import { useNavigate } from "react-router-dom";

import type { TodayDose, TodayPrescription } from "../api/types";
import { AppShell, Notice } from "../components/AppShell";
import { Icon, type IconName } from "../components/Icon";
import { useCatalog } from "../content/reference";
import { ru } from "../content/ru";
import { useDialog } from "../dialog/DialogContext";
import { classify } from "../dialog/step";
import { useSession } from "../session/SessionContext";
import { WeekDots } from "./Meds";
import { humanDate, useToday } from "./useToday";

// Spec «Модуль Лекарства»: the expected-effect card is pushed on these days of therapy.
const EFFECT_DAYS = [1, 7, 14];

function Task({
  icon,
  title,
  sub,
  hero,
  chip,
  onClick,
  disabled,
}: {
  icon: IconName;
  title: string;
  sub: string;
  hero?: boolean;
  chip?: string;
  onClick: () => void;
  disabled?: boolean;
}) {
  return (
    <button type="button" className={hero ? "task task--hero" : "task"} onClick={onClick} disabled={disabled}>
      <span className={hero ? "task__icon" : "task__icon task__icon--teal"}>
        <Icon name={icon} />
      </span>
      <span className="task__text">
        <span className="task__title">{title}</span>
        <span className="task__sub">{sub}</span>
      </span>
      {chip ? <span className="chip chip--teal-solid">{chip}</span> : <Icon name="chevronRight" />}
    </button>
  );
}

function VisitCard({ date, onOpen }: { date: string; onOpen: () => void }) {
  return (
    <button type="button" className="row-card" onClick={onOpen}>
      <span className="tile-icon tile-icon--blue">
        <Icon name="calendar" />
      </span>
      <span className="row-card__text">
        <span className="row-card__sub">{ru.today.visit}</span>
        <span className="row-card__title">{humanDate(date)}</span>
      </span>
      <Icon name="chevronRight" />
    </button>
  );
}

function WeekCard({ rx, onOpen }: { rx: TodayPrescription; onOpen: () => void }) {
  const taken = rx.week.filter((w) => w.status === "taken").length;
  const counted = rx.week.filter((w) => w.status !== "none").length;
  return (
    <button type="button" className="card weekcard" onClick={onOpen}>
      <span className="card__head">
        <span className="tile-icon tile-icon--teal">
          <Icon name="pill" />
        </span>
        <span className="row-card__text">
          <span className="row-card__sub">{ru.today.week}</span>
          <span className="row-card__title">{ru.today.weekTaken(taken, counted)}</span>
        </span>
        <Icon name="chevronRight" />
      </span>
      <WeekDots week={rx.week} />
    </button>
  );
}

// C1 / C2 · Сегодня
export function Today() {
  const t = ru.today;
  const navigate = useNavigate();
  const { session } = useSession();
  const dialog = useDialog();
  const { plan, failed } = useToday();
  const catalog = useCatalog();

  // An unanswered engine question (reminder, check-in, scale, unfinished onboarding) waits on the focus screen.
  const waiting = classify(dialog.pending);
  // A paused questionnaire is not an open step: the «continue the questionnaire» card below resumes it.
  const paused = waiting?.kind === "notice" && waiting.primary?.data === "intake:resume";
  const hasOpenStep = waiting !== null && waiting.kind !== "idle" && waiting.kind !== "ack" && !paused;
  const surveyItem = waiting?.kind === "survey" ? catalog?.items[waiting.itemId] : undefined;
  const surveyForm = surveyItem ? catalog?.forms[surveyItem.form] : undefined;

  const go = (button: string, label: string) =>
    void dialog.send({ type: "button", button }, label).then((ok) => ok && navigate("/flow"));

  // Questionnaires (stage 1 intake → stage 2 diary) replace the simple check-in once they are switched on.
  const q = plan?.questionnaires;
  const surveys = q?.enabled === true;
  const intakeOpen = surveys && q.intake !== "complete" && q.intake !== "review";
  const diaryDue = surveys && q.intake === "complete" && !q.diary_done;
  const effectRx = plan?.prescriptions.find((p) => p.ref_id && p.therapy_day && EFFECT_DAYS.includes(p.therapy_day));

  const pendingDoses = plan?.doses.filter((d) => d.status === "pending") ?? [];
  const takenDoses = plan?.doses.filter((d) => d.status === "taken") ?? [];
  const doseNow = pendingDoses.some((d) => d.time <= (plan?.now ?? "00:00"));
  const allDone =
    plan !== null &&
    pendingDoses.length === 0 &&
    plan.checkin_done &&
    !hasOpenStep &&
    !intakeOpen &&
    !diaryDue &&
    q?.intake !== "review";
  const nextDose = plan?.prescriptions.flatMap((p) => p.times).sort()[0];
  const noDoctor = session?.mode === "anonymous" || (plan !== null && !plan.has_doctor);

  const now = plan?.now ?? "00:00";
  const openDose = (d: TodayDose) => navigate(`/dose/${d.id}`);
  const visit = plan?.next_visit ? <VisitCard date={plan.next_visit} onOpen={() => navigate("/doctor")} /> : null;
  const hasDone = takenDoses.length > 0 || plan?.checkin_done;

  return (
    <AppShell aside={visit}>
      <div className="dash">
        <header className="today-head dash__head">
          <div>
            <h1 className="h1">{t.title}</h1>
            {plan && <p className="muted">{humanDate(plan.today)}</p>}
          </div>
          <button
            type="button"
            className="icon-btn icon-btn--bell"
            onClick={() => navigate("/messages")}
            aria-label={ru.nav.messages}
          >
            <Icon name="bell" />
            {dialog.unread > 0 && <span className="dot" />}
          </button>
        </header>

        {failed && <Notice tone="danger">{ru.common.networkError}</Notice>}

        <section className="dash__main" aria-label={t.title}>
          {hasOpenStep &&
            (waiting?.kind === "survey" ? (
              <Task
                hero
                icon={surveyForm?.section === "diary" ? "book" : "clipboard"}
                title={surveyForm?.section === "diary" ? t.diary : t.intakeResume}
                sub={t.intakeResumeHint}
                chip={t.continue}
                onClick={() => navigate("/flow")}
              />
            ) : (
              <Task
                hero
                icon="message"
                title={t.newMessage}
                sub={dialog.pending[0]?.text.split("\n")[0].slice(0, 90) ?? ""}
                chip={t.open}
                onClick={() => navigate("/flow")}
              />
            ))}

          {surveys && q.intake === "review" && <Notice>{t.intakeReview}</Notice>}

          {effectRx && (
            <button type="button" className="effect" onClick={() => navigate(`/meds/${effectRx.ref_id}`)}>
              <span className="effect__day">
                <span className="effect__num">{effectRx.therapy_day}</span>
                <span className="effect__unit">день</span>
              </span>
              <span className="task__text">
                <span className="task__title">{t.therapyDay(effectRx.therapy_day!)}</span>
                <span className="task__sub">{t.effectHint}</span>
              </span>
              <Icon name="chevronRight" />
            </button>
          )}

          {allDone ? (
            <div className="alldone">
              <span className="done__badge" aria-hidden="true">
                <Icon name="check" size={36} />
              </span>
              <h2 className="h2 center">{t.allDoneTitle}</h2>
              <p className="muted center">{nextDose ? t.allDoneNext(`завтра в ${nextDose}`) : t.allDoneNoMeds}</p>
              {plan && plan.prescriptions.length > 0 && (
                <button type="button" className="btn btn--primary btn--auto" onClick={() => navigate("/meds")}>
                  {t.viewMeds}
                  <Icon name="chevronRight" size={20} />
                </button>
              )}
            </div>
          ) : (
            <div className="tasks">
              {pendingDoses.map((d) => (
                <button
                  key={d.id}
                  type="button"
                  className={d.time <= now && !hasOpenStep ? "task task--hero" : "task"}
                  onClick={() => openDose(d)}
                >
                  <span className="task__icon task__icon--teal">
                    <Icon name="pill" />
                  </span>
                  <span className="task__text">
                    <span className="task__title">{t.takeMed}</span>
                    <span className="task__sub">
                      {d.time} · {d.drug}, {d.dose}
                    </span>
                  </span>
                  {d.time <= now && <span className="chip chip--teal-solid">{t.now}</span>}
                  <Icon name="chevronRight" />
                </button>
              ))}
              {intakeOpen && waiting?.kind !== "survey" && (
                <Task
                  hero={!hasOpenStep && !doseNow}
                  icon="clipboard"
                  title={t.intakeStart}
                  sub={q.intake === "none" ? t.intakeStartHint : t.intakeResumeHint}
                  chip={q.intake === "none" ? undefined : t.continue}
                  disabled={dialog.busy}
                  onClick={() =>
                    q.intake === "none" ? go("intake:start", t.intakeStart) : go("intake:resume", t.intakeResume)
                  }
                />
              )}
              {diaryDue && waiting?.kind !== "survey" && (
                <Task
                  icon="book"
                  title={q.diary_next ? t.diaryPart[q.diary_next] : t.diary}
                  sub={q.diary_next ? t.diaryPartHint[q.diary_next] : t.diaryHint}
                  disabled={dialog.busy}
                  onClick={() => go("menu:checkin", q.diary_next ? t.diaryPart[q.diary_next] : t.diary)}
                />
              )}
              {plan && !surveys && !plan.checkin_done && (
                <Task
                  icon="smile"
                  title={t.checkin}
                  sub={t.checkinHint}
                  disabled={dialog.busy}
                  onClick={() => go("menu:checkin", t.checkin)}
                />
              )}
            </div>
          )}

        </section>

        <section className="dash__side">
          {plan?.next_visit && (
            <div className="only-phone">
              <VisitCard date={plan.next_visit} onOpen={() => navigate("/doctor")} />
            </div>
          )}

          {!allDone && hasDone && (
            <div className="card">
              <h2 className="h3">{t.done}</h2>
              {takenDoses.map((d) => (
                <div key={d.id} className="done-row">
                  <span className="badge-icon badge-icon--teal">
                    <Icon name="check" size={16} />
                  </span>
                  <span>
                    <span className="done-row__title">{t.medTaken}</span>
                    <span className="done-row__sub">{t.medTakenAt(d.time)}</span>
                  </span>
                </div>
              ))}
              {plan?.checkin_done && (
                <div className="done-row">
                  <span className="badge-icon badge-icon--teal">
                    <Icon name="check" size={16} />
                  </span>
                  <span className="done-row__title">{surveys ? t.diaryDone : t.checkinDone}</span>
                </div>
              )}
            </div>
          )}

          {plan?.prescriptions[0] && <WeekCard rx={plan.prescriptions[0]} onOpen={() => navigate("/meds")} />}

          {noDoctor ? (
            <Notice>{t.noDoctor}</Notice>
          ) : (
            <div className="quick">
              <button
                type="button"
                className="quick__btn"
                onClick={() => go("menu:med_question", t.medQuestion)}
                disabled={dialog.busy}
              >
                <span className="tile-icon tile-icon--blue">
                  <Icon name="question" />
                </span>
                <span>
                  <span className="quick__title">{t.medQuestion}</span>
                  <span className="quick__sub">{t.medQuestionHint}</span>
                </span>
              </button>
              <button
                type="button"
                className="quick__btn"
                onClick={() => go("menu:contact_doctor", t.messageDoctor)}
                disabled={dialog.busy}
              >
                <span className="tile-icon tile-icon--blue">
                  <Icon name="message" />
                </span>
                <span>
                  <span className="quick__title">{t.messageDoctor}</span>
                  <span className="quick__sub">{t.messageDoctorHint}</span>
                </span>
              </button>
            </div>
          )}
        </section>
      </div>
    </AppShell>
  );
}