'use client';

import { useCallback, useState } from 'react';
import { toast } from 'sonner';
import type { BunnyDownloadPreference, Comment, DownloadTarget, Version, VideoData } from '@/components/video-page/types';
import { resolvePublicBunnyCdnHostname } from '@/lib/bunny-cdn';

function sanitizeDownloadFileName(value: string): string {
  return value
    .replace(/[<>:"/\\|?*\u0000-\u001F]/g, '-')
    .replace(/\s+/g, ' ')
    .trim();
}

function getAllowedHosts() {
  const bunnyCdnHostname = resolvePublicBunnyCdnHostname();
  return [
    ...(bunnyCdnHostname ? [bunnyCdnHostname] : []),
    ...(process.env.NEXT_PUBLIC_DIRECT_DOWNLOAD_ALLOWED_HOSTS ?? '').split(','),
  ]
    .map((host) => host.trim().toLowerCase())
    .filter(Boolean);
}

function getSafeDirectDownloadUrl(rawUrl: string): string | null {
  try {
    const parsed = new URL(rawUrl);
    if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') {
      return null;
    }

    const allowedHosts = getAllowedHosts();
    if (allowedHosts.length === 0) {
      return null;
    }

    const normalizedHost = parsed.hostname.toLowerCase();
    if (!allowedHosts.includes(normalizedHost)) {
      return null;
    }

    return parsed.toString();
  } catch {
    return null;
  }
}

interface UseDownloadActionsParams {
  activeVersion: (Version & { comments: Comment[] }) | undefined;
  video: VideoData | null;
}

export function useDownloadActions({ activeVersion, video }: UseDownloadActionsParams) {
  const [activeDownloadTarget, setActiveDownloadTarget] = useState<DownloadTarget | null>(null);
  const isDownloadingVideo = activeDownloadTarget !== null;

  const startDownload = useCallback(async (preference: BunnyDownloadPreference = 'compressed') => {
    if (!activeVersion || !video || isDownloadingVideo) return;
    if (!video.canDownload) {
      toast.error('Download is disabled for this shared link');
      return;
    }
    if (activeVersion.providerId !== 'bunny' && activeVersion.providerId !== 'direct') {
      toast.error('This video source does not support direct download');
      return;
    }

    const target: DownloadTarget = activeVersion.providerId === 'bunny' ? preference : 'direct';
    setActiveDownloadTarget(target);
    try {
      let downloadUrl: string | null = null;

      if (activeVersion.providerId === 'bunny') {
        const prepareRes = await fetch(`/api/versions/${activeVersion.id}/download?source=${preference}&prepare=1`, {
          cache: 'no-store',
        });

        if (!prepareRes.ok) {
          const prepareBody = await prepareRes.json().catch(() => null);
          const fallbackError = preference === 'original'
            ? 'Original file is not available for this video'
            : 'Compressed file is not available for this video';
          const errorMessage = typeof prepareBody?.error === 'string'
            ? prepareBody.error
            : fallbackError;
          throw new Error(errorMessage);
        }

        downloadUrl = `/api/versions/${activeVersion.id}/download?source=${preference}`;
      } else {
        downloadUrl = getSafeDirectDownloadUrl(activeVersion.originalUrl);
        if (!downloadUrl) {
          throw new Error('Direct download URL is not allowed');
        }
      }

      if (!downloadUrl) {
        throw new Error('Missing download URL');
      }

      const versionLabel = activeVersion.versionLabel?.trim() || `v${activeVersion.versionNumber}`;
      const baseName = sanitizeDownloadFileName(`${video.title} ${versionLabel}`) || 'video';
      const a = document.createElement('a');
      a.href = downloadUrl;
      if (activeVersion.providerId === 'direct') {
        a.download = `${baseName}.mp4`;
      }
      document.body.appendChild(a);
      a.click();
      a.remove();
    } catch (error) {
      console.error('Failed to start video download:', error);
      if (error instanceof Error && error.message === 'Direct download URL is not allowed') {
        toast.error('This direct download host is not allowed');
      } else if (error instanceof Error && error.message) {
        toast.error(error.message);
      } else {
        toast.error('Failed to start download');
      }
    } finally {
      setActiveDownloadTarget(null);
    }
  }, [activeVersion, video, isDownloadingVideo]);

  return {
    activeDownloadTarget,
    isDownloadingVideo,
    startDownload,
  };
}