export type MockVendor = {
  id: string;
  name: string;
};

export type MockInvoiceStatus = "pending_approval" | "approved" | "scheduled" | "paid";

export type MockInvoice = {
  id: string;
  invoiceNumber: string;
  invoiceNumbers: string;
  vendorId: string;
  vendorName: string;
  amountDue: number;
  amount: number;
  dueDate: string;
  payDate: string | null;
  sendPaymentOn: string | null;
  status: MockInvoiceStatus;
  paymentMethod: "check" | "ach";
};

export const mockVendors: MockVendor[] = [
  { id: "vendor-1", name: "Acme Supplies Co" },
  { id: "vendor-2", name: "Harbor Maintenance LLC" },
  { id: "vendor-3", name: "Northwind Utilities" },
  { id: "vendor-4", name: "Coastal Office Supply" },
];

const seedInvoices: MockInvoice[] = [
  {
    id: "inv-1",
    invoiceNumber: "INV-1001",
    invoiceNumbers: "INV-1001",
    vendorId: "vendor-1",
    vendorName: "Acme Supplies Co",
    amountDue: 1250.5,
    amount: 1250.5,
    dueDate: "2026-08-20",
    payDate: "2026-08-15",
    sendPaymentOn: "2026-08-15",
    status: "approved",
    paymentMethod: "check",
  },
  {
    id: "inv-2",
    invoiceNumber: "INV-1002",
    invoiceNumbers: "INV-1002",
    vendorId: "vendor-2",
    vendorName: "Harbor Maintenance LLC",
    amountDue: 4800,
    amount: 4800,
    dueDate: "2026-08-25",
    payDate: null,
    sendPaymentOn: "2026-08-20",
    status: "pending_approval",
    paymentMethod: "ach",
  },
  {
    id: "inv-3",
    invoiceNumber: "INV-1003",
    invoiceNumbers: "INV-1003",
    vendorId: "vendor-3",
    vendorName: "Northwind Utilities",
    amountDue: 312.75,
    amount: 312.75,
    dueDate: "2026-08-12",
    payDate: "2026-08-10",
    sendPaymentOn: "2026-08-10",
    status: "approved",
    paymentMethod: "check",
  },
  {
    id: "inv-4",
    invoiceNumber: "INV-1004",
    invoiceNumbers: "INV-1004",
    vendorId: "vendor-4",
    vendorName: "Coastal Office Supply",
    amountDue: 890.25,
    amount: 900,
    dueDate: "2026-09-01",
    payDate: null,
    sendPaymentOn: "2026-08-27",
    status: "pending_approval",
    paymentMethod: "ach",
  },
  {
    id: "inv-5",
    invoiceNumber: "INV-1005",
    invoiceNumbers: "INV-1005",
    vendorId: "vendor-1",
    vendorName: "Acme Supplies Co",
    amountDue: 2100,
    amount: 2100,
    dueDate: "2026-07-30",
    payDate: "2026-07-25",
    sendPaymentOn: "2026-07-25",
    status: "scheduled",
    paymentMethod: "check",
  },
  {
    id: "inv-6",
    invoiceNumber: "INV-1006",
    invoiceNumbers: "INV-1006",
    vendorId: "vendor-2",
    vendorName: "Harbor Maintenance LLC",
    amountDue: 0,
    amount: 1550,
    dueDate: "2026-07-15",
    payDate: "2026-07-10",
    sendPaymentOn: "2026-07-10",
    status: "paid",
    paymentMethod: "ach",
  },
  {
    id: "inv-7",
    invoiceNumber: "INV-1007",
    invoiceNumbers: "INV-1007",
    vendorId: "vendor-3",
    vendorName: "Northwind Utilities",
    amountDue: 645.1,
    amount: 645.1,
    dueDate: "2026-08-28",
    payDate: "2026-08-22",
    sendPaymentOn: "2026-08-22",
    status: "approved",
    paymentMethod: "ach",
  },
];

/** Mutable in-memory invoice store for mock POC interactions. */
let invoiceStore: MockInvoice[] = seedInvoices.map((invoice) => ({ ...invoice }));

/** Mocks are the default data path until the API is wired. */
export function areMocksEnabled(): boolean {
  return import.meta.env.VITE_USE_MOCKS !== "false";
}

export function getMockInvoices(): MockInvoice[] {
  if (!areMocksEnabled()) {
    return [];
  }
  return invoiceStore.map((invoice) => ({ ...invoice }));
}

export function getMockVendors(): MockVendor[] {
  if (!areMocksEnabled()) {
    return [];
  }
  return mockVendors;
}

export function updateMockInvoicePayDate(id: string, payDate: string | null): MockInvoice {
  const index = invoiceStore.findIndex((invoice) => invoice.id === id);
  if (index === -1) {
    throw new Error(`Mock invoice not found: ${id}`);
  }

  const updated: MockInvoice = { ...invoiceStore[index], payDate };
  invoiceStore = [...invoiceStore.slice(0, index), updated, ...invoiceStore.slice(index + 1)];
  return { ...updated };
}

/** Test helper to restore seed data between unit tests. */
export function resetMockInvoices(): void {
  invoiceStore = seedInvoices.map((invoice) => ({ ...invoice }));
}