graph

type DOTEdge interface {
	DOTer
	Edge
}

type DOTGraph interface {
	Graph
	// DOTID returns grapph DOT ID.
	DOTID() string
	// DOTAttributers returns graph DOT attributes.
	DOTAttributers() (graph, node, edge encoding.Attributer)
	// DOT returns Graphviz DOT graph.
	DOT() (string, error)
}

type DOTNode interface {
	DOTer
	Node
}

type DOTOption func(*Options)

type DOTOptions struct {
	GraphAttrs attrs.DOT
	NodeAttrs  attrs.DOT
	EdgeAttrs  attrs.DOT
}

type DOTer interface {
	// DOTID returns Graphviz DOT ID.
	DOTID() string
	// SetDOTID sets Graphviz DOT ID.
	SetDOTID(string)
}

type Edge interface {
	Object
	// FromNode returns the from node of the edge.
	FromNode(context.Context) (Node, error)
	// ToNode returns the to node of the edge.
	ToNode(context.Context) (Node, error)
	// Weight returns edge weight.
	Weight() float64
}

type Entity interface {
	space.Entity
}

type Graph interface {
	// UID returns graph uid.
	UID() uuid.UID
	// Node returns node with given uid.
	Node(context.Context, uuid.UID) (Node, error)
	// Nodes returns all graph nodes.
	Nodes(context.Context) ([]Node, error)
	// Edge returns the edge between the two nodes.
	Edge(ctx context.Context, from, to uuid.UID) (Edge, error)
	// Edges returns all graph edges.
	Edges(context.Context) ([]Edge, error)
}

type LinkRemover interface {
	// RemoveEdge removes edge(s) from the graph.
	RemoveLink(ctx context.Context, from, to uuid.UID) error
}

type Node interface {
	Object
	space.Entity
}

type NodeAdder interface {
	// NewNode returns a new Node.
	NewNode(context.Context, space.Entity, ...Option) (Node, error)
	// AddNode adds a new node to the graph.
	AddNode(context.Context, Node) error
}

type NodeLinker interface {
	// Link links two nodes and returns the new edge.
	Link(ctx context.Context, from, to uuid.UID, opts ...Option) (Edge, error)
}

type NodeRemover interface {
	// RemoveNode removes node from the graph.
	RemoveNode(context.Context, uuid.UID) error
}

type Object interface {
	space.Object
}

type Option func(*Options)

type Options struct {
	UID        uuid.UID
	DOTID      string
	Attrs      attrs.Attrs
	Weight     float64
	DOTOptions DOTOptions
}

type Querier interface {
	// Query the graph and return the results.
	Query(context.Context, query.Query) ([]Object, error)
}

type SubGrapher interface {
	// SubGraph returns the max subgraph of graph
	// starting at node with given uid up to given depth.
	SubGraph(ctx context.Context, uid uuid.UID, depth int, opts ...Option) (Graph, error)
}