Flow visualizer (#1377)

* Almost working!

* It fully works but not clean enought

* Working but not clean engouth

* Everything is workign

* WIP. Working on adding and & or to flows. In the middle of setting up template for flow as well

* template working

* Everything is working

* More changes and todos

* Add more support for @start

* Router working now

* minor tweak to

* minor tweak to conditions and event handling

* Update logs

* Too trigger happy with cleanup

* Added in Thiago fix

* Flow passing results again

* Working on docs.

* made more progress updates on docs

* Finished talking about controlling flows

* add flow output

* fixed flow output section

* add crews to flows section is looking good now

* more flow doc changes

* Update docs and add more examples

* drop visualizer

* save visualizer

* pyvis is beginning to work

* pyvis working

* it is working

* regular methods and triggers working. Need to work on router next.

* properly identifying router and router children nodes. Need to fix color

* children router working. Need to support loops

* curving cycles but need to add curve conditionals

* everythin is showing up properly need to fix curves

* all working. needs to be cleaned up

* adjust padding

* drop lib

* clean up prior to PR

* incorporate joao feedback

* final tweaks for joao

* Refactor to make crews easier to understand

* update CLI and templates

* Fix crewai version in flows

* Fix merge conflict

src/crewai/flow/utils.py

@@ -0,0 +1,143 @@
+def calculate_node_levels(flow):
+    levels = {}
+    queue = []
+    visited = set()
+    pending_and_listeners = {}
+
+    # Make all start methods at level 0
+    for method_name, method in flow._methods.items():
+        if hasattr(method, "__is_start_method__"):
+            levels[method_name] = 0
+            queue.append(method_name)
+
+    # Breadth-first traversal to assign levels
+    while queue:
+        current = queue.pop(0)
+        current_level = levels[current]
+        visited.add(current)
+
+        for listener_name, (
+            condition_type,
+            trigger_methods,
+        ) in flow._listeners.items():
+            if condition_type == "OR":
+                if current in trigger_methods:
+                    if (
+                        listener_name not in levels
+                        or levels[listener_name] > current_level + 1
+                    ):
+                        levels[listener_name] = current_level + 1
+                        if listener_name not in visited:
+                            queue.append(listener_name)
+            elif condition_type == "AND":
+                if listener_name not in pending_and_listeners:
+                    pending_and_listeners[listener_name] = set()
+                if current in trigger_methods:
+                    pending_and_listeners[listener_name].add(current)
+                if set(trigger_methods) == pending_and_listeners[listener_name]:
+                    if (
+                        listener_name not in levels
+                        or levels[listener_name] > current_level + 1
+                    ):
+                        levels[listener_name] = current_level + 1
+                        if listener_name not in visited:
+                            queue.append(listener_name)
+
+        # Handle router connections
+        if current in flow._routers.values():
+            router_method_name = current
+            paths = flow._router_paths.get(router_method_name, [])
+            for path in paths:
+                for listener_name, (
+                    condition_type,
+                    trigger_methods,
+                ) in flow._listeners.items():
+                    if path in trigger_methods:
+                        if (
+                            listener_name not in levels
+                            or levels[listener_name] > current_level + 1
+                        ):
+                            levels[listener_name] = current_level + 1
+                            if listener_name not in visited:
+                                queue.append(listener_name)
+    return levels
+
+
+def count_outgoing_edges(flow):
+    counts = {}
+    for method_name in flow._methods:
+        counts[method_name] = 0
+    for method_name in flow._listeners:
+        _, trigger_methods = flow._listeners[method_name]
+        for trigger in trigger_methods:
+            if trigger in flow._methods:
+                counts[trigger] += 1
+    return counts
+
+
+def build_ancestor_dict(flow):
+    ancestors = {node: set() for node in flow._methods}
+    visited = set()
+    for node in flow._methods:
+        if node not in visited:
+            dfs_ancestors(node, ancestors, visited, flow)
+    return ancestors
+
+
+def dfs_ancestors(node, ancestors, visited, flow):
+    if node in visited:
+        return
+    visited.add(node)
+
+    # Handle regular listeners
+    for listener_name, (_, trigger_methods) in flow._listeners.items():
+        if node in trigger_methods:
+            ancestors[listener_name].add(node)
+            ancestors[listener_name].update(ancestors[node])
+            dfs_ancestors(listener_name, ancestors, visited, flow)
+
+    # Handle router methods separately
+    if node in flow._routers.values():
+        router_method_name = node
+        paths = flow._router_paths.get(router_method_name, [])
+        for path in paths:
+            for listener_name, (_, trigger_methods) in flow._listeners.items():
+                if path in trigger_methods:
+                    # Only propagate the ancestors of the router method, not the router method itself
+                    ancestors[listener_name].update(ancestors[node])
+                    dfs_ancestors(listener_name, ancestors, visited, flow)
+
+
+def is_ancestor(node, ancestor_candidate, ancestors):
+    return ancestor_candidate in ancestors.get(node, set())
+
+
+def build_parent_children_dict(flow):
+    parent_children = {}
+
+    # Map listeners to their trigger methods
+    for listener_name, (_, trigger_methods) in flow._listeners.items():
+        for trigger in trigger_methods:
+            if trigger not in parent_children:
+                parent_children[trigger] = []
+            if listener_name not in parent_children[trigger]:
+                parent_children[trigger].append(listener_name)
+
+    # Map router methods to their paths and to listeners
+    for router_method_name, paths in flow._router_paths.items():
+        for path in paths:
+            # Map router method to listeners of each path
+            for listener_name, (_, trigger_methods) in flow._listeners.items():
+                if path in trigger_methods:
+                    if router_method_name not in parent_children:
+                        parent_children[router_method_name] = []
+                    if listener_name not in parent_children[router_method_name]:
+                        parent_children[router_method_name].append(listener_name)
+
+    return parent_children
+
+
+def get_child_index(parent, child, parent_children):
+    children = parent_children.get(parent, [])
+    children.sort()
+    return children.index(child)