import type { AppRouter } from "beenvoice/server/api/root";
import type { inferRouterInputs, inferRouterOutputs } from "@trpc/server";

export type InvoicePdfPreviewInput = inferRouterInputs<AppRouter>["invoices"]["previewPdf"];
type InvoiceDetail = NonNullable<inferRouterOutputs<AppRouter>["invoices"]["getById"]>;

export type InvoicePdfFormFields = {
  invoiceNumber: string;
  invoicePrefix?: string | null;
  businessId?: string | null;
  clientId: string;
  issueDate: Date;
  dueDate: Date;
  status?: "draft" | "sent" | "paid";
  notes?: string | null;
  emailMessage?: string | null;
  taxRate: number;
  currency: string;
  items: Array<{
    date: Date;
    description: string;
    hours: number | string;
    rate: number | string;
  }>;
};

export function buildPreviewPdfInput(fields: InvoicePdfFormFields): InvoicePdfPreviewInput | null {
  if (!fields.clientId.trim()) return null;

  const items = fields.items.map((item) => ({
    date: item.date,
    description: item.description.trim() || "Service",
    hours: Number(item.hours) || 0,
    rate: Number(item.rate) || 0,
  }));

  if (items.length === 0) return null;

  return {
    invoiceNumber: fields.invoiceNumber.trim() || "DRAFT",
    invoicePrefix: fields.invoicePrefix?.trim() || "#",
    businessId: fields.businessId?.trim() || "",
    clientId: fields.clientId,
    issueDate: fields.issueDate,
    dueDate: fields.dueDate,
    status: fields.status ?? "draft",
    notes: fields.notes?.trim() ?? "",
    emailMessage: fields.emailMessage?.trim() ?? "",
    taxRate: fields.taxRate,
    currency: fields.currency,
    items,
  };
}

export function buildPreviewPdfInputFromInvoice(invoice: InvoiceDetail): InvoicePdfPreviewInput {
  return {
    invoiceNumber: invoice.invoiceNumber,
    invoicePrefix: invoice.invoicePrefix ?? "#",
    businessId: invoice.businessId ?? "",
    clientId: invoice.clientId,
    issueDate: new Date(invoice.issueDate),
    dueDate: new Date(invoice.dueDate),
    status: invoice.status as "draft" | "sent" | "paid",
    notes: invoice.notes ?? "",
    emailMessage: invoice.emailMessage ?? "",
    taxRate: invoice.taxRate,
    currency: invoice.currency ?? "USD",
    items: invoice.items.map((item) => ({
      date: new Date(item.date),
      description: item.description,
      hours: item.hours,
      rate: item.rate,
    })),
  };
}

export function canPreviewPdfInput(input: InvoicePdfPreviewInput | null): input is InvoicePdfPreviewInput {
  if (!input?.clientId) return false;
  return input.items.every((item) => item.description.trim().length > 0);
}