Codebase visualization tutorial (#175)

# Motivation
Adds important documentation on codebase visualizations

# Content

# Testing
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# Please check the following before marking your PR as ready for review

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Co-authored-by: codegen-bot <[email protected]>

Author: jemeza-codegen

docs/images/blast-radius.png

@@ -73,6 +73,7 @@
 			"pages": [
 				"tutorials/at-a-glance",
 				"tutorials/migrating-apis",
+				"tutorials/codebase-visualization",
 				"tutorials/organize-your-codebase",
 				"tutorials/modularity",
 				"tutorials/deleting-dead-code",

docs/mint.json

@@ -0,0 +1,383 @@
+---
+title: "Codebase Visualization"
+sidebarTitle: "Codebase Visualization"
+description: "This guide will show you how to create codebase visualizations using [codegen](/introduction/overview)."
+icon: "flashlight"
+iconType: "solid"
+---
+
+<Frame caption="Blast radius visualization of the `export_asset` function. Click and drag to pan, scroll to zoom.">
+  <iframe
+  width="100%"
+  height="600px"
+  scrolling="no"
+  src={`https://codegen.sh/embedded/graph?id=347d349e-263b-481a-9601-1cd205b332b9&zoom=1&targetNodeName=export_asset`}
+  className="rounded-xl "
+  style={{
+    backgroundColor: "#15141b",
+  }}
+></iframe>
+</Frame>
+
+## Overview
+
+To demonstrate the visualization capabilities of the codegen we will generate three different visualizations of PostHog's open source [repository](https://github.com/PostHog/posthog).
+ - [Call Trace Visualization](#call-trace-visualization)
+ - [Function Dependency Graph](#function-dependency-graph)
+ - [Blast Radius Visualization](#blast-radius-visualization)
+
+
+## Call Trace Visualization
+
+Visualizing the call trace of a function is a great way to understand the flow of a function and for debugging. In this tutorial we will create a call trace visualization of the `patch` method of the `SharingConfigurationViewSet` class. View the source code [here](https://github.com/PostHog/posthog/blob/c2986d9ac7502aa107a4afbe31b3633848be6582/posthog/api/sharing.py#L163).
+
+
+### Basic Setup
+First, we'll set up our codebase, graph and configure some basic parameters:
+
+```python
+import networkx as nx
+from codegen import Codebase
+
+# Initialize codebase
+codebase = Codebase("path/to/posthog/")
+
+# Create a directed graph for representing call relationships 
+G = nx.DiGraph()
+
+# Configuration flags
+IGNORE_EXTERNAL_MODULE_CALLS = True  # Skip calls to external modules
+IGNORE_CLASS_CALLS = False           # Include class definition calls
+MAX_DEPTH = 10
+
+COLOR_PALETTE = {
+    "StartFunction": "#9cdcfe",     # Light blue - Start Function
+    "PyFunction": "#a277ff",        # Soft purple/periwinkle - PyFunction
+    "PyClass": "#ffca85",           # Warm peach/orange - PyClass
+    "ExternalModule": "#f694ff"     # Bright magenta/pink - ExternalModule
+}
+```
+
+### Building the Visualization
+We'll create a function that will recursively traverse the call trace of a function and add nodes and edges to the graph:
+
+```python
+def create_downstream_call_trace(src_func: Function, depth: int = 0):
+    """Creates call graph by recursively traversing function calls
+    
+    Args:
+        src_func (Function): Starting function for call graph
+        depth (int): Current recursion depth
+    """
+    # Prevent infinite recursion
+    if MAX_DEPTH <= depth:
+        return
+        
+    # External modules are not functions
+    if isinstance(src_func, ExternalModule):
+        return
+
+    # Process each function call
+    for call in src_func.function_calls:
+        # Skip self-recursive calls
+        if call.name == src_func.name:
+            continue
+            
+        # Get called function definition
+        func = call.function_definition
+        if not func:
+            continue
+            
+        # Apply configured filters
+        if isinstance(func, ExternalModule) and IGNORE_EXTERNAL_MODULE_CALLS:
+            continue
+        if isinstance(func, Class) and IGNORE_CLASS_CALLS:
+            continue
+
+        # Generate display name (include class for methods)
+        if isinstance(func, Class) or isinstance(func, ExternalModule):
+            func_name = func.name
+        elif isinstance(func, Function):
+            func_name = f"{func.parent_class.name}.{func.name}" if func.is_method else func.name
+
+        # Add node and edge with metadata
+        G.add_node(func, name=func_name, 
+                  color=COLOR_PALETTE.get(func.__class__.__name__))
+        G.add_edge(src_func, func, **generate_edge_meta(call))
+
+        # Recurse for regular functions
+        if isinstance(func, Function):
+            create_downstream_call_trace(func, depth + 1)
+```
+
+### Adding Edge Metadata
+We can enrich our edges with metadata about the function calls:
+
+```python
+def generate_edge_meta(call: FunctionCall) -> dict:
+    """Generate metadata for call graph edges
+    
+    Args:
+        call (FunctionCall): Function call information
+        
+    Returns:
+        dict: Edge metadata including name and location
+    """
+    return {
+        "name": call.name,
+        "file_path": call.filepath,
+        "start_point": call.start_point,
+        "end_point": call.end_point,
+        "symbol_name": "FunctionCall"
+    }
+```
+### Visualizing the Graph
+Finally, we can visualize our call graph starting from a specific function:
+```python
+# Get target function to analyze
+target_class = codebase.get_class('SharingConfigurationViewSet')
+target_method = target_class.get_method('patch')
+
+# Add root node 
+G.add_node(target_method, 
+           name=f"{target_class.name}.{target_method.name}",
+           color=COLOR_PALETTE["StartFunction"])
+
+# Build the call graph
+create_downstream_call_trace(target_method)
+
+# Render the visualization
+codebase.visualize(G)
+```
+
+### Common Use Cases
+The call graph visualization is particularly useful for:
+ - Understanding complex codebases
+ - Planning refactoring efforts
+ - Identifying tightly coupled components
+ - Analyzing critical paths
+ - Documenting system architecture
+
+### Take a look
+<iframe
+  width="100%"
+  height="600px"
+  scrolling="no"
+  src={`https://codegen.sh/embedded/graph?id=9a141c52-c0c2-4737-bdc3-5d164791d3b5&zoom=1&targetNodeName=SharingConfigurationViewSet.patch`}
+  className="rounded-xl "
+  style={{
+    backgroundColor: "#15141b",
+  }}
+></iframe>
+
+## Function Dependency Graph
+
+Understanding symbol dependencies is crucial for maintaining and refactoring code. This tutorial will show you how to create visual dependency graphs using Codegen and NetworkX. We will be creating a dependency graph of the `get_query_runner` function. View the source code [here](https://github.com/PostHog/posthog/blob/c2986d9ac7502aa107a4afbe31b3633848be6582/posthog/hogql_queries/query_runner.py#L152).
+
+### Basic Setup
+<Info>
+We'll use the same basic setup as the [Call Trace Visualization](/tutorials/codebase-visualization#call-trace-visualization) tutorial.
+</Info>
+
+### Building the Dependency Graph
+The core function for building our dependency graph:
+```python
+def create_dependencies_visualization(symbol: Symbol, depth: int = 0):
+    """Creates visualization of symbol dependencies
+    
+    Args:
+        symbol (Symbol): Starting symbol to analyze
+        depth (int): Current recursion depth
+    """
+    # Prevent excessive recursion
+    if depth >= MAX_DEPTH:
+        return
+    
+    # Process each dependency
+    for dep in symbol.dependencies:
+        dep_symbol = None
+        
+        # Handle different dependency types
+        if isinstance(dep, Symbol):
+            # Direct symbol reference
+            dep_symbol = dep
+        elif isinstance(dep, Import):
+            # Import statement - get resolved symbol
+            dep_symbol = dep.resolved_symbol if dep.resolved_symbol else None
+
+        if dep_symbol:
+            # Add node with appropriate styling
+            G.add_node(dep_symbol, 
+                      color=COLOR_PALETTE.get(dep_symbol.__class__.__name__, 
+                                            "#f694ff"))
+            
+            # Add dependency relationship
+            G.add_edge(symbol, dep_symbol)
+            
+            # Recurse unless it's a class (avoid complexity)
+            if not isinstance(dep_symbol, PyClass):
+                create_dependencies_visualization(dep_symbol, depth + 1)
+```
+
+### Visualizing the Graph
+Finally, we can visualize our dependency graph starting from a specific symbol:
+```python
+# Get target symbol
+target_func = codebase.get_function("get_query_runner")
+
+# Add root node 
+G.add_node(target_func, color=COLOR_PALETTE["StartFunction"])
+
+# Generate dependency graph
+create_dependencies_visualization(target_func)
+
+# Render visualization
+codebase.visualize(G)
+```
+
+### Take a look
+<iframe
+  width="100%"
+  height="600px"
+  scrolling="no"
+  src={`https://codegen.sh/embedded/graph?id=bb7b227b-cc89-4e92-b71f-fb0d6265eb3d&zoom=0.8&targetNodeName=get_query_runner`}
+  className="rounded-xl "
+  style={{
+    backgroundColor: "#15141b",
+  }}
+></iframe>
+
+## Blast Radius visualization
+
+Understanding the impact of code changes is crucial for safe refactoring. A blast radius visualization shows how changes to one function might affect other parts of the codebase by tracing usage relationships. In this tutorial we will create a blast radius visualization of the `export_asset` function. View the source code [here](https://github.com/PostHog/posthog/blob/c2986d9ac7502aa107a4afbe31b3633848be6582/posthog/tasks/exporter.py#L57).
+
+### Basic Setup
+<Info>
+We'll use the same basic setup as the [Call Trace Visualization](/tutorials/codebase-visualization#call-trace-visualization) tutorial.
+</Info>
+
+### Helper Functions
+We'll create some utility functions to help build our visualization:
+```python
+# List of HTTP methods to highlight
+HTTP_METHODS = ["get", "put", "patch", "post", "head", "delete"]
+
+def generate_edge_meta(usage: Usage) -> dict:
+    """Generate metadata for graph edges
+    
+    Args:
+        usage (Usage): Usage relationship information
+        
+    Returns:
+        dict: Edge metadata including name and location
+    """
+    return {
+        "name": usage.match.source,
+        "file_path": usage.match.filepath, 
+        "start_point": usage.match.start_point,
+        "end_point": usage.match.end_point,
+        "symbol_name": usage.match.__class__.__name__
+    }
+
+def is_http_method(symbol: PySymbol) -> bool:
+    """Check if a symbol is an HTTP endpoint method
+    
+    Args:
+        symbol (PySymbol): Symbol to check
+        
+    Returns:
+        bool: True if symbol is an HTTP method
+    """
+    if isinstance(symbol, PyFunction) and symbol.is_method:
+        return symbol.name in HTTP_METHODS
+    return False
+```
+
+### Building the Blast Radius Visualization
+The main function for creating our blast radius visualization:
+```python
+def create_blast_radius_visualization(symbol: PySymbol, depth: int = 0):
+    """Create visualization of symbol usage relationships
+    
+    Args:
+        symbol (PySymbol): Starting symbol to analyze
+        depth (int): Current recursion depth
+    """
+    # Prevent excessive recursion
+    if depth >= MAX_DEPTH:
+        return
+    
+    # Process each usage of the symbol
+    for usage in symbol.usages:
+        usage_symbol = usage.usage_symbol
+        
+        # Determine node color based on type
+        if is_http_method(usage_symbol):
+            color = COLOR_PALETTE.get("HTTP_METHOD")
+        else:
+            color = COLOR_PALETTE.get(usage_symbol.__class__.__name__, "#f694ff")
+
+        # Add node and edge to graph
+        G.add_node(usage_symbol, color=color)
+        G.add_edge(symbol, usage_symbol, **generate_edge_meta(usage))
+        
+        # Recursively process usage symbol
+        create_blast_radius_visualization(usage_symbol, depth + 1)
+```
+
+### Visualizing the Graph
+Finally, we can create our blast radius visualization:
+```python
+# Get target function to analyze
+target_func = codebase.get_function('export_asset')
+
+# Add root node
+G.add_node(target_func, color=COLOR_PALETTE.get("StartFunction"))
+
+# Build the visualization
+create_blast_radius_visualization(target_func)
+
+# Render reversed graph to show impact flow
+codebase.visualize(G.reverse())
+```
+
+### Take a look
+<iframe
+  width="100%"
+  height="600px"
+  scrolling="no"
+  src={`https://codegen.sh/embedded/graph?id=347d349e-263b-481a-9601-1cd205b332b9&zoom=1&targetNodeName=export_asset`}
+  className="rounded-xl "
+  style={{
+    backgroundColor: "#15141b",
+  }}
+></iframe>
+
+## What's Next?
+
+<CardGroup cols={2}>
+  <Card
+    title="Codebase Modularity"
+    icon="diagram-project"
+    href="/tutorials/modularity"
+  >
+    Learn how to use Codegen to create modular codebases.
+  </Card>
+  <Card
+    title="Deleting Dead Code"
+    icon="trash"
+    href="/tutorials/deleting-dead-code"
+  >
+    Learn how to use Codegen to delete dead code.
+  </Card>
+  <Card
+    title="Increase Type Coverage"
+    icon="shield-check"
+    href="/tutorials/increase-type-coverage"
+  >
+    Learn how to use Codegen to increase type coverage.
+  </Card>
+  <Card title="API Reference" icon="code" href="/api-reference">
+    Explore the complete API documentation for all Codegen classes and methods.
+  </Card>
+</CardGroup>