import dgram = require("dgram");
import stream = require("stream");

export type Tags = { [key: string]: string } | string[];
export interface ClientOptions {
  bufferFlushInterval?: number;
  bufferHolder?: { buffer: string };
  cacheDns?: boolean;
  cacheDnsTtl?: number;
  errorHandler?: (err: Error) => void;
  globalTags?: Tags;
  includeDataDogTags?: boolean;
  globalize?: boolean;
  host?: string;
  isChild?: boolean;
  maxBufferSize?: number;
  mock?: boolean;
  path?: string;
  port?: number;
  prefix?: string;
  protocol?: 'tcp' | 'udp' | 'uds' | 'stream';
  sampleRate?: number;
  socket?: dgram.Socket;
  stream?: stream.Writable;
  suffix?: string;
  telegraf?: boolean;
  useDefaultRoute?: boolean;
  tagPrefix?: string;
  tagSeparator?: string;
  tcpGracefulErrorHandling?: boolean;
  tcpGracefulRestartRateLimit?: number;
  udsGracefulErrorHandling?: boolean;
  udsGracefulRestartRateLimit?: number;
  closingFlushInterval?: number;
  udpSocketOptions?: dgram.SocketOptions;
  udsRetryOptions?: {
    retries?: number;
    retryDelayMs?: number;
    maxRetryDelayMs?: number;
    backoffFactor?: number;
  };
  includeDatadogTelemetry?: boolean;
  telemetryFlushInterval?: number;
}

export interface ChildClientOptions {
  globalTags?: Tags;
  prefix?: string;
  suffix?: string;
  errorHandler?: (err: Error) => void;
}

export interface CheckOptions {
  date_happened?: Date;
  hostname?: string;
  message?: string;
}

export interface DatadogChecks {
  OK: 0;
  WARNING: 1;
  CRITICAL: 2;
  UNKNOWN: 3;
}

type unionFromInterfaceValues4<
  T,
  K1 extends keyof T,
  K2 extends keyof T,
  K3 extends keyof T,
  K4 extends keyof T,
  > = T[K1] | T[K2] | T[K3] | T[K4];

export type DatadogChecksValues = unionFromInterfaceValues4<DatadogChecks, "OK", "WARNING", "CRITICAL", "UNKNOWN">;

export interface EventOptions {
  aggregation_key?: string;
  alert_type?: "info" | "warning" | "success" | "error";
  date_happened?: Date;
  hostname?: string;
  priority?: "low" | "normal";
  source_type_name?: string;
}

export interface MetricOptions {
  sampleRate?: number;
  tags?: Tags;
  /** Timestamp for the metric (DogStatsD only). Can be a Date or Unix timestamp in seconds. */
  timestamp?: Date | number;
}

/**
 * Context object passed to timer/asyncTimer/asyncDistTimer wrapped functions.
 * Allows adding tags dynamically during function execution.
 */
export interface TimerContext {
  /**
   * Add tags to be included when the metric is recorded.
   * Can be called multiple times to accumulate tags.
   * @param tags Tags to add. Can be an object like {key: 'value'} or array like ['key:value']
   */
  addTags(tags: Tags): void;
}

export type StatsCb = (error?: Error, bytes?: number) => void;

export class StatsD {
  constructor(options?: ClientOptions);
  childClient(options?: ChildClientOptions): StatsD;

  increment(stat: string, tags?: Tags): void;
  increment(stat: string | string[], value: number, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  increment(stat: string | string[], value: number, tags?: Tags, callback?: StatsCb): void;
  increment(stat: string | string[], value: number, callback?: StatsCb): void;
  increment(stat: string | string[], value: number, sampleRate?: number, callback?: StatsCb): void;
  increment(stat: string | string[], value: number, options?: MetricOptions, callback?: StatsCb): void;

  decrement(stat: string): void;
  decrement(stat: string, tags?: Tags): void;
  decrement(stat: string | string[], value: number, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  decrement(stat: string | string[], value: number, tags?: Tags, callback?: StatsCb): void;
  decrement(stat: string | string[], value: number, callback?: StatsCb): void;
  decrement(stat: string | string[], value: number, sampleRate?: number, callback?: StatsCb): void;
  decrement(stat: string | string[], value: number, options?: MetricOptions, callback?: StatsCb): void;

  timing(stat: string | string[], value: number | Date, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  timing(stat: string | string[], value: number | Date, tags?: Tags, callback?: StatsCb): void;
  timing(stat: string | string[], value: number | Date, callback?: StatsCb): void;
  timing(stat: string | string[], value: number | Date, sampleRate?: number, callback?: StatsCb): void;
  timing(stat: string | string[], value: number | Date, options?: MetricOptions, callback?: StatsCb): void;

  /**
   * Wraps a function to record its execution time. The wrapped function receives a TimerContext
   * as its last argument, which can be used to add tags dynamically during execution.
   */
  timer<P extends any[], R>(func: (...args: [...P, TimerContext]) => R, stat: string | string[], sampleRate?: number, tags?: Tags, callback?: StatsCb): (...args: P) => R;
  timer<P extends any[], R>(func: (...args: [...P, TimerContext]) => R, stat: string | string[], tags?: Tags, callback?: StatsCb): (...args: P) => R;
  timer<P extends any[], R>(func: (...args: [...P, TimerContext]) => R, stat: string | string[], callback?: StatsCb): (...args: P) => R;
  timer<P extends any[], R>(func: (...args: [...P, TimerContext]) => R, stat: string | string[], sampleRate?: number, callback?: StatsCb): (...args: P) => R;
  timer<P extends any[], R>(func: (...args: [...P, TimerContext]) => R, stat: string | string[], options?: MetricOptions, callback?: StatsCb): (...args: P) => R;

  /**
   * Wraps an async function to record its execution time. The wrapped function receives a TimerContext
   * as its last argument, which can be used to add tags dynamically during execution.
   */
  asyncTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], sampleRate?: number, tags?: Tags, callback?: StatsCb): (...args: P) => Promise<R>;
  asyncTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], tags?: Tags, callback?: StatsCb): (...args: P) => Promise<R>;
  asyncTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], callback?: StatsCb): (...args: P) => Promise<R>;
  asyncTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], sampleRate?: number, callback?: StatsCb): (...args: P) => Promise<R>;
  asyncTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], options?: MetricOptions, callback?: StatsCb): (...args: P) => Promise<R>;

  /**
   * Wraps an async function to record its execution time as a distribution. The wrapped function receives
   * a TimerContext as its last argument, which can be used to add tags dynamically during execution.
   */
  asyncDistTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], sampleRate?: number, tags?: Tags, callback?: StatsCb): (...args: P) => Promise<R>;
  asyncDistTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], tags?: Tags, callback?: StatsCb): (...args: P) => Promise<R>;
  asyncDistTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], callback?: StatsCb): (...args: P) => Promise<R>;
  asyncDistTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], sampleRate?: number, callback?: StatsCb): (...args: P) => Promise<R>;
  asyncDistTimer<P extends any[], R>(func: (...args: [...P, TimerContext]) => Promise<R>, stat: string | string[], options?: MetricOptions, callback?: StatsCb): (...args: P) => Promise<R>;

  histogram(stat: string | string[], value: number, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  histogram(stat: string | string[], value: number, tags?: Tags, callback?: StatsCb): void;
  histogram(stat: string | string[], value: number, callback?: StatsCb): void;
  histogram(stat: string | string[], value: number, sampleRate?: number, callback?: StatsCb): void;
  histogram(stat: string | string[], value: number, options?: MetricOptions, callback?: StatsCb): void;

  distribution(stat: string | string[], value: number, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  distribution(stat: string | string[], value: number, tags?: Tags, callback?: StatsCb): void;
  distribution(stat: string | string[], value: number, callback?: StatsCb): void;
  distribution(stat: string | string[], value: number, sampleRate?: number, callback?: StatsCb): void;
  distribution(stat: string | string[], value: number, options?: MetricOptions, callback?: StatsCb): void;

  gauge(stat: string | string[], value: number, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  gauge(stat: string | string[], value: number, tags?: Tags, callback?: StatsCb): void;
  gauge(stat: string | string[], value: number, callback?: StatsCb): void;
  gauge(stat: string | string[], value: number, sampleRate?: number, callback?: StatsCb): void;
  gauge(stat: string | string[], value: number, options?: MetricOptions, callback?: StatsCb): void;

  gaugeDelta(stat: string | string[], value: number, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  gaugeDelta(stat: string | string[], value: number, tags?: Tags, callback?: StatsCb): void;
  gaugeDelta(stat: string | string[], value: number, callback?: StatsCb): void;
  gaugeDelta(stat: string | string[], value: number, sampleRate?: number, callback?: StatsCb): void;
  gaugeDelta(stat: string | string[], value: number, options?: MetricOptions, callback?: StatsCb): void;

  set(stat: string | string[], value: number | string, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  set(stat: string | string[], value: number | string, tags?: Tags, callback?: StatsCb): void;
  set(stat: string | string[], value: number | string, callback?: StatsCb): void;
  set(stat: string | string[], value: number | string, sampleRate?: number, callback?: StatsCb): void;
  set(stat: string | string[], value: number | string, options?: MetricOptions, callback?: StatsCb): void;

  unique(stat: string | string[], value: number | string, sampleRate?: number, tags?: Tags, callback?: StatsCb): void;
  unique(stat: string | string[], value: number | string, tags?: Tags, callback?: StatsCb): void;
  unique(stat: string | string[], value: number | string, callback?: StatsCb): void;
  unique(stat: string | string[], value: number | string, sampleRate?: number, callback?: StatsCb): void;
  unique(stat: string | string[], value: number | string, options?: MetricOptions, callback?: StatsCb): void;

  close(callback?: (error?: Error) => void): void;

  event(title: string, text?: string, options?: EventOptions, tags?: Tags, callback?: StatsCb): void;
  event(title: string, text?: string, options?: EventOptions, callback?: StatsCb): void;
  check(name: string, status: DatadogChecksValues, options?: CheckOptions, tags?: Tags, callback?: StatsCb): void;

  public CHECKS: DatadogChecks;
  public mockBuffer?: string[];
  public socket: dgram.Socket;
}

declare const StatsDClient: new (options?: ClientOptions) => StatsD;
export default StatsDClient;