Relay Integration

class Node(Interface):
    """
    Relay Node interface implementation with global ID support.
    
    Features:
    - Automatic ID field injection
    - Global ID encoding/decoding
    - Type validation for node objects
    - Integration with Relay client libraries
    
    Class Methods:
        Field(*args, **kwargs): Creates NodeField for single node queries
        get_node_from_global_id(info, global_id, only_type=None): Node retrieval
        to_global_id(type_, id): Global ID creation
        resolve_global_id(info, global_id): Global ID parsing
    
    Usage:
        class User(graphene.ObjectType):
            class Meta:
                interfaces = (Node,)
            
            name = graphene.String()
            email = graphene.String()
            
            @classmethod
            def get_node(cls, info, id):
                return get_user_by_id(id)
    """

class GlobalID(Field):
    """
    Automatic global ID field generation for Node types.
    
    Parameters:
        node: Node type this ID represents
        parent_type: Parent type for ID resolution
        required: Whether field is NonNull
        global_id_type: Custom GlobalIDType implementation
    
    Features:
    - Automatic ID resolution and encoding
    - Configurable ID type implementations
    - Integration with Relay pagination
    
    Usage:
        class User(graphene.ObjectType):
            class Meta:
                interfaces = (Node,)
            
            id = GlobalID()
            name = graphene.String()
    """

def is_node(objecttype):
    """
    Check if ObjectType implements Node interface.
    
    Args:
        objecttype: GraphQL ObjectType to check
        
    Returns:
        bool: True if type implements Node interface
    
    Usage:
        if graphene.is_node(User):
            print("User implements Node interface")
    """

class BaseGlobalIDType:
    """
    Base class for global ID type implementations.
    
    Attributes:
        graphene_type: GraphQL scalar type used (default: ID)
    
    Abstract Methods:
        resolve_global_id(global_id): Parse global ID to (type, id) tuple
        to_global_id(type_, id): Encode type and ID to global ID string
    
    Usage:
        class CustomGlobalIDType(BaseGlobalIDType):
            def resolve_global_id(self, global_id):
                parts = global_id.split('.')
                return (parts[0], parts[1])
                
            def to_global_id(self, type_, id):
                return f"{type_}.{id}"
    """

class DefaultGlobalIDType(BaseGlobalIDType):
    """
    Base64-encoded "TypeName:id" format (Relay standard).
    
    Features:
    - Standard Relay specification compliance
    - Base64 encoding for opacity
    - Type safety with parsing validation
    - Compatible with Relay client libraries
    
    Methods:
        Uses graphql-relay's to_global_id/from_global_id functions
    
    Format: base64("TypeName:id")
    Example: "VXNlcjox" -> "User:1"
    """

class SimpleGlobalIDType(BaseGlobalIDType):
    """
    Pass-through ID type that uses raw ID values.
    
    Warning: User responsible for ensuring global uniqueness
    Features:
    - No encoding/decoding overhead
    - Direct ID passthrough
    - Requires globally unique IDs
    
    Use Case: When IDs are already globally unique (UUIDs, etc.)
    """

class UUIDGlobalIDType(BaseGlobalIDType):
    """
    UUID-based global IDs with native UUID support.
    
    Features:
    - Uses UUID GraphQL type instead of ID
    - Inherently global uniqueness
    - No type prefix needed
    - Automatic UUID validation
    
    Attributes:
        graphene_type: UUID (instead of ID)
    """

class Connection(ObjectType):
    """
    Relay cursor-based pagination container.
    
    Features:
    - Automatic Edge class generation
    - PageInfo integration for pagination metadata
    - Configurable strict typing
    - Cursor-based navigation
    
    Meta Options:
        node: Required ObjectType that this connection contains
        name: Custom connection name (defaults to {Node}Connection)
        strict_types: Enforce strict edge/connection typing
    
    Generated Fields:
        edges: List of Edge objects containing nodes and cursors
        page_info: PageInfo object with pagination metadata
    
    Usage:
        class UserConnection(Connection):
            class Meta:
                node = User
                
        # Automatically generates:
        # - UserEdge with node and cursor fields
        # - edges field returning [UserEdge]
        # - page_info field returning PageInfo
    """

class ConnectionField(Field):
    """
    Field that automatically handles Relay-style pagination.
    
    Features:
    - Automatic Relay pagination arguments (before, after, first, last)
    - Iterable to connection conversion
    - Resolver wrapping for pagination
    - Integration with Connection types
    
    Auto Arguments:
        before: Cursor for backward pagination
        after: Cursor for forward pagination  
        first: Number of items from start
        last: Number of items from end
    
    Methods:
        resolve_connection(): Converts iterables to connections
        connection_resolver(): Wraps resolvers for pagination
    
    Usage:
        class Query(graphene.ObjectType):
            users = ConnectionField(UserConnection)
            
            def resolve_users(self, info, **args):
                # Return iterable - automatically converted to connection
                return User.objects.all()
    """

class PageInfo(ObjectType):
    """
    Relay pagination metadata following the specification.
    
    Fields:
        has_next_page: Boolean indicating if more items exist forward
        has_previous_page: Boolean indicating if more items exist backward
        start_cursor: Cursor of first item in current page
        end_cursor: Cursor of last item in current page
    
    Features:
    - Relay specification compliant
    - Automatic cursor generation
    - Pagination state management
    - Client navigation support
    
    Usage:
        # Automatically included in Connection types
        # Used by Relay clients for pagination UI
        query {
            users(first: 10) {
                edges {
                    node {
                        name
                    }
                    cursor
                }
                pageInfo {
                    hasNextPage
                    hasPreviousPage
                    startCursor
                    endCursor
                }
            }
        }
    """

class ClientIDMutation(Mutation):
    """
    Relay-style mutations with client mutation ID support.
    
    Features:
    - Automatic Input class generation
    - client_mutation_id field injection
    - Payload naming convention ({MutationName}Payload)
    - Support for optimistic updates
    
    Required Method:
        mutate_and_get_payload(): Implementation method with client ID
    
    Generated Features:
    - Input class with client_mutation_id field
    - Payload class with client_mutation_id field
    - Automatic argument extraction
    
    Usage:
        class CreateUser(ClientIDMutation):
            class Input:
                name = graphene.String(required=True)
                email = graphene.String()
            
            user = graphene.Field(User)
            
            @classmethod
            def mutate_and_get_payload(cls, root, info, **input):
                # client_mutation_id automatically handled
                user = create_user(
                    name=input['name'],
                    email=input.get('email')
                )
                return CreateUser(user=user)
        
        # Generates mutation field that accepts:
        # input {
        #   name: String!
        #   email: String
        #   clientMutationId: String
        # }
        #
        # Returns payload:
        # {
        #   user: User
        #   clientMutationId: String
        # }
    """

import graphene
from graphene import relay

class User(graphene.ObjectType):
    class Meta:
        interfaces = (relay.Node,)
    
    name = graphene.String()
    email = graphene.String()
    posts = relay.ConnectionField('PostConnection')
    
    @classmethod
    def get_node(cls, info, id):
        """Required method for Node interface."""
        return get_user_by_id(id)
    
    def resolve_posts(self, info, **args):
        return get_posts_for_user(self.id)

class Post(graphene.ObjectType):
    class Meta:
        interfaces = (relay.Node,)
    
    title = graphene.String()
    content = graphene.String()
    author = graphene.Field(User)
    
    @classmethod
    def get_node(cls, info, id):
        return get_post_by_id(id)

# Connection classes
class PostConnection(relay.Connection):
    class Meta:
        node = Post

class UserConnection(relay.Connection):
    class Meta:
        node = User

# Query with Node field
class Query(graphene.ObjectType):
    node = relay.Node.Field()
    users = relay.ConnectionField(UserConnection)
    posts = relay.ConnectionField(PostConnection)
    
    def resolve_users(self, info, **args):
        return User.objects.all()
    
    def resolve_posts(self, info, **args):
        return Post.objects.all()

import graphene
from graphene import relay
import uuid

class UUIDNode(relay.Node):
    """Node interface using UUID global IDs."""
    
    class Meta:
        # Use UUID-based global ID type
        global_id_type = relay.UUIDGlobalIDType()

class User(graphene.ObjectType):
    class Meta:
        interfaces = (UUIDNode,)
    
    # ID field will use UUID type instead of ID
    name = graphene.String()
    
    @classmethod
    def get_node(cls, info, id):
        # id is already a UUID object
        return get_user_by_uuid(id)

# Custom global ID type
class PrefixedGlobalIDType(relay.BaseGlobalIDType):
    """Custom global ID with prefix."""
    
    def to_global_id(self, type_, id):
        return f"app_{type_}_{id}"
    
    def resolve_global_id(self, global_id):
        parts = global_id.split('_')
        if len(parts) >= 3 and parts[0] == 'app':
            return (parts[1], '_'.join(parts[2:]))
        raise ValueError(f"Invalid global ID format: {global_id}")

class CustomNode(relay.Node):
    class Meta:
        global_id_type = PrefixedGlobalIDType()

import graphene
from graphene import relay

class CreateUserInput(graphene.InputObjectType):
    name = graphene.String(required=True)
    email = graphene.String(required=True)
    age = graphene.Int()

class CreateUser(relay.ClientIDMutation):
    class Input:
        data = graphene.Field(CreateUserInput, required=True)
    
    user = graphene.Field(User)
    success = graphene.Boolean()
    errors = graphene.List(graphene.String)
    
    @classmethod
    def mutate_and_get_payload(cls, root, info, data, client_mutation_id=None):
        errors = []
        
        # Validation
        if len(data.name) < 2:
            errors.append("Name must be at least 2 characters")
        
        if '@' not in data.email:
            errors.append("Invalid email format")
        
        if errors:
            return CreateUser(success=False, errors=errors)
        
        # Create user
        user = create_user(
            name=data.name,
            email=data.email,
            age=data.age
        )
        
        return CreateUser(
            user=user,
            success=True,
            errors=[]
        )

class UpdateUser(relay.ClientIDMutation):
    class Input:
        id = graphene.ID(required=True)
        name = graphene.String()
        email = graphene.String()
    
    user = graphene.Field(User)
    
    @classmethod
    def mutate_and_get_payload(cls, root, info, id, **input):
        # Resolve node from global ID
        node_type, node_id = relay.Node.resolve_global_id(info, id)
        
        if node_type != 'User':
            raise Exception('Invalid user ID')
        
        user = get_user_by_id(node_id)
        if not user:
            raise Exception('User not found')
        
        # Update fields
        for field, value in input.items():
            if value is not None:
                setattr(user, field, value)
        
        save_user(user)
        return UpdateUser(user=user)

class Mutation(graphene.ObjectType):
    create_user = CreateUser.Field()
    update_user = UpdateUser.Field()

import graphene
from graphene import relay

class UserConnection(relay.Connection):
    class Meta:
        node = User
    
    total_count = graphene.Int()
    
    def resolve_total_count(self, info):
        return len(self.iterable)

class Query(graphene.ObjectType):
    users = relay.ConnectionField(
        UserConnection,
        # Custom arguments for filtering
        name_contains=graphene.String(),
        active_only=graphene.Boolean(),
        sort_by=graphene.String()
    )
    
    def resolve_users(self, info, name_contains=None, active_only=None, sort_by=None, **args):
        queryset = User.objects.all()
        
        # Apply filters
        if name_contains:
            queryset = queryset.filter(name__icontains=name_contains)
        
        if active_only:
            queryset = queryset.filter(is_active=True)
        
        # Apply sorting
        if sort_by == 'name':
            queryset = queryset.order_by('name')
        elif sort_by == 'created':
            queryset = queryset.order_by('-created_at')
        
        return queryset

# Usage in GraphQL query:
# query {
#   users(first: 10, nameContains: "john", activeOnly: true, sortBy: "name") {
#     edges {
#       node {
#         name
#         email
#       }
#       cursor
#     }
#     pageInfo {
#       hasNextPage
#       endCursor
#     }
#     totalCount
#   }
# }