import type { SubscriptionDunning } from '../../services/BillingContext.tsx';

// What a failing card SAYS, and who sees it.
//
// Spencer, 2026-08-14: *"a warning message at the top of admin view... if the card has already failed
// as well as 1 retry then a warning should appear at the [top] of all staff views so everyone is aware
// the subscription is about to expire and the system will stop working."*
//
// THE COPY IS THE FEATURE, so it is a pure function. The two audiences need different sentences and
// the difference is not tone - it is what the reader can DO. An admin is told to fix a card. A
// receptionist cannot fix a card, so telling them to would be useless; they are told what is about to
// happen to their work and who to tell.

export interface SubscriptionWarning {
    /** `error` once the whole practice is being told - this is no longer a routine reminder. */
    severity: 'warning' | 'error';
    message: string;
    /** FALSE at the all-staff stage: a banner about the system stopping is not one to wave away. */
    dismissible: boolean;
    /** Only the people who can act on it get a link to act. */
    actionHref?: string;
    actionLabel?: string;
}

const daysPhrase = (days: number | undefined): string =>
    // No invented number. "expires in 7 days" made up from nothing is a false statement a practice
    // will act on - the costliest form of this codebase's recurring defaulting mistake, because it is
    // acted on rather than merely read.
    days === undefined
        ? 'soon'
        : days === 0
            ? 'today'
            : days === 1
                ? 'tomorrow'
                : `in ${days} days`;

/**
 * A practice whose subscription a contractor pays, and who owns it as read for this viewer: the viewer, someone
 * else, nobody yet, or not known. Only an accepted owner may take billing back.
 */
export interface SponsoredBilling {
    owner: 'viewer' | 'other' | 'none' | 'unknown';
}

/** Where the contractor-access panel, and its existing Take billing back control, opens. */
export const TAKE_BILLING_BACK_HREF = '#/dashboard/organization/account?panel=agency';
const PRACTICE_ACCOUNT_HREF = '#/dashboard/organization/account';

/**
 * An administrator of a contractor-paid practice cannot fix the contractor's card, so they are told who handles it
 * and given the remedy they actually have. Nothing here buys anything: the link only opens the existing control.
 */
function sponsoredWarning(dunning: SubscriptionDunning, sponsorship: SponsoredBilling): SubscriptionWarning {
    const lead = 'The contractor-paid subscription for this practice needs billing attention';
    const consequence = dunning.stage === 'stopped'
        ? `${lead}, so paid add-ons are off. The core system keeps working.`
        : `${lead}, and paid add-ons switch off ${daysPhrase(dunning.daysRemaining)} if it isn’t settled.`;
    const remedy = {
        viewer: { text: 'You own this practice, so you can take billing back from the contractor.', actionHref: TAKE_BILLING_BACK_HREF, actionLabel: 'Take billing back' },
        other: { text: 'Contact the practice owner or the contractor.' },
        none: { text: 'This practice has no owner yet, and only an owner can take billing back. Set one up under Practice account.', actionHref: PRACTICE_ACCOUNT_HREF, actionLabel: 'Practice account' },
        unknown: { text: 'The contractor handles this practice’s billing.' },
    }[sponsorship.owner];
    return {
        severity: dunning.stage === 'admin-only' ? 'warning' : 'error',
        message: `${consequence} ${remedy.text}`,
        dismissible: dunning.stage === 'admin-only',
        ...('actionHref' in remedy ? { actionHref: remedy.actionHref, actionLabel: remedy.actionLabel } : {}),
    };
}

/**
 * The banner for this viewer, or null when there is nothing to say to them.
 *
 * `isAdmin` decides only whether the ADMIN-ONLY stage is shown; once the stage widens, everyone sees it.
 * `sponsorship`, for an administrator of a contractor-paid practice, replaces the payment-method remedy.
 */
export function resolveSubscriptionWarning(
    dunning: SubscriptionDunning | null | undefined,
    isAdmin: boolean,
    sponsorship?: SponsoredBilling,
): SubscriptionWarning | null {
    if (!dunning || dunning.stage === 'none') return null;
    if (isAdmin && sponsorship) return sponsoredWarning(dunning, sponsorship);

    if (dunning.stage === 'stopped') {
        // Stopped is also a live subscription whose payment is overdue, so it never claims the subscription ended.
        return {
            severity: 'error',
            message: isAdmin
                ? 'Your subscription needs attention, so paid add-ons are off. The core system keeps working. Update your payment method to restore them.'
                : 'This practice’s subscription needs attention, so paid add-ons are off. The core system keeps working. Please let an administrator know.',
            dismissible: false,
            ...(isAdmin ? { actionHref: '#/dashboard/subscription', actionLabel: 'Update payment method' } : {}),
        };
    }

    if (dunning.stage === 'admin-only') {
        // Nobody but an admin. A receptionist can do nothing about a card, and a banner they cannot
        // act on is one they learn to ignore - which is precisely the banner we need them to READ at the
        // next stage. Spending their attention here is what makes the real warning worthless.
        if (!isAdmin) return null;
        return {
            severity: 'warning',
            message: `We couldn’t take payment for your subscription. We’ll try again, but paid add-ons switch off ${daysPhrase(dunning.daysRemaining)} if it isn’t settled.`,
            // Dismissible at this stage: it is a reminder to one person who can act on it today.
            dismissible: true,
            actionHref: '#/dashboard/subscription',
            actionLabel: 'Update payment method',
        };
    }

    // all-staff - the card has failed and a retry has failed too.
    return {
        severity: 'error',
        message: isAdmin
            ? `Payment has failed more than once. This practice’s paid add-ons switch off ${daysPhrase(dunning.daysRemaining)} — update your payment method to keep them.`
            // Says what stops, not that a payment failed; whose card it is, a receptionist does not need.
            : `This practice’s subscription payment has failed and paid add-ons switch off ${daysPhrase(dunning.daysRemaining)}. The core system keeps working. Please tell an administrator.`,
        // NOT dismissible. Everyone is being told because features they use are about to stop;
        // a warning you can wave away is one that is gone by the morning it matters.
        dismissible: false,
        ...(isAdmin ? { actionHref: '#/dashboard/subscription', actionLabel: 'Update payment method' } : {}),
    };
}