import { formatMoney } from '../../utils/money';

// - how a receipt reads on the subscription page.
//
// The settled design's rule 11: receipts live in the product, and Stripe's portal keeps the payment
// method and cancellation only. The rendering decisions live here rather than in the page so they can be
// argued about - and mutation-tested - without a DOM.
//
// ONLY EXCEPTIONS EARN A WORD. Almost every receipt is paid, so a "Paid" chip on every row is a column
// of noise that trains the reader to skip the exact place an unpaid one would appear. Same rule the
// receptionist board settled on for its own queues.

/** The server's projection (`GET /R4/Stripe/invoices`). Deliberately the same shape, field for field. */
export interface Receipt {
    id: string;
    number?: string;
    /** ISO instant. */
    date: string;
    status: string;
    amountCents?: number;
    currency?: string;
    hostedUrl?: string;
    pdfUrl?: string;
}

export interface DescribedReceipt {
    label: string;
    /** Absent when the date could not be read - never the string "Invalid Date". */
    dateLabel?: string;
    /** Absent when the amount is unknown. Never "$0.00" for an amount we could not read. */
    amountLabel?: string;
    /** Absent for the ordinary paid case. Present only when the reader needs to act or know. */
    statusLabel?: string;
    documentUrl?: string;
}

/**
 * Our words for the Stripe states we understand. An unrecognised code returns nothing rather than
 * being shown raw - the same rule the FHIR status vocabulary follows. "uncollectible_retry" on a
 * practice's billing page reads as a system talking to itself.
 */
const STATUS_WORDS: Record<string, string> = {
    open: 'Due',
    void: 'Cancelled',
    uncollectible: 'Unpaid',
};

export function describeReceipt(receipt: Receipt): DescribedReceipt {
    const parsed = new Date(receipt.date);
    const dateLabel = Number.isNaN(parsed.getTime())
        ? undefined
        : parsed.toLocaleDateString(undefined, { day: 'numeric', month: 'long', year: 'numeric' });

    return {
        // Never the Stripe id as a fallback: `in_1KcZ...` is our support identifier, not something a
        // practice can reconcile against a bank statement. The date is what they would look for.
        label: receipt.number ?? (dateLabel ? `Receipt — ${dateLabel}` : 'Receipt'),
        dateLabel,
        amountLabel:
            typeof receipt.amountCents === 'number'
                ? formatMoney(receipt.amountCents, (receipt.currency ?? 'usd').toUpperCase())
                : undefined,
        statusLabel: STATUS_WORDS[receipt.status],
        // Stripe's invoice PDF is the bill: once paid it still reads "Amount due" and "Pay online". A paid
        // receipt opens the hosted page instead, which says it was paid and offers the receipt to download. Without
        // one it offers no document at all, never that PDF.
        documentUrl: receipt.status === 'paid'
            ? receipt.hostedUrl
            : receipt.pdfUrl ?? receipt.hostedUrl,
    };
}