import { useMemo, useState } from "react";
import { useTranslation } from "react-i18next";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import {
  Ban,
  Download,
  Pause,
  Play,
  Plus,
  Scissors,
  Settings2,
  Share2,
  Pencil,
  Trash2,
} from "lucide-react";
import clsx from "clsx";
import Tabs, { usePersistedTab } from "./Tabs";
import Modal from "./Modal";
import DownloadDialog from "./DownloadDialog";
import ProfileEditor from "./ProfileEditor";
import VideoEditor from "./VideoEditor";
import ShareDialog from "./ShareDialog";
import { useConfirm } from "./ConfirmProvider";
import { useLiveQuery } from "../lib/useLiveQuery";
import { api, type DownloadJob, type Me } from "../lib/api";
import { notify } from "../lib/notifications";
import { formatBytes, formatDuration, formatEta, formatSpeed } from "../lib/format";

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 GiB = 1024 ** 3;

const STATUS_CLS: Record<string, string> = {
  queued: "text-muted",
  running: "text-accent",
  paused: "text-amber-400",
  done: "text-emerald-400",
  error: "text-red-400",
  canceled: "text-muted",
};

// Byte-progress phases (show a % bar) vs ffmpeg post-steps (no %, indeterminate pulse).
// "editing" (the phase-2 editor) reports a real % from ffmpeg's out_time, so it gets a bar.
const DOWNLOAD_PHASES = ["video", "audio", "editing"];
const PHASE_KEYS = [
  "video", "audio", "editing", "merging", "audio_extract", "thumbnail", "sponsorblock", "metadata", "processing",
];

function StatusPill({ job }: { job: DownloadJob }) {
  const { t } = useTranslation();
  // While downloading, show the concrete phase (video / audio / merging) so the user isn't
  // confused by the bar resetting between the separate video and audio streams.
  if (job.status === "running" && job.phase && PHASE_KEYS.includes(job.phase)) {
    return <span className="text-xs font-medium text-accent">{t(`downloads.phase.${job.phase}`)}</span>;
  }
  const key = job.expired ? "expired" : job.status;
  return (
    <span className={clsx("text-xs font-medium", STATUS_CLS[job.status] ?? "text-muted")}>
      {t(`downloads.status.${key}`)}
    </span>
  );
}

function Thumb({ job }: { job: DownloadJob }) {
  const url = job.asset?.thumbnail_url;
  return (
    <div className="w-28 aspect-video shrink-0 rounded-lg overflow-hidden bg-surface border border-border">
      {url ? <img src={url} alt="" loading="lazy" className="w-full h-full object-cover" /> : null}
    </div>
  );
}

function jobTitle(job: DownloadJob): string {
  return job.display_name || job.asset?.title || job.source_ref;
}

function IconBtn({
  onClick,
  title,
  danger,
  children,
}: {
  onClick: () => void;
  title: string;
  danger?: boolean;
  children: React.ReactNode;
}) {
  return (
    <button
      onClick={onClick}
      title={title}
      className={clsx(
        "p-1.5 rounded-md hover:bg-surface text-muted transition",
        danger ? "hover:text-red-400" : "hover:text-fg"
      )}
    >
      {children}
    </button>
  );
}

function DownloadRow({
  job,
  children,
}: {
  job: DownloadJob;
  children?: React.ReactNode;
}) {
  const { t } = useTranslation();
  const running = job.status === "running";
  return (
    <div className="flex gap-3 p-2.5 rounded-xl bg-card/40 hover:bg-card transition">
      <Thumb job={job} />
      <div className="min-w-0 flex-1">
        <div className="font-medium leading-snug line-clamp-1 flex items-center gap-1.5">
          {job.job_kind === "edit" && (
            <span className="inline-flex items-center gap-1 shrink-0 px-1.5 py-0.5 rounded text-[10px] font-semibold uppercase tracking-wide bg-accent/15 text-accent">
              <Scissors className="w-3 h-3" /> {t("downloads.clipBadge")}
            </span>
          )}
          <span className="truncate">{jobTitle(job)}</span>
        </div>
        <div className="text-xs text-muted truncate mt-0.5">
          {job.asset?.uploader || job.source_ref}
        </div>
        <div className="flex items-center gap-2 mt-1 text-xs">
          <StatusPill job={job} />
          {job.asset?.size_bytes ? <span className="text-muted">· {formatBytes(job.asset.size_bytes)}</span> : null}
          {job.asset?.duration_s ? <span className="text-muted">· {formatDuration(job.asset.duration_s)}</span> : null}
          {job.error ? <span className="text-red-400 truncate">· {job.error}</span> : null}
        </div>
        {running && (
          <div className="mt-1.5">
            {job.phase && !DOWNLOAD_PHASES.includes(job.phase) ? (
              // ffmpeg post-steps aren't byte-progress — show an indeterminate pulse, no %.
              <div className="h-1.5 rounded-full bg-surface overflow-hidden">
                <div className="h-full w-full bg-accent/60 animate-pulse" />
              </div>
            ) : (
              <>
                <div className="h-1.5 rounded-full bg-surface overflow-hidden">
                  <div className="h-full bg-accent transition-all" style={{ width: `${job.progress}%` }} />
                </div>
                <div className="text-[11px] text-muted mt-0.5 flex gap-2">
                  <span>{job.progress}%</span>
                  {job.speed_bps ? <span>{formatSpeed(job.speed_bps)}</span> : null}
                  {job.eta_s ? <span>{formatEta(job.eta_s)}</span> : null}
                </div>
              </>
            )}
          </div>
        )}
      </div>
      <div className="flex items-start gap-0.5 shrink-0">{children}</div>
    </div>
  );
}

// --- Rename + Share small modals ------------------------------------------------------------

function RenameModal({ job, onClose }: { job: DownloadJob; onClose: () => void }) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const [name, setName] = useState(jobTitle(job));
  const save = useMutation({
    mutationFn: () => api.renameDownload(job.id, name.trim()),
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ["downloads"] });
      onClose();
    },
  });
  return (
    <Modal title={t("downloads.rename.title")} onClose={onClose}>
      <label className="block text-sm font-medium mb-1">{t("downloads.rename.label")}</label>
      <input value={name} onChange={(e) => setName(e.target.value)} className={inputCls} autoFocus />
      <p className="text-xs text-muted mt-2 mb-4">{t("downloads.rename.hint")}</p>
      <div className="flex justify-end">
        <button
          onClick={() => save.mutate()}
          disabled={!name.trim() || save.isPending}
          className="px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 transition"
        >
          {t("downloads.rename.save")}
        </button>
      </div>
    </Modal>
  );
}

// --- Usage bar ------------------------------------------------------------------------------

function UsageBar() {
  const { t } = useTranslation();
  const usage = useQuery({ queryKey: ["download-usage"], queryFn: api.downloadUsage });
  const u = usage.data;
  if (!u) return null;
  const pct = u.unlimited || !u.max_bytes ? 0 : Math.min(100, (u.footprint_bytes / u.max_bytes) * 100);
  return (
    <div className="rounded-xl bg-card/40 p-3 mb-4">
      <div className="flex justify-between text-sm mb-1.5">
        <span className="font-medium">{t("downloads.usage.title")}</span>
        <span className="text-muted">
          {formatBytes(u.footprint_bytes)}
          {u.unlimited ? "" : ` / ${formatBytes(u.max_bytes)}`} ·{" "}
          {u.unlimited ? t("downloads.usage.unlimited") : t("downloads.usage.items", { used: u.active_jobs, max: u.max_jobs })}
        </span>
      </div>
      {!u.unlimited && (
        <div className="h-2 rounded-full bg-surface overflow-hidden">
          <div className={clsx("h-full transition-all", pct > 90 ? "bg-red-400" : "bg-accent")} style={{ width: `${pct}%` }} />
        </div>
      )}
    </div>
  );
}

// --- Admin system tab -----------------------------------------------------------------------

function QuotaModal({ userId, email, onClose }: { userId: number; email: string; onClose: () => void }) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const q = useQuery({ queryKey: ["dl-quota", userId], queryFn: () => api.adminGetDownloadQuota(userId) });
  const [form, setForm] = useState<{ gb: number; jobs: number; conc: number; unlimited: boolean } | null>(null);
  const cur = q.data;
  const state = form ?? (cur ? { gb: Math.round((cur.max_bytes / GiB) * 10) / 10, jobs: cur.max_jobs, conc: cur.max_concurrent, unlimited: cur.unlimited } : null);
  const done = () => {
    qc.invalidateQueries({ queryKey: ["dl-quota", userId] });
    qc.invalidateQueries({ queryKey: ["admin-storage"] });
    onClose();
  };
  const save = useMutation({
    mutationFn: () =>
      api.adminSetDownloadQuota(userId, {
        max_bytes: Math.round((state!.gb) * GiB),
        max_jobs: state!.jobs,
        max_concurrent: state!.conc,
        unlimited: state!.unlimited,
      }),
    onSuccess: done,
  });
  const reset = useMutation({ mutationFn: () => api.adminResetDownloadQuota(userId), onSuccess: done });
  if (!state) return null;
  const upd = (p: Partial<typeof state>) => setForm({ ...state, ...p });
  return (
    <Modal title={t("downloads.admin.quotaTitle", { email })} onClose={onClose}>
      <div className="space-y-3">
        <div className="grid grid-cols-3 gap-3">
          <label className="text-sm">
            {t("downloads.admin.maxBytes")}
            <input type="number" value={state.gb} onChange={(e) => upd({ gb: Number(e.target.value) })} className={inputCls} disabled={state.unlimited} />
          </label>
          <label className="text-sm">
            {t("downloads.admin.maxJobs")}
            <input type="number" value={state.jobs} onChange={(e) => upd({ jobs: Number(e.target.value) })} className={inputCls} />
          </label>
          <label className="text-sm">
            {t("downloads.admin.maxConcurrent")}
            <input type="number" value={state.conc} onChange={(e) => upd({ conc: Number(e.target.value) })} className={inputCls} />
          </label>
        </div>
        <label className="flex items-center gap-2 text-sm cursor-pointer">
          <input type="checkbox" checked={state.unlimited} onChange={(e) => upd({ unlimited: e.target.checked })} />
          {t("downloads.admin.unlimited")}
        </label>
        <div className="flex justify-between pt-1">
          <button onClick={() => reset.mutate()} className="px-3 py-1.5 rounded-lg text-sm text-muted hover:text-fg hover:bg-surface transition">
            {t("downloads.admin.reset")}
          </button>
          <button onClick={() => save.mutate()} disabled={save.isPending} className="px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 disabled:opacity-50 transition">
            {t("downloads.admin.save")}
          </button>
        </div>
      </div>
    </Modal>
  );
}

// Pick ANY user to set a download quota for — even one who hasn't downloaded anything yet (the
// footprint list below only shows users who already have files).
function QuotaUserPicker({ onPick }: { onPick: (u: { id: number; email: string }) => void }) {
  const { t } = useTranslation();
  const [q, setQ] = useState("");
  const [open, setOpen] = useState(false);
  const users = useQuery({ queryKey: ["admin-users"], queryFn: api.adminUsers });
  const list = (users.data ?? []).filter((u) => !u.is_demo);
  const filtered = useMemo(() => {
    const s = q.trim().toLowerCase();
    const base = s
      ? list.filter((u) => u.email.toLowerCase().includes(s) || (u.display_name ?? "").toLowerCase().includes(s))
      : list;
    return base.slice(0, 8);
  }, [q, list]);
  return (
    <div className="relative w-full sm:w-72">
      <input
        value={q}
        onChange={(e) => {
          setQ(e.target.value);
          setOpen(true);
        }}
        onFocus={() => setOpen(true)}
        onBlur={() => setTimeout(() => setOpen(false), 150)}
        placeholder={t("downloads.admin.quotaPickPlaceholder")}
        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={() => {
                onPick({ id: u.id, email: u.email });
                setQ("");
                setOpen(false);
              }}
              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>
  );
}

function AdminSystem() {
  const { t } = useTranslation();
  const storage = useLiveQuery(["admin-storage"], api.adminDownloadStorage, { intervalMs: 5000 });
  const jobs = useLiveQuery(["admin-downloads"], api.adminDownloads, { intervalMs: 5000 });
  const [quotaFor, setQuotaFor] = useState<{ id: number; email: string } | null>(null);
  const s = storage.data;
  return (
    <div>
      {s && (
        <div className="grid grid-cols-2 sm:grid-cols-4 gap-3 mb-5">
          {[
            [t("downloads.admin.readyFiles"), String(s.ready_files)],
            [t("downloads.admin.totalSize"), formatBytes(s.total_bytes)],
            [t("downloads.admin.cap"), s.total_cap_bytes ? formatBytes(s.total_cap_bytes) : t("downloads.admin.noCap")],
          ].map(([label, val]) => (
            <div key={label} className="rounded-xl bg-card/40 p-3">
              <div className="text-xs text-muted">{label}</div>
              <div className="text-lg font-semibold mt-0.5">{val}</div>
            </div>
          ))}
        </div>
      )}

      {s && (
        <div className="mb-6">
          <div className="flex items-center justify-between gap-3 mb-2 flex-wrap">
            <div className="text-sm font-medium">{t("downloads.admin.perUser")}</div>
            {/* Set a quota for any user, regardless of whether they've downloaded anything. */}
            <QuotaUserPicker onPick={setQuotaFor} />
          </div>
          <div className="space-y-1">
            {s.per_user.map((u) => (
              <div key={u.user_id} className="flex items-center gap-2 text-sm px-3 py-1.5 rounded-lg bg-card/40">
                <span className="flex-1 truncate">{u.email}</span>
                <span className="text-muted">{formatBytes(u.footprint_bytes)}</span>
                <button
                  onClick={() => setQuotaFor({ id: u.user_id, email: u.email ?? "" })}
                  className="p-1 rounded hover:bg-surface text-muted hover:text-fg"
                  title={t("downloads.admin.editQuota")}
                >
                  <Settings2 className="w-4 h-4" />
                </button>
              </div>
            ))}
            {s.per_user.length === 0 && (
              <div className="text-xs text-muted px-3 py-2">{t("downloads.admin.noFootprint")}</div>
            )}
          </div>
        </div>
      )}

      <div className="text-sm font-medium mb-2">{t("downloads.tabs.system")}</div>
      <div className="space-y-1.5">
        {(jobs.data ?? []).map((j) => (
          <div key={j.id} className="flex items-center gap-3 text-sm px-3 py-1.5 rounded-lg bg-card/40">
            <span className="flex-1 truncate">{jobTitle(j)}</span>
            <span className="text-muted truncate w-40">{j.user_email}</span>
            <StatusPill job={j} />
            <span className="text-muted w-16 text-right">{j.asset?.size_bytes ? formatBytes(j.asset.size_bytes) : ""}</span>
          </div>
        ))}
        {jobs.data && jobs.data.length === 0 && <div className="text-sm text-muted py-6 text-center">{t("downloads.empty.admin")}</div>}
      </div>

      {quotaFor && <QuotaModal userId={quotaFor.id} email={quotaFor.email} onClose={() => setQuotaFor(null)} />}
    </div>
  );
}

// --- Main -----------------------------------------------------------------------------------

export default function DownloadCenter({ me }: { me: Me }) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const confirm = useConfirm();
  const [tab, setTab] = usePersistedTab("siftlode.downloadTab", "queue");
  const [addUrl, setAddUrl] = useState("");
  const [addSource, setAddSource] = useState<string | null>(null);
  const [manage, setManage] = useState(false);
  const [renameJob, setRenameJob] = useState<DownloadJob | null>(null);
  const [shareJob, setShareJob] = useState<DownloadJob | null>(null);
  const [editJob, setEditJob] = useState<DownloadJob | null>(null);

  const jobsQ = useLiveQuery(["downloads"], api.downloads, { intervalMs: 2000 });
  const sharedQ = useQuery({ queryKey: ["downloads-shared"], queryFn: api.downloadsShared, enabled: tab === "shared" });
  const jobs = jobsQ.data ?? [];
  const queue = jobs.filter((j) => ["queued", "running", "paused", "error"].includes(j.status));
  const library = jobs.filter((j) => j.status === "done");

  const invalidate = () => {
    qc.invalidateQueries({ queryKey: ["downloads"] });
    qc.invalidateQueries({ queryKey: ["download-index"] });
    qc.invalidateQueries({ queryKey: ["download-usage"] });
  };
  const act = useMutation({
    mutationFn: ({ id, op }: { id: number; op: "pause" | "resume" | "cancel" | "delete" }) =>
      op === "pause" ? api.pauseDownload(id)
      : op === "resume" ? api.resumeDownload(id)
      : op === "cancel" ? api.cancelDownload(id)
      : api.deleteDownload(id),
    onSuccess: invalidate,
  });

  // Remove a shared-with-me item from your list (only your grant; the owner's file is untouched).
  const removeShared = useMutation({
    mutationFn: (id: number) => api.removeSharedDownload(id),
    onSuccess: () => qc.invalidateQueries({ queryKey: ["downloads-shared"] }),
  });

  const confirmThen = async (title: string, body: string, fn: () => void) => {
    if (await confirm({ title, message: body, confirmLabel: title, danger: true })) fn();
  };

  const tabs = [
    { id: "queue", label: t("downloads.tabs.queue"), badge: queue.length },
    { id: "done", label: t("downloads.tabs.done"), badge: library.length },
    { id: "shared", label: t("downloads.tabs.shared") },
    ...(me.role === "admin" ? [{ id: "system", label: t("downloads.tabs.system") }] : []),
  ];

  const saveBtn = (job: DownloadJob) => (
    <a
      href={api.downloadFileUrl(job.id)}
      title={t("downloads.actions.download")}
      className="p-1.5 rounded-md hover:bg-surface text-muted hover:text-fg transition"
    >
      <Download className="w-4 h-4" />
    </a>
  );

  return (
    <div className="p-4 max-w-4xl w-full mx-auto">
      <div className="flex items-center justify-between gap-3 mb-1">
        <h1 className="text-xl font-semibold">{t("downloads.page.title")}</h1>
        <button
          onClick={() => setManage(true)}
          className="inline-flex items-center gap-1.5 px-2.5 py-1.5 rounded-lg text-sm text-muted hover:text-fg hover:bg-surface transition"
        >
          <Settings2 className="w-4 h-4" /> {t("downloads.page.manage")}
        </button>
      </div>
      <p className="text-sm text-muted mb-4">{t("downloads.page.subtitle")}</p>

      <Tabs tabs={tabs} active={tab} onChange={setTab} />

      {tab === "queue" && (
        <>
          <div className="flex gap-2 mb-4">
            <input
              value={addUrl}
              onChange={(e) => setAddUrl(e.target.value)}
              onKeyDown={(e) => e.key === "Enter" && addUrl.trim() && setAddSource(addUrl.trim())}
              placeholder={t("downloads.page.addUrl")}
              className={inputCls}
            />
            <button
              onClick={() => addUrl.trim() && setAddSource(addUrl.trim())}
              className="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium bg-accent text-accent-fg hover:opacity-90 transition shrink-0"
            >
              <Plus className="w-4 h-4" /> {t("downloads.page.add")}
            </button>
          </div>
          <div className="space-y-2">
            {queue.map((job) => (
              <DownloadRow key={job.id} job={job}>
                {(job.status === "queued" || job.status === "running") && (
                  <IconBtn onClick={() => act.mutate({ id: job.id, op: "pause" })} title={t("downloads.actions.pause")}>
                    <Pause className="w-4 h-4" />
                  </IconBtn>
                )}
                {(job.status === "paused" || job.status === "error") && (
                  <IconBtn onClick={() => act.mutate({ id: job.id, op: "resume" })} title={t(job.status === "error" ? "downloads.actions.retry" : "downloads.actions.resume")}>
                    <Play className="w-4 h-4" />
                  </IconBtn>
                )}
                <IconBtn
                  onClick={() => confirmThen(t("downloads.confirm.cancelTitle"), t("downloads.confirm.cancelBody"), () => act.mutate({ id: job.id, op: "cancel" }))}
                  title={t("downloads.actions.cancel")}
                  danger
                >
                  <Ban className="w-4 h-4" />
                </IconBtn>
              </DownloadRow>
            ))}
            {queue.length === 0 && <div className="text-sm text-muted py-10 text-center">{t("downloads.empty.queue")}</div>}
          </div>
        </>
      )}

      {tab === "done" && (
        <>
          <UsageBar />
          <div className="space-y-2">
            {library.map((job) => (
              <DownloadRow key={job.id} job={job}>
                {saveBtn(job)}
                {job.can_download && (job.asset?.duration_s ?? 0) > 0 && (
                  <IconBtn onClick={() => setEditJob(job)} title={t("downloads.actions.edit")}>
                    <Scissors className="w-4 h-4" />
                  </IconBtn>
                )}
                <IconBtn onClick={() => setRenameJob(job)} title={t("downloads.actions.rename")}>
                  <Pencil className="w-4 h-4" />
                </IconBtn>
                <IconBtn onClick={() => setShareJob(job)} title={t("downloads.actions.share")}>
                  <Share2 className="w-4 h-4" />
                </IconBtn>
                <IconBtn
                  onClick={() => confirmThen(t("downloads.confirm.deleteTitle"), t("downloads.confirm.deleteBody"), () => act.mutate({ id: job.id, op: "delete" }))}
                  title={t("downloads.actions.delete")}
                  danger
                >
                  <Trash2 className="w-4 h-4" />
                </IconBtn>
              </DownloadRow>
            ))}
            {library.length === 0 && <div className="text-sm text-muted py-10 text-center">{t("downloads.empty.done")}</div>}
          </div>
        </>
      )}

      {tab === "shared" && (
        <div className="space-y-2">
          {(sharedQ.data ?? []).map((job) => (
            <DownloadRow key={job.id} job={job}>
              {job.can_download && saveBtn(job)}
              {job.can_download && (job.asset?.duration_s ?? 0) > 0 && (
                <IconBtn onClick={() => setEditJob(job)} title={t("downloads.actions.edit")}>
                  <Scissors className="w-4 h-4" />
                </IconBtn>
              )}
              <IconBtn
                onClick={() =>
                  confirmThen(
                    t("downloads.confirm.removeSharedTitle"),
                    t("downloads.confirm.removeSharedBody"),
                    () => removeShared.mutate(job.id)
                  )
                }
                title={t("downloads.actions.removeShared")}
                danger
              >
                <Trash2 className="w-4 h-4" />
              </IconBtn>
            </DownloadRow>
          ))}
          {sharedQ.data && sharedQ.data.length === 0 && (
            <div className="text-sm text-muted py-10 text-center">{t("downloads.empty.shared")}</div>
          )}
        </div>
      )}

      {tab === "system" && me.role === "admin" && <AdminSystem />}

      {addSource && (
        <DownloadDialog
          source={addSource}
          onClose={() => {
            setAddSource(null);
            setAddUrl("");
          }}
        />
      )}
      {manage && <ProfileEditor onClose={() => setManage(false)} />}
      {renameJob && <RenameModal job={renameJob} onClose={() => setRenameJob(null)} />}
      {shareJob && <ShareDialog job={shareJob} onClose={() => setShareJob(null)} />}
      {editJob && <VideoEditor job={editJob} onClose={() => setEditJob(null)} />}
    </div>
  );
}