import type { Organization } from 'fhir/r4';

// (telehealth booking S3, client half) - mirrors
// aws/sam/services/api/src/utils/appointmentPolicy.ts.
//
// The OUTERMOST of telehealth's three gates: does this practice offer video visits at all? (The other
// two are per-service - - and per-schedule-block, S4 half.)
//
// Deliberately shaped like appointmentReminderPolicy.ts, its sibling in this folder, because the server
// module it mirrors is deliberately shaped like the reminder one. Keeping the two families parallel is
// what makes a drift between plugin and server visible.
//
// SCOPE, and please keep it: the server file is the home for future appointment policy (booking horizon,
// lead time, cancellation window), but today it carries ONE field. An empty policy framework is scope
// nobody asked for.

export interface AppointmentPolicy {
    telehealthEnabled: boolean;
}

/**
 * `telehealthEnabled: false` is deliberate, and it is the same reasoning as the reminder policy's
 * `enabled: false`: deploying a feature must not switch it on for every practice. An org that has never
 * opened this page is not offering video visits. Same posture as S2's absent-extension rule.
 */
export const DEFAULT_APPOINTMENT_POLICY: AppointmentPolicy = {
    telehealthEnabled: false,
};

// There is no GET /R4/appointment-policy-settings - the org's saved policy travels only on the
// Organization resource, as this extension. The server WRITES this exact URL (setAppointmentPolicy in
// its own copy of this file); the plugin READS it back here, so the literal MUST match byte for byte.
// A drifted character reads as "never saved" forever: the org sets telehealth on, the server stores it,
// and every booking surface still sees it off.
export const ORG_APPOINTMENT_POLICY_EXTENSION_URL =
    'https://akashichealthrecords.com/fhir/StructureDefinition/organization-appointment-policy';

const TELEHEALTH_ENABLED_SUB_URL = 'telehealthEnabled';

/**
 * Pure reader - mirrors the server's resolveEffectiveAppointmentPolicy exactly (same extension URL,
 * same child url), so every surface seeds from whatever the org last saved. Falls back to
 * DEFAULT_APPOINTMENT_POLICY when the org has never saved a policy, same as the server default.
 *
 * The `=== true` is not redundant: it fails CLOSED on a non-boolean. The server's validator rejects
 * those, but a resource written by another path or an older build could still carry one, and a truthy
 * string reading as ON is a trap this codebase has already been bitten by.
 */
export function resolveOrgAppointmentPolicy(organization?: Organization | null): AppointmentPolicy {
    const ext = organization?.extension?.find((e) => e.url === ORG_APPOINTMENT_POLICY_EXTENSION_URL);
    if (!ext) return { ...DEFAULT_APPOINTMENT_POLICY };

    const telehealth = (ext.extension ?? []).find((e) => e.url === TELEHEALTH_ENABLED_SUB_URL);
    return {
        telehealthEnabled: telehealth?.valueBoolean === true,
    };
}