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

export enum TokenKind {
  LCurly, // {
  RCurly, // }
  Pipe, // |
  PipeEquals, // |=
  PipeRegex, // |~
  Equals, // =
  NotEquals, // !=
  RegexEquals, // =~
  RegexNotEquals, // !~
  GreaterThan, // >
  GreaterEquals, // >=
  LessThan, // <
  LessEquals, // <=
  String, // "...", '...', `...`
  Number, // 123, 45.6
  Duration, // 5m, 1h30m
  Bytes, // 42MB
  Ident, // identifier / keyword
  Comma, // ,
  LParen, // (
  RParen, // )
  LBracket, // [
  RBracket, // ]
  Comment, // #...
  Whitespace,
  EOF,
  Error,
}

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

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

export interface LokiQuery {
  streamSelector: StreamSelector | null;
  pipeline: PipelineStage[];
  metricExpr: MetricExpr | null;
  errors: ParseError[];
}

export interface StreamSelector {
  matchers: Matcher[];
}

export interface Matcher {
  label: string;
  operator: string; // = != =~ !~
  value: string;
}

export type PipelineStage = LineFilter | JsonParser | LogfmtParser | RegexpParser | LabelFilter | UnrecognizedStage;

export interface LineFilter {
  type: 'lineFilter';
  operator: string; // |= != |~ !~
  value: string;
}

export interface JsonParser {
  type: 'jsonParser';
  expressions?: string[];
}

export interface LogfmtParser {
  type: 'logfmtParser';
  expressions?: string[];
}

export interface RegexpParser {
  type: 'regexpParser';
  pattern: string;
}

export interface LabelFilter {
  type: 'labelFilter';
  conditions: LabelFilterCondition[];
}

export interface LabelFilterCondition {
  label: string;
  operator: string;
  value: string;
}

export interface UnrecognizedStage {
  type: 'unrecognized';
  keyword: string;
  rest: string;
}

export interface MetricExpr {
  func: string;
  range: string;
  grouping?: Grouping;
}

export interface Grouping {
  by: boolean; // true = by, false = without
  labels: string[];
}

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

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

export type SituationKind = 'NONE' | 'IN_SELECTOR_LABEL' | 'IN_SELECTOR_VALUE' | 'AFTER_PIPE' | 'IN_PIPELINE_ARG' | 'IN_LABEL_FILTER' | 'IN_FUNCTION_PARENS' | 'IN_GROUPING';

export interface Situation {
  kind: SituationKind;
  prefix: string;
  replaceRange: { start: number; end: number };
  /** The label name when completing a selector value (IN_SELECTOR_VALUE). */
  labelName?: string;
  /** The index of the matcher being edited within the stream selector (IN_SELECTOR_VALUE). */
  matcherIndex?: number;
  /** True when cursor is inside an existing string literal (quotes already present). */
  insideString?: boolean;
}