// / D3 - the three sentences the three levels say, all built from ONE `CountingView`.
//
// | level | the question it answers | example |
// |---|---|---|
// | strip | *is there anything I have not seen?* | `6 unread messages - oldest 3d` |
// | row | *is this the only one of these?* | `+ 2 more tasks - 1 form, 1 to review` |
// | tier | *what else is in here?* | `+ 4 more this week` |
//
// These take a `CountingView`, never raw arrays - so a surface cannot quietly count one thing and
// describe another. That is the defect (B14 - B16 - B28 - B43), and the type signature is what forbids it.
import { formatMoney } from '../money';
import type { CountingView } from './countingSelector';

/**
 * D3: **counts carry an AGE wherever neglect is possible.** "6 unread" says how many; "oldest 3d" says
 * whether you are failing. A bare count becomes wallpaper once it never reaches zero.
 *
 * The age is omitted below 1 day rather than shown as "0d": today's items are not neglect, and a
 * permanent "oldest 0d" is exactly the wallpaper this rule exists to avoid.
 */
export function stripText(view: CountingView, noun: string, pluralNoun?: string): string {
    if (view.total === 0) return '';

    const word = view.total === 1 ? noun : (pluralNoun ?? `${noun}s`);
    const age = view.oldestDays !== undefined && view.oldestDays >= 1
        ? ` · oldest ${view.oldestDays}d`
        : '';

    return `${view.total} ${word}${age}`;
}

export interface PeerTextOptions {
    /** "task" / "invoice" - singularised by `total`, not by `more`. */
    noun: string;
    pluralNoun?: string;
    /**
 * D3 - staff peer counts group BY PERSON, not by type: *"1 more for Alice - records authorization
 * expired"*, because the front desk should handle everything for one patient in one interaction.
 */
    groupByPerson?: boolean;
    /** D3 - invoice peer counts carry the aggregate: the total is the question a patient actually has. */
    withTotal?: boolean;
}

/**
 * The row-level *"is this the only one of these?"*.
 *
 * **The single hidden item is NAMED** - *"1 more for Alice - records authorization expired"* rather
 * than *"1 more"*. D3 calls that the line between signposted and buried, and it is the difference
 * between a count that helps and a count that only admits something is missing.
 */
export function peerText(view: CountingView, options: PeerTextOptions): string {
    if (view.more === 0) return '';

    const { noun, pluralNoun, groupByPerson = false, withTotal = false } = options;
    const word = view.more === 1 ? noun : (pluralNoun ?? `${noun}s`);

    let lead = `+ ${view.more} more ${word}`;

    if (groupByPerson) {
        const names = [...new Set(view.hidden.map((item) => item.personName).filter(Boolean))];
        // Only when the hidden set is ONE person: "1 more for Alice and Bob" reads as one item shared
        // between them. With several people the plain count is the honest sentence.
        if (names.length === 1) lead = `${view.more} more for ${names[0]}`;
    }

    const detail: string[] = [];

    // Name the item when there is exactly one - the whole point of the rule. With several, listing them
    // reproduces the list the count is standing in for.
    if (view.more === 1 && view.hidden[0]?.label) {
        detail.push(view.hidden[0].label);
    }

    if (withTotal && view.totalCents !== undefined) {
        // `formatMoney` already takes integer CENTS ("28500 -> $285.00"). Dividing here first produced
        // "$1.65" for $165.00 - a double conversion that reads as a plausible price, which is exactly the
        // kind of wrong number a reader cannot spot. The field name carries the unit; trust it.
        detail.push(`${formatMoney(view.totalCents)} owed in total`);
    }

    return detail.length > 0 ? `${lead} · ${detail.join(', ')}` : lead;
}

/**
 * The end-of-tier *"what else is in here?"* - `+ 4 more this week`.
 * `scopeLabel` is the tier's own words, so the sentence stays true to what the tier actually holds.
 */
export function tierText(view: CountingView, scopeLabel: string): string {
    if (view.more === 0) return '';
    return `+ ${view.more} more ${scopeLabel}`;
}