import { NextRequest, NextResponse } from 'next/server';
import { createClient } from '@/lib/supabase/server';
import { isAgencyRole, userRole } from '@/lib/agency';
import { resolveActiveTenant } from '@/lib/tenant-context';
import {
  filterDriveEntriesForClientRoot,
  isAppGeneratedDriveFolderName,
} from '@/lib/assets-client-scope';
import {
  findClientesRootFolder,
  getDriveDownloadUrl,
  getDriveFileMeta,
  getTenantDriveFolderId,
  isUnderDriveFolder,
  listFilesInFolder,
} from '@/lib/google-drive';

export const dynamic = 'force-dynamic';

const FOLDER_MIME = 'application/vnd.google-apps.folder';

async function listAppGeneratedRootFolderIds(
  clientRootId: string
): Promise<string[]> {
  const rootFiles = await listFilesInFolder(clientRootId);
  return rootFiles
    .filter(
      (f) =>
        f.mimeType === FOLDER_MIME && isAppGeneratedDriveFolderName(f.name)
    )
    .map((f) => f.id);
}

async function isUnderAppGeneratedTree(
  fileOrFolderId: string,
  clientRootId: string,
  appRootIds?: string[]
): Promise<boolean> {
  const roots =
    appRootIds ?? (await listAppGeneratedRootFolderIds(clientRootId));
  for (const appId of roots) {
    if (fileOrFolderId === appId) return true;
    if (await isUnderDriveFolder(fileOrFolderId, appId)) return true;
  }
  return false;
}

/** GET — Drive tree for active tenant. Agency: full tree. Client: app folders only. */
export async function GET(req: NextRequest) {
  const supabase = await createClient();
  const {
    data: { user },
  } = await supabase.auth.getUser();
  if (!user) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
  }

  const ctx = await resolveActiveTenant(user);
  if (!ctx.tenantId || ctx.portfolioWide) {
    return NextResponse.json(
      { error: 'Selecciona un cliente en Contexto' },
      { status: 400 }
    );
  }

  const agency = isAgencyRole(userRole(user));

  const downloadId = req.nextUrl.searchParams.get('download')?.trim();
  if (downloadId) {
    try {
      const link = await getTenantDriveFolderId(ctx.tenantId);
      if (!link) {
        return NextResponse.json(
          { error: 'Sin carpeta Drive del cliente' },
          { status: 400 }
        );
      }
      const ok = await isUnderDriveFolder(downloadId, link.folderId);
      if (!ok) {
        return NextResponse.json(
          { error: 'Archivo fuera de la carpeta del cliente' },
          { status: 403 }
        );
      }
      if (!agency) {
        const inApp = await isUnderAppGeneratedTree(downloadId, link.folderId);
        if (!inApp) {
          return NextResponse.json(
            { error: 'Archivo fuera del alcance del cliente' },
            { status: 403 }
          );
        }
      }
      const url = await getDriveDownloadUrl(downloadId);
      return NextResponse.json({ url });
    } catch (e) {
      return NextResponse.json(
        { error: e instanceof Error ? e.message : 'download failed' },
        { status: 500 }
      );
    }
  }

  const link = await getTenantDriveFolderId(ctx.tenantId);
  if (!link) {
    return NextResponse.json({
      files: [],
      linked: false,
      agency,
      clientScope: agency ? 'full' : 'app_generated',
      warning:
        'Sin carpeta Drive del cliente. En Agencia → auto-match bajo la carpeta «Clientes».',
    });
  }

  // Soft check: linked folder should live under «Clientes»
  let scopeWarning: string | null = null;
  try {
    const clientes = await findClientesRootFolder();
    if (clientes) {
      const ok = await isUnderDriveFolder(link.folderId, clientes.id);
      if (!ok) {
        scopeWarning = `La carpeta enlazada («${link.folderName || link.folderId}») no está dentro de «Clientes». Rematch en Agencia.`;
      }
    }
  } catch {
    /* ignore */
  }

  const requested = req.nextUrl.searchParams.get('folderId')?.trim();
  let folderId = link.folderId;
  let appRootIds: string[] | undefined;

  if (requested && requested !== link.folderId) {
    const allowed = await isUnderDriveFolder(requested, link.folderId);
    if (!allowed) {
      return NextResponse.json(
        {
          error:
            'Carpeta fuera del árbol del cliente. Solo se permite navegar dentro de su carpeta en Clientes.',
          rootFolderId: link.folderId,
          folderName: link.folderName,
        },
        { status: 403 }
      );
    }
    if (!agency) {
      appRootIds = await listAppGeneratedRootFolderIds(link.folderId);
      const inApp = await isUnderAppGeneratedTree(
        requested,
        link.folderId,
        appRootIds
      );
      if (!inApp) {
        return NextResponse.json(
          {
            error:
              'Solo puedes abrir carpetas generadas por el Centro de Mando (creatividades, calendarios…).',
            rootFolderId: link.folderId,
            folderName: link.folderName,
          },
          { status: 403 }
        );
      }
    }
    folderId = requested;
  }

  try {
    const currentMeta = await getDriveFileMeta(folderId);
    const files = await listFilesInFolder(folderId);
    let mapped = files
      .map((f) => ({
        id: f.id,
        name: f.name,
        mimeType: f.mimeType,
        bytes: f.size ? Number(f.size) : null,
        modifiedTime: f.modifiedTime,
        webViewLink: f.webViewLink,
        isFolder: f.mimeType === FOLDER_MIME,
        source: 'drive' as const,
      }))
      .sort((a, b) => {
        if (a.isFolder !== b.isFolder) return a.isFolder ? -1 : 1;
        return a.name.localeCompare(b.name, 'es');
      });

    const atClientRoot = folderId === link.folderId;
    if (!agency && atClientRoot) {
      mapped = filterDriveEntriesForClientRoot(mapped);
      if (!mapped.length && !scopeWarning) {
        scopeWarning =
          'Aún no hay carpetas generadas por la app (p. ej. Pipeline-creatividades). El resto del Drive solo lo ve la agencia.';
      }
    }

    return NextResponse.json({
      linked: true,
      agency,
      clientScope: agency ? 'full' : 'app_generated',
      rootFolderId: link.folderId,
      rootFolderName: link.folderName,
      folderId,
      folderName: currentMeta?.name || link.folderName,
      driveOpenUrl: agency
        ? `https://drive.google.com/drive/folders/${encodeURIComponent(folderId)}`
        : null,
      files: mapped,
      warning: scopeWarning,
    });
  } catch (e) {
    return NextResponse.json({
      linked: true,
      agency,
      clientScope: agency ? 'full' : 'app_generated',
      rootFolderId: link.folderId,
      rootFolderName: link.folderName,
      folderId,
      folderName: link.folderName,
      files: [],
      warning: scopeWarning || (e instanceof Error ? e.message : 'Drive error'),
    });
  }
}