import { NextResponse } from 'next/server';
import fs from 'fs';
import path from 'path';
import { getDatasetsRoot } from '@/server/settings';

const sanitizeSegment = (value: string): string => {
  if (!value || typeof value !== 'string') {
    return '';
  }

  return value
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '_')
    .replace(/^_+|_+$/g, '');
};

export async function POST(request: Request) {
  try {
    const body = await request.json();
    const { currentName, newName } = body ?? {};

    if (!currentName || typeof currentName !== 'string') {
      return NextResponse.json({ error: 'Current dataset name is required' }, { status: 400 });
    }

    if (!newName || typeof newName !== 'string') {
      return NextResponse.json({ error: 'New dataset name is required' }, { status: 400 });
    }

    const datasetsRoot = await getDatasetsRoot();

    const sanitizedCurrent = sanitizeSegment(currentName);
    const currentPath = path.join(datasetsRoot, sanitizedCurrent);

    if (!fs.existsSync(currentPath)) {
      return NextResponse.json({ error: `Dataset '${currentName}' not found` }, { status: 404 });
    }

    const sanitizedNew = sanitizeSegment(newName);
    if (!sanitizedNew) {
      return NextResponse.json({ error: 'New dataset name is invalid' }, { status: 400 });
    }

    if (sanitizedCurrent === sanitizedNew) {
      return NextResponse.json({ success: true, name: sanitizedCurrent, path: currentPath });
    }

    const newPath = path.join(datasetsRoot, sanitizedNew);
    if (fs.existsSync(newPath)) {
      return NextResponse.json({ error: `Dataset '${sanitizedNew}' already exists` }, { status: 409 });
    }

    fs.renameSync(currentPath, newPath);

    return NextResponse.json({ success: true, name: sanitizedNew, path: newPath });
  } catch (error: any) {
    console.error('Dataset rename error:', error);
    return NextResponse.json({ error: error?.message || 'Failed to rename dataset' }, { status: 500 });
  }
}