import { randomUUID } from "crypto";
import { prisma } from "../database/client";
import { nodeConnectionManager } from "../websocket/manager";
import type { SubtitleHit } from "../opensubtitles/client";

type LocalSubCacheEntry = {
  contentBase64: string;
  fileName: string;
  format: string;
  language: string;
  mediaFileId: string;
  expiresAt: number;
};

const localSubCache = new Map<number, LocalSubCacheEntry>();
const CACHE_TTL_MS = 30 * 60_000;

export function stableLocalFileId(key: string): number {
  let h = 2166136261;
  for (let i = 0; i < key.length; i++) {
    h ^= key.charCodeAt(i);
    h = Math.imul(h, 16777619);
  }
  const n = Math.abs(h) % 2_000_000_000;
  return n === 0 ? 1 : n;
}

function putLocalCache(fileId: number, entry: Omit<LocalSubCacheEntry, "expiresAt">) {
  localSubCache.set(fileId, { ...entry, expiresAt: Date.now() + CACHE_TTL_MS });
}

export function getLocalSubtitleCache(fileId: number): LocalSubCacheEntry | null {
  const hit = localSubCache.get(fileId);
  if (!hit) return null;
  if (Date.now() > hit.expiresAt) {
    localSubCache.delete(fileId);
    return null;
  }
  return hit;
}

/** Ask node for sidecar .srt/.ass next to the video; cache + upsert library_subtitles. */
export async function discoverSidecarSubtitles(mediaFileId: string): Promise<SubtitleHit[]> {
  const file = await prisma.mediaFile.findUnique({
    where: { id: mediaFileId },
    include: {
      movie: { select: { id: true, tmdbId: true, imdbId: true } },
      episode: {
        select: {
          imdbId: true,
          series: { select: { imdbId: true, tmdbId: true } },
        },
      },
    },
  });
  if (!file || !nodeConnectionManager.isOnline(file.nodeId)) return [];

  const requestId = randomUUID();
  const ack = await nodeConnectionManager.findSidecarSubtitlesAcked(
    file.nodeId,
    { requestId, localFileId: file.localFileId },
    15_000
  );
  if (!ack.ok || !ack.subtitles?.length) return [];

  const hits: SubtitleHit[] = [];
  for (const sub of ack.subtitles) {
    const format = (sub.format || "srt").toLowerCase();
    const language = (sub.language || "nl").toLowerCase();
    const fileName = sub.fileName || `local.${format}`;
    const fileId = stableLocalFileId(`${mediaFileId}:${fileName}`);
    putLocalCache(fileId, {
      contentBase64: sub.contentBase64,
      fileName,
      format,
      language,
      mediaFileId,
    });

    // Persist for Stremio stream.subtitles
    try {
      const content = Buffer.from(sub.contentBase64, "base64").toString("utf8");
      if (content.trim()) {
        const movieId = file.movieId ?? null;
        const tmdbId = file.movie?.tmdbId ?? file.episode?.series?.tmdbId ?? null;
        const imdbId =
          file.movie?.imdbId || file.episode?.imdbId || file.episode?.series?.imdbId || null;
        const linkFilter = [
          ...(movieId ? [{ movieId }] : []),
          ...(tmdbId != null ? [{ tmdbId }] : []),
          ...(imdbId ? [{ imdbId }] : []),
        ];
        const existing =
          linkFilter.length > 0
            ? await prisma.librarySubtitle.findFirst({
                where: { fileName, OR: linkFilter },
              })
            : await prisma.librarySubtitle.findFirst({
                where: { fileName, content },
              });
        if (existing) {
          await prisma.librarySubtitle.update({
            where: { id: existing.id },
            data: { content, language, format, updatedAt: new Date() },
          });
        } else {
          await prisma.librarySubtitle.create({
            data: {
              movieId,
              tmdbId,
              imdbId,
              language,
              format,
              content,
              fileName,
            },
          });
        }
      }
    } catch (err) {
      console.warn("[sidecars] library_subtitles upsert:", err);
    }

    hits.push({
      fileId,
      language,
      release: `Lokaal · ${fileName}`,
      fileName,
      downloadCount: 9_999_999,
      hearingImpaired: /\b(sdh|hi|hearing)\b/i.test(fileName),
      fps: null,
      uploader: "lokaal",
      source: "local",
    });
  }
  return hits;
}