import { useEffect, useState, type ReactNode } from "react";
import { useTranslation } from "react-i18next";
import { CalendarClock, Copy, Link2, Scissors } from "lucide-react";
import clsx from "clsx";
import { qk } from "../lib/queryKeys";
import { useLiveQuery } from "../lib/useLiveQuery";
import { api, type DownloadJob } from "../lib/api";
import { notify } from "../lib/notifications";
import { copyText } from "../lib/clipboard";
import { formatBytes, formatDuration, formatEta, formatSpeed, relativeTime } from "../lib/format";

// Download-row presentation + the small shared primitives (status pill, icon button, usage bar),
// split out of DownloadCenter (all purely prop-driven, no shared state). Rendered by the queue,
// library, shared, and admin tabs.

const STATUS_CLS: Record<string, string> = {
  queued: "text-muted",
  running: "text-accent",
  paused: "text-warn",
  done: "text-success",
  error: "text-danger",
  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",
];

export 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 }) {
  // Prefer OUR self-hosted poster: it's always present on disk, never expires, and is same-origin, so
  // a source-CDN signature expiry (Facebook's fbcdn URLs expire within days) or an ad-blocker/Shields
  // rule on the source domain can't break it. The source's remote thumbnail_url is only a fallback for
  // the rare poster-less asset (a thumbnail-less source whose ffmpeg frame-cut also failed).
  const remote = job.asset?.thumbnail_url ?? null;
  // `job.poster_url` only SIGNALS a poster exists; the actual <img> src must carry ?account= (see
  // api.posterImageUrl). A plain <img> can't send the X-Siftlode-Account header, so without it the
  // poster resolves to the session-default account and 404s for a per-tab account's download — which,
  // now that the poster is the primary image, reads as a blank Library thumbnail.
  const poster = job.poster_url ? api.posterImageUrl(job.id) : null;
  const primary = poster || remote;
  // On load failure (a genuinely missing poster file) fall back to the remote source thumbnail.
  const [src, setSrc] = useState(primary);
  useEffect(() => setSrc(primary), [primary]);
  return (
    <div className="w-28 aspect-video shrink-0 rounded-lg overflow-hidden bg-surface border border-border">
      {src ? (
        <img
          src={src}
          alt=""
          loading="lazy"
          className="w-full h-full object-cover"
          onError={() => {
            if (remote && src !== remote) setSrc(remote);
          }}
        />
      ) : null}
    </div>
  );
}

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

// The channel to show under the title: a user override wins over the auto-extracted asset value.
// `url` is null for sources without a channel link (e.g. reddit) — then it renders as plain text.
function jobChannel(job: DownloadJob): { name: string; url: string | null } {
  return {
    name: job.display_uploader || job.asset?.uploader || job.source_ref,
    url: job.display_uploader_url || job.asset?.uploader_url || null,
  };
}

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

// Compact display of a URL: drop the protocol + trailing slash so "youtube.com/watch?v=…" fits.
function displayUrl(url: string): string {
  try {
    const u = new URL(url);
    return (u.host + u.pathname + u.search).replace(/\/$/, "");
  } catch {
    return url;
  }
}

// "Downloaded from" reference: opens the original page in a new tab, or copies the link.
function SourceRef({ url }: { url: string }) {
  const { t } = useTranslation();
  const copy = async () => {
    if (await copyText(url)) {
      notify({ level: "success", message: t("downloads.source.copied") });
    } else {
      notify({ level: "error", message: t("downloads.source.copyFailed") });
    }
  };
  return (
    <div className="flex items-center gap-1 mt-1 text-xs text-muted min-w-0">
      <Link2 className="w-3 h-3 shrink-0" />
      <a
        href={url}
        target="_blank"
        rel="noopener noreferrer"
        title={`${t("downloads.source.open")} — ${url}`}
        className="truncate hover:text-accent hover:underline"
      >
        {displayUrl(url)}
      </a>
      <button
        onClick={copy}
        aria-label={t("downloads.source.copy")}
        title={t("downloads.source.copy")}
        className="shrink-0 p-0.5 rounded-sm hover:bg-surface hover:text-fg transition"
      >
        <Copy className="w-3 h-3" />
      </button>
    </div>
  );
}

// Channel under the title — a clickable link when a channel URL is known, plain text otherwise.
function ChannelLine({ job }: { job: DownloadJob }) {
  const { name, url } = jobChannel(job);
  if (url) {
    return (
      <div className="text-xs mt-0.5 truncate">
        <a
          href={url}
          target="_blank"
          rel="noopener noreferrer"
          title={url}
          className="text-muted hover:text-accent hover:underline"
        >
          {name}
        </a>
      </div>
    );
  }
  return <div className="text-xs text-muted truncate mt-0.5">{name}</div>;
}

export function DownloadRow({
  job,
  onShowError,
  children,
}: {
  job: DownloadJob;
  onShowError?: (job: DownloadJob) => void;
  children?: ReactNode;
}) {
  const { t } = useTranslation();
  const running = job.status === "running";
  return (
    <div className="flex gap-3 p-2.5 rounded-xl glass-card glass-hover 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-sm text-3xs 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>
        <ChannelLine job={job} />
        <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.status === "done" && job.created_at ? (
            <span
              className="text-muted inline-flex items-center gap-1"
              title={new Date(job.created_at).toLocaleString()}
            >
              · <CalendarClock className="w-3 h-3" /> {relativeTime(job.created_at)}
            </span>
          ) : null}
          {job.status === "error" ? (
            <button
              onClick={() => onShowError?.(job)}
              className="text-danger hover:opacity-80 inline-flex items-center gap-1 truncate"
              title={t("downloads.errors.fail.title")}
            >
              · {t(`downloads.errors.fail.cat.${job.error_code || "unknown"}.short`)}
              <span className="text-muted underline">{t("downloads.errors.fail.detailsLink")}</span>
            </button>
          ) : null}
        </div>
        {job.source_url && <SourceRef url={job.source_url} />}
        {job.extra_links?.map((url) => (
          <SourceRef key={url} url={url} />
        ))}
        {running && (
          <div className="mt-1.5">
            {job.phase && !DOWNLOAD_PHASES.includes(job.phase) ? (
              // ffmpeg post-steps aren't byte-progress — show an indeterminate pulse, no %.
              <div className="h-1.5 rounded-full bg-surface overflow-hidden">
                <div className="h-full w-full bg-accent/60 animate-pulse" />
              </div>
            ) : (
              <>
                <div className="h-1.5 rounded-full bg-surface overflow-hidden">
                  <div
                    className="h-full bg-accent transition-all"
                    style={{ width: `${job.progress}%` }}
                  />
                </div>
                <div className="text-2xs 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>
  );
}

export function UsageBar() {
  const { t } = useTranslation();
  // Poll live (like the library list) so the footprint updates the moment the worker finishes an
  // edit/download — enqueue only creates a queued job (0 bytes), the size lands asynchronously, so
  // a one-shot fetch at enqueue time would show a stale 0 B until a manual reload. The footprint
  // only moves while a job is in flight, so poll fast (2s) then and idle-back-off to 15s otherwise
  // (running_jobs counts queued+running — it flips back to 2s on the first poll after a new enqueue).
  const usage = useLiveQuery(qk.downloadUsage(), api.downloadUsage, {
    intervalMs: (u) => (u?.running_jobs ? 2000 : 15000),
  });
  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 glass-card 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 ? "" : ` / ${formatBytes(u.max_bytes)}`} ·{" "}
          {u.unlimited
            ? t("downloads.usage.unlimited")
            : t("downloads.usage.items", { used: u.active_jobs, max: u.max_jobs })}
        </span>
      </div>
      {!u.unlimited && (
        <div className="h-2 rounded-full bg-surface overflow-hidden">
          <div
            className={clsx("h-full transition-all", pct > 90 ? "bg-danger" : "bg-accent")}
            style={{ width: `${pct}%` }}
          />
        </div>
      )}
    </div>
  );
}