"use client";

import { ArrowPathIcon, CalendarDaysIcon, FireIcon, SparklesIcon } from "@heroicons/react/24/outline";
import { useEffect, useMemo, useState } from "react";
import { todayKey } from "@/lib/hellth-data";
import { trpc } from "@/lib/trpc";

function fmt(value: number) {
  return Math.round(value).toLocaleString("de-DE");
}

function prognosis(balance: number) {
  if (balance >= 1000) return { label: "entspannt im Ziel", color: "text-emerald-700 bg-emerald-50" };
  if (balance >= -300) return { label: "gut steuerbar", color: "text-blue-700 bg-blue-50" };
  return { label: "leicht drüber - flexibel ausgleichen", color: "text-amber-700 bg-amber-50" };
}

type ExtraDraft = { extraCalories: string; note: string };

export default function WochenbudgetPage() {
  const utils = trpc.useUtils();
  const [selectedDate, setSelectedDate] = useState(todayKey());
  const [saved, setSaved] = useState(false);
  // Pro Tag eingeplanter Mehrbedarf ("Blocker"), bevor er verteilt wird.
  const [drafts, setDrafts] = useState<Record<string, ExtraDraft>>({});

  const summaryQuery = trpc.health.statsSummary.useQuery({ referenceDate: selectedDate });
  const summary = summaryQuery.data?.week ?? null;
  const prediction = summary ? prognosis(summary.balance) : null;

  const setExtrasMutation = trpc.health.setWeeklyExtras.useMutation({
    onSuccess: async () => {
      // Ohne Key-Filter invalidieren, damit Dashboard + Statistiken mitziehen.
      await utils.health.statsSummary.invalidate();
      await utils.health.overview.invalidate();
      setSaved(true);
      window.setTimeout(() => setSaved(false), 1500);
    },
  });

  // Entwurf aus den gespeicherten Tageswerten vorbefüllen, sobald die Woche geladen ist.
  useEffect(() => {
    if (!summary) return;
    setDrafts((current) => {
      const next: Record<string, ExtraDraft> = {};
      for (const day of summary.days) {
        next[day.date] = current[day.date] ?? {
          extraCalories: day.extraCalories ? String(day.extraCalories) : "",
          note: day.note ?? "",
        };
      }
      return next;
    });
  }, [summary]);

  const totalExtra = useMemo(
    () => Object.values(drafts).reduce((sum, draft) => sum + (Number(draft.extraCalories) || 0), 0),
    [drafts],
  );

  function updateDraft(date: string, patch: Partial<ExtraDraft>) {
    setDrafts((current) => ({ ...current, [date]: { ...current[date], ...patch } as ExtraDraft }));
  }

  function redistribute() {
    if (!summary) return;
    setExtrasMutation.mutate({
      weekStart: summary.weekStart,
      days: summary.days.map((day) => ({
        date: day.date,
        extraCalories: Math.max(0, Number(drafts[day.date]?.extraCalories) || 0),
        note: drafts[day.date]?.note?.trim() || null,
      })),
    });
  }

  if (!summary || !prediction) {
    return (
      <div className="mx-auto max-w-6xl space-y-5 pb-24">
        <section className="rounded-[2rem] bg-white p-6 shadow-sm ring-1 ring-gray-100">
          <p className="text-sm font-black text-gray-400">Wochenbudget wird geladen.</p>
        </section>
      </div>
    );
  }

  return (
    <div className="mx-auto max-w-6xl space-y-5 pb-24">
      <header className="rounded-[2rem] bg-white p-6 shadow-sm ring-1 ring-gray-100">
        <div className="flex flex-col gap-4 sm:flex-row sm:items-end sm:justify-between">
          <div>
            <p className="text-sm font-black uppercase text-[#0F766E]">Flexible Planung</p>
            <h1 className="mt-2 text-4xl font-black tracking-normal text-gray-950">Wochenbudget</h1>
            <p className="mt-3 max-w-2xl text-sm font-semibold text-gray-400">
              Trag pro Tag ein, wenn du mehr brauchst (z. B. Familienfeier +800). Mit
              „kcal neu verteilen" hebt Hellth Hub diese Tage an und gleicht den Rest der Woche
              gleichmäßig aus. Dein Wochenziel bleibt gleich.
            </p>
          </div>
          <input type="date" value={selectedDate} onChange={(event) => setSelectedDate(event.target.value || todayKey())} className="rounded-full border border-gray-200 px-4 py-3 text-sm font-bold" />
        </div>
      </header>

      <section className="grid gap-4 lg:grid-cols-4">
        <div className="rounded-[2rem] bg-white p-5 shadow-sm ring-1 ring-gray-100">
          <FireIcon className="h-8 w-8 text-orange-500" />
          <p className="mt-3 text-3xl font-black text-gray-950">{fmt(summary.baseBudget)}</p>
          <p className="text-sm font-bold text-gray-400">Wochenziel</p>
        </div>
        <div className="rounded-[2rem] bg-white p-5 shadow-sm ring-1 ring-gray-100">
          <CalendarDaysIcon className="h-8 w-8 text-blue-500" />
          <p className="mt-3 text-3xl font-black text-gray-950">{fmt(summary.eatenCalories)}</p>
          <p className="text-sm font-bold text-gray-400">gegessen/geplant</p>
        </div>
        <div className="rounded-[2rem] bg-white p-5 shadow-sm ring-1 ring-gray-100">
          <SparklesIcon className="h-8 w-8 text-emerald-500" />
          <p className="mt-3 text-3xl font-black text-gray-950">+{fmt(summary.activityCalories)}</p>
          <p className="text-sm font-bold text-gray-400">Sportbonus (Woche)</p>
        </div>
        <div className="rounded-[2rem] bg-white p-5 shadow-sm ring-1 ring-gray-100">
          <div className={`inline-flex rounded-full px-3 py-1 text-xs font-black ${prediction.color}`}>{prediction.label}</div>
          <p className="mt-3 text-3xl font-black text-gray-950">{fmt(summary.availableCalories)}</p>
          <p className="text-sm font-bold text-gray-400">noch verfügbar</p>
        </div>
      </section>

      <section className="rounded-[2rem] bg-white p-5 shadow-sm ring-1 ring-gray-100">
        <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
          <div>
            <h2 className="text-xl font-black text-gray-950">Tagesverteilung</h2>
            <p className="mt-1 text-sm font-semibold text-gray-400">
              {totalExtra > 0
                ? `${fmt(totalExtra)} kcal Mehrbedarf eingeplant – wird beim Verteilen auf die übrigen Tage ausgeglichen.`
                : "Trag bei einzelnen Tagen einen Mehrbedarf ein und verteile anschließend."}
            </p>
          </div>
          <button
            type="button"
            onClick={redistribute}
            disabled={setExtrasMutation.isPending}
            className="inline-flex items-center justify-center gap-2 rounded-2xl bg-gray-950 px-5 py-3 text-sm font-black text-white disabled:opacity-40"
          >
            <ArrowPathIcon className="h-5 w-5" />
            {setExtrasMutation.isPending ? "Verteile…" : "kcal neu verteilen"}
          </button>
        </div>

        <div className="mt-5 grid gap-3">
          {summary.days.map((day) => {
            const date = new Date(`${day.date}T12:00:00`);
            const over = day.eatenCalories > day.plannedCalories + day.activityCalories;
            const draft = drafts[day.date] ?? { extraCalories: "", note: "" };
            const isBlocker = (Number(draft.extraCalories) || 0) > 0;
            return (
              <div key={day.date} className={`grid gap-3 rounded-3xl p-4 md:grid-cols-[120px_1fr_150px_150px_110px] md:items-center ${isBlocker ? "bg-amber-50 ring-1 ring-amber-200" : "bg-gray-50"}`}>
                <div>
                  <p className="text-lg font-black text-gray-950">{date.toLocaleDateString("de-DE", { weekday: "short" })}</p>
                  <p className="text-xs font-bold text-gray-400">{date.toLocaleDateString("de-DE")}</p>
                </div>
                <div>
                  <div className="h-3 overflow-hidden rounded-full bg-white">
                    <div className={`h-full rounded-full ${over ? "bg-amber-500" : "bg-emerald-500"}`} style={{ width: `${Math.min(100, (day.eatenCalories / Math.max(1, day.plannedCalories + day.activityCalories)) * 100)}%` }} />
                  </div>
                  <p className="mt-2 text-sm font-bold text-gray-400">
                    {fmt(day.eatenCalories)} / {fmt(day.plannedCalories)} kcal
                    {day.activityCalories ? ` + ${fmt(day.activityCalories)} Sport` : ""}
                  </p>
                </div>
                <label className="flex items-center gap-2">
                  <span className="text-sm font-black text-gray-400">+</span>
                  <input
                    type="number"
                    inputMode="numeric"
                    min={0}
                    value={draft.extraCalories}
                    onChange={(event) => updateDraft(day.date, { extraCalories: event.target.value })}
                    placeholder="kcal"
                    className="w-full rounded-2xl border border-gray-200 px-3 py-3 text-sm font-bold"
                  />
                </label>
                <input
                  value={draft.note}
                  onChange={(event) => updateDraft(day.date, { note: event.target.value })}
                  placeholder="Anlass"
                  className="rounded-2xl border border-gray-200 px-3 py-3 text-sm font-bold"
                />
                <p className={`text-sm font-black ${day.balance >= 0 ? "text-emerald-700" : "text-amber-700"}`}>
                  {day.balance >= 0 ? "+" : ""}{fmt(day.balance)} kcal
                </p>
              </div>
            );
          })}
        </div>
      </section>

      {saved ? <div className="fixed bottom-24 left-1/2 z-50 -translate-x-1/2 rounded-full bg-emerald-600 px-5 py-3 text-sm font-black text-white shadow-lg">Gespeichert</div> : null}
    </div>
  );
}