basic-fabric.py

from time import sleep
import json

# Simplified version of get_node_from_instance
def get_node_from_instance(inst):
    # For simplicity, we assume inst is already the node.
    return inst

# Guarded Callback Handling
def invoke_guarded_callback_impl(name, func, context, *args):
    try:
        func(context, *args)
    except Exception as error:
        reporter.on_error(error)

class Reporter:
    def __init__(self):
        self.has_error = False
        self.caught_error = None

    def on_error(self, error):
        self.has_error = True
        self.caught_error = error

reporter = Reporter()

# Synthetic Event System
class SyntheticEvent:
    def __init__(self, dispatch_config, target_inst, native_event, native_event_target):
        self.dispatch_config = dispatch_config
        self._target_inst = target_inst
        self.native_event = native_event
        self._dispatch_instances = self._dispatch_listeners = None
        dispatch_config = self.__class__.Interface
        for prop_name in dispatch_config:
            if prop_name in dispatch_config:
                self[prop_name] = dispatch_config[prop_name](native_event) if dispatch_config[prop_name] else native_event.get(prop_name, None)
        self.target = native_event_target

    def prevent_default(self):
        self.is_default_prevented = True

    def stop_propagation(self):
        self.is_propagation_stopped = True


# Responder Event Handling
class ResponderSyntheticEvent(SyntheticEvent):
    def __init__(self, dispatch_config, target_inst, native_event, native_event_target):
        super().__init__(dispatch_config, target_inst, native_event, native_event_target)
        self.touch_history = None

class ResponderEventPlugin:
    @staticmethod
    def extract_events(top_level_type, target_inst, native_event, native_event_target):
        # Implement touch event extraction logic here, similar to JavaScript version
        pass

# Node Creation and Updates
class Node:
    def __init__(self, node_type, props=None, context=None):
        self.node_type = node_type
        self.props = props or {}
        self.context = context
        self.children = []

    def add_child(self, child):
        self.children.append(child)

    def update_props(self, new_props):
        self.props.update(new_props)

    def to_dict(self):
        """Recursively converts the node and its children to a dictionary."""
        return {
            "node_type": self.node_type,
            "props": self.props,
            "children": [child.to_dict() for child in self.children]
        }

    def to_json(self):
        """Converts the node tree to a JSON string."""
        return json.dumps(self.to_dict(), indent=4)
    

# Creating and cloning nodes
def create_node(context, node_type, root_container, props, internal_instance_handle):
    return Node(node_type, props, context)

def clone_node_with_new_props(node, new_props):
    node.update_props(new_props)
    return node

# Guarded callback wrapper to catch and handle errors
def invoke_guarded_callback_and_catch_first_error(listener, event):
    try:
        listener(event)  # Execute the listener with the event
    except Exception as e:
        print(f"Error occurred while executing callback: {e}")
        # Additional error handling logic can go here if needed


# Event Dispatching
def execute_dispatch(event, listener, inst):
    event.current_target = get_node_from_instance(inst)
    invoke_guarded_callback_and_catch_first_error(listener, event)
    event.current_target = None

def execute_direct_dispatch(event):
    dispatch_listener = event._dispatch_listeners
    event.current_target = dispatch_listener and get_node_from_instance(event._dispatch_instances) or None
    if dispatch_listener:
        dispatch_listener(event)
    event.current_target = None
    event._dispatch_listeners = None
    event._dispatch_instances = None
    return dispatch_listener


def schedule_callback(callback, priority=1):
    sleep(priority)  # Simulate delay based on priority
    callback()

def cancel_callback(callback):
    # Logic to cancel the scheduled callback (if needed)
    pass

def should_yield():
    # Placeholder to control when to yield to other tasks
    return False

# Basic Reconciliation Logic
def diff_trees(old_node, new_node):
    changes = []

    # Type change
    if old_node.node_type != new_node.node_type:
        changes.append(("REPLACE", new_node))
        return changes

    # Prop change
    for key in new_node.props:
        if new_node.props.get(key) != old_node.props.get(key):
            changes.append(("UPDATE_PROP", key, new_node.props[key]))

    # Child changes
    old_children = old_node.children
    new_children = new_node.children
    for i, child in enumerate(new_children):
        if i < len(old_children):
            changes.extend(diff_trees(old_children[i], child))
        else:
            changes.append(("ADD_CHILD", child))

    return changes

# Node Update Handling
def apply_changes(node, changes):
    for change in changes:
        if change[0] == "REPLACE":
            node = change[1]  # Replace the node with the new one
        elif change[0] == "UPDATE_PROP":
            node.props[change[1]] = change[2]  # Update the property
        elif change[0] == "ADD_CHILD":
            node.add_child(change[1])  # Add a new child
    return node

# Simplified Scheduler and Task Management
class Task:
    def __init__(self, callback, priority=1):
        self.callback = callback
        self.priority = priority

class Scheduler:
    def __init__(self):
        self.queue = []

    def schedule(self, task):
        self.queue.append(task)
        self.queue.sort(key=lambda x: x.priority, reverse=True)  # Sort by priority

    def run(self):
        while self.queue:
            task = self.queue.pop(0)
            task.callback()

# Example usage of Scheduler
scheduler = Scheduler()
scheduler.schedule(Task(lambda: print("Task 1"), priority=2))
scheduler.schedule(Task(lambda: print("Task 2"), priority=1))
scheduler.run()

# UI Rendering Logic
class Renderer:
    def __init__(self):
        self.root_node = None

    def set_root(self, root_node):
        self.root_node = root_node

    def render(self):
        if self.root_node:
            self._render_node(self.root_node)

    def _render_node(self, node):
        print(f"Rendering {node.node_type} with props: {node.props}")
        for child in node.children:
            self._render_node(child)

# Example of setting up and rendering a simple UI
root = Node("View", {"style": "background-color: blue"})
child = Node("Text", {"value": "Hello, World!"})
root.add_child(child)

renderer = Renderer()
renderer.set_root(root)
renderer.render()

# Simplified Event Propagation
class Event:
    def __init__(self, type, target):
        self.type = type
        self.target = target
        self.current_target = target
        self.is_propagation_stopped = False
        self.is_default_prevented = False

    def stop_propagation(self):
        self.is_propagation_stopped = True

    def prevent_default(self):
        self.is_default_prevented = True

class EventDispatcher:
    def __init__(self):
        self.listeners = {}

    def add_event_listener(self, target, event_type, listener):
        if target not in self.listeners:
            self.listeners[target] = {}
        if event_type not in self.listeners[target]:
            self.listeners[target][event_type] = []
        self.listeners[target][event_type].append(listener)

    def dispatch_event(self, event):
        if event.target in self.listeners and event.type in self.listeners[event.target]:
            for listener in self.listeners[event.target][event.type]:
                listener(event)
                if event.is_propagation_stopped:
                    break

# React-like Component System
class Component:
    def __init__(self, props=None):
        self.props = props or {}
        self.state = {}

    def set_state(self, new_state):
        self.state.update(new_state)
        self.render()

    def render(self):
        raise NotImplementedError("Subclasses must implement render()")

class View(Component):
    def __init__(self, props=None):
        super().__init__(props)

    def render(self):
        print(f"Rendering View with props: {self.props} and state: {self.state}")

class Text(Component):
    def __init__(self, props=None):
        super().__init__(props)

    def render(self):
        print(f"Rendering Text with props: {self.props} and state: {self.state}")

# Example of usage
view = View({"style": "background-color: red"})
text = Text({"value": "Hello, ReactPy!"})

view.set_state({"background_color": "blue"})
view.render()
text.render()

# Node Reconciliation and Diffing
def reconcile(old_node, new_node):
    changes = []

    # Check if node types are different
    if old_node.node_type != new_node.node_type:
        changes.append(("REPLACE", new_node))
        return changes

    # Check if node properties have changed
    for key, value in new_node.props.items():
        if old_node.props.get(key) != value:
            changes.append(("UPDATE_PROP", key, value))

    # Handle child nodes (diffing them)
    old_children = old_node.children
    new_children = new_node.children

    for i, new_child in enumerate(new_children):
        if i < len(old_children):
            changes.extend(reconcile(old_children[i], new_child))
        else:
            changes.append(("ADD_CHILD", new_child))

    # Remove any extra children
    for i in range(len(new_children), len(old_children)):
        changes.append(("REMOVE_CHILD", old_children[i]))

    return changes

# Applying Changes to Nodes
def apply_reconciliation_changes(node, changes):
    for change in changes:
        if change[0] == "REPLACE":
            node = change[1]  # Replace the node with a new one
        elif change[0] == "UPDATE_PROP":
            node.props[change[1]] = change[2]  # Update the property
        elif change[0] == "ADD_CHILD":
            node.add_child(change[1])  # Add a new child
        elif change[0] == "REMOVE_CHILD":
            node.children.remove(change[1])  # Remove the child
    return node

# Component Lifecycle
class Component:
    def __init__(self, props=None):
        self.props = props or {}
        self.state = {}
        self._is_mounted = False

    def set_state(self, new_state):
        self.state.update(new_state)
        self.render()

    def render(self):
        raise NotImplementedError("Subclasses must implement render()")

    def component_did_mount(self):
        print(f"{self.__class__.__name__} mounted.")

    def component_will_unmount(self):
        print(f"{self.__class__.__name__} will unmount.")

    def mount(self):
        if not self._is_mounted:
            self._is_mounted = True
            self.component_did_mount()

    def unmount(self):
        if self._is_mounted:
            self._is_mounted = False
            self.component_will_unmount()

# Example of a Component with Lifecycle Methods
class MyComponent(Component):
    def __init__(self, props=None):
        super().__init__(props)
        self.state = {"count": 0}

    def render(self):
        print(f"Rendering MyComponent with props: {self.props} and state: {self.state}")

    def increment(self):
        self.set_state({"count": self.state["count"] + 1})
        print(f"Count incremented: {self.state['count']}")

# Creating and mounting the component
my_component = MyComponent(props={"name": "Test Component"})
my_component.mount()  # Trigger the componentDidMount lifecycle method
my_component.render()  # Initial render

# Updating the state and triggering the lifecycle method
my_component.increment()
my_component.render()

# Unmounting the component
my_component.unmount()  # Trigger componentWillUnmount lifecycle method

# Handling Node Update in a UI Tree
class UIUpdater:
    def __init__(self, root_node):
        self.root_node = root_node

    def update_node(self, old_node, new_node):
        changes = reconcile(old_node, new_node)  # Get differences between old and new node
        return apply_reconciliation_changes(old_node, changes)  # Apply changes to the node

    def update_ui(self, new_tree):
        self.root_node = self.update_node(self.root_node, new_tree)
        print("UI updated to reflect changes.")

# Event Listener Management
class EventListenerManager:
    def __init__(self):
        self.listeners = {}

    def add_listener(self, target, event_type, listener):
        if target not in self.listeners:
            self.listeners[target] = {}
        if event_type not in self.listeners[target]:
            self.listeners[target][event_type] = []
        self.listeners[target][event_type].append(listener)

    def remove_listener(self, target, event_type, listener):
        if target in self.listeners and event_type in self.listeners[target]:
            self.listeners[target][event_type].remove(listener)
            if not self.listeners[target][event_type]:
                del self.listeners[target][event_type]
            if not self.listeners[target]:
                del self.listeners[target]

    def dispatch_event(self, event):
        if event.target in self.listeners and event.type in self.listeners[event.target]:
            for listener in self.listeners[event.target][event.type]:
                listener(event)
                if event.is_propagation_stopped:
                    break

# Handling Task Scheduling and Execution
class TaskScheduler:
    def __init__(self):
        self.task_queue = []

    def schedule_task(self, task, priority=1):
        self.task_queue.append({"task": task, "priority": priority})
        self.task_queue.sort(key=lambda x: x["priority"], reverse=True)  # Sort by priority

    def execute_tasks(self):
        while self.task_queue:
            task = self.task_queue.pop(0)["task"]
            task()  # Execute the task

# Example usage of TaskScheduler
scheduler = TaskScheduler()

# Schedule tasks with different priorities
scheduler.schedule_task(lambda: print("High priority task"), priority=2)
scheduler.schedule_task(lambda: print("Low priority task"), priority=1)

# Execute the tasks
scheduler.execute_tasks()

# Complete Example and Final Integration with Child Node Update
class MyApp:
    def __init__(self):
        self.scheduler = TaskScheduler()
        self.event_manager = EventListenerManager()
        self.ui_updater = UIUpdater(None)  # Initial empty root node
        self.root = Node("View", {"style": "background-color: white"})
        self.ui_updater.root_node = self.root  # Set the root node for UI updates

        # Create child nodes and add them to the root
        self.child1 = Node("Text", {"value": "Child 1"})
        self.child2 = Node("Text", {"value": "Child 2"})
        self.root.add_child(self.child1)
        self.root.add_child(self.child2)

    def update_child_node(self, child, new_props):
        # Update the child node's props and trigger a re-render
        print(f"Updating {child.node_type} with new props: {new_props}")
        child.update_props(new_props)
        self.ui_updater.update_ui(self.root)  # Reconcile the root to apply changes

    def start(self):
        # Schedule and run tasks
        self.scheduler.schedule_task(lambda: print("App has started"))
        self.scheduler.execute_tasks()

        # Initial UI render
        print("Initial UI Render:")
        self.ui_updater.update_ui(self.root)
        print(f"Root node style: {self.root.props['style']}")

        # Simulate updating the child nodes
        print("\nUpdating child nodes:")
        self.update_child_node(self.child1, {"value": "Updated Child 1"})
        self.update_child_node(self.child2, {"value": "Updated Child 2"})

        # Simulate an event dispatch (just an example)
        event = Event(type="click", target=self.root)
        self.event_manager.add_listener(self.root, "click", lambda e: print(f"Event {e.type} triggered on {e.target.node_type}"))
        self.event_manager.dispatch_event(event)

        print("Current UI Tree in JSON:")
        print(self.root.to_json())

# Running the application
app = MyApp()
app.start()