// Shared utilities for working with the helix-engage Doctor entity
// after the multi-clinic visit-slot rework. The doctor data model
// changed from { clinic: RELATION, visitingHours: TEXT } to many
// DoctorVisitSlot records (one per day-of-week × clinic), so every
// service that fetches doctors needs to:
//
//   1. Query `visitSlots { dayOfWeek startTime endTime clinic { id clinicName } }`
//      instead of the legacy flat fields.
//   2. Fold the slots back into a "where do they visit" summary string
//      and a list of unique clinics for branch-matching.
//
// This file provides:
//
//   - DOCTOR_VISIT_SLOTS_FRAGMENT: a string fragment that callers can
//     splice into their `doctors { edges { node { ... } } }` query so
//     the field selection stays consistent across services.
//
//   - normalizeDoctor(d): takes the raw GraphQL node and returns the
//     same object plus three derived fields:
//       * `clinics: { id, clinicName }[]` — unique list of clinics
//         the doctor visits, deduped by id.
//       * `clinic: { clinicName } | null` — first clinic for legacy
//         consumers that only show one (the AI prompt KB, etc.).
//       * `visitingHours: string` — pre-formatted summary like
//         "Mon 09:00-13:00 (Koramangala) · Wed 14:00-18:00 (Indiranagar)"
//         suitable for inlining into AI prompts.
//
// Keeping the legacy field names (`clinic`, `visitingHours`) on the
// normalized object means call sites that previously read those
// fields keep working — only the GraphQL query and the call to
// normalizeDoctor need to be added.

export type RawDoctorVisitSlot = {
    dayOfWeek?: string | null;
    startTime?: string | null;
    endTime?: string | null;
    clinic?: { id?: string | null; clinicName?: string | null } | null;
};

export type RawDoctor = {
    id?: string;
    name?: string | null;
    fullName?: { firstName?: string | null; lastName?: string | null } | null;
    department?: string | null;
    specialty?: string | null;
    visitSlots?: { edges?: Array<{ node: RawDoctorVisitSlot }> } | null;
    [key: string]: any;
};

// Tightened shape — `id` and `name` are always strings (with sensible
// fallbacks) so consumers can assign them to typed maps without
// "string | undefined" errors. The remaining fields keep their
// nullable nature from RawDoctor.
export type NormalizedDoctor = Omit<RawDoctor, 'id' | 'name'> & {
    id: string;
    name: string;
    clinics: Array<{ id: string; clinicName: string }>;
    clinic: { clinicName: string } | null;
    visitingHours: string;
};

// GraphQL fragment for the visit-slots reverse relation. Spliced into
// each doctors query so all services fetch the same shape. Capped at
// 20 slots per doctor — generous for any realistic schedule (7 days
// × 2-3 clinics).
export const DOCTOR_VISIT_SLOTS_FRAGMENT = `visitSlots(first: 20) {
    edges { node {
        dayOfWeek startTime endTime
        clinic { id clinicName }
    } }
}`;

const DAY_ABBREV: Record<string, string> = {
    MONDAY: 'Mon',
    TUESDAY: 'Tue',
    WEDNESDAY: 'Wed',
    THURSDAY: 'Thu',
    FRIDAY: 'Fri',
    SATURDAY: 'Sat',
    SUNDAY: 'Sun',
};

const formatTime = (t: string | null | undefined): string => {
    if (!t) return '';
    // Times come in as "HH:MM" or "HH:MM:SS" — strip seconds for
    // display compactness.
    return t.length > 5 ? t.slice(0, 5) : t;
};

// Best-effort doctor name derivation — prefer the platform's `name`
// field, then fall back to the composite fullName, then to a generic
// label so consumers never see undefined.
const deriveName = (raw: RawDoctor): string => {
    if (raw.name && raw.name.trim()) return raw.name.trim();
    const first = raw.fullName?.firstName?.trim() ?? '';
    const last = raw.fullName?.lastName?.trim() ?? '';
    const full = `${first} ${last}`.trim();
    if (full) return full;
    return 'Unknown doctor';
};

export const normalizeDoctor = (raw: RawDoctor): NormalizedDoctor => {
    const slots = raw.visitSlots?.edges?.map((e) => e.node) ?? [];

    // Unique clinics, preserving the order they were encountered.
    const seen = new Set<string>();
    const clinics: Array<{ id: string; clinicName: string }> = [];
    for (const slot of slots) {
        const id = slot.clinic?.id;
        const name = slot.clinic?.clinicName;
        if (!id || !name || seen.has(id)) continue;
        seen.add(id);
        clinics.push({ id, clinicName: name });
    }

    // Visiting hours summary — `Day HH:MM-HH:MM (Clinic)` joined by
    // " · ". Slots without a clinic or without a day get dropped.
    const segments: string[] = [];
    for (const slot of slots) {
        const day = slot.dayOfWeek ? (DAY_ABBREV[slot.dayOfWeek] ?? slot.dayOfWeek) : null;
        const start = formatTime(slot.startTime);
        const end = formatTime(slot.endTime);
        const clinic = slot.clinic?.clinicName;
        if (!day || !start || !clinic) continue;
        segments.push(`${day} ${start}${end ? `-${end}` : ''} (${clinic})`);
    }

    return {
        ...raw,
        id: raw.id ?? '',
        name: deriveName(raw),
        clinics,
        // Bridge field — first clinic, so legacy consumers that read
        // `d.clinic.clinicName` keep working.
        clinic: clinics.length > 0 ? { clinicName: clinics[0].clinicName } : null,
        visitingHours: segments.join(' · '),
    };
};

// Convenience: normalize an array of raw GraphQL nodes in one call.
export const normalizeDoctors = (raws: RawDoctor[]): NormalizedDoctor[] => raws.map(normalizeDoctor);

// Branch-matching helper: a doctor "matches" a branch if any of their
// visit slots is at a clinic whose name contains the branch substring
// (case-insensitive). Used by widget chat tools to filter doctors by
// the visitor's selected branch.
export const doctorMatchesBranch = (d: NormalizedDoctor, branch: string | undefined | null): boolean => {
    if (!branch) return true;
    const needle = branch.toLowerCase();
    return d.clinics.some((c) => c.clinicName.toLowerCase().includes(needle));
};