import { useMemo, useState } from "react";
import { useTranslation } from "react-i18next";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { Check, Copy, Link2, Lock, Trash2, UserPlus, Eye } from "lucide-react";
import clsx from "clsx";
import Modal from "./Modal";
import { useConfirm } from "./ConfirmProvider";
import { notify } from "../lib/notifications";
import { api, type DownloadJob, type ShareLink } from "../lib/api";

const inputCls =
  "w-full rounded-lg bg-surface border border-border px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-accent/40";
const btn = "px-3 py-1.5 rounded-lg text-sm font-medium transition disabled:opacity-50";
const EXPIRY_DAYS = [null, 1, 7, 30] as const;

// --- share with a registered user (ACL) -----------------------------------------------------

function UserShare({ job }: { job: DownloadJob }) {
  const { t } = useTranslation();
  const [q, setQ] = useState("");
  const [open, setOpen] = useState(false);
  const recipients = useQuery({ queryKey: ["share-recipients"], queryFn: api.shareRecipients });
  const list = recipients.data ?? [];
  const filtered = useMemo(() => {
    const s = q.trim().toLowerCase();
    if (!s) return list.slice(0, 8);
    return list
      .filter((u) => u.email.toLowerCase().includes(s) || (u.display_name ?? "").toLowerCase().includes(s))
      .slice(0, 8);
  }, [q, list]);

  const share = useMutation({
    mutationFn: (email: string) => api.shareDownload(job.id, email),
    onSuccess: (r) => {
      notify({ level: "success", message: t("downloads.share.done", { email: r.shared_with }) });
      setQ("");
      setOpen(false);
    },
    onError: () => notify({ level: "error", message: t("downloads.share.failed") }),
  });

  return (
    <div>
      <div className="flex items-center gap-2 text-sm font-medium mb-1">
        <UserPlus className="w-4 h-4 text-muted" /> {t("downloads.share.userSection")}
      </div>
      <p className="text-xs text-muted mb-2">{t("downloads.share.userHint")}</p>
      <div className="relative">
        <input
          value={q}
          onChange={(e) => {
            setQ(e.target.value);
            setOpen(true);
          }}
          onFocus={() => setOpen(true)}
          // Close on blur, but after a tick so a click on a dropdown row still registers.
          onBlur={() => setTimeout(() => setOpen(false), 150)}
          placeholder={t("downloads.share.pickPlaceholder")}
          className={inputCls}
        />
        {open && filtered.length > 0 && (
          <div className="absolute z-10 mt-1 w-full rounded-lg border border-border bg-card shadow-xl overflow-hidden">
            {filtered.map((u) => (
              <button
                key={u.id}
                onClick={() => share.mutate(u.email)}
                disabled={share.isPending}
                className="w-full text-left px-3 py-2 text-sm hover:bg-surface transition flex flex-col"
              >
                <span className="truncate">{u.display_name || u.email}</span>
                {u.display_name && <span className="text-xs text-muted truncate">{u.email}</span>}
              </button>
            ))}
          </div>
        )}
      </div>
      {recipients.data && list.length === 0 && (
        <p className="text-xs text-muted mt-1">{t("downloads.share.noUsers")}</p>
      )}
    </div>
  );
}

// --- share by public link -------------------------------------------------------------------

function LinkRow({ link, onChanged }: { link: ShareLink; onChanged: () => void }) {
  const { t } = useTranslation();
  const confirm = useConfirm();
  const [copied, setCopied] = useState(false);
  const fullUrl = window.location.origin + link.url;

  const copy = async () => {
    try {
      await navigator.clipboard.writeText(fullUrl);
      setCopied(true);
      setTimeout(() => setCopied(false), 1500);
    } catch {
      notify({ level: "error", message: t("downloads.share.copyFailed") });
    }
  };
  const toggle = useMutation({
    mutationFn: () => api.updateDownloadLink(link.id, { allow_download: !link.allow_download }),
    onSuccess: onChanged,
  });
  const revoke = useMutation({
    mutationFn: () => api.revokeDownloadLink(link.id),
    onSuccess: onChanged,
  });

  const badges: string[] = [];
  if (link.has_password) badges.push(t("downloads.share.hasPassword"));
  if (link.allow_download) badges.push(t("downloads.share.downloadable"));
  if (link.expires_at) badges.push(t("downloads.share.expiresOn", { date: new Date(link.expires_at).toLocaleDateString() }));

  return (
    <div className="rounded-lg bg-card/40 p-2.5 space-y-2">
      <div className="flex items-center gap-2">
        <Link2 className="w-4 h-4 text-muted shrink-0" />
        <input readOnly value={fullUrl} className="flex-1 min-w-0 bg-transparent text-xs text-muted truncate outline-none" />
        <button onClick={copy} title={t("downloads.share.copy")} className="p-1.5 rounded-md hover:bg-surface text-muted hover:text-fg transition">
          {copied ? <Check className="w-4 h-4 text-emerald-400" /> : <Copy className="w-4 h-4" />}
        </button>
        <button
          onClick={async () => {
            if (await confirm({ title: t("downloads.share.revoke"), message: t("downloads.share.revokeConfirm"), confirmLabel: t("downloads.share.revoke"), danger: true }))
              revoke.mutate();
          }}
          title={t("downloads.share.revoke")}
          className="p-1.5 rounded-md hover:bg-surface text-muted hover:text-red-400 transition"
        >
          <Trash2 className="w-4 h-4" />
        </button>
      </div>
      <div className="flex items-center gap-2 text-xs text-muted flex-wrap">
        <span className="inline-flex items-center gap-1"><Eye className="w-3 h-3" /> {t("downloads.share.views", { n: link.view_count })}</span>
        {badges.map((b) => (
          <span key={b} className="inline-flex items-center gap-1 px-1.5 py-0.5 rounded bg-surface">
            {b === t("downloads.share.hasPassword") && <Lock className="w-3 h-3" />}
            {b}
          </span>
        ))}
        <div className="flex-1" />
        <label className="inline-flex items-center gap-1.5 cursor-pointer">
          <input type="checkbox" checked={link.allow_download} onChange={() => toggle.mutate()} />
          {t("downloads.share.allowDownload")}
        </label>
      </div>
    </div>
  );
}

function LinkShare({ job }: { job: DownloadJob }) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const links = useQuery({ queryKey: ["download-links", job.id], queryFn: () => api.downloadLinks(job.id) });
  const [creating, setCreating] = useState(false);
  const [allowDownload, setAllowDownload] = useState(false);
  const [expiryDays, setExpiryDays] = useState<number | null>(null);
  const [password, setPassword] = useState("");
  const invalidate = () => qc.invalidateQueries({ queryKey: ["download-links", job.id] });

  const create = useMutation({
    mutationFn: () =>
      api.createDownloadLink(job.id, {
        allow_download: allowDownload,
        expires_days: expiryDays,
        password: password.trim() || undefined,
      }),
    onSuccess: () => {
      invalidate();
      setCreating(false);
      setAllowDownload(false);
      setExpiryDays(null);
      setPassword("");
    },
  });

  return (
    <div>
      <div className="flex items-center gap-2 text-sm font-medium mb-1">
        <Link2 className="w-4 h-4 text-muted" /> {t("downloads.share.linkSection")}
      </div>
      <p className="text-xs text-muted mb-2">{t("downloads.share.linkHint")}</p>

      <div className="space-y-2">
        {(links.data ?? []).map((l) => (
          <LinkRow key={l.id} link={l} onChanged={invalidate} />
        ))}
        {links.data && links.data.length === 0 && !creating && (
          <p className="text-xs text-muted">{t("downloads.share.noLinks")}</p>
        )}
      </div>

      {creating ? (
        <div className="mt-2 rounded-lg border border-border p-3 space-y-3">
          <label className="flex items-center gap-2 text-sm cursor-pointer">
            <input type="checkbox" checked={allowDownload} onChange={(e) => setAllowDownload(e.target.checked)} />
            {t("downloads.share.allowDownload")}
          </label>
          <div className="flex items-center gap-2 text-sm">
            <span className="text-muted">{t("downloads.share.expiry")}:</span>
            {EXPIRY_DAYS.map((d) => (
              <button
                key={String(d)}
                onClick={() => setExpiryDays(d)}
                className={clsx(
                  "px-2 py-1 rounded-md border text-xs transition",
                  expiryDays === d ? "border-accent bg-accent/10 text-accent" : "border-border text-muted hover:text-fg"
                )}
              >
                {d === null ? t("downloads.share.expiryNever") : t("downloads.share.days", { n: d })}
              </button>
            ))}
          </div>
          <input
            type="password"
            value={password}
            onChange={(e) => setPassword(e.target.value)}
            placeholder={t("downloads.share.password")}
            className={inputCls}
            autoComplete="new-password"
          />
          <div className="flex justify-end gap-2">
            <button onClick={() => setCreating(false)} className={clsx(btn, "text-muted hover:text-fg hover:bg-surface")}>
              {t("common.cancel")}
            </button>
            <button onClick={() => create.mutate()} disabled={create.isPending} className={clsx(btn, "bg-accent text-accent-fg hover:opacity-90")}>
              {t("downloads.share.createLink")}
            </button>
          </div>
        </div>
      ) : (
        <button
          onClick={() => setCreating(true)}
          className={clsx(btn, "mt-2 border border-border text-muted hover:text-fg hover:border-muted inline-flex items-center gap-1.5")}
        >
          <Link2 className="w-4 h-4" /> {t("downloads.share.newLink")}
        </button>
      )}
    </div>
  );
}

export default function ShareDialog({ job, onClose }: { job: DownloadJob; onClose: () => void }) {
  const { t } = useTranslation();
  return (
    <Modal title={t("downloads.share.title")} onClose={onClose}>
      <div className="space-y-5">
        <UserShare job={job} />
        <div className="border-t border-border" />
        <LinkShare job={job} />
      </div>
    </Modal>
  );
}
