import type { TSKRType } from './skr.types.js';

/**
 * Invoice direction
 */
export type TInvoiceDirection = 'inbound' | 'outbound';

/**
 * Supported e-invoice formats
 */
export type TInvoiceFormat = 'xrechnung' | 'zugferd' | 'facturx' | 'peppol' | 'ubl';

/**
 * Invoice status in the system
 */
export type TInvoiceStatus = 'draft' | 'validated' | 'posted' | 'partially_paid' | 'paid' | 'cancelled' | 'error';

/**
 * Tax scenario classification
 */
export type TTaxScenario = 
  | 'domestic_taxed'      // Standard domestic with VAT
  | 'domestic_exempt'     // Domestic tax-exempt
  | 'reverse_charge'      // §13b UStG
  | 'intra_eu_supply'     // Intra-EU supply
  | 'intra_eu_acquisition' // Intra-EU acquisition
  | 'export'              // Export outside EU
  | 'small_business';     // §19 UStG small business

/**
 * VAT rate categories
 */
export interface IVATCategory {
  code: string;           // S (Standard), Z (Zero), E (Exempt), AE (Reverse charge), etc.
  rate: number;           // Tax rate percentage
  exemptionReason?: string;
}

/**
 * Party information (supplier/customer)
 */
export interface IInvoiceParty {
  id: string;
  name: string;
  address: {
    street?: string;
    city?: string;
    postalCode?: string;
    countryCode: string;
  };
  vatId?: string;
  taxId?: string;
  email?: string;
  phone?: string;
  bankAccount?: {
    iban: string;
    bic?: string;
    accountHolder?: string;
  };
}

/**
 * Invoice line item
 */
export interface IInvoiceLine {
  lineNumber: number;
  description: string;
  quantity: number;
  unitPrice: number;
  netAmount: number;
  vatCategory: IVATCategory;
  vatAmount: number;
  grossAmount: number;
  accountNumber?: string;    // SKR account for booking
  costCenter?: string;
  productCode?: string;
  allowances?: IAllowanceCharge[];
  charges?: IAllowanceCharge[];
}

/**
 * Allowance or charge
 */
export interface IAllowanceCharge {
  reason: string;
  amount: number;
  percentage?: number;
  vatCategory?: IVATCategory;
  vatAmount?: number;
}

/**
 * Payment terms
 */
export interface IPaymentTerms {
  dueDate: Date;
  paymentTermsNote?: string;
  skonto?: {
    percentage: number;
    days: number;
    baseAmount: number;
  }[];
}

/**
 * Validation result
 */
export interface IValidationResult {
  isValid: boolean;
  syntax: {
    valid: boolean;
    errors: string[];
    warnings: string[];
  };
  semantic: {
    valid: boolean;
    errors: string[];
    warnings: string[];
  };
  businessRules: {
    valid: boolean;
    errors: string[];
    warnings: string[];
  };
  countrySpecific?: {
    valid: boolean;
    errors: string[];
    warnings: string[];
  };
  validatedAt: Date;
  validatorVersion: string;
}

/**
 * Booking information
 */
export interface IBookingInfo {
  journalEntryId: string;
  transactionIds: string[];
  bookedAt: Date;
  bookedBy: string;
  bookingRules: {
    vendorAccount?: string;
    customerAccount?: string;
    expenseAccounts?: string[];
    revenueAccounts?: string[];
    vatAccounts?: string[];
  };
  confidence: number;       // 0-100
  autoBooked: boolean;
}

/**
 * Payment information
 */
export interface IPaymentInfo {
  paymentId: string;
  paymentDate: Date;
  amount: number;
  currency: string;
  bankTransactionId?: string;
  endToEndId?: string;
  remittanceInfo?: string;
  skontoTaken?: number;
}

/**
 * Main invoice entity
 */
export interface IInvoice {
  // Identity
  id: string;
  direction: TInvoiceDirection;
  format: TInvoiceFormat;
  
  // EN16931 Business Terms
  invoiceNumber: string;      // BT-1
  issueDate: Date;            // BT-2
  invoiceTypeCode?: string;   // BT-3 (380=Invoice, 381=Credit note)
  currencyCode: string;       // BT-5
  taxCurrencyCode?: string;   // BT-6
  taxPointDate?: Date;        // BT-7 (Leistungsdatum)
  paymentDueDate?: Date;      // BT-9
  buyerReference?: string;    // BT-10
  projectReference?: string;  // BT-11
  contractReference?: string; // BT-12
  orderReference?: string;    // BT-13
  sellerOrderReference?: string; // BT-14
  
  // Parties
  supplier: IInvoiceParty;
  customer: IInvoiceParty;
  payee?: IInvoiceParty;      // If different from supplier
  
  // Line items
  lines: IInvoiceLine[];
  
  // Document level allowances/charges
  allowances?: IAllowanceCharge[];
  charges?: IAllowanceCharge[];
  
  // Amounts
  lineNetAmount: number;      // Sum of line net amounts
  allowanceTotalAmount?: number;
  chargeTotalAmount?: number;
  taxExclusiveAmount: number; // BT-109
  taxInclusiveAmount: number; // BT-112
  prepaidAmount?: number;     // BT-113
  payableAmount: number;      // BT-115
  
  // VAT breakdown
  vatBreakdown: {
    vatCategory: IVATCategory;
    taxableAmount: number;    // BT-116
    taxAmount: number;        // BT-117
  }[];
  totalVATAmount: number;     // BT-110
  
  // Payment
  paymentTerms?: IPaymentTerms;
  paymentMeans?: {
    code: string;             // 30=Bank transfer, 48=Card, etc.
    account?: IInvoiceParty['bankAccount'];
  };
  payments?: IPaymentInfo[];
  
  // Notes
  invoiceNote?: string;       // BT-22
  
  // Processing metadata
  status: TInvoiceStatus;
  taxScenario?: TTaxScenario;
  skrType?: TSKRType;
  
  // Storage
  contentHash: string;        // SHA-256 of normalized XML
  xmlContent?: string;
  pdfHash?: string;
  pdfContent?: Buffer;
  
  // Validation
  validationResult?: IValidationResult;
  
  // Booking
  bookingInfo?: IBookingInfo;
  
  // Audit trail
  createdAt: Date;
  createdBy: string;
  modifiedAt?: Date;
  modifiedBy?: string;
  
  // Additional metadata
  metadata?: {
    importSource?: string;
    importedAt?: Date;
    parserVersion?: string;
    originalFilename?: string;
    originalFormat?: string;
    [key: string]: any;
  };
}

/**
 * Invoice import options
 */
export interface IInvoiceImportOptions {
  autoBook?: boolean;
  confidenceThreshold?: number;
  validateOnly?: boolean;
  skipDuplicateCheck?: boolean;
  bookingRules?: {
    vendorDefaults?: Record<string, string>;
    customerDefaults?: Record<string, string>;
    productCategoryMapping?: Record<string, string>;
  };
}

/**
 * Invoice export options
 */
export interface IInvoiceExportOptions {
  format: TInvoiceFormat;
  embedInPdf?: boolean;
  sign?: boolean;
  validate?: boolean;
}

/**
 * Invoice search filter
 */
export interface IInvoiceFilter {
  direction?: TInvoiceDirection;
  status?: TInvoiceStatus;
  format?: TInvoiceFormat;
  dateFrom?: Date;
  dateTo?: Date;
  supplierId?: string;
  customerId?: string;
  minAmount?: number;
  maxAmount?: number;
  invoiceNumber?: string;
  reference?: string;
  isPaid?: boolean;
  isOverdue?: boolean;
}

/**
 * Duplicate check result
 */
export interface IDuplicateCheckResult {
  isDuplicate: boolean;
  matchedInvoiceId?: string;
  matchedContentHash?: string;
  matchedFields?: string[];
  confidence: number;
}

/**
 * Booking rules configuration
 */
export interface IBookingRules {
  skrType: TSKRType;
  
  // Control accounts
  vendorControlAccount: string;
  customerControlAccount: string;
  
  // VAT accounts
  vatAccounts: {
    inputVAT19: string;
    inputVAT7: string;
    outputVAT19: string;
    outputVAT7: string;
    reverseChargeVAT: string;
  };
  
  // Default accounts
  defaultExpenseAccount: string;
  defaultRevenueAccount: string;
  
  // Mappings
  productCategoryMapping?: Record<string, string>;
  vendorMapping?: Record<string, string>;
  customerMapping?: Record<string, string>;
  
  // Skonto
  skontoMethod?: 'net' | 'gross';
  skontoExpenseAccount?: string;
  skontoRevenueAccount?: string;
}