mermaid-go/pkg/ast/state.go

// State diagram AST structures based on stateDiagram.jison
package ast

// StateDiagram represents a state diagram
type StateDiagram struct {
	States      map[string]*StateNode `json:"states"`
	Transitions []*StateTransition    `json:"transitions"`
	StartState  *string               `json:"startState,omitempty"`
	EndStates   []string              `json:"endStates,omitempty"`
	Direction   string                `json:"direction,omitempty"`
	Title       *string               `json:"title,omitempty"`
	Config      map[string]any        `json:"config,omitempty"`
}

type StateNode struct {
	ID          string                `json:"id"`
	Label       string                `json:"label"`
	Type        StateType             `json:"type"`
	Description *string               `json:"description,omitempty"`
	SubStates   map[string]*StateNode `json:"subStates,omitempty"`
	Note        *StateNote            `json:"note,omitempty"`
	CssClasses  []string              `json:"cssClasses,omitempty"`
	// State actions and behaviors
	EntryAction *string `json:"entry,omitempty"` // entry / action
	ExitAction  *string `json:"exit,omitempty"`  // exit / action
	DoAction    *string `json:"do,omitempty"`    // do / action
	// Parallel regions (for concurrent states)
	Regions []*StateRegion `json:"regions,omitempty"`
}

type StateType string

const (
	StateTypeDefault     StateType = "default"
	StateTypeStart       StateType = "start"       // [*]
	StateTypeEnd         StateType = "end"         // [*]
	StateTypeFork        StateType = "fork"        // <<fork>>
	StateTypeJoin        StateType = "join"        // <<join>>
	StateTypeChoice      StateType = "choice"      // <<choice>>
	StateTypeHistory     StateType = "history"     // <<history>>
	StateTypeDeepHistory StateType = "deepHistory" // <<deepHistory>>
)

type StateTransition struct {
	From      string  `json:"from"`
	To        string  `json:"to"`
	Label     *string `json:"label,omitempty"`
	Condition *string `json:"condition,omitempty"` // [guard]
	Action    *string `json:"action,omitempty"`    // /action
}

type StateNote struct {
	Position NotePlace `json:"position"`
	Text     string    `json:"text"`
}

// StateRegion represents a parallel region in a composite state
type StateRegion struct {
	Name        string                `json:"name"`
	States      map[string]*StateNode `json:"states"`
	Transitions []*StateTransition    `json:"transitions,omitempty"`
}

// Type returns the diagram type
func (s *StateDiagram) Type() DiagramType {
	return DiagramTypeStateDiagram
}

// Validate checks if the state diagram is valid
func (s *StateDiagram) Validate() error {
	// Validate transitions reference valid states
	for _, trans := range s.Transitions {
		if trans.From != "[*]" {
			if _, exists := s.States[trans.From]; !exists {
				return NewValidationError("transition references non-existent state: " + trans.From)
			}
		}
		if trans.To != "[*]" {
			if _, exists := s.States[trans.To]; !exists {
				return NewValidationError("transition references non-existent state: " + trans.To)
			}
		}
	}
	return nil
}

// NewStateDiagram creates a new state diagram
func NewStateDiagram() *StateDiagram {
	return &StateDiagram{
		States:      make(map[string]*StateNode),
		Transitions: make([]*StateTransition, 0),
		EndStates:   make([]string, 0),
		Config:      make(map[string]any),
	}
}