/**
 * Input validation utilities for user inputs and transaction data
 */

import { validateBrazilianTaxId } from './validation';

export interface ValidationResult {
  valid: boolean;
  errors: string[];
  warnings: string[];
}

/**
 * Validate transaction amount
 */
export function validateAmount(amount: number | string): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  const numAmount = typeof amount === 'string' ? parseFloat(amount) : amount;

  if (isNaN(numAmount)) {
    errors.push('Amount must be a valid number');
  } else if (numAmount <= 0) {
    errors.push('Amount must be greater than zero');
  } else if (numAmount > 1000000000) {
    warnings.push('Amount exceeds 1 billion - please verify');
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate currency code (ISO 4217)
 */
export function validateCurrency(currency: string): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!currency || currency.trim().length === 0) {
    errors.push('Currency code is required');
  } else if (currency.length !== 3) {
    errors.push('Currency code must be 3 characters (ISO 4217)');
  } else if (!/^[A-Z]{3}$/.test(currency)) {
    errors.push('Currency code must be uppercase letters only');
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate email address
 */
export function validateEmail(email: string | undefined): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!email) {
    return { valid: true, errors, warnings };
  }

  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  if (!emailRegex.test(email)) {
    errors.push('Invalid email address format');
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate phone number (basic validation)
 */
export function validatePhone(phone: string | undefined): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!phone) {
    return { valid: true, errors, warnings };
  }

  const phoneRegex = /^[\d\s\-\+\(\)]+$/;
  if (!phoneRegex.test(phone)) {
    errors.push('Invalid phone number format');
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate account number or IBAN
 */
export function validateAccountNumber(
  accountNumber: string | undefined,
  iban: string | undefined
): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!accountNumber && !iban) {
    errors.push('Either account number or IBAN is required');
    return { valid: false, errors, warnings };
  }

  if (iban) {
    // Basic IBAN validation (2 letters + 2 digits + up to 30 alphanumeric)
    const ibanRegex = /^[A-Z]{2}\d{2}[A-Z0-9]{4,30}$/;
    if (!ibanRegex.test(iban.replace(/\s/g, ''))) {
      errors.push('Invalid IBAN format');
    }
  }

  if (accountNumber && accountNumber.trim().length === 0) {
    errors.push('Account number cannot be empty');
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate purpose of payment
 */
export function validatePurposeOfPayment(
  purpose: string | undefined
): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!purpose || purpose.trim().length === 0) {
    errors.push('Purpose of payment is required');
  } else if (purpose.trim().length < 5) {
    warnings.push('Purpose of payment is very short - provide more detail');
  } else if (purpose.length > 140) {
    warnings.push('Purpose of payment exceeds 140 characters - may be truncated');
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate name field
 */
export function validateName(name: string | undefined, fieldName: string): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!name || name.trim().length === 0) {
    errors.push(`${fieldName} is required`);
  } else if (name.trim().length < 2) {
    errors.push(`${fieldName} must be at least 2 characters`);
  } else if (name.length > 140) {
    warnings.push(`${fieldName} exceeds 140 characters`);
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate address
 */
export function validateAddress(
  address: string | undefined,
  city: string | undefined,
  country: string | undefined
): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!address && !city) {
    errors.push('Either address or city is required');
  }

  if (!country) {
    errors.push('Country is required');
  } else if (country.length !== 2) {
    errors.push('Country must be a 2-letter ISO code');
  }

  return {
    valid: errors.length === 0,
    errors,
    warnings,
  };
}

/**
 * Validate tax ID (CPF or CNPJ)
 */
export function validateTaxId(taxId: string | undefined, fieldName: string): ValidationResult {
  const errors: string[] = [];
  const warnings: string[] = [];

  if (!taxId) {
    errors.push(`${fieldName} is required`);
    return { valid: false, errors, warnings };
  }

  const validation = validateBrazilianTaxId(taxId);
  if (!validation.valid) {
    errors.push(`${fieldName}: ${validation.error || 'Invalid format'}`);
  }

  return {
    valid: validation.valid,
    errors,
    warnings,
  };
}

/**
 * Sanitize string input (remove dangerous characters)
 */
export function sanitizeString(input: string): string {
  return input
    .replace(/[<>]/g, '') // Remove potential HTML/XML tags
    .replace(/[\x00-\x1F\x7F]/g, '') // Remove control characters
    .trim();
}

/**
 * Sanitize number input
 */
export function sanitizeNumber(input: string | number): number {
  if (typeof input === 'number') {
    return isNaN(input) ? 0 : input;
  }
  const num = parseFloat(input.replace(/[^\d.-]/g, ''));
  return isNaN(num) ? 0 : num;
}