import { useEffect, useState } from "react";
import { useTranslation } from "react-i18next";
import { api } from "../../api";
import { useToast } from "../../toast";
import { useConfirm } from "../../confirm";
import Icon from "../../components/Icon";
import Modal from "../../components/Modal";

const LEER = {
  name: "", host: "", port: 993, security: "ssl", username: "", password: "",
  folder: "INBOX", done_folder: "", mark_seen: true, is_active: true, poll_minutes: 15,
};

/**
 * Postfächer für den Mail-Abruf.
 *
 * Raiffeisen und Revolut melden Überweisungen per E-Mail. Certain holt sie ab
 * und macht daraus Vorschläge – gebucht wird nur, was der Nutzer abnickt.
 *
 * Kartenzahlungen im Laden melden die Banken NICHT per Mail, nur per Push in
 * ihrer App. Dafür gibt es die Schnellerfassung per Kurzbefehl unter
 * „Mein Konto".
 */
export default function Postfaecher() {
  const { t } = useTranslation();
  const toast = useToast();
  const confirm = useConfirm();

  const [quellen, setQuellen] = useState([]);
  const [konten, setKonten] = useState([]);
  const [form, setForm] = useState(null);      // null = Formular zu
  const [ordner, setOrdner] = useState(null);  // Ergebnis des Verbindungstests
  const [absender, setAbsender] = useState({});
  const [busy, setBusy] = useState(false);
  // Was beim letzten Abruf durchgefallen ist – beim Einrichten die einzige
  // Möglichkeit zu sehen, was in den Absender-Filter gehört.
  const [uebergangen, setUebergangen] = useState([]);

  async function laden() {
    try {
      const [q, k] = await Promise.all([api.listMailSources(), api.listAccounts()]);
      setQuellen(q);
      setKonten(k);
      const je = {};
      for (const s of q) je[s.id] = await api.listMailSenders(s.id);
      setAbsender(je);
    } catch (e) {
      toast(e.message, "error");
    }
  }
  useEffect(() => { laden(); }, []);

  const setzen = (teil) => setForm((f) => ({ ...f, ...teil }));

  async function speichern(e) {
    e.preventDefault();
    setBusy(true);
    try {
      const koerper = { ...form };
      if (form.id && !koerper.password) delete koerper.password;
      if (form.id) await api.updateMailSource(form.id, koerper);
      else await api.createMailSource(koerper);
      setForm(null);
      setOrdner(null);
      laden();
    } catch (e) {
      toast(e.message, "error");
    } finally {
      setBusy(false);
    }
  }

  async function testen(quelle) {
    setBusy(true);
    try {
      const r = await api.testMailSource(quelle.id);
      setOrdner(r.folders);
      toast(t("mailbox.testOk", { n: r.count }));
    } catch (e) {
      toast(e.message, "error");
    } finally {
      setBusy(false);
    }
  }

  async function abrufen(quelle) {
    setBusy(true);
    try {
      const r = await api.fetchMailSource(quelle.id);
      // „0 neu" allein sagt nicht, ob nichts da war oder nichts passte.
      toast(r.gefunden === 0
        ? t("mailbox.fetchedNone")
        : t("mailbox.fetched", { gefunden: r.gefunden, neu: r.neu, unklar: r.unklar }));
      setUebergangen(r.ohne_zuordnung || []);
      laden();
    } catch (e) {
      toast(e.message, "error");
    } finally {
      setBusy(false);
    }
  }

  async function loeschen(quelle) {
    if (!(await confirm({
      title: t("mailbox.delete"), message: t("mailbox.deleteConfirm", { name: quelle.name || quelle.host }),
      danger: true, confirmLabel: t("common.delete"),
    }))) return;
    try { await api.deleteMailSource(quelle.id); laden(); } catch (e) { toast(e.message, "error"); }
  }

  async function absenderAnlegen(quelle, daten) {
    try {
      await api.createMailSender(quelle.id, daten);
      laden();
    } catch (e) { toast(e.message, "error"); }
  }

  return (
    <div className="card">
      <div className="card-head">
        <Icon name="mail" size={18} />
        <h2>{t("mailbox.title")}</h2>
      </div>
      <p className="muted small">{t("mailbox.intro")}</p>

      {quellen.map((q) => (
        <div key={q.id} className="mail-source">
          <div><strong>{q.name || q.host}</strong></div>
          <div className="muted small">{q.username} · {q.folder} · {q.security.toUpperCase()}</div>
          <div className="muted small">
            {q.last_error
              ? `${t("mailbox.lastError")}: ${q.last_error}`
              : q.last_poll_at ? t("mailbox.lastPoll") : t("mailbox.neverPolled")}
          </div>
          <div className="muted small" style={{ marginTop: "var(--sp-2)" }}>
            {(absender[q.id] || []).length === 0
              ? t("mailbox.noSenders")
              : (absender[q.id] || []).map((a) => {
                  const konto = konten.find((k) => k.id === a.account_id);
                  return `${a.from_contains || "*"} → ${konto ? konto.name : t("mailbox.noAccount")}`;
                }).join(" · ")}
          </div>
          <SenderForm konten={konten} onAdd={(d) => absenderAnlegen(q, d)} t={t} />
          {uebergangen.length > 0 && (
            <div className="alert" style={{ display: "block", marginTop: "var(--sp-2)" }}>
              <strong className="small">{t("mailbox.skippedTitle")}</strong>
              <p className="muted small">{t("mailbox.skippedHint")}</p>
              <ul className="muted small" style={{ paddingLeft: "1.2em", margin: 0 }}>
                {uebergangen.map((m, i) => (
                  <li key={i} className="selectable">{m.from} — {m.subject}</li>
                ))}
              </ul>
            </div>
          )}
          <div className="mail-actions">
            <button className="btn sm" disabled={busy} onClick={() => testen(q)}>{t("mailbox.test")}</button>
            <button className="btn sm primary" disabled={busy} onClick={() => abrufen(q)}>{t("mailbox.fetchNow")}</button>
            <button className="btn sm ghost" title={t("common.edit")}
                    onClick={() => { setForm({ ...LEER, ...q, password: "" }); setOrdner(null); }}>
              <Icon name="edit" size={15} />
            </button>
            <button className="btn sm danger" title={t("common.delete")}
                    onClick={() => loeschen(q)}><Icon name="trash" size={15} /></button>
          </div>
        </div>
      ))}

      <button className="btn" style={{ marginTop: "var(--sp-3)" }} onClick={() => setForm({ ...LEER })}>
        <Icon name="plus" size={15} /> {t("mailbox.add")}
      </button>

      {form !== null && (
        <Modal
          title={form.id ? t("mailbox.edit") : t("mailbox.add")}
          onClose={() => { setForm(null); setOrdner(null); }}
          footer={
            <>
              <button type="button" className="btn ghost"
                      onClick={() => { setForm(null); setOrdner(null); }}>
                {t("common.cancel")}
              </button>
              <button type="submit" form="postfach-form" className="btn primary" disabled={busy}>
                {t("common.save")}
              </button>
            </>
          }
        >
        <form id="postfach-form" onSubmit={speichern}>
          <label className="field">
            <span>{t("mailbox.name")}</span>
            <input value={form.name} onChange={(e) => setzen({ name: e.target.value })}
                   placeholder={t("mailbox.namePlaceholder")} />
          </label>
          <label className="field">
            <span>{t("mailbox.host")}</span>
            <input value={form.host} required onChange={(e) => setzen({ host: e.target.value })}
                   placeholder="imap.example.com" />
          </label>
          <label className="field">
            <span>{t("mailbox.security")}</span>
            <select value={form.security}
                    onChange={(e) => {
                      // Der uebliche Port haengt an der Verschluesselung – gleich
                      // mitziehen, damit die haeufigste Fehlerquelle wegfaellt.
                      const art = e.target.value;
                      const port = art === "ssl" ? 993 : 143;
                      setzen({ security: art, port });
                    }}>
              <option value="ssl">{t("mailbox.secSsl")}</option>
              <option value="starttls">{t("mailbox.secStarttls")}</option>
              <option value="none">{t("mailbox.secNone")}</option>
            </select>
          </label>
          {form.security === "none" && <p className="muted small">{t("mailbox.secNoneWarn")}</p>}
          <label className="field">
            <span>{t("mailbox.port")}</span>
            <input type="number" value={form.port}
                   onChange={(e) => setzen({ port: Number(e.target.value) })} />
          </label>
          <label className="field">
            <span>{t("mailbox.username")}</span>
            <input value={form.username} required autoComplete="off"
                   onChange={(e) => setzen({ username: e.target.value })} />
          </label>
          <label className="field">
            <span>{form.id ? t("mailbox.passwordKeep") : t("mailbox.password")}</span>
            <input type="password" value={form.password} autoComplete="new-password"
                   onChange={(e) => setzen({ password: e.target.value })} />
          </label>
          <p className="muted small">{t("mailbox.passwordHint")}</p>
          <label className="field">
            <span>{t("mailbox.folder")}</span>
            {ordner ? (
              <select value={form.folder} onChange={(e) => setzen({ folder: e.target.value })}>
                {ordner.map((o) => <option key={o} value={o}>{o}</option>)}
              </select>
            ) : (
              <input value={form.folder} onChange={(e) => setzen({ folder: e.target.value })} />
            )}
          </label>
          <p className="muted small">{t("mailbox.folderHint")}</p>
          <label className="field">
            <span>{t("mailbox.doneFolder")}</span>
            <input value={form.done_folder || ""} placeholder={t("mailbox.doneFolderPlaceholder")}
                   onChange={(e) => setzen({ done_folder: e.target.value })} />
          </label>
          <label className="field">
            <span>{t("mailbox.pollMinutes")}</span>
            <input type="number" min="5" max="1440" value={form.poll_minutes}
                   onChange={(e) => setzen({ poll_minutes: Number(e.target.value) })} />
          </label>
        </form>
        </Modal>
      )}
    </div>
  );
}

/** Absender einem Konto zuordnen – ohne das weiss Certain nicht, wohin gebucht wird. */
function SenderForm({ konten, onAdd, t }) {
  const [von, setVon] = useState("");
  const [konto, setKonto] = useState("");
  return (
    <div style={{ marginTop: "var(--sp-2)" }}>
      <input style={{ width: "100%" }} placeholder={t("mailbox.fromPlaceholder")} value={von}
             onChange={(e) => setVon(e.target.value)} />
      <select style={{ width: "100%", marginTop: 4 }} value={konto}
              onChange={(e) => setKonto(e.target.value)}>
        <option value="">{t("mailbox.noAccount")}</option>
        {konten.map((k) => <option key={k.id} value={k.id}>{k.name}</option>)}
      </select>
      <button type="button" className="btn sm" style={{ marginTop: 4 }} disabled={!von.trim()}
              onClick={() => { onAdd({ from_contains: von.trim(), account_id: konto ? Number(konto) : null }); setVon(""); }}>
        <Icon name="plus" size={14} /> {t("mailbox.addSender")}
      </button>
    </div>
  );
}