"use client";

import { useCallback, useEffect, useState } from "react";
import Link from "next/link";
import {
  addDays,
  dishCodes,
  entriesFor,
  formatDateLong,
  formatPrice,
  mondayOf,
  todayISO,
  weekdayIndex,
} from "@/lib/menu";
import { formatMessage } from "@/lib/i18n/shared";
import { localized } from "@/lib/types";
import type { Dish, MenuEntry, Section } from "@/lib/types";
import { useDict, useLocale } from "@/components/i18n/LocaleProvider";

export default function WeekEditor({ monday }: { monday: string }) {
  const dict = useDict();
  const locale = useLocale();
  const friday = addDays(monday, 4);
  const days = dict.weekdays.long.map((weekday, i) => ({
    weekday,
    short: dict.weekdays.short[i],
    iso: addDays(monday, i),
  }));
  const isCurrentWeek = monday === mondayOf(todayISO());
  const todayIdx = isCurrentWeek ? weekdayIndex(todayISO()) : -1;

  const [sections, setSections] = useState<Section[]>([]);
  const [dishes, setDishes] = useState<Dish[]>([]);
  const [entries, setEntries] = useState<MenuEntry[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  // Zelle, in der gerade ein Gericht hinzugefügt wird
  const [adding, setAdding] = useState<{ iso: string; section: string } | null>(
    null
  );
  const [selectedDish, setSelectedDish] = useState("");
  const [dishSearch, setDishSearch] = useState("");
  // Mobil: ein Tag auf einmal statt aller fünf gleichzeitig
  const [selectedDayIdx, setSelectedDayIdx] = useState(todayIdx >= 0 ? todayIdx : 0);

  function startAdding(iso: string, section: string) {
    setAdding({ iso, section });
    setSelectedDish("");
    setDishSearch("");
  }

  function cancelAdding() {
    setAdding(null);
    setSelectedDish("");
    setDishSearch("");
  }

  const load = useCallback(async () => {
    setError(null);
    const [se, di, en] = await Promise.all([
      fetch("/api/sections"),
      fetch("/api/dishes"),
      fetch(`/api/menu-entries?from=${monday}&to=${friday}`),
    ]);
    if (!se.ok || !di.ok || !en.ok) {
      setError(formatMessage(dict.weekEditor.loadError, { message: "load failed" }));
    } else {
      setSections(await se.json());
      setDishes(await di.json());
      setEntries(await en.json());
    }
    setLoading(false);
  }, [monday, friday, dict]);

  useEffect(() => {
    setLoading(true);
    load();
  }, [load]);

  async function addEntry() {
    if (!adding || !selectedDish) return;
    const res = await fetch("/api/menu-entries", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        menu_date: adding.iso,
        section_key: adding.section,
        dish_id: selectedDish,
      }),
    });
    if (!res.ok) {
      const data = await res.json().catch(() => ({}));
      setError(
        data.error === "duplicate_entry"
          ? dict.weekEditor.duplicateEntry
          : formatMessage(dict.weekEditor.saveError, { message: data.error ?? String(res.status) })
      );
    }
    cancelAdding();
    await load();
  }

  async function removeEntry(id: string) {
    const res = await fetch(`/api/menu-entries/${id}`, { method: "DELETE" });
    if (!res.ok)
      setError(formatMessage(dict.weekEditor.deleteError, { message: String(res.status) }));
    await load();
  }

  const [hintBefore, hintAfter] = dict.weekEditor.newDishesHint.split("{link}");
  const selectedDishObj = dishes.find((d) => d.id === selectedDish) ?? null;
  const query = dishSearch.trim().toLowerCase();
  const filteredDishes = query
    ? dishes.filter((d) => localized(d, locale).toLowerCase().includes(query))
    : dishes;

  // Inhalt einer Tag/Essenszeit-Zelle: Eintragsliste + "hinzufügen"-Flow.
  // Identisches Fragment für Desktop-Tabelle und Mobile-Karten, damit der
  // Bearbeitungs-Zustand (adding/selectedDish/dishSearch) nicht dupliziert
  // werden muss – nur eine Zelle kann gleichzeitig bearbeitet werden,
  // unabhängig davon, welche Ansicht gerade rendert.
  function renderCell(iso: string, sectionKey: string) {
    const isAdding = adding?.iso === iso && adding?.section === sectionKey;
    return (
      <>
        {entriesFor(entries, iso, sectionKey).map((e) => {
          const codes = dishCodes(e.dish);
          return (
            <div key={e.id} className="dish">
              <span className="font-bold">{localized(e.dish, locale)}</span>
              {codes && <sup className="dish-codes">{codes}</sup>}
              {" – "}
              {formatPrice(e.dish.price)}
              <div className="mt-1">
                <button
                  type="button"
                  className="btn btn-del"
                  onClick={() => removeEntry(e.id)}
                >
                  {dict.common.delete}
                </button>
              </div>
            </div>
          );
        })}
        {isAdding ? (
          <div className="mt-2 space-y-1 text-left">
            {selectedDishObj ? (
              <div className="flex items-center gap-1 text-sm">
                <span className="mr-auto">
                  {localized(selectedDishObj, locale)} (
                  {formatPrice(selectedDishObj.price)})
                </span>
                <button
                  type="button"
                  className="text-gray-400 hover:text-[var(--c-primary)]"
                  onClick={() => {
                    setSelectedDish("");
                    setDishSearch("");
                  }}
                  aria-label={dict.weekEditor.changeDish}
                  title={dict.weekEditor.changeDish}
                >
                  ×
                </button>
              </div>
            ) : (
              <>
                <input
                  type="search"
                  className="input"
                  autoFocus
                  placeholder={dict.dishManager.searchPlaceholder}
                  value={dishSearch}
                  onChange={(e) => setDishSearch(e.target.value)}
                />
                <ul className="max-h-32 overflow-y-auto border border-gray-200 rounded-md bg-white divide-y divide-gray-100">
                  {filteredDishes.map((dish) => (
                    <li key={dish.id}>
                      <button
                        type="button"
                        className="w-full text-left px-2 py-1 text-sm hover:bg-[var(--c-row-bg-alt)]"
                        onClick={() => setSelectedDish(dish.id)}
                      >
                        {localized(dish, locale)} ({formatPrice(dish.price)})
                      </button>
                    </li>
                  ))}
                  {filteredDishes.length === 0 && (
                    <li className="px-2 py-1 text-sm text-gray-500">
                      {formatMessage(dict.dishManager.noResults, {
                        query: dishSearch,
                      })}
                    </li>
                  )}
                </ul>
              </>
            )}
            <div className="flex gap-1 justify-center">
              <button
                type="button"
                className="btn btn-add"
                onClick={addEntry}
                disabled={!selectedDish}
              >
                {dict.common.add}
              </button>
              <button type="button" className="btn btn-neutral" onClick={cancelAdding}>
                {dict.common.cancel}
              </button>
            </div>
          </div>
        ) : (
          <button
            type="button"
            className="btn btn-add mt-1"
            onClick={() => startAdding(iso, sectionKey)}
          >
            {dict.weekEditor.addMeal}
          </button>
        )}
      </>
    );
  }

  const selectedDay = days[selectedDayIdx];

  return (
    <div>
      <div className="flex flex-wrap items-center gap-3 mb-4">
        <h1 className="text-xl font-bold text-[var(--c-primary)] mr-auto">
          {dict.weekEditor.title}
        </h1>
        <Link href={`/intern?woche=${addDays(monday, -7)}`} className="btn btn-add">
          {dict.publicMenu.prevWeek}
        </Link>
        <Link
          href={`/intern?woche=${mondayOf(todayISO())}`}
          className="btn btn-primary"
        >
          {dict.publicMenu.today}
        </Link>
        <Link href={`/intern?woche=${addDays(monday, 7)}`} className="btn btn-add">
          {dict.publicMenu.nextWeek}
        </Link>
      </div>

      {error && (
        <p className="mb-3 text-sm text-[var(--c-del)]" role="alert">
          {error}
        </p>
      )}
      {loading ? (
        <p className="text-gray-500">{dict.weekEditor.loading}</p>
      ) : (
        <>
          {/* Mobil (< "sm"): ein Tag auf einmal, per Tabs gewählt */}
          <div className="sm:hidden">
            <div className="flex gap-1 mb-3">
              {days.map((d, i) => (
                <button
                  key={d.iso}
                  type="button"
                  onClick={() => setSelectedDayIdx(i)}
                  className={`flex-1 rounded-md py-1.5 text-sm font-semibold border transition-colors ${
                    i === selectedDayIdx
                      ? "bg-[var(--c-primary)] text-white border-[var(--c-primary)]"
                      : "bg-white text-gray-600 border-gray-200"
                  } ${i === todayIdx ? "ring-2 ring-[var(--c-accent)] ring-offset-1" : ""}`}
                >
                  {d.short}
                </button>
              ))}
            </div>
            <h2 className="font-bold text-[var(--c-primary)] mb-2">
              {selectedDay.weekday} · {formatDateLong(selectedDay.iso, dict.dateLocale)}
            </h2>
            <div className="space-y-3">
              {sections.map((s) => (
                <div key={s.key} className="rounded-md border border-gray-200 overflow-hidden">
                  <div className="bg-[var(--c-primary)] text-[var(--c-header-text)] px-3 py-1.5 text-sm">
                    <span className="font-semibold">{localized(s, locale)}</span>{" "}
                    <span className="opacity-80">· {s.time_range}</span>
                  </div>
                  <div className="bg-[var(--c-row-bg)] px-3 py-2 text-sm text-center">
                    {renderCell(selectedDay.iso, s.key)}
                  </div>
                </div>
              ))}
            </div>
          </div>

          {/* Ab "sm": klassische Wochentabelle */}
          <div className="hidden sm:block">
            <table className="menu-table">
              <thead>
                <tr>
                  <th className="section-head w-52" aria-hidden />
                  {days.map((d) => (
                    <th key={d.iso} className="day-head">
                      <span className="font-bold">{d.weekday}</span>
                      <br />
                      {formatDateLong(d.iso, dict.dateLocale)}
                    </th>
                  ))}
                </tr>
              </thead>
              <tbody>
                {sections.map((s) => (
                  <tr key={s.key}>
                    <th className="section-head">
                      <div>{localized(s, locale)}</div>
                      <div className="time">{s.time_range}</div>
                    </th>
                    {days.map((d) => (
                      <td key={d.iso} className="cell">
                        {renderCell(d.iso, s.key)}
                      </td>
                    ))}
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        </>
      )}
      <p className="mt-4 text-sm text-gray-500">
        {hintBefore}
        <Link href="/intern/gerichte" className="underline">
          {dict.weekEditor.newDishesLinkLabel}
        </Link>
        {hintAfter}
      </p>
    </div>
  );
}