/**
 * @file BackupSettings.tsx
 * @description Settings → Data → Backup: the daily database backup of
 * `server/lib/db-backup.js` — the folder (best on another disk), the server's
 * local hour, how many to keep, "Back up now" (polls `GET /api/settings/backup`
 * while it runs, then toasts the outcome) and the newest backup in the folder.
 * Saved through `PUT /api/settings/backup`, sending only the fields changed; a
 * field the environment set is read-only. Restoring is manual and the card says
 * how.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useState } from "react";
import { useTranslation } from "react-i18next";
import { AlertTriangle, DatabaseBackup } from "lucide-react";
import { api } from "../../lib/api";
import type { BackupState } from "../../lib/api";
import { formatBytes, formatDateTime } from "../../lib/format";
import { toast } from "../../lib/toast";
import { Select } from "../Select";
import { SettingsSection } from "./SettingsRow";

const HOURS = Array.from({ length: 24 }, (_, h) => h);
const pad = (n: number) => String(n).padStart(2, "0");

export function BackupSettings() {
  const { t } = useTranslation("settings");
  const [state, setState] = useState<BackupState | null>(null);
  const [dir, setDir] = useState("");
  const [hour, setHour] = useState(2);
  const [keep, setKeep] = useState("7");
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const apply = (s: BackupState) => {
    setState(s);
    setDir(s.dir);
    setHour(s.hour);
    setKeep(String(s.keep));
  };

  useEffect(() => {
    api.settings.backup
      .get()
      .then(apply)
      .catch(() => undefined);
  }, []);

  // A backup takes tens of seconds on a large database: poll until it ends.
  const running = !!state?.running;
  useEffect(() => {
    if (!running) return;
    const id = window.setInterval(() => {
      api.settings.backup
        .get()
        .then((s) => {
          setState(s); // the form keeps its drafts
          if (s.running || !s.last) return;
          if (s.last.ok) toast.success(t("backup.done", { file: s.last.file }));
          else toast.error(t("backup.failed", { error: s.last.error }));
        })
        .catch(() => undefined);
    }, 2000);
    return () => window.clearInterval(id);
  }, [running, t]);

  const keepN = Number(keep);
  const keepValid = Number.isInteger(keepN) && keepN >= 1 && keepN <= 365;
  const patch: { dir?: string; hour?: number; keep?: number } = {};
  if (state) {
    if (dir.trim() !== state.dir) patch.dir = dir.trim();
    if (hour !== state.hour) patch.hour = hour;
    if (keepN !== state.keep) patch.keep = keepN;
  }
  const changed = Object.keys(patch).length > 0;

  async function save() {
    setSaving(true);
    setError(null);
    try {
      apply(await api.settings.backup.save(patch));
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    } finally {
      setSaving(false);
    }
  }

  async function runNow() {
    try {
      setState(await api.settings.backup.run());
    } catch (err) {
      toast.error(err);
    }
  }

  const owned = state?.env_owned;
  const newest = state?.files[0];
  const total = state?.files.reduce((n, f) => n + f.size, 0) ?? 0;

  return (
    <SettingsSection
      id="backup"
      title={
        <span className="flex items-center gap-2">
          <DatabaseBackup className="w-4 h-4 text-fg-muted" />
          {t("backup.title")}
        </span>
      }
      description={t("backup.description")}
    >
      <div className="py-3 space-y-3">
        <label className="block text-xs text-fg-muted">
          {t("backup.folder")}
          <input
            className="input mt-1 w-full font-mono text-xs"
            placeholder="/mnt/hdd/agenthub-backups"
            value={dir}
            disabled={!state || owned?.dir}
            onChange={(e) => {
              setDir(e.target.value);
              setError(null);
            }}
          />
        </label>
        <p className="text-xs text-fg-muted">{t("backup.folderHint")}</p>
        <div className="flex flex-wrap items-end gap-3">
          <div className="w-28">
            <Select
              value={String(hour)}
              onChange={(v) => setHour(Number(v))}
              label={t("backup.hour")}
              disabled={!state || owned?.hour}
              options={HOURS.map((h) => ({ value: String(h), label: `${pad(h)}:00` }))}
            />
          </div>
          <label className="text-xs text-fg-muted">
            {t("backup.keep")}
            <input
              type="number"
              min={1}
              max={365}
              step={1}
              className="input mt-1 block w-24 text-sm"
              value={keep}
              disabled={!state || owned?.keep}
              onChange={(e) => setKeep(e.target.value)}
            />
          </label>
        </div>
        <div className="flex flex-wrap items-center gap-2">
          <button
            type="button"
            className="btn-primary px-4 py-2 text-sm disabled:opacity-50 disabled:cursor-not-allowed"
            disabled={saving || !changed || !keepValid}
            onClick={() => void save()}
          >
            {saving ? t("homeDir.saving") : t("homeDir.save")}
          </button>
          <button
            type="button"
            className="btn-ghost text-sm disabled:opacity-50 disabled:cursor-not-allowed"
            disabled={!state?.dir || running || changed}
            onClick={() => void runNow()}
          >
            <DatabaseBackup className={`w-4 h-4 ${running ? "animate-pulse" : ""}`} />{" "}
            {running ? t("backup.running") : t("backup.runNow")}
          </button>
        </div>
        {error && <p className="text-xs text-status-danger">{error}</p>}
        <p className="text-xs text-fg-secondary">
          {newest
            ? t("backup.newest", {
                time: formatDateTime(newest.mtime),
                size: formatBytes(newest.size),
                n: state?.files.length,
                total: formatBytes(total),
              })
            : state?.dir
              ? t("backup.none")
              : t("backup.off")}
        </p>
        {state?.last && !state.last.ok && (
          <p className="text-xs text-status-danger">
            {t("backup.lastFailed", {
              time: formatDateTime(state.last.at),
              error: state.last.error,
            })}
          </p>
        )}
        {state?.dir_error && <p className="text-xs text-status-danger">{state.dir_error}</p>}
        <p className="text-xs text-fg-muted">{t("backup.restoreHint")}</p>
        {(owned?.dir || owned?.hour || owned?.keep) && (
          <p className="text-xs text-status-warning flex items-start gap-1.5">
            <AlertTriangle className="w-3.5 h-3.5 flex-shrink-0 mt-px" />
            {t("privacy.envOwned")}
          </p>
        )}
      </div>
    </SettingsSection>
  );
}