
+    repo_root = Path(__file__).parent.parent
+    
+    print("📊 Generating System Prompt Library growth chart...")
+    
+    # Check if matplotlib is available
+    try:
+        import matplotlib.pyplot as plt
+        import matplotlib.dates as mdates
+    except ImportError:
+        print("❌ matplotlib is required. Install with: pip install matplotlib")
+        return 1
+    
+    success = generate_growth_chart(repo_root)
+    
+    if success:
+        print("✅ Growth chart generation completed successfully")
+    else:
+        print("❌ Failed to generate growth chart")
+        return 1
+    
+    return 0
+
+
+if __name__ == "__main__":
+    exit(main())

scripts/generate_growth_chart.py

@@ -8,6 +8,8 @@
 
 import json
 import re
+import subprocess
+import sys
 from pathlib import Path
 from datetime import datetime
 from typing import List, Dict
@@ -37,6 +39,35 @@ def generate_sparkline(counts: List[int]) -> str:
     return sparkline
 
 
+def generate_growth_chart(repo_root: Path) -> bool:
+    """Generate growth chart using the chart generation script."""
+    try:
+        # Run the chart generation script in the virtual environment
+        venv_python = repo_root / "chart-env" / "bin" / "python3"
+        chart_script = repo_root / "scripts" / "generate_growth_chart.py"
+        
+        if venv_python.exists() and chart_script.exists():
+            result = subprocess.run(
+                [str(venv_python), str(chart_script)],
+                cwd=str(repo_root),
+                capture_output=True,
+                text=True
+            )
+            return result.returncode == 0
+        else:
+            # Fallback: try with system python
+            result = subprocess.run(
+                [sys.executable, str(chart_script)],
+                cwd=str(repo_root),
+                capture_output=True,
+                text=True
+            )
+            return result.returncode == 0
+    except Exception as e:
+        print(f"⚠️ Chart generation failed: {e}")
+        return False
+
+
 def load_growth_data(repo_root: Path) -> tuple:
     """Load growth history and current metadata."""
     growth_file = repo_root / "growth_history.json"
@@ -80,18 +111,26 @@ def update_readme_with_stats(repo_root: Path):
     except:
         formatted_date = datetime.now().strftime('%Y-%m-%d')
 
-    # Generate sparkline from growth history
+    # Generate growth chart
+    chart_generated = generate_growth_chart(repo_root)
+    
+    # Get counts for fallback text
     counts = [entry["count"] for entry in growth_data.get("entries", [])]
     if not counts:
         counts = [current_count]
 
-    sparkline = generate_sparkline(counts)
+    # Create stats section with proper chart
+    if chart_generated:
+        chart_section = "![Growth Chart](images/growth_chart.png)"
+    else:
+        # Fallback to sparkline if chart generation fails
+        chart_section = generate_sparkline(counts)
 
     # Create stats section
     stats_section = f"""
 ## 📊 Library Statistics
 
-{sparkline}
+{chart_section}
 
 **Total System Prompts:** {current_count:,} | **Last Updated:** {formatted_date}
 
@@ -103,26 +142,31 @@ def update_readme_with_stats(repo_root: Path):
     with open(readme_file, 'r', encoding='utf-8') as f:
         content = f.read()
 
-    # Check if stats section already exists
-    stats_pattern = r'## 📊 Library Statistics.*?(?=##|\Z)'
-    
-    if re.search(stats_pattern, content, re.DOTALL):
-        # Replace existing stats section
-        new_content = re.sub(stats_pattern, stats_section.strip() + '\n\n', content, flags=re.DOTALL)
-        print("✅ Updated existing statistics section")
+    # Use markers to only update the statistics section, preserving manual edits
+    stats_begin_marker = "<!-- BEGIN_STATS_SECTION -->"
+    stats_end_marker = "<!-- END_STATS_SECTION -->"
+    
+    # Check if markers exist
+    if stats_begin_marker in content and stats_end_marker in content:
+        # Replace only the content between markers
+        pattern = f"{stats_begin_marker}.*?{stats_end_marker}"
+        replacement = f"{stats_begin_marker}\n{stats_section.strip()}\n{stats_end_marker}"
+        new_content = re.sub(pattern, replacement, content, flags=re.DOTALL)
+        print("✅ Updated existing statistics section between markers")
     else:
-        # Insert stats section after the badges but before Table of Contents
+        # Insert stats section with markers after the badges but before Table of Contents
         # Look for the pattern: badges -> image -> Table of Contents
         toc_pattern = r'(!\[alt text\].*?\n\n)(## Table of Contents)'
 
         if re.search(toc_pattern, content, re.DOTALL):
+            stats_with_markers = f"{stats_begin_marker}\n{stats_section.strip()}\n{stats_end_marker}\n\n"
             new_content = re.sub(
                 toc_pattern, 
-                r'\1' + stats_section + r'\2', 
+                r'\1' + stats_with_markers + r'\2', 
                 content, 
                 flags=re.DOTALL
             )
-            print("✅ Added new statistics section before Table of Contents")
+            print("✅ Added new statistics section with markers before Table of Contents")
         else:
             # Fallback: add after the first heading
             lines = content.split('\n')
@@ -132,9 +176,10 @@ def update_readme_with_stats(repo_root: Path):
                     insert_pos = i
                     break
 
-            lines.insert(insert_pos, stats_section.strip())
+            stats_with_markers = f"{stats_begin_marker}\n{stats_section.strip()}\n{stats_end_marker}"
+            lines.insert(insert_pos, stats_with_markers)
             new_content = '\n'.join(lines)
-            print("✅ Added new statistics section (fallback method)")
+            print("✅ Added new statistics section with markers (fallback method)")
 
     # Write updated content
     with open(readme_file, 'w', encoding='utf-8') as f: