import { NextRequest } from 'next/server';
import { db } from '@/lib/db';
import { auth, checkProjectAccess } from '@/lib/auth';
import { rateLimit } from '@/lib/rate-limit';
import { cleanupBunnyStreamVideosBestEffort } from '@/lib/bunny-stream-cleanup';
import { deleteMediaFilesBestEffort } from '@/lib/r2-cleanup';
import { buildCleanupWarnings, logCleanupWarnings } from '@/lib/cleanup-warnings';
import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
import { logError } from '@/lib/logger';

type RouteParams = { params: Promise<{ projectId: string; videoId: string; versionId: string }> };

async function getVersionWithAccess(
  projectId: string,
  videoId: string,
  versionId: string,
  userId: string
) {
  const version = await db.videoVersion.findFirst({
    where: { id: versionId, videoParentId: videoId },
    include: {
      video: {
        include: {
          project: true,
        },
      },
    },
  });

  if (!version || version.video.projectId !== projectId) {
    return null;
  }

  const project = version.video.project;
  const access = await checkProjectAccess(project, userId);

  return { version, canEdit: access.canEdit, isOwner: access.isOwner };
}

// PATCH /api/projects/[projectId]/videos/[videoId]/versions/[versionId]
export async function PATCH(request: NextRequest, { params }: RouteParams) {
  try {
    const limited = await rateLimit(request, 'mutate');
    if (limited) return limited;

    const session = await auth();
    const { projectId, videoId, versionId } = await params;

    if (!session?.user?.id) {
      return apiErrors.unauthorized();
    }

    const result = await getVersionWithAccess(projectId, videoId, versionId, session.user.id);
    if (!result) {
      return apiErrors.notFound('Version');
    }
    if (!result.canEdit) {
      return apiErrors.forbidden('Access denied');
    }

    const body = await request.json();
    const { duration, versionLabel, isActive } = body;

    if (
      duration !== undefined &&
      (typeof duration !== 'number' || !isFinite(duration) || duration < 0)
    ) {
      return apiErrors.badRequest('Invalid duration value');
    }

    const updateData: Record<string, unknown> = {};
    if (duration !== undefined) updateData.duration = duration;
    if (versionLabel !== undefined) updateData.versionLabel = versionLabel?.trim() || null;

    if (isActive === true) {
      // Deactivate all other versions, then activate this one
      await db.videoVersion.updateMany({
        where: { videoParentId: videoId },
        data: { isActive: false },
      });
      updateData.isActive = true;
    }

    const updated = await db.videoVersion.update({
      where: { id: versionId },
      data: updateData,
    });

    const response = successResponse(updated);
    return withCacheControl(response, 'private, no-store');
  } catch (error) {
    logError('Error updating version:', error);
    return apiErrors.internalError('Failed to update version');
  }
}

// DELETE /api/projects/[projectId]/videos/[videoId]/versions/[versionId]
export async function DELETE(request: NextRequest, { params }: RouteParams) {
  try {
    const limited = await rateLimit(request, 'mutate');
    if (limited) return limited;

    const session = await auth();
    const { projectId, videoId, versionId } = await params;

    if (!session?.user?.id) {
      return apiErrors.unauthorized();
    }

    const result = await getVersionWithAccess(projectId, videoId, versionId, session.user.id);
    if (!result) {
      return apiErrors.notFound('Version');
    }
    if (!result.canEdit) {
      return apiErrors.forbidden('Access denied');
    }

    // Check there's more than one version — can't delete the last one
    const versionCount = await db.videoVersion.count({
      where: { videoParentId: videoId },
    });

    if (versionCount <= 1) {
      return apiErrors.badRequest('Cannot delete the only version. Delete the video instead.');
    }

    const wasActive = result.version.isActive;
    const bunnyRef = {
      providerId: result.version.providerId,
      videoId: result.version.videoId,
    };

    // Read before the delete: the rows cascade away with the version, and their stored
    // objects would then have nothing pointing at them. Subtitles live in our own storage
    // whatever hosts the video, so this runs for a Bunny-hosted cut too.
    const subtitles = await db.videoSubtitle.findMany({
      where: { versionId },
      select: { sourceUrl: true },
    });

    await db.$transaction(async (tx) => {
      // Delete the version (cascades to comments).
      await tx.videoVersion.delete({ where: { id: versionId } });

      // If the deleted version was active, activate the latest remaining one.
      if (wasActive) {
        const latestVersion = await tx.videoVersion.findFirst({
          where: { videoParentId: videoId },
          orderBy: { versionNumber: 'desc' },
        });
        if (latestVersion) {
          await tx.videoVersion.update({
            where: { id: latestVersion.id },
            data: { isActive: true },
          });
        }
      }
    });

    const versionMediaUrls = [
      ...subtitles.map((subtitle) => subtitle.sourceUrl),
      ...(result.version.providerId === 'r2'
        ? [result.version.originalUrl, result.version.thumbnailUrl]
        : []),
    ].filter((url): url is string => Boolean(url));

    const [bunnyCleanupResult, r2CleanupResult] = await Promise.all([
      cleanupBunnyStreamVideosBestEffort([bunnyRef]),
      deleteMediaFilesBestEffort(versionMediaUrls),
    ]);
    const cleanupInput = { bunny: bunnyCleanupResult, r2: r2CleanupResult };
    const cleanupWarnings = buildCleanupWarnings(cleanupInput);
    if (cleanupWarnings) {
      logCleanupWarnings({ entityType: 'video-version', entityId: versionId }, cleanupInput);
    }

    const response = successResponse({
      message: 'Version deleted',
      ...(cleanupWarnings ? { cleanupWarnings } : {}),
    });
    return withCacheControl(response, 'private, no-store');
  } catch (error) {
    logError('Error deleting version:', error);
    return apiErrors.internalError('Failed to delete version');
  }
}