import { AppError } from "../security/errors";

export type SubtitleSource = "com" | "org";

export type SubtitleHit = {
  fileId: number;
  language: string;
  release: string;
  fileName: string;
  downloadCount: number;
  hearingImpaired: boolean;
  fps: number | null;
  uploader: string | null;
  source: SubtitleSource;
};

type OsLogin = { token: string; baseUrl: string; expiresAt: number };

/**
 * OpenSubtitles.com REST API (v1).
 * Requires OPENSUBTITLES_API_KEY; login optional but needed for higher download quotas.
 */
export class OpenSubtitlesClient {
  private loginCache: OsLogin | null = null;

  constructor(
    private readonly apiKey: string,
    private readonly username?: string,
    private readonly password?: string
  ) {}

  private headers(extra?: Record<string, string>): Record<string, string> {
    return {
      "Api-Key": this.apiKey,
      "User-Agent": "MediaCluster v1.3",
      Accept: "application/json",
      ...extra,
    };
  }

  private root(): string {
    const base = this.loginCache?.baseUrl?.replace(/\/+$/, "");
    if (base && !base.startsWith("http")) return `https://${base}`;
    if (base) return base;
    return "https://api.opensubtitles.com";
  }

  async ensureLogin(): Promise<string | null> {
    if (!this.username?.trim() || !this.password?.trim()) return null;
    if (this.loginCache && Date.now() < this.loginCache.expiresAt) {
      return this.loginCache.token;
    }
    const res = await fetch(`${this.root()}/api/v1/login`, {
      method: "POST",
      headers: this.headers({ "Content-Type": "application/json" }),
      body: JSON.stringify({
        username: this.username.trim(),
        password: this.password.trim(),
      }),
    });
    if (!res.ok) {
      const text = await res.text().catch(() => "");
      throw new AppError(
        "OPENSUBTITLES",
        `OpenSubtitles login mislukt (${res.status}): ${text.slice(0, 160)}`,
        400
      );
    }
    const data = (await res.json()) as { token?: string; base_url?: string };
    if (!data.token) throw new AppError("OPENSUBTITLES", "OpenSubtitles: geen token", 400);
    this.loginCache = {
      token: data.token,
      baseUrl: data.base_url || "api.opensubtitles.com",
      expiresAt: Date.now() + 20 * 60 * 60 * 1000,
    };
    return data.token;
  }

  async search(opts: {
    imdbId?: string;
    languages?: string;
    query?: string;
  }): Promise<SubtitleHit[]> {
    const languages = (opts.languages || "nl").trim() || "nl";
    const params = new URLSearchParams({
      languages,
      type: "movie",
      order_by: "download_count",
      order_direction: "desc",
    });
    const imdb = opts.imdbId?.trim().replace(/^tt/i, "");
    if (imdb && /^\d+$/.test(imdb)) params.set("imdb_id", imdb);
    if (opts.query?.trim()) params.set("query", opts.query.trim());
    if (!params.has("imdb_id") && !params.has("query")) return [];

    const token = await this.ensureLogin().catch(() => null);
    const headers = this.headers(
      token ? { Authorization: `Bearer ${token}` } : undefined
    );

    const res = await fetch(`${this.root()}/api/v1/subtitles?${params}`, { headers });
    if (!res.ok) {
      const text = await res.text().catch(() => "");
      throw new AppError(
        "OPENSUBTITLES",
        `OpenSubtitles.com zoeken mislukt (${res.status}): ${text.slice(0, 160)}`,
        400
      );
    }

    const body = (await res.json()) as {
      data?: Array<{
        attributes?: {
          language?: string;
          release?: string;
          download_count?: number;
          hearing_impaired?: boolean;
          fps?: number;
          files?: Array<{ file_id?: number; file_name?: string }>;
          uploader?: { name?: string };
        };
      }>;
    };

    const out: SubtitleHit[] = [];
    for (const row of body.data ?? []) {
      const a = row.attributes;
      const file = a?.files?.[0];
      if (!file?.file_id) continue;
      out.push({
        fileId: file.file_id,
        language: (a?.language || languages).toLowerCase(),
        release: a?.release || file.file_name || "",
        fileName: file.file_name || a?.release || `sub-${file.file_id}.srt`,
        downloadCount: a?.download_count ?? 0,
        hearingImpaired: !!a?.hearing_impaired,
        fps: a?.fps ?? null,
        uploader: a?.uploader?.name ?? null,
        source: "com",
      });
    }
    return out.slice(0, 40);
  }

  async downloadFile(fileId: number): Promise<{ content: Buffer; fileName: string }> {
    const token = await this.ensureLogin();
    if (!token) {
      throw new AppError(
        "OPENSUBTITLES",
        "OpenSubtitles.com download vereist gebruikersnaam + wachtwoord (Instellingen)",
        400
      );
    }
    const headers = this.headers({
      "Content-Type": "application/json",
      Authorization: `Bearer ${token}`,
    });

    const res = await fetch(`${this.root()}/api/v1/download`, {
      method: "POST",
      headers,
      body: JSON.stringify({ file_id: fileId }),
    });
    if (!res.ok) {
      const text = await res.text().catch(() => "");
      throw new AppError(
        "OPENSUBTITLES",
        `OpenSubtitles.com download mislukt (${res.status}): ${text.slice(0, 200)}`,
        400
      );
    }
    const data = (await res.json()) as { link?: string; file_name?: string };
    if (!data.link) {
      throw new AppError("OPENSUBTITLES", "OpenSubtitles.com: geen download-link", 400);
    }
    const fileRes = await fetch(data.link);
    if (!fileRes.ok) {
      throw new AppError("OPENSUBTITLES", `Subtitle ophalen mislukt (${fileRes.status})`, 400);
    }
    const buf = Buffer.from(await fileRes.arrayBuffer());
    if (!buf.length) {
      throw new AppError("OPENSUBTITLES", "OpenSubtitles.com: leeg ondertitelbestand", 400);
    }
    return {
      content: buf,
      fileName: data.file_name || `subtitle-${fileId}.srt`,
    };
  }
}

/** Keep release tags for filename / OpenSubtitles matching. */
export function extractReleaseTags(
  release: string,
  title: string,
  year?: number | null
): string {
  let s = release.trim();
  s = s.replace(/\.(mkv|mp4|m4v|avi|ts|m2ts|srt|ass|sub)$/i, "");
  s = s.replace(/[._]+/g, " ");
  for (const w of title.split(/\s+/)) {
    const t = w.trim();
    if (t.length < 2) continue;
    const re = new RegExp(`\\b${escapeRegExp(t)}\\b`, "ig");
    s = s.replace(re, " ");
  }
  if (year && year > 1900) {
    s = s.replace(new RegExp(`\\b${year}\\b`, "g"), " ");
  }
  s = s.replace(/\s+/g, " ").trim();
  return s;
}

/** Strip resolution/codec noise so subtitle search can fall back to title match. */
export function stripQualityTokens(s: string): string {
  return s
    .replace(/[._]+/g, " ")
    .replace(
      /\b(2160p|1080p|720p|480p|4k|uhd|hdr10\+?|hdr|dv|dovi|atmos|truehd|dts(?:-hd)?(?:\s*ma)?|flac|aac|ac3|eac3|ddp5\.1|bluray|blu-ray|remux|web-?dl|webrip|hdtv|x265|x264|hevc|avc|h\.?265|h\.?264|proper|repack|extended|directors?\s*cut)\b/gi,
      " "
    )
    .replace(/\s+/g, " ")
    .trim();
}

function escapeRegExp(s: string): string {
  return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
}