import type {
  AllergyIntolerance,
  Appointment,
  Coverage,
  FamilyMemberHistory,
  MedicationStatement,
  Patient,
  RelatedPerson,
} from "fhir/r4";
import { getAllCommPreferences } from "../config/communicationPreferences";
import { isSelfPayCoverage } from "./coverageKind";

// A visit that already happened also answers "schedule your first appointment".
const SCHEDULED_APPOINTMENT_STATUSES = new Set<string>(["booked", "arrived", "checked-in", "fulfilled"]);

export type PatientSystemTaskChecklistItem = {
  id: string;
  label: string;
  completed: boolean;
};

export type PatientSystemTaskDefinition = {
  id: string;
  title: string;
  shortLabel: string;
  description: string;
  priority: "routine" | "high" | "urgent" | "asap";
  route: string;
  completed: boolean;
  progressCurrent: number;
  progressTotal: number;
  progressPercent: number;
  checklistItems?: PatientSystemTaskChecklistItem[];
};

export type PatientSystemTaskSummary = {
  completed: boolean;
  completedCount: number;
  totalCount: number;
  incompleteLabels: string[];
  tasks: PatientSystemTaskDefinition[];
};

type BuildPatientSystemTasksInput = {
  patient?: Patient;
  relatedPersons: RelatedPerson[];
  medicationStatements: MedicationStatement[];
  allergyIntolerances: AllergyIntolerance[];
  coverages: Coverage[];
  hasConfirmedNoCurrentMedications: boolean;
  hasConfirmedNoKnownAllergies: boolean;
  familyMemberHistories: FamilyMemberHistory[];
  hasConfirmedNoKnownFamilyHistory: boolean;
  hasConfirmedNoRelatedPersons?: boolean;
  appointments: Appointment[];
};

export const buildPatientSystemTasks = ({
  patient,
  relatedPersons,
  medicationStatements,
  allergyIntolerances,
  coverages,
  hasConfirmedNoCurrentMedications,
  hasConfirmedNoKnownAllergies,
  familyMemberHistories,
  hasConfirmedNoKnownFamilyHistory,
  hasConfirmedNoRelatedPersons = false,
  appointments,
}: BuildPatientSystemTasksInput): PatientSystemTaskDefinition[] => {
  const profileChecklistItems: PatientSystemTaskChecklistItem[] = [
    { id: "name", label: "Full name", completed: Boolean(patient?.name?.[0]) },
    // THESE CHECKLIST ITEMS ARE COMPUTED AND NEVER RENDERED TO A PATIENT. `PatientHomeBanner` - the
    // only consumer of these tasks - renders `task.title` and nothing else; `checklistItems` is read by
    // `OnboardingTaskFocus`, which belongs to the ORG onboarding and is fed by `ResolvedOrgTask`.
    // Found the hard way: messaging explanation was first put on the label below, where it
    // would never have been seen. It lives on the profile task's TITLE instead - see `profileTitle`.
    // Do not add patient-facing wording here expecting it to appear.
    { id: "birthDate", label: "Birth date", completed: Boolean(patient?.birthDate) },
    { id: "gender", label: "Gender", completed: Boolean(patient?.gender) },
    {
      id: "telecom",
      label: "Contact information",
      completed: Boolean(patient?.telecom?.length),
    },
    { id: "address", label: "Address", completed: Boolean(patient?.address?.length) },
  ];

  const profileCurrent = profileChecklistItems.filter((item) => item.completed).length;
  const profileTotal = profileChecklistItems.length;
  const profileCompleted = profileCurrent === profileTotal;
  // The title is all the band and the list show, so it names what is still missing.
  const PROFILE_GAP_WORDS: Record<string, string> = {
    name: "name", birthDate: "date of birth", gender: "gender", telecom: "contact details", address: "address",
  };
  const profileGaps = profileChecklistItems.filter((item) => !item.completed).map((item) => PROFILE_GAP_WORDS[item.id] ?? item.label);
  const profileGapList = profileGaps.length > 1
    ? `${profileGaps.slice(0, -1).join(", ")} and ${profileGaps[profileGaps.length - 1]}`
    : profileGaps[0];

  const hasRelatedPersons = relatedPersons.some(
    (relatedPerson) => relatedPerson.active !== false,
  );
  const relatedPersonsCompleted = hasRelatedPersons || hasConfirmedNoRelatedPersons;
  const hasMedicationHistory = medicationStatements.some(
    (medicationStatement) => medicationStatement.status !== "entered-in-error",
  );
  const medicationsCompleted =
    hasMedicationHistory || hasConfirmedNoCurrentMedications;
  const hasAllergyHistory = allergyIntolerances.some(
    (allergyIntolerance) =>
      allergyIntolerance.verificationStatus?.coding?.[0]?.code !== "entered-in-error",
  );
  const allergiesCompleted = hasAllergyHistory || hasConfirmedNoKnownAllergies;
  const hasFamilyHistory = familyMemberHistories.some(
    (familyMemberHistory) => familyMemberHistory.status !== "entered-in-error",
  );
  const familyHistoryCompleted = hasFamilyHistory || hasConfirmedNoKnownFamilyHistory;
  const hasAppointment = appointments.some((appointment) =>
    SCHEDULED_APPOINTMENT_STATUSES.has(appointment.status),
  );

  // A plan, or an explicit "uninsured". Self-pay is a per-visit choice at the desk, so a stored
  // self-pay record answers nothing.
  const coverageAnswered = coverages.some(
    (coverage) =>
      coverage.status === "active" &&
      !isSelfPayCoverage(coverage) &&
      !(coverage.period?.end && new Date(coverage.period.end) < new Date()),
  );

  // Completed once the patient has recorded ANY communication-channel decision (opt-in or explicit off).
  const communicationPreferencesSet =
    patient !== undefined && Object.keys(getAllCommPreferences(patient)).length > 0;

  return [
    {
      id: "system-first-appointment",
      title: "Schedule your first appointment",
      shortLabel: "First appointment",
      description: "Book a visit with your practice.",
      priority: "high",
      route: "/dashboard/my-appointments",
      completed: hasAppointment,
      progressCurrent: hasAppointment ? 1 : 0,
      progressTotal: 1,
      progressPercent: hasAppointment ? 100 : 0,
    },
    {
      id: "system-profile",
      // ADOLESCENT GATE FAILS CLOSED ON AN UNKNOWN AGE, and this title is the only place a
      // patient can find that out. Both the client nav and `isAdolescentPatientCaller` on the server hide
      // and refuse messaging when there is no usable `birthDate` - deliberately, so a missing field cannot
      // become a way to message as a minor. The server's own comment names the cost, *"an ADULT with no
      // birthDate on file loses messaging"*, and says it *"should surface loudly"*.
      // It surfaces loudly IN CLOUDWATCH. To the patient it surfaced as nothing at all - Messages and
      // Collaboration teams simply were not in the menu, with no explanation and no way to work out the
      // remedy, while being the only person who could apply it.
      // Observed in a browser 2026-08-19 on a brand-new adult patient with an empty date of birth.
      // It does NOT weaken the gate and must not be "fixed" by weakening it.
      // On the TITLE because that is the only field `PatientHomeBanner` renders - the first version of
      // this put it on the birth-date checklist item, which is computed and never shown.
      title: !patient?.birthDate
        ? "Complete your profile — your date of birth is what enables messages"
        : profileCompleted
          ? "Complete your profile"
          : `Complete your profile — add your ${profileGapList}`,
      shortLabel: "Profile",
      description: "Add your personal details and contact information.",
      priority: "high",
      route: "/dashboard/profile",
      completed: profileCompleted,
      progressCurrent: profileCurrent,
      progressTotal: profileTotal,
      progressPercent: Math.round((profileCurrent / profileTotal) * 100),
      checklistItems: profileChecklistItems,
    },
    {
      id: "system-related-persons",
      title: "Add family & caregivers",
      shortLabel: "Family & caregivers",
      description: "Add family members, caregivers, or emergency contacts.",
      priority: "routine",
      route: "/dashboard/related-persons",
      completed: relatedPersonsCompleted,
      progressCurrent: relatedPersonsCompleted ? 1 : 0,
      progressTotal: 1,
      progressPercent: relatedPersonsCompleted ? 100 : 0,
    },
    {
      id: "system-medications",
      title: "Add your medications",
      shortLabel: "Medications",
      description: "Document current medications before your visit.",
      priority: "routine",
      route: "/dashboard/patient/medications/medication-statements",
      completed: medicationsCompleted,
      progressCurrent: medicationsCompleted ? 1 : 0,
      progressTotal: 1,
      progressPercent: medicationsCompleted ? 100 : 0,
    },
    {
      id: "system-allergies",
      title: "Add your allergies",
      shortLabel: "Allergies",
      description: "Document known allergies or intolerances.",
      priority: "routine",
      route: "/dashboard/patient/clinical/allergy-intolerances",
      completed: allergiesCompleted,
      progressCurrent: allergiesCompleted ? 1 : 0,
      progressTotal: 1,
      progressPercent: allergiesCompleted ? 100 : 0,
    },
    {
      id: "system-insurance",
      title: "Add your insurance",
      shortLabel: "Insurance",
      description: "Add your insurance plan, or tell us you have none.",
      priority: "routine",
      route: "/dashboard/patient/insurance",
      completed: coverageAnswered,
      progressCurrent: coverageAnswered ? 1 : 0,
      progressTotal: 1,
      progressPercent: coverageAnswered ? 100 : 0,
    },
    {
      id: "system-family-history",
      title: "Add your family history",
      shortLabel: "Family history",
      description: "Document conditions that run in your family.",
      priority: "routine",
      route: "/dashboard/patient/clinical/family-history",
      completed: familyHistoryCompleted,
      progressCurrent: familyHistoryCompleted ? 1 : 0,
      progressTotal: 1,
      progressPercent: familyHistoryCompleted ? 100 : 0,
    },
    {
      id: "system-communication-preferences",
      title: "Set your communication preferences",
      shortLabel: "Notifications",
      description: "Choose whether Akashic can contact you by email or text message.",
      priority: "routine",
      route: "/dashboard/settings",
      completed: communicationPreferencesSet,
      progressCurrent: communicationPreferencesSet ? 1 : 0,
      progressTotal: 1,
      progressPercent: communicationPreferencesSet ? 100 : 0,
    },
  ];
};

// Which system setup-step tasks to show for the current view. On the patient overview the Outstanding/Completed
// tabs split them by completion, so a FINISHED setup step appears under Completed instead of silently vanishing
// ( / AHR-224 - completing profile/meds/allergies used to just drop the nudge, never surfacing it as
// done). On the full tasks page (no tabs) only the outstanding nudges show, as before.
export function selectSystemTasksForTab<T extends { completed: boolean }>(
  tasks: T[],
  isHomePage: boolean,
  taskTab: "outstanding" | "completed",
): T[] {
  if (!isHomePage) {
    return tasks.filter((task) => !task.completed);
  }
  return tasks.filter((task) =>
    taskTab === "completed" ? task.completed : !task.completed,
  );
}

export const summarizePatientSystemTasks = (
  tasks: PatientSystemTaskDefinition[],
): PatientSystemTaskSummary => {
  const completedCount = tasks.filter((task) => task.completed).length;

  return {
    completed: tasks.length > 0 && completedCount === tasks.length,
    completedCount,
    totalCount: tasks.length,
    incompleteLabels: tasks
      .filter((task) => !task.completed)
      .map((task) => task.shortLabel),
    tasks,
  };
};