import type { FilePreview } from "@umt/contracts";
import { Download, ExternalLink } from "lucide-react";
import {
  type FileEntry,
  type FileRoot,
  fileDownloadUrl,
  filesErrorText,
  filesMockEnabled,
  useFilePreview,
} from "~/api/files.ts";
import { DetailSection } from "~/components/console/detail-sheet.tsx";
import { LoadingState } from "~/components/console/empty-state.tsx";
import { KvList } from "~/components/console/kv-list.tsx";
import { StatusBadge } from "~/components/console/status-badge.tsx";
import { TechInfo } from "~/components/console/tech-info.tsx";
import { buttonVariants } from "~/components/ui/button.tsx";
import { formatBytes, formatDateTime } from "~/lib/utils.ts";
import { cueTime, prettyJson, previewKindOf } from "./model.ts";

/** 图片原图经 /files/download 内联,上限与下载一致 */
const IMAGE_INLINE_MAX = 20 * 1024 * 1024;

const ENCODING_LABEL: Record<string, string> = {
  "utf-8": "UTF-8",
  "utf-16le": "UTF-16 LE",
  "utf-16be": "UTF-16 BE",
  gb18030: "GBK / GB18030",
  big5: "Big5",
  "windows-1252": "Latin-1",
};
const encLabel = (e: string | null) => (e ? (ENCODING_LABEL[e] ?? e) : null);

const preBox =
  "max-h-[28rem] overflow-auto rounded-xl border border-border bg-foreground/[0.03] p-3 font-mono text-meta whitespace-pre-wrap break-words";

function Meta({ items }: { items: (string | null | false | undefined)[] }) {
  return <p className="mb-2 text-meta text-muted-foreground">{items.filter(Boolean).join(" · ")}</p>;
}

function TextView({ p }: { p: Extract<FilePreview, { type: "text" }> }) {
  const body = p.format === "json" ? prettyJson(p.text, p.truncated) : p.text;
  return (
    <>
      {body.trim() ? (
        <pre className={preBox}>{body}</pre>
      ) : (
        <p className="text-caption text-muted-foreground">空文件。</p>
      )}
      {p.truncated ? <p className="mt-1 text-meta text-muted-foreground">只显示前 1 MB</p> : null}
      <TechInfo
        className="mt-2"
        items={[
          { label: "格式", value: p.format.toUpperCase() },
          { label: "编码", value: encLabel(p.encoding) },
          { label: "大小", value: formatBytes(p.size, 1) },
        ]}
      />
    </>
  );
}

function SubtitleView({ p }: { p: Extract<FilePreview, { type: "subtitle" }> }) {
  const graphic = p.format === "sup";
  const count =
    p.parsed > p.cues.length
      ? `共 ${p.parsed}${p.truncated ? "+" : ""} 条，显示前 ${p.cues.length} 条`
      : `${p.cues.length} 条`;
  return (
    <>
      <Meta items={[p.title, count]} />
      {graphic ? <p className="mb-2 text-caption text-muted-foreground">PGS 图形字幕没有文字，只列时间轴。</p> : null}
      {p.cues.length ? (
        <ol className="max-h-[28rem] divide-y divide-border overflow-auto rounded-xl border border-border">
          {p.cues.map((c, i) => (
            <li key={i} className="flex gap-3 px-3 py-1.5 text-caption">
              <span className="shrink-0 font-mono text-meta text-muted-foreground tabular-nums">
                {cueTime(c.start)}
                {graphic ? ` → ${cueTime(c.end)}` : ""}
              </span>
              {graphic ? null : <span className="min-w-0 whitespace-pre-wrap break-words">{c.text}</span>}
            </li>
          ))}
        </ol>
      ) : (
        <p className="text-caption text-muted-foreground">没有读到字幕条目。</p>
      )}
      {p.truncated ? <p className="mt-1 text-meta text-muted-foreground">只读了文件前 1 MB</p> : null}
      <TechInfo
        className="mt-2"
        items={[
          { label: "格式", value: p.format.toUpperCase() },
          { label: "编码", value: encLabel(p.encoding) },
          { label: "大小", value: formatBytes(p.size, 1) },
        ]}
      />
    </>
  );
}

function TorrentView({ p }: { p: Extract<FilePreview, { type: "torrent" }> }) {
  const prefix = `${p.name}/`;
  return (
    <div className="space-y-4">
      <KvList
        items={[
          { label: "名称", value: p.name, wide: true },
          { label: "总大小", value: `${formatBytes(p.totalSize, 2)} · ${p.fileCount} 个文件` },
          { label: "私有种子", value: p.private ? <StatusBadge tone="warning">私有</StatusBadge> : "否" },
          ...(p.comment ? [{ label: "注释", value: p.comment, wide: true }] : []),
        ]}
      />
      <div>
        <p className="mb-1 text-meta text-muted-foreground">
          文件 {p.fileCount}
          {p.fileCount > p.files.length ? `，显示前 ${p.files.length} 个` : ""}
        </p>
        <ul className="max-h-72 divide-y divide-border overflow-auto rounded-xl border border-border">
          {p.files.map((f) => (
            <li key={f.path} className="flex items-baseline gap-3 px-3 py-1.5 text-caption">
              <span className="min-w-0 flex-1 font-mono text-meta break-all">
                {f.path.startsWith(prefix) ? f.path.slice(prefix.length) : f.path}
              </span>
              <span className="shrink-0 text-meta text-muted-foreground tabular-nums">{formatBytes(f.length, 1)}</span>
            </li>
          ))}
        </ul>
      </div>
      <TechInfo
        items={[
          { label: "infohash", value: p.infohashV1 ?? p.hash, wide: true },
          p.infohashV2 ? { label: "infohash v2", value: p.infohashV2, wide: true } : null,
          { label: "分块", value: p.pieceLength ? formatBytes(p.pieceLength, 0) : null },
          { label: "创建时间", value: p.createdAt ? formatDateTime(p.createdAt) : null },
          { label: "创建工具", value: p.createdBy },
          { label: ".torrent 大小", value: formatBytes(p.size, 1) },
        ]}
      >
        <div>
          <p className="mb-1 text-meta text-muted-foreground">Tracker {p.trackers.length}（passkey 已隐藏）</p>
          {p.trackers.length ? (
            <ul className="space-y-0.5 font-mono text-meta break-all">
              {p.trackers.map((t) => (
                <li key={t}>{t}</li>
              ))}
            </ul>
          ) : (
            <p className="text-caption text-muted-foreground">没有 tracker，只能走 DHT。</p>
          )}
        </div>
      </TechInfo>
    </div>
  );
}

function ImageView({
  root,
  entry,
  p,
}: {
  root: FileRoot;
  entry: FileEntry;
  p: Extract<FilePreview, { type: "image" }>;
}) {
  const dims = p.width && p.height ? `${p.width} × ${p.height}` : null;
  const meta = <Meta items={[dims, formatBytes(p.size, 1)]} />;
  if (filesMockEnabled())
    return (
      <>
        {meta}
        <p className="text-caption text-muted-foreground">演示数据没有图片内容。</p>
      </>
    );
  if (p.size > IMAGE_INLINE_MAX)
    return (
      <>
        {meta}
        <p className="text-caption text-muted-foreground">图片超过 20 MB，不在这里显示。</p>
      </>
    );
  const src = fileDownloadUrl(root.id, entry.path, true);
  return (
    <>
      {meta}
      <a href={src} target="_blank" rel="noreferrer" className="block">
        <img
          src={src}
          alt={entry.name}
          loading="lazy"
          decoding="async"
          className="max-h-[28rem] rounded-xl border border-border object-contain"
        />
        <span className="mt-1 inline-flex items-center gap-1 text-meta text-muted-foreground">
          <ExternalLink className="h-3 w-3" /> 在新窗口打开原图
        </span>
      </a>
    </>
  );
}

/** 详情抽屉的「预览」节:文本/NFO、字幕、.torrent、图片;其它类型不渲染 */
export function FilePreviewSection({ root, entry }: { root: FileRoot; entry: FileEntry }) {
  const kind = previewKindOf(entry);
  const q = useFilePreview(root.id, entry.path, !!kind && !entry.escape);
  if (!kind || entry.escape) return null;
  return (
    <DetailSection
      title="预览"
      actions={
        filesMockEnabled() || entry.size > IMAGE_INLINE_MAX ? null : (
          <a
            className={buttonVariants({ size: "xs", variant: "outline" })}
            href={fileDownloadUrl(root.id, entry.path)}
            download={entry.name}
          >
            <Download />
            下载
          </a>
        )
      }
    >
      {q.isPending ? (
        <LoadingState rows={3} />
      ) : q.error ? (
        <p className="text-caption text-destructive">{filesErrorText(q.error, "预览失败")}</p>
      ) : q.data.type === "text" ? (
        <TextView p={q.data} />
      ) : q.data.type === "subtitle" ? (
        <SubtitleView p={q.data} />
      ) : q.data.type === "torrent" ? (
        <TorrentView p={q.data} />
      ) : (
        <ImageView root={root} entry={entry} p={q.data} />
      )}
    </DetailSection>
  );
}