// ─── Token types ──────────────────────────────────────────────────

export enum TokenKind {
  LParen, // (
  RParen, // )
  LCurly, // {
  RCurly, // }
  Colon, // :
  Lt, // <
  Lte, // <=
  Gt, // >
  Gte, // >=
  String, // "..."
  Ident, // unquoted literal (may contain wildcards, spaces and escapes)
  And, // 'and' surrounded by whitespace
  Or, // 'or' surrounded by whitespace
  Not, // 'not' followed by whitespace
  Whitespace,
  EOF,
}

export interface Token {
  kind: TokenKind;
  value: string;
  start: number;
  end: number;
}

// ─── AST types ────────────────────────────────────────────────────

export type RangeOperator = 'lt' | 'lte' | 'gt' | 'gte';

export interface LiteralNode {
  type: 'literal';
  value: string;
  isQuoted: boolean;
  isWildcard: boolean;
  start: number;
  end: number;
}

export interface ValueListNode {
  type: 'valueList';
  values: KQLNode[];
  start: number;
  end: number;
}

export interface IsNode {
  type: 'is';
  /** null when matching the default field (bare value expression) */
  field: LiteralNode | null;
  /** null when the input is incomplete (e.g. "field:") */
  value: LiteralNode | ValueListNode | null;
  start: number;
  end: number;
}

export interface RangeNode {
  type: 'range';
  field: LiteralNode;
  operator: RangeOperator;
  value: LiteralNode | null;
  start: number;
  end: number;
}

export interface NotNode {
  type: 'not';
  child: KQLNode | null;
  start: number;
  end: number;
}

export interface AndNode {
  type: 'and';
  children: KQLNode[];
  start: number;
  end: number;
}

export interface OrNode {
  type: 'or';
  children: KQLNode[];
  start: number;
  end: number;
}

export interface NestedNode {
  type: 'nested';
  field: LiteralNode;
  query: KQLNode | null;
  start: number;
  end: number;
}

export type KQLNode = OrNode | AndNode | NotNode | NestedNode | IsNode | RangeNode | ValueListNode | LiteralNode;

export interface KQLQuery {
  root: KQLNode | null;
  errors: ParseError[];
}

export interface ParseError {
  message: string;
  start: number;
  end: number;
}

// ─── Completion situation ─────────────────────────────────────────

export type SituationKind = 'NONE' | 'IN_FIELD' | 'AFTER_FIELD' | 'IN_VALUE' | 'IN_VALUE_LIST' | 'AFTER_EXPRESSION' | 'IN_NESTED';

export interface Situation {
  kind: SituationKind;
  prefix: string;
  replaceRange: { start: number; end: number };
  /** Field name for value completion (IN_VALUE / IN_VALUE_LIST), dotted inside nested queries */
  fieldName?: string;
  /** Dotted nested path when inside path:{ } (IN_NESTED), e.g. "user.tags" */
  nestedPath?: string;
  /** True when the cursor is inside an existing quoted string */
  insideString?: boolean;
}