"use client";

import { ArrowPathIcon, CalendarDaysIcon, FireIcon, SparklesIcon } from "@heroicons/react/24/outline";
import { 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" };
}

export default function WochenbudgetPage() {
  const utils = trpc.useUtils();
  const [selectedDate, setSelectedDate] = useState(todayKey());
  const [extraDate, setExtraDate] = useState(todayKey());
  const [extraCalories, setExtraCalories] = useState("800");
  const [saved, setSaved] = useState(false);

  const summaryQuery = trpc.health.statsSummary.useQuery({ referenceDate: selectedDate });
  const summary = summaryQuery.data?.week ?? null;
  const prediction = summary ? prognosis(summary.balance) : null;
  const upsertPlanMutation = trpc.health.upsertWeeklyCaloriePlan.useMutation({
    onSuccess: async () => {
      await utils.health.statsSummary.invalidate({ referenceDate: selectedDate });
      setSaved(true);
      window.setTimeout(() => setSaved(false), 1500);
    },
  });

  const dayByDate = useMemo(() => new Map((summary?.days ?? []).map((day) => [day.date, day])), [summary?.days]);

  function updatePlan(date: string, plannedCalories: number, note?: string) {
    upsertPlanMutation.mutate({
      date,
      plannedCalories: Math.max(800, Math.min(6000, Math.round(plannedCalories))),
      note: note ?? dayByDate.get(date)?.note ?? null,
    });
  }

  function applyRestaurantDistribution() {
    if (!summary) return;
    const extra = Math.max(0, Number(extraCalories) || 0);
    const days = summary.days;
    const targetDay = days.find((day) => day.date === extraDate);
    if (!targetDay) return;

    const otherDays = days.filter((day) => day.date !== extraDate);
    const savingPerOtherDay = otherDays.length ? Math.ceil(extra / otherDays.length) : 0;

    updatePlan(extraDate, targetDay.plannedCalories + extra, targetDay.note ?? "Restaurant / höherer Tag");
    for (const day of otherDays) {
      updatePlan(day.date, Math.max(1200, day.plannedCalories - savingPerOtherDay), day.note);
    }
  }

  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">
              Ein höherer Tag ist kein Problem. Hellth Hub verteilt den Ausgleich freundlich auf die Woche.
            </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</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">
        <h2 className="text-xl font-black text-gray-950">Tagesverteilung</h2>
        <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;
            return (
              <div key={day.date} className="grid gap-3 rounded-3xl bg-gray-50 p-4 md:grid-cols-[130px_1fr_160px_120px] md:items-center">
                <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` : ""}
                    {day.note ? ` - ${day.note}` : ""}
                  </p>
                </div>
                <input
                  type="number"
                  value={day.plannedCalories}
                  onChange={(event) => updatePlan(day.date, Number(event.target.value) || summary.dailyGoal, day.note)}
                  className="rounded-2xl border border-gray-200 px-4 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>

      <section className="rounded-[2rem] bg-white p-5 shadow-sm ring-1 ring-gray-100">
        <h2 className="text-xl font-black text-gray-950">Restaurantbesuch einplanen</h2>
        <p className="mt-1 text-sm font-semibold text-gray-400">
          Beispiel: Samstag +800 kcal. Die App verteilt den Ausgleich auf die restlichen Tage.
        </p>
        <div className="mt-4 grid gap-3 md:grid-cols-[1fr_160px_180px]">
          <input type="date" value={extraDate} onChange={(event) => setExtraDate(event.target.value)} className="rounded-2xl border border-gray-200 px-4 py-3 text-sm font-bold" />
          <input value={extraCalories} onChange={(event) => setExtraCalories(event.target.value)} placeholder="+ kcal" className="rounded-2xl border border-gray-200 px-4 py-3 text-sm font-bold" />
          <button type="button" onClick={applyRestaurantDistribution} disabled={upsertPlanMutation.isPending} className="inline-flex items-center justify-center gap-2 rounded-2xl bg-gray-950 px-4 py-3 text-sm font-black text-white disabled:opacity-40">
            <ArrowPathIcon className="h-5 w-5" />
            Verteilen
          </button>
        </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>
  );
}