import { encodeBase64 } from "@std/encoding/base64";
import { getLogger } from "./logger.ts";

export class Mail {
  message_id: string | null = null;
  aws_message_id: string | null = null;

  constructor(public raw: string) {}

  encodeUtf8(): Uint8Array {
    const utf8Encoder = new TextEncoder();
    // TODO: A problem here is if mail is VERY long, this will block for a long time.
    // Maybe some task queue can be used.
    return utf8Encoder.encode(this.raw);
  }

  getRawBase64(): string {
    return encodeBase64(this.raw);
  }

  appendHeaders(
    rawMail: string,
    headers: [key: string, value: string][],
  ): string {
    const separatorMatch = rawMail.match(/(\r\n|\n)(\r\n|\n)/);
    if (separatorMatch == null) {
      throw new Error(
        "No header/body separator (2 successive EOLs) found. Cannot append headers.",
      );
    }

    if (separatorMatch[1] !== separatorMatch[2]) {
      getLogger().warn("Different EOLs (\\r\\n and \\n) found in mail!");
    }

    const headerStr = headers.map(([k, v]) => `${k}: ${v}${separatorMatch[1]}`)
      .join("");
    const endOfHeadersIndex = separatorMatch.index! + separatorMatch[1].length;
    return rawMail.slice(0, endOfHeadersIndex) + headerStr +
      rawMail.slice(endOfHeadersIndex);
  }
}