import { UNIT_LABELS } from "../lib/types";
import { computeLineAmount } from "../lib/invoice";
import { formatAmount, formatDate } from "../lib/format";
import type { InvoicePdfProps } from "../pdf/InvoiceDocument";

const money = (n: number) => `₹${formatAmount(n)}`;

/** On-screen preview that mirrors the exported PDF layout. */
export function InvoicePreview(props: InvoicePdfProps) {
  const {
    vendor,
    bank,
    logoDataUri,
    signatureDataUri,
    number,
    invoiceDate,
    dueDate,
    clientName,
    clientAddress,
    clientGstin,
    poNumber,
    placeOfSupplyStateCode,
    items,
    subtotal,
    discount,
    taxType,
    taxRate,
    cgst,
    sgst,
    igst,
    total,
    amountInWords,
    notes,
  } = props;

  const isTaxInvoice = taxType !== "none";
  const contact = [vendor.vendorEmail, vendor.vendorPhone].filter(Boolean).join("  ·  ");

  return (
    <div className="inv-preview-wrap">
      <div className="inv-paper">
        <div className="inv-top">
          <div className="inv-vendor">
            {logoDataUri ? <img className="inv-vendor__logo" src={logoDataUri} alt="" /> : null}
            <div>
              <h2 className="inv-vendor__name">{vendor.vendorName || "Vendor"}</h2>
              <p className="inv-vendor__line">{vendor.vendorAddress}</p>
              {contact ? <p className="inv-vendor__line">{contact}</p> : null}
              {vendor.vendorPan ? <p className="inv-vendor__line">PAN: {vendor.vendorPan}</p> : null}
              <p className="inv-vendor__line">GSTIN: {vendor.vendorGstin || "NA"}</p>
            </div>
          </div>
          <div className="inv-meta">
            <h3 className="inv-meta__title">{isTaxInvoice ? "Tax Invoice" : "Invoice"}</h3>
            <div className="inv-meta__row">
              <span className="inv-meta__label">Invoice No.</span>
              <span className="inv-meta__value">{number}</span>
            </div>
            <div className="inv-meta__row">
              <span className="inv-meta__label">Date</span>
              <span className="inv-meta__value">{formatDate(invoiceDate)}</span>
            </div>
            {dueDate ? (
              <div className="inv-meta__row">
                <span className="inv-meta__label">Due Date</span>
                <span className="inv-meta__value">{formatDate(dueDate)}</span>
              </div>
            ) : null}
          </div>
        </div>

        <div className="inv-split">
          <div className="inv-block" style={{ maxWidth: "60%" }}>
            <p className="inv-block__label">Billed To</p>
            <div className="inv-block__strong">{clientName || "—"}</div>
            {clientAddress ? <div style={{ whiteSpace: "pre-line" }}>{clientAddress}</div> : null}
            {clientGstin ? <div>GSTIN: {clientGstin}</div> : null}
            {placeOfSupplyStateCode ? <div>Place of Supply: {placeOfSupplyStateCode}</div> : null}
          </div>
          {poNumber ? (
            <div className="inv-block">
              <p className="inv-block__label">PO Number</p>
              <div className="inv-block__strong">{poNumber}</div>
            </div>
          ) : null}
        </div>

        <table className="inv-table">
          <thead>
            <tr>
              <th>Description</th>
              <th className="num">Unit Price</th>
              <th className="num">Qty</th>
              <th className="num">Total</th>
            </tr>
          </thead>
          <tbody>
            {items.map((item, index) => (
              <tr key={item.id ?? index}>
                <td>{item.description || "—"}</td>
                <td className="num">
                  {item.mode === "rate" ? `${money(item.rate)} ${UNIT_LABELS[item.unit]}` : "—"}
                </td>
                <td className="num">{item.mode === "rate" ? item.quantity : 1}</td>
                <td className="num">{money(computeLineAmount(item))}</td>
              </tr>
            ))}
          </tbody>
        </table>

        <div className="inv-totals">
          <div className="inv-totals__table">
            <div className="inv-totals__row">
              <span>Subtotal</span>
              <span>{money(subtotal)}</span>
            </div>
            {discount > 0 ? (
              <div className="inv-totals__row">
                <span>Discount</span>
                <span>- {money(discount)}</span>
              </div>
            ) : null}
            {taxType === "cgst_sgst" ? (
              <>
                <div className="inv-totals__row">
                  <span>CGST ({(taxRate / 2).toFixed(2)}%)</span>
                  <span>{money(cgst)}</span>
                </div>
                <div className="inv-totals__row">
                  <span>SGST ({(taxRate / 2).toFixed(2)}%)</span>
                  <span>{money(sgst)}</span>
                </div>
              </>
            ) : null}
            {taxType === "igst" ? (
              <div className="inv-totals__row">
                <span>IGST ({taxRate.toFixed(2)}%)</span>
                <span>{money(igst)}</span>
              </div>
            ) : null}
            <div className="inv-totals__row inv-totals__row--grand">
              <span>Total</span>
              <span>{money(total)}</span>
            </div>
          </div>
        </div>

        <p className="inv-words">Amount in words: {amountInWords}</p>

        {notes ? (
          <div style={{ marginTop: 16 }}>
            <p className="inv-block__label">Notes</p>
            <div style={{ whiteSpace: "pre-line" }}>{notes}</div>
          </div>
        ) : null}

        <div className="inv-bottom">
          <div className="inv-block" style={{ maxWidth: "55%" }}>
            {bank ? (
              <>
                <p className="inv-block__label">Pay To</p>
                <div className="inv-block__strong">{bank.accountName || vendor.vendorName}</div>
                <div>{bank.bankName}</div>
                {bank.accountNo ? <div>Account No.: {bank.accountNo}</div> : null}
                {bank.branch ? <div>Branch: {bank.branch}</div> : null}
                {bank.ifsc ? <div>IFSC: {bank.ifsc}</div> : null}
              </>
            ) : null}
          </div>
          <div className="inv-signature">
            {signatureDataUri ? (
              <>
                <img className="inv-signature__img" src={signatureDataUri} alt="Signature" />
                <div className="inv-signature__name">{vendor.vendorName}</div>
              </>
            ) : (
              <>
                <div className="inv-signature__name">{vendor.vendorName}</div>
                <p className="inv-fineprint">Computer-generated invoice; no signature is required.</p>
              </>
            )}
          </div>
        </div>

        <div className="inv-footer">
          <span>{vendor.vendorName}</span>
          <span>Generated with Voiced — a Bongbetic product</span>
        </div>
      </div>
    </div>
  );
}