"use client";

import { useCallback, useEffect, useMemo, useState } from "react";
import Link from "next/link";
import { createClient } from "@/lib/supabase/client";
import { addDays, formatDateLong, formatPrice, WEEKDAYS } from "@/lib/menu";
import type { Dish, MenuEntry, Section } from "@/lib/types";

export default function WeekEditor({ monday }: { monday: string }) {
  const supabase = useMemo(() => createClient(), []);
  const friday = addDays(monday, 4);
  const days = WEEKDAYS.map((weekday, i) => ({
    weekday,
    iso: addDays(monday, i),
  }));

  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 load = useCallback(async () => {
    setError(null);
    const [se, di, en] = await Promise.all([
      supabase.from("sections").select("*").order("sort"),
      supabase.from("dishes").select("*").order("name"),
      supabase
        .from("menu_entries")
        .select("id, menu_date, section_key, position, dish:dishes(id, name, price)")
        .gte("menu_date", monday)
        .lte("menu_date", friday)
        .order("position")
        .order("created_at"),
    ]);
    const problem = se.error ?? di.error ?? en.error;
    if (problem) {
      setError(`Laden fehlgeschlagen: ${problem.message}`);
    } else {
      setSections(se.data as Section[]);
      setDishes(di.data as Dish[]);
      setEntries(en.data as unknown as MenuEntry[]);
    }
    setLoading(false);
  }, [supabase, monday, friday]);

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

  async function addEntry() {
    if (!adding || !selectedDish) return;
    const { error } = await supabase.from("menu_entries").insert({
      menu_date: adding.iso,
      section_key: adding.section,
      dish_id: selectedDish,
    });
    if (error) {
      setError(
        /duplicate key/i.test(error.message)
          ? "Dieses Gericht ist an diesem Tag bereits zugewiesen."
          : `Speichern fehlgeschlagen: ${error.message}`
      );
    }
    setAdding(null);
    setSelectedDish("");
    await load();
  }

  async function removeEntry(id: string) {
    const { error } = await supabase.from("menu_entries").delete().eq("id", id);
    if (error) setError(`Löschen fehlgeschlagen: ${error.message}`);
    await load();
  }

  const cell = (iso: string, sectionKey: string) =>
    entries.filter((e) => e.menu_date === iso && e.section_key === sectionKey);

  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">
          Wochenplan
        </h1>
        <Link href={`/intern?woche=${addDays(monday, -7)}`} className="btn btn-add">
          ← Vorherige Woche
        </Link>
        <Link href={`/intern?woche=${addDays(monday, 7)}`} className="btn btn-add">
          Nächste Woche →
        </Link>
      </div>

      {error && (
        <p className="mb-3 text-sm text-[var(--c-del)]" role="alert">
          {error}
        </p>
      )}
      {loading ? (
        <p className="text-gray-500">Lade Wochenplan…</p>
      ) : (
        <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)}
                </th>
              ))}
            </tr>
          </thead>
          <tbody>
            {sections.map((s) => (
              <tr key={s.key}>
                <th className="section-head">
                  <div>{s.label}</div>
                  <div className="time">{s.time_range}</div>
                </th>
                {days.map((d) => {
                  const isAdding =
                    adding?.iso === d.iso && adding?.section === s.key;
                  return (
                    <td key={d.iso} className="cell">
                      {cell(d.iso, s.key).map((e) => (
                        <div key={e.id} className="dish">
                          <span className="font-bold">{e.dish.name}</span>
                          {" – "}
                          {formatPrice(e.dish.price)}
                          <div className="mt-1">
                            <button
                              type="button"
                              className="btn btn-del"
                              onClick={() => removeEntry(e.id)}
                            >
                              Löschen
                            </button>
                          </div>
                        </div>
                      ))}
                      {isAdding ? (
                        <div className="mt-2 space-y-1 text-left">
                          <select
                            className="input"
                            value={selectedDish}
                            onChange={(e) => setSelectedDish(e.target.value)}
                          >
                            <option value="">– Gericht wählen –</option>
                            {dishes.map((dish) => (
                              <option key={dish.id} value={dish.id}>
                                {dish.name} ({formatPrice(dish.price)})
                              </option>
                            ))}
                          </select>
                          <div className="flex gap-1 justify-center">
                            <button
                              type="button"
                              className="btn btn-add"
                              onClick={addEntry}
                              disabled={!selectedDish}
                            >
                              Hinzufügen
                            </button>
                            <button
                              type="button"
                              className="btn btn-neutral"
                              onClick={() => {
                                setAdding(null);
                                setSelectedDish("");
                              }}
                            >
                              Abbrechen
                            </button>
                          </div>
                        </div>
                      ) : (
                        <button
                          type="button"
                          className="btn btn-add mt-1"
                          onClick={() => {
                            setAdding({ iso: d.iso, section: s.key });
                            setSelectedDish("");
                          }}
                        >
                          Mahlzeit hinzufügen
                        </button>
                      )}
                    </td>
                  );
                })}
              </tr>
            ))}
          </tbody>
        </table>
      )}
      <p className="mt-4 text-sm text-gray-500">
        Neue Gerichte legst du unter{" "}
        <Link href="/intern/gerichte" className="underline">
          Gerichte
        </Link>{" "}
        an.
      </p>
    </div>
  );
}