import jsPDF from "jspdf";

export type BillLineItem = {
  description?: string | null;
  name?: string | null;
  quantity?: number | null;
  unit_price?: number | null;
  amount?: number | null;
};

// One-page "summarized bill" PDF for the Bill Approvals page.
export type BillSummaryData = {
  association: string;
  vendor: string;
  invoiceNumber?: string | null;
  billDate?: string | null;
  dueDate?: string | null;
  amount: number;
  account?: string | null;
  description?: string | null;
  status?: string | null;
  createdAt?: string | null;
  lineItems?: BillLineItem[];
  approvals?: { name: string; status: string }[];
};

const money = (n: number) =>
  "$" + Number(n || 0).toLocaleString("en-US", { minimumFractionDigits: 2, maximumFractionDigits: 2 });

const fmtDate = (d?: string | null) => {
  if (!d) return "—";
  const x = new Date(d.length <= 10 ? d + "T12:00:00" : d);
  return isNaN(+x) ? "—" : x.toLocaleDateString("en-US", { year: "numeric", month: "short", day: "numeric" });
};

const cap = (s?: string | null) => (s ? s.charAt(0).toUpperCase() + s.slice(1) : "—");

export function generateBillSummaryPDF(bill: BillSummaryData): void {
  const doc = new jsPDF({ unit: "pt", format: "letter" });
  const W = doc.internal.pageSize.getWidth();
  const H = doc.internal.pageSize.getHeight();
  const M = 48;

  // Header bar
  doc.setFillColor(44, 62, 80);
  doc.rect(0, 0, W, 64, "F");
  doc.setTextColor(255, 255, 255);
  doc.setFont("helvetica", "bold");
  doc.setFontSize(18);
  doc.text("Bill Summary", M, 38);
  doc.setFont("helvetica", "normal");
  doc.setFontSize(9);
  doc.text(bill.association || "", W - M, 28, { align: "right" });
  doc.text("Generated: " + fmtDate(new Date().toISOString()), W - M, 44, { align: "right" });

  // Vendor
  let y = 98;
  doc.setTextColor(44, 62, 80);
  doc.setFont("helvetica", "bold");
  doc.setFontSize(15);
  doc.text(bill.vendor || "Vendor", M, y);
  y += 10;
  doc.setDrawColor(236, 240, 241);
  doc.setLineWidth(1);
  doc.line(M, y, W - M, y);
  y += 24;

  // Field grid
  const col2 = M + (W - 2 * M) / 2;
  const field = (label: string, value: string, x: number, yy: number) => {
    doc.setFont("helvetica", "bold");
    doc.setFontSize(9);
    doc.setTextColor(52, 73, 94);
    doc.text(label, x, yy);
    doc.setFont("helvetica", "normal");
    doc.setFontSize(11);
    doc.setTextColor(44, 62, 80);
    doc.text(value || "—", x, yy + 15);
  };
  field("Invoice #", bill.invoiceNumber || "—", M, y);
  field("Status", cap(bill.status), col2, y);
  y += 42;
  field("Bill Date", fmtDate(bill.billDate), M, y);
  field("Due Date", fmtDate(bill.dueDate), col2, y);
  y += 42;
  field("Expense Account", bill.account || "—", M, y);
  field("Submitted", fmtDate(bill.createdAt), col2, y);
  y += 46;

  // ── Line items table ───────────────────────────────────────────────
  const rawItems = (bill.lineItems ?? []).filter(
    (li) => li && (li.amount != null || (li.description ?? li.name)),
  );
  const items: BillLineItem[] = rawItems.length
    ? rawItems
    : [{ description: bill.description || bill.account || "Bill amount", quantity: null, unit_price: null, amount: bill.amount }];

  // Columns (right edges)
  const amtR = W - M;
  const unitR = amtR - 95;
  const qtyR = unitR - 70;
  const descX = M;
  const descW = qtyR - 70 - descX;

  doc.setFont("helvetica", "bold");
  doc.setFontSize(11);
  doc.setTextColor(44, 62, 80);
  doc.text("Line Items", M, y);
  y += 14;

  // table header
  doc.setFillColor(44, 62, 80);
  doc.rect(M, y, W - 2 * M, 20, "F");
  doc.setTextColor(255, 255, 255);
  doc.setFont("helvetica", "bold");
  doc.setFontSize(9);
  doc.text("Description", descX + 6, y + 14);
  doc.text("Qty", qtyR, y + 14, { align: "right" });
  doc.text("Unit Price", unitR, y + 14, { align: "right" });
  doc.text("Amount", amtR - 4, y + 14, { align: "right" });
  y += 20;

  doc.setFont("helvetica", "normal");
  doc.setTextColor(44, 62, 80);
  let itemsTotal = 0;
  for (const li of items) {
    const desc = (li.description ?? li.name ?? "—").toString();
    const lines = doc.splitTextToSize(desc, descW);
    const rowH = Math.max(18, lines.length * 12 + 6);
    if (y + rowH > H - 90) { doc.addPage(); y = M; }
    doc.setFontSize(10);
    doc.text(lines, descX + 6, y + 13);
    if (li.quantity != null) doc.text(String(li.quantity), qtyR, y + 13, { align: "right" });
    if (li.unit_price != null) doc.text(money(Number(li.unit_price)), unitR, y + 13, { align: "right" });
    const amt = Number(li.amount ?? 0);
    itemsTotal += amt;
    doc.text(money(amt), amtR - 4, y + 13, { align: "right" });
    doc.setDrawColor(236, 240, 241);
    doc.setLineWidth(0.5);
    doc.line(M, y + rowH, W - M, y + rowH);
    y += rowH;
  }

  // Total row (authoritative bill amount)
  y += 6;
  doc.setFont("helvetica", "bold");
  doc.setFontSize(12);
  doc.text("Total", unitR, y + 6, { align: "right" });
  doc.text(money(bill.amount), amtR - 4, y + 6, { align: "right" });
  y += 14;
  // Note if itemized lines don't sum to the bill total
  if (Math.abs(itemsTotal - Number(bill.amount)) > 0.01 && rawItems.length) {
    doc.setFont("helvetica", "italic");
    doc.setFontSize(8);
    doc.setTextColor(120, 120, 120);
    doc.text(`(line items subtotal ${money(itemsTotal)})`, amtR - 4, y + 8, { align: "right" });
    y += 12;
  }
  y += 14;

  // Approvals
  if (y > H - 110) { doc.addPage(); y = M; }
  doc.setDrawColor(236, 240, 241);
  doc.setLineWidth(1);
  doc.line(M, y, W - M, y);
  y += 22;
  doc.setFont("helvetica", "bold");
  doc.setFontSize(11);
  doc.setTextColor(44, 62, 80);
  doc.text("Board Approvals", M, y);
  y += 18;
  doc.setFontSize(10);
  const approvals = bill.approvals ?? [];
  if (approvals.length) {
    for (const a of approvals) {
      const mark = a.status === "approved" ? "[Approved]"
        : a.status === "denied" || a.status === "rejected" ? "[Denied]" : "[Pending]";
      doc.setFont("helvetica", "normal");
      doc.setTextColor(44, 62, 80);
      doc.text(`${mark}  ${a.name}`, M, y);
      y += 16;
    }
  } else {
    doc.setFont("helvetica", "italic");
    doc.setTextColor(120, 120, 120);
    doc.text("No approvers assigned.", M, y);
  }

  const slug = (bill.vendor || "bill").replace(/[^a-z0-9]+/gi, "-").toLowerCase().replace(/^-|-$/g, "");
  doc.save(`bill-summary-${slug}-${(bill.billDate || "").slice(0, 10) || "draft"}.pdf`);
}