/**
 * Merges mandate core fields with billing settings for SysAdmin mandate forms.
 * Billing is stored separately (BillingSettings); attributes API only exposes Mandate model fields.
 */

import type { AttributeDefinition } from '../components/FormGenerator/FormGeneratorForm';
import type { BillingSettings, BillingSettingsUpdate } from '../api/billingApi';

export const mandateBillingFieldNames = [
  'warningThresholdPercent',
  'notifyOnWarning',
  'notifyEmails',
] as const;

export type MandateBillingFieldName = (typeof mandateBillingFieldNames)[number];

/** FormGenerator attribute definitions for mandate billing (appended after /api/attributes/Mandate). */
export function getMandateBillingFormAttributes(): AttributeDefinition[] {
  return [
    {
      name: 'warningThresholdPercent',
      type: 'float',
      label: 'Warnschwelle (%)',
      description: 'Benachrichtigung, wenn das Guthaben unter diesem Prozentsatz fällt.',
      required: false,
      default: 10,
      editable: true,
      order: 102,
    },
    {
      name: 'notifyOnWarning',
      type: 'checkbox',
      label: 'Bei Warnung benachrichtigen',
      required: false,
      default: true,
      editable: true,
      order: 102,
    },
    {
      name: 'notifyEmails',
      type: 'textarea',
      label: 'Benachrichtigungs-E-Mails',
      description: 'Eine Adresse pro Zeile oder durch Komma/Semikolon getrennt.',
      required: false,
      default: '',
      editable: true,
      order: 103,
      minRows: 2,
      maxRows: 6,
    },
  ];
}

function _parseNotifyEmailsInput(val: unknown): string[] {
  if (Array.isArray(val)) {
    return val.map(String).map(s => s.trim()).filter(Boolean);
  }
  if (typeof val !== 'string') {
    return [];
  }
  return val
    .split(/[\n,;]+/)
    .map(s => s.trim())
    .filter(Boolean);
}

export function mergeBillingIntoMandateFormData(
  mandate: Record<string, unknown>,
  settings: BillingSettings | null
): Record<string, unknown> {
  if (!settings) {
    return {
      ...mandate,
      warningThresholdPercent: 10,
      notifyOnWarning: true,
      notifyEmails: '',
    };
  }
  return {
    ...mandate,
    warningThresholdPercent: Number(settings.warningThresholdPercent ?? 10),
    notifyOnWarning: settings.notifyOnWarning ?? true,
    notifyEmails: (settings.notifyEmails || []).join('\n'),
  };
}

/** Mandate fields that the AdminMandates form is allowed to update. */
const _MANDATE_INVOICE_FIELDS = [
  'invoiceCompanyName',
  'invoiceContactName',
  'invoiceEmail',
  'invoiceLine1',
  'invoiceLine2',
  'invoicePostalCode',
  'invoiceCity',
  'invoiceState',
  'invoiceCountry',
  'invoiceVatNumber',
] as const;

/**
 * Split form submit payload into mandate PUT body and billing POST body.
 *
 * Only fields that the user can actually edit are forwarded. Audit-only /
 * read-only fields (id, deletedAt, isSystem, ...) are intentionally dropped.
 * The structured ``invoice*`` address fields are round-tripped here so the
 * address entered in the form is persisted on Mandate; empty strings are
 * normalized to ``null`` so the backend stores nothing instead of "".
 */
export function splitMandateAndBillingFromForm(
  formData: Record<string, unknown>
): { mandatePayload: Record<string, unknown>; billingUpdate: BillingSettingsUpdate } {
  const mandatePayload: Record<string, unknown> = {};
  if ('name' in formData) mandatePayload.name = formData.name;
  if ('label' in formData) mandatePayload.label = formData.label;
  if ('enabled' in formData) mandatePayload.enabled = formData.enabled;
  for (const fieldName of _MANDATE_INVOICE_FIELDS) {
    if (!(fieldName in formData)) continue;
    const raw = formData[fieldName];
    if (raw === null || raw === undefined) {
      mandatePayload[fieldName] = null;
    } else if (typeof raw === 'string') {
      const trimmed = raw.trim();
      mandatePayload[fieldName] = trimmed.length === 0 ? null : trimmed;
    } else {
      mandatePayload[fieldName] = raw;
    }
  }

  const billingUpdate: BillingSettingsUpdate = {};
  if (
    'warningThresholdPercent' in formData &&
    formData.warningThresholdPercent !== undefined &&
    formData.warningThresholdPercent !== ''
  ) {
    const n = Number(formData.warningThresholdPercent);
    if (!Number.isNaN(n)) billingUpdate.warningThresholdPercent = n;
  }
  if ('notifyOnWarning' in formData) {
    billingUpdate.notifyOnWarning = Boolean(formData.notifyOnWarning);
  }
  if ('notifyEmails' in formData) {
    billingUpdate.notifyEmails = _parseNotifyEmailsInput(formData.notifyEmails);
  }

  return { mandatePayload, billingUpdate };
}