import { z } from 'zod';
import { stripHtml } from '../services/sanitize.js';

const panPattern = /^[A-Z]{5}[0-9]{4}[A-Z]$/;
const ifscPattern = /^[A-Z]{4}0[A-Z0-9]{6}$/;
const gstinPattern = /^[0-9]{2}[A-Z]{5}[0-9]{4}[A-Z][1-9A-Z]Z[0-9A-Z]$/;
const accountPattern = /^[0-9]{9,18}$/;

const emptyToUndefined = (value) => (value === '' || value === null ? undefined : value);

/**
 * @param {z.ZodTypeAny} schema
 */
function text(schema) {
  return z.preprocess((value) => (typeof value === 'string' ? stripHtml(value) : value), schema);
}

export const applicationSchema = z.object({
  agreement_date: z.string().regex(/^\d{4}-\d{2}-\d{2}$/),
  full_name: text(z.string().trim().min(1)),
  age: z.number().int().min(21).max(100),
  address: text(z.string().trim().min(1)),
  registration_no: text(z.string().trim().min(1)),
  medical_council: text(z.string().trim().min(1)),
  pan: text(z.string().regex(panPattern)),
  gstin: z.preprocess(emptyToUndefined, text(z.string().regex(gstinPattern)).optional()),
  bank_name: text(z.string().trim().min(1)),
  account_holder: text(z.string().trim().min(1)),
  account_number: text(z.string().regex(accountPattern)),
  ifsc: text(z.string().regex(ifscPattern)),
});

const emptyToNull = (value) => (value === '' ? null : value);

const optionalText = (schema) => z.preprocess(emptyToNull, schema.nullable().optional());

export const draftApplicationSchema = z
  .object({
    agreement_date: optionalText(z.string().regex(/^\d{4}-\d{2}-\d{2}$/)),
    full_name: optionalText(text(z.string().trim().min(1))),
    age: z.preprocess((value) => {
      if (value === '' || value === null) {
        return null;
      }

      if (typeof value === 'string' && /^\d+$/.test(value)) {
        return Number(value);
      }

      return value;
    }, z.number().int().min(21).max(100).nullable().optional()),
    address: optionalText(text(z.string().trim().min(1))),
    registration_no: optionalText(text(z.string().trim().min(1))),
    medical_council: optionalText(text(z.string().trim().min(1))),
    pan: optionalText(text(z.string().regex(panPattern))),
    gstin: optionalText(text(z.string().regex(gstinPattern))),
    bank_name: optionalText(text(z.string().trim().min(1))),
    account_holder: optionalText(text(z.string().trim().min(1))),
    account_number: optionalText(text(z.string().regex(accountPattern))),
    ifsc: optionalText(text(z.string().regex(ifscPattern))),
    accepted: z.boolean().optional(),
    /** Optional cancelled-cheque image as a data URL, or null to remove. */
    cancelled_cheque: z.union([z.string().min(1), z.null()]).optional(),
  })
  .strict();

export const finalizeApplicationSchema = applicationSchema.extend({
  accepted: z.literal(true),
});