"use client";

// Verwaltung der Essenszeiten (Brotzeit, Mittagessen, …):
// anlegen, umbenennen, Uhrzeit ändern, löschen, Reihenfolge anpassen.

import { useCallback, useEffect, useMemo, useState } from "react";
import { createClient } from "@/lib/supabase/client";
import { formatMessage } from "@/lib/i18n/shared";
import { localized } from "@/lib/types";
import type { Section } from "@/lib/types";
import { useDict, useLocale } from "@/components/i18n/LocaleProvider";

interface SectionForm {
  key: string | null; // null = neue Essenszeit
  label: string;
  labelEn: string;
  labelPl: string;
  timeFrom: string;
  timeTo: string;
}

const EMPTY_FORM: SectionForm = {
  key: null,
  label: "",
  labelEn: "",
  labelPl: "",
  timeFrom: "",
  timeTo: "",
};

function splitTimeRange(range: string): { from: string; to: string } {
  const [from, to] = range.split("-").map((s) => s.trim());
  return { from: from ?? "", to: to ?? "" };
}

export default function SectionManager() {
  const supabase = useMemo(() => createClient(), []);
  const dict = useDict();
  const locale = useLocale();
  const [sections, setSections] = useState<Section[]>([]);
  const [form, setForm] = useState<SectionForm | null>(null);
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);
  const [busy, setBusy] = useState(false);

  const load = useCallback(async () => {
    const { data, error } = await supabase.from("sections").select("*").order("sort");
    if (error)
      setError(formatMessage(dict.sectionManager.loadError, { message: error.message }));
    else setSections(data as Section[]);
    setLoading(false);
  }, [supabase, dict]);

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

  async function save(e: React.FormEvent) {
    e.preventDefault();
    if (!form) return;
    setError(null);
    const label = form.label.trim();
    if (!label || !form.timeFrom || !form.timeTo) return;
    const payload = {
      label,
      label_en: form.labelEn.trim() || null,
      label_pl: form.labelPl.trim() || null,
      time_range: `${form.timeFrom} - ${form.timeTo}`,
    };

    let dbError;
    if (form.key) {
      ({ error: dbError } = await supabase
        .from("sections")
        .update(payload)
        .eq("key", form.key));
    } else {
      // Frisch aus der DB lesen statt den lokalen State zu nutzen, damit
      // ein veralteter Snapshot nicht zu doppelten sort-Werten führt.
      const { data: maxRow } = await supabase
        .from("sections")
        .select("sort")
        .order("sort", { ascending: false })
        .limit(1)
        .maybeSingle();
      ({ error: dbError } = await supabase
        .from("sections")
        .insert({ ...payload, sort: (maxRow?.sort ?? 0) + 1 }));
    }
    if (dbError) {
      setError(formatMessage(dict.sectionManager.saveError, { message: dbError.message }));
      return;
    }
    setForm(null);
    await load();
  }

  async function remove(section: Section) {
    if (
      !window.confirm(
        formatMessage(dict.sectionManager.confirmDelete, { name: section.label })
      )
    )
      return;
    const { error } = await supabase.from("sections").delete().eq("key", section.key);
    if (error)
      setError(formatMessage(dict.sectionManager.deleteError, { message: error.message }));
    await load();
  }

  async function move(section: Section, direction: -1 | 1) {
    const idx = sections.findIndex((s) => s.key === section.key);
    const neighbor = sections[idx + direction];
    if (!neighbor) return;
    setBusy(true);
    setError(null);
    const [r1, r2] = await Promise.all([
      supabase.from("sections").update({ sort: neighbor.sort }).eq("key", section.key),
      supabase.from("sections").update({ sort: section.sort }).eq("key", neighbor.key),
    ]);
    const dbError = r1.error ?? r2.error;
    if (dbError)
      setError(formatMessage(dict.sectionManager.saveError, { message: dbError.message }));
    setBusy(false);
    await load();
  }

  return (
    <div className="max-w-3xl">
      <div className="flex items-center gap-3 mb-4">
        <h1 className="text-xl font-bold text-[var(--c-primary)] mr-auto">
          {dict.sectionManager.title}
        </h1>
        <button
          type="button"
          className="btn btn-add"
          onClick={() => setForm(EMPTY_FORM)}
        >
          {dict.sectionManager.newSection}
        </button>
      </div>

      {error && (
        <p className="mb-3 text-sm text-[var(--c-del)]" role="alert">
          {error}
        </p>
      )}

      {form && (
        <form onSubmit={save} className="card mb-4 space-y-4">
          <h2 className="font-semibold">
            {form.key ? dict.sectionManager.editSection : dict.sectionManager.newSection}
          </h2>
          <div>
            <label className="label" htmlFor="section-label">
              {dict.sectionManager.nameLabel}
            </label>
            <input
              id="section-label"
              className="input"
              value={form.label}
              onChange={(e) => setForm({ ...form, label: e.target.value })}
              required
            />
          </div>
          <div className="grid gap-3 sm:grid-cols-2">
            <div>
              <label className="label" htmlFor="section-label-en">
                {dict.sectionManager.nameEnLabel}
              </label>
              <input
                id="section-label-en"
                className="input"
                value={form.labelEn}
                onChange={(e) => setForm({ ...form, labelEn: e.target.value })}
              />
            </div>
            <div>
              <label className="label" htmlFor="section-label-pl">
                {dict.sectionManager.namePlLabel}
              </label>
              <input
                id="section-label-pl"
                className="input"
                value={form.labelPl}
                onChange={(e) => setForm({ ...form, labelPl: e.target.value })}
              />
            </div>
          </div>
          <div className="flex gap-3">
            <div className="max-w-32">
              <label className="label" htmlFor="section-time-from">
                {dict.sectionManager.timeFrom}
              </label>
              <input
                id="section-time-from"
                type="time"
                className="input"
                value={form.timeFrom}
                onChange={(e) => setForm({ ...form, timeFrom: e.target.value })}
                required
              />
            </div>
            <div className="max-w-32">
              <label className="label" htmlFor="section-time-to">
                {dict.sectionManager.timeTo}
              </label>
              <input
                id="section-time-to"
                type="time"
                className="input"
                value={form.timeTo}
                onChange={(e) => setForm({ ...form, timeTo: e.target.value })}
                required
              />
            </div>
          </div>
          <div className="flex gap-2">
            <button type="submit" className="btn btn-add">
              {dict.common.save}
            </button>
            <button
              type="button"
              className="btn btn-neutral"
              onClick={() => setForm(null)}
            >
              {dict.common.cancel}
            </button>
          </div>
        </form>
      )}

      {loading ? (
        <p className="text-gray-500">{dict.common.loading}</p>
      ) : (
        <ul className="divide-y divide-gray-200 border border-gray-200 rounded-md bg-white">
          {sections.map((section, idx) => (
            <li key={section.key} className="flex items-center gap-3 px-4 py-2">
              <div className="flex flex-col">
                <button
                  type="button"
                  className="text-gray-400 hover:text-[var(--c-primary)] disabled:opacity-30"
                  onClick={() => move(section, -1)}
                  disabled={busy || idx === 0}
                  aria-label={dict.sectionManager.moveUp}
                  title={dict.sectionManager.moveUp}
                >
                  ▲
                </button>
                <button
                  type="button"
                  className="text-gray-400 hover:text-[var(--c-primary)] disabled:opacity-30"
                  onClick={() => move(section, 1)}
                  disabled={busy || idx === sections.length - 1}
                  aria-label={dict.sectionManager.moveDown}
                  title={dict.sectionManager.moveDown}
                >
                  ▼
                </button>
              </div>
              <span className="mr-auto">
                <span className="font-semibold">{localized(section, locale)}</span>{" "}
                <span className="text-gray-500">– {section.time_range}</span>
              </span>
              <button
                type="button"
                className="btn btn-primary"
                onClick={() => {
                  const { from, to } = splitTimeRange(section.time_range);
                  setForm({
                    key: section.key,
                    label: section.label,
                    labelEn: section.label_en ?? "",
                    labelPl: section.label_pl ?? "",
                    timeFrom: from,
                    timeTo: to,
                  });
                }}
              >
                {dict.common.edit}
              </button>
              <button
                type="button"
                className="btn btn-del"
                onClick={() => remove(section)}
              >
                {dict.common.delete}
              </button>
            </li>
          ))}
          {sections.length === 0 && (
            <li className="px-4 py-3 text-gray-500">{dict.sectionManager.empty}</li>
          )}
        </ul>
      )}
    </div>
  );
}