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import { BufReader, TextProtoReader, writeAll } from "./deps.ts";
export type Command = (string | number)[];export type Reply = string | number | null | Reply[];
const CRLF = "\r\n";const encoder = new TextEncoder();
function removePrefix(line: string): string {  return line.slice(1);}
/** * Transforms a command, which is an array of arguments, into an RESP request string. * @see https://redis.io/docs/reference/protocol-spec/#send-commands-to-a-redis-server */function stringifyRequest(command: Command): string {  let request = "*" + command.length + CRLF;  for (const arg of command) {    request += "$" + arg.toString().length + CRLF;    request += arg + CRLF;  }  return request;}
/** Encodes and sends the request string to the server. */async function writeRequest(  conn: Deno.Conn,  request: string,): Promise<void> {  await writeAll(conn, encoder.encode(request));}
async function readNonNullArray(  tpReader: TextProtoReader,  length: number,): Promise<Reply[]> {  const array = [];  for (let i = 0; i < length; i++) {    const reply: Reply = await readReply(tpReader);    array.push(reply);  }  return array;}
/** * Reads and processes the response line-by-line. * @see https://redis.io/docs/reference/protocol-spec/#resp-protocol-description */async function readReply(tpReader: TextProtoReader): Promise<Reply> {  const line = await tpReader.readLine();  switch (line!.charAt(0)) {    /** Simple string */    case "+":      return removePrefix(line!);    /** Error */    case "-":      return Promise.reject(removePrefix(line!));    /** Integer */    case ":":      return Number(removePrefix(line!));    /** Bulk string */    case "$":      return Number(removePrefix(line!)) === -1        ? null        : /** Skip to reading the next line, which is a string */          await readReply(tpReader);    /** Array */    case "*": {      const length = Number(removePrefix(line!));      return length === -1 ? null : await readNonNullArray(tpReader, length);    }    /** No prefix */    default:      return line;  }}
function toTpReader(redisConn: Deno.Conn): TextProtoReader {  return new TextProtoReader(new BufReader(redisConn));}
/** * Sends a command to the Redis server and returns the parsed reply. * * Example: * ```ts * import { sendCommand } from "https://deno.land/x/r2d2/mod.ts"; * * const redisConn = await Deno.connect({ port: 6379 }); * * // Resolves to "OK" * await sendCommand(redisConn, ["SET", "hello", "world"]); * * // Prints "world" * console.log(await sendCommand(redisConn, ["GET", "hello"])); * ``` * @param redisConn Redis connection to the server. * @param command Redis command, which is an array of arguments. * @returns Parsed Redis reply */export async function sendCommand(  redisConn: Deno.Conn,  command: Command,): Promise<Reply> {  await writeRequest(redisConn, stringifyRequest(command));  return await readReply(toTpReader(redisConn));}