/* Mail and password-reset administration view. */

class MailAdmin {
  /**
   * goal   : Connect mail settings, test delivery and TLS controls to the API.
   * pre    : The mail administration form exists in the document.
   * post   : Save, test and TLS-change events are handled by this controller.
   * result : A directly usable mail administration controller.
   */
  constructor(api, translate) {
    this.api = api;
    this.translate = translate;
    this.form = document.getElementById("mail-settings-form");
    this.status = document.getElementById("mail-settings-status");
    this.testButton = document.getElementById("mail-test-button");
    this.tls = document.getElementById("mail-smtp-tls");
    this.acceptUntrusted = document.getElementById(
      "mail-smtp-accept-untrusted-certificates");

    this.form.addEventListener("submit", (event) => this.#save(event));
    this.testButton.addEventListener("click", () => this.#test());
    this.tls.addEventListener("change", () => this.#syncTlsControls());
  }

  /**
   * goal   : Load stored mail settings and initialize the test recipient.
   * pre    : The current session has administrator permission.
   * post   : All form controls represent the stored server configuration.
   * result : A promise that resolves after the form has been initialized.
   */
  async load(currentUserEmail = "") {
    const settings = await this.api("/api/admin/mail-settings");
    document.getElementById("mail-public-url").value =
      settings.publicUrl || window.location.origin;
    document.getElementById("mail-smtp-host").value = settings.smtpHost || "";
    document.getElementById("mail-smtp-port").value = settings.smtpPort || "587";
    document.getElementById("mail-smtp-from").value = settings.smtpFrom || "";
    document.getElementById("mail-smtp-user").value = settings.smtpUser || "";
    document.getElementById("mail-smtp-password").value = "";
    this.tls.checked = settings.smtpTls !== false;
    this.acceptUntrusted.checked = settings.smtpAcceptUntrustedCertificates === true;
    document.getElementById("mail-reset-limit").value = settings.resetLimit || "2";
    document.getElementById("mail-test-recipient").value = currentUserEmail;
    document.getElementById("mail-password-help").textContent = settings.hasPassword
      ? this.translate(
        "smtp-password-kept", "A password is stored; leave empty to keep it.")
      : "";
    this.status.textContent = "";
    this.acceptUntrusted.disabled = !this.tls.checked;
  }

  /** Read the mail form using the public server API field names. */
  #formData() {
    return {
      publicUrl: document.getElementById("mail-public-url").value,
      smtpHost: document.getElementById("mail-smtp-host").value,
      smtpPort: document.getElementById("mail-smtp-port").value,
      smtpFrom: document.getElementById("mail-smtp-from").value,
      smtpUser: document.getElementById("mail-smtp-user").value,
      smtpPassword: document.getElementById("mail-smtp-password").value,
      smtpTls: this.tls.checked,
      smtpAcceptUntrustedCertificates: this.acceptUntrusted.checked,
      resetLimit: document.getElementById("mail-reset-limit").value
    };
  }

  /** Store the current mail settings and retain an omitted password. */
  async #save(event) {
    event.preventDefault();
    try {
      await this.api("/api/admin/mail-settings", {
        method: "PUT",
        body: JSON.stringify(this.#formData())
      });
      document.getElementById("mail-smtp-password").value = "";
      document.getElementById("mail-password-help").textContent = this.translate(
        "smtp-password-kept", "A password is stored; leave empty to keep it.");
      this.status.textContent = this.translate("saved", "Saved");
    } catch (error) {
      this.status.textContent = error.message;
    }
  }

  /** Send one test message using the unsaved values currently in the form. */
  async #test() {
    const recipient = document.getElementById("mail-test-recipient").value.trim();
    this.testButton.disabled = true;
    this.status.textContent = this.translate(
      "sending-test-mail", "Sending test email…");
    try {
      await this.api("/api/admin/mail-settings/test", {
        method: "POST",
        body: JSON.stringify({ ...this.#formData(), recipient })
      });
      this.status.textContent = this.translate(
        "test-mail-sent", "Test email accepted by SMTP server");
    } catch (error) {
      console.error("SMTP test failed", error);
      this.status.textContent = this.#smtpErrorMessage(error);
    } finally {
      this.testButton.disabled = false;
    }
  }

  /** Translate known TLS failures and retain other server error messages. */
  #smtpErrorMessage(error) {
    const message = error && error.message ? error.message : String(error);
    const certificateFailure = message.includes("certificate verify failed") ||
      message.includes("TLS certificate verification failed");
    if (certificateFailure) {
      return this.translate(
        "smtp-certificate-verification-failed",
        "The SMTP server certificate could not be verified. Install a valid certificate, or select the local-server exception if this is a trusted local SMTP server.");
    }
    if (message.includes("no protocols available")) {
      return this.translate(
        "smtp-no-modern-tls",
        "The SMTP connection attempted an obsolete TLS protocol. Install the current Racket Wiki version, which negotiates modern TLS automatically.");
    }
    return message;
  }

  /** Disable the certificate exception whenever STARTTLS is disabled. */
  #syncTlsControls() {
    this.acceptUntrusted.disabled = !this.tls.checked;
    if (this.acceptUntrusted.disabled) this.acceptUntrusted.checked = false;
  }
}

export { MailAdmin };