/**
 * Token types for QuestLang
 */
export enum TokenType {
  // Literals
  IDENTIFIER = 'IDENTIFIER',
  STRING = 'STRING',
  NUMBER = 'NUMBER',

  // Keywords
  QUEST = 'квест',
  GOAL = 'цель',
  GRAPH = 'граф',
  NODES = 'узлы',
  START = 'начало',
  END = 'конец',
  TYPE = 'тип',
  DESCRIPTION = 'описание',
  TRANSITIONS = 'переходы',
  OPTIONS = 'варианты',
  TITLE = 'название',

  // Module system keywords
  MODULE = 'модуль',
  IMPORT = 'импорт',
  EXPORT = 'экспорт',
  FROM = 'из',

  // Node types
  INITIAL = 'начальный',
  ACTION = 'действие',
  ENDING = 'концовка',

  // Symbols
  SEMICOLON = ';',
  COLON = ':',
  COMMA = ',',
  DOT = '.',
  AT = '@',
  LEFT_BRACE = '{',
  RIGHT_BRACE = '}',
  LEFT_BRACKET = '[',
  RIGHT_BRACKET = ']',
  LEFT_PAREN = '(',
  RIGHT_PAREN = ')',

  // Special
  EOF = 'EOF',
  NEWLINE = 'NEWLINE',
  COMMENT = 'COMMENT',
  WHITESPACE = 'WHITESPACE',
}

/**
 * Represents a token in the source code
 */
export interface Token {
  type: TokenType;
  value: string;
  line: number;
  column: number;
  start: number;
  end: number;
}

/**
 * Position in source code
 */
export interface Position {
  line: number;
  column: number;
  offset: number;
}

/**
 * Abstract Syntax Tree node types for QuestLang
 */
export interface ASTNode {
  type: string;
  line: number;
  column: number;
}

/**
 * Root node of the program
 */
export interface QuestProgram extends ASTNode {
  type: 'QuestProgram';
  name: string;
  goal: string;
  graph: GraphNode;
  // Imports are only used by module-enabled programs; optional for backward compatibility
  imports?: ImportNode[];
}

/**
 * Graph definition
 */
export interface GraphNode extends ASTNode {
  type: 'Graph';
  nodes: Record<string, NodeDefinition>;
  start: string;
}

/**
 * Base node definition
 */
export interface NodeDefinition extends ASTNode {
  nodeType: 'начальный' | 'действие' | 'концовка';
  id: string;
  description: string;
}

/**
 * Initial node
 */
export interface InitialNode extends NodeDefinition {
  nodeType: 'начальный';
  transitions: string[];
}

/**
 * Action node
 */
export interface ActionNode extends NodeDefinition {
  nodeType: 'действие';
  options: OptionChoice[];
}

/**
 * Ending node
 */
export interface EndingNode extends NodeDefinition {
  nodeType: 'концовка';
  title: string;
}

/**
 * Option choice in action nodes
 */
export interface OptionChoice extends ASTNode {
  type: 'OptionChoice';
  text: string;
  // Target can be a local node id ("узел") or a module-qualified reference ("@Модуль.узел") as a raw string
  target: string;
}

/**
 * String literal
 */
export interface StringLiteral extends ASTNode {
  type: 'StringLiteral';
  value: string;
}

/**
 * Identifier
 */
export interface Identifier extends ASTNode {
  type: 'Identifier';
  name: string;
}

/**
 * Module declaration AST
 */
export interface ModuleNode extends ASTNode {
  type: 'Module';
  name: string;
  nodes: Record<string, NodeDefinition>;
  exports: string[];
  imports?: ImportNode[];
}

/**
 * Import declaration AST
 */
export interface ImportNode extends ASTNode {
  type: 'Import';
  moduleName: string;
  modulePath: string; // path in quotes as provided in source
  alias?: string;
}

/**
 * Module reference helper type (not necessarily emitted in AST; we encode as string "@Module.node")
 */
export interface ModuleReference {
  module: string;
  nodeId: string;
}