import { createClient } from '@supabase/supabase-js';

const FB_SOURCE = 'srv';
const PROJECT_DEFAULT_SUBFOLDERS = ['00 Project Files'];
const REQUEST_DEFAULT_SUBFOLDERS = ['Old Books', 'Working Files', 'Survey'];

export const config = { api: { bodyParser: false, sizeLimit: '50mb' } };

function json(res, status, body) {
  res.status(status).setHeader('Content-Type', 'application/json');
  res.setHeader('Cache-Control', 'no-store');
  res.send(JSON.stringify(body));
}

function normalizePath(path) {
  const raw = String(path || '/').trim();
  const parts = raw.split('/').filter(Boolean);
  const clean = [];
  for (const part of parts) {
    if (part === '.') continue;
    if (part === '..') throw new Error('Invalid path: path traversal not allowed');
    clean.push(part);
  }
  return `/${clean.join('/')}`;
}

function joinPath(...parts) {
  return normalizePath(parts.join('/'));
}

function safeName(value, fallback = '') {
  const cleaned = String(value || '')
    .trim()
    .replace(/[\\/:*?"<>|#%{}^~[\]`]+/g, '-')
    .replace(/\s+/g, ' ')
    .replace(/^-+|-+$/g, '');
  return cleaned || fallback;
}

async function readBody(req) {
  return new Promise((resolve, reject) => {
    const chunks = [];
    req.on('data', (chunk) => chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk)));
    req.on('end', () => resolve(Buffer.concat(chunks)));
    req.on('error', reject);
  });
}

function getConfig() {
  const url = String(process.env.FILEBROWSER_URL || '').trim().replace(/\/+$/, '');
  return {
    url,
    token: process.env.FILEBROWSER_TOKEN || '',
    clientRoot: normalizePath(process.env.FILEBROWSER_CLIENT_ROOT || '/fourgebranding/Clients'),
    subsRoot: normalizePath(process.env.FILEBROWSER_SUBS_ROOT || '/fourgebranding/team'),
    configured: Boolean(url),
  };
}

function getToken(config) {
  const token = String(config.token || '').trim();
  if (!token) throw new Error('FILEBROWSER_TOKEN not configured');
  return token;
}

async function fbFetch(config, method, endpoint, { params = {}, headers = {}, body } = {}) {
  const qs = new URLSearchParams({ source: FB_SOURCE, ...params }).toString();
  const url = `${config.url}${endpoint}?${qs}`;
  const token = getToken(config);
  const response = await fetch(url, {
    method,
    headers: { Authorization: `Bearer ${token}`, ...headers },
    body,
  });

  if (!response.ok) {
    const text = await response.text().catch(() => '');
    const error = new Error(text || `FileBrowser ${response.status}`);
    error.status = response.status;
    throw error;
  }

  const text = await response.text();
  try {
    return text ? JSON.parse(text) : null;
  } catch {
    return text;
  }
}

async function createCallerClient(authHeader) {
  const supabaseUrl = process.env.VITE_SUPABASE_URL || process.env.SUPABASE_URL;
  const supabaseAnonKey = process.env.VITE_SUPABASE_ANON_KEY || process.env.SUPABASE_ANON_KEY;
  if (!supabaseUrl || !supabaseAnonKey) throw new Error('Supabase env not configured');
  return createClient(supabaseUrl, supabaseAnonKey, {
    auth: { persistSession: false, autoRefreshToken: false },
    global: { headers: { Authorization: authHeader } },
  });
}

async function requirePortalUser(authHeader) {
  const callerClient = await createCallerClient(authHeader);
  const { data: userData, error: userError } = await callerClient.auth.getUser();
  if (userError || !userData?.user) return { ok: false, status: 401, message: 'Unauthorized' };

  const { data: profile, error: profileError } = await callerClient
    .from('profiles')
    .select('id, role, company:companies(id, name)')
    .eq('id', userData.user.id)
    .single();

  if (profileError) return { ok: false, status: 500, message: profileError.message };
  if (!['team', 'client'].includes(profile?.role)) {
    return { ok: false, status: 403, message: 'Forbidden' };
  }

  const clientCompanies = [];
  if (profile.role === 'client') {
    const seen = new Set();
    if (profile.company?.id) {
      clientCompanies.push(profile.company);
      seen.add(profile.company.id);
    }
    const { data: memberships } = await callerClient
      .from('company_members')
      .select('company:companies(id, name)')
      .eq('profile_id', userData.user.id);
    for (const row of memberships || []) {
      if (row.company?.id && !seen.has(row.company.id)) {
        seen.add(row.company.id);
        clientCompanies.push(row.company);
      }
    }
  }

  return {
    ok: true,
    profile: { ...profile, clientCompanies },
  };
}

function createAdminClient() {
  const supabaseUrl = process.env.VITE_SUPABASE_URL || process.env.SUPABASE_URL;
  const serviceKey = process.env.SUPABASE_SERVICE_ROLE_KEY;
  if (!supabaseUrl || !serviceKey) throw new Error('Supabase admin env not configured');
  return createClient(supabaseUrl, serviceKey, {
    auth: { persistSession: false, autoRefreshToken: false },
  });
}

function isAlreadyExistsError(error) {
  const message = String(error?.message || '').toLowerCase();
  return error?.status === 409 || message.includes('exist') || message.includes('conflict');
}

async function ensureDirectory(config, fullPath) {
  const parts = normalizePath(fullPath).split('/').filter(Boolean);
  let current = '/';
  for (const part of parts) {
    current = joinPath(current, part);
    try {
      await fbFetch(config, 'POST', '/api/resources', {
        params: { path: current, isDir: 'true' },
      });
    } catch (error) {
      if (!isAlreadyExistsError(error)) throw error;
    }
  }
}

async function renameDirectory(config, fromPath, toPath) {
  const sourcePath = normalizePath(fromPath);
  const targetPath = normalizePath(toPath);
  if (sourcePath === targetPath) return { renamed: false, skipped: true, path: targetPath };

  try {
    await fbFetch(config, 'PATCH', '/api/resources', {
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'rename',
        items: [{ fromSource: FB_SOURCE, fromPath: sourcePath, toSource: FB_SOURCE, toPath: targetPath }],
        overwrite: false,
      }),
    });
    return { renamed: true, path: targetPath };
  } catch (error) {
    if (error?.status === 404) {
      await ensureDirectory(config, targetPath);
      return { renamed: false, ensured: true, path: targetPath };
    }
    throw error;
  }
}

export default async function handler(req, res) {
  const action = String(req.query?.action || '').trim();
  if (req.method !== 'POST' || ![
    'ensure-company-folder',
    'ensure-project-folder',
    'ensure-request-folder',
    'ensure-profile-folder',
    'upload-request-file',
    'rename-company-folder',
    'rename-project-folder',
    'rename-profile-folder',
  ].includes(action)) {
    return json(res, 405, { error: 'Method not allowed' });
  }

  const authHeader = req.headers.authorization || '';
  if (!authHeader.startsWith('Bearer ')) {
    return json(res, 401, { error: 'Unauthorized' });
  }

  const config = getConfig();
  if (!config.configured) {
    return json(res, 200, { ok: false, configured: false, warning: 'FileBrowser is not configured.' });
  }

  try {
    const rawBody = await readBody(req);
    const body = (() => {
      if (!rawBody.length) return {};
      const contentType = String(req.headers['content-type'] || '').split(';')[0].trim();
      if (contentType === 'application/json') {
        try {
          return JSON.parse(rawBody.toString());
        } catch {
          return {};
        }
      }
      return {};
    })();
    const auth = await requirePortalUser(authHeader);
    if (!auth.ok) return json(res, auth.status, { error: auth.message });

    const admin = createAdminClient();
    if (action === 'ensure-company-folder') {
      if (auth.profile.role !== 'team') {
        return json(res, 403, { error: 'Forbidden' });
      }
      const companyId = String(body.companyId || '').trim();
      if (!companyId) return json(res, 400, { error: 'companyId is required.' });

      const { data: company, error: companyError } = await admin
        .from('companies')
        .select('id, name')
        .eq('id', companyId)
        .single();
      if (companyError || !company) return json(res, 404, { error: 'Company not found.' });

      const fullPath = joinPath(config.clientRoot, safeName(company.name, company.id));
      await ensureDirectory(config, fullPath);
      return json(res, 200, { ok: true, configured: true, path: fullPath });
    }

    if (action === 'rename-company-folder') {
      if (auth.profile.role !== 'team') {
        return json(res, 403, { error: 'Forbidden' });
      }
      const companyId = String(body.companyId || '').trim();
      const oldName = safeName(body.oldName, '');
      const newName = safeName(body.newName, '');
      if (!companyId || !oldName || !newName) return json(res, 400, { error: 'companyId, oldName, and newName are required.' });

      const { data: company, error: companyError } = await admin
        .from('companies')
        .select('id')
        .eq('id', companyId)
        .single();
      if (companyError || !company) return json(res, 404, { error: 'Company not found.' });

      const result = await renameDirectory(config, joinPath(config.clientRoot, oldName), joinPath(config.clientRoot, newName));
      return json(res, 200, { ok: true, configured: true, ...result });
    }

    if (action === 'ensure-profile-folder') {
      if (auth.profile.role !== 'team') {
        return json(res, 403, { error: 'Forbidden' });
      }
      const profileId = String(body.profileId || '').trim();
      if (!profileId) return json(res, 400, { error: 'profileId is required.' });

      const { data: profile, error: profileError } = await admin
        .from('profiles')
        .select('id, name, role')
        .eq('id', profileId)
        .single();
      if (profileError || !profile) return json(res, 404, { error: 'Profile not found.' });
      if (profile.role !== 'external') return json(res, 400, { error: 'Only subcontractor folders are supported here.' });

      const fullPath = joinPath(config.subsRoot, safeName(profile.name, profile.id));
      await ensureDirectory(config, fullPath);
      return json(res, 200, { ok: true, configured: true, path: fullPath });
    }

    if (action === 'rename-profile-folder') {
      if (auth.profile.role !== 'team') {
        return json(res, 403, { error: 'Forbidden' });
      }
      const profileId = String(body.profileId || '').trim();
      const oldName = safeName(body.oldName, '');
      const newName = safeName(body.newName, '');
      if (!profileId || !oldName || !newName) return json(res, 400, { error: 'profileId, oldName, and newName are required.' });

      const { data: profile, error: profileError } = await admin
        .from('profiles')
        .select('id, role')
        .eq('id', profileId)
        .single();
      if (profileError || !profile) return json(res, 404, { error: 'Profile not found.' });
      if (profile.role !== 'external') return json(res, 400, { error: 'Only subcontractor folders are supported here.' });

      const result = await renameDirectory(config, joinPath(config.subsRoot, oldName), joinPath(config.subsRoot, newName));
      return json(res, 200, { ok: true, configured: true, ...result });
    }

    const projectId = String(req.query?.projectId || body.projectId || '').trim();
    if (!projectId) return json(res, 400, { error: 'projectId is required.' });

    const { data: project, error: projectError } = await admin
      .from('projects')
      .select('id, name, company_id, company:companies(id, name)')
      .eq('id', projectId)
      .single();
    if (projectError || !project) return json(res, 404, { error: 'Project not found.' });

    if (auth.profile.role === 'client') {
      const allowedCompanyIds = new Set((auth.profile.clientCompanies || []).map(company => company.id));
      if (!allowedCompanyIds.has(project.company_id)) return json(res, 403, { error: 'Forbidden' });
    }

    const companyName = safeName(project.company?.name, String(project.company_id || 'company'));
    const projectName = safeName(project.name, projectId);

    if (action === 'rename-project-folder') {
      const oldName = safeName(body.oldName, '');
      const newName = safeName(body.newName, '');
      if (!oldName || !newName) return json(res, 400, { error: 'oldName and newName are required.' });
      const result = await renameDirectory(
        config,
        joinPath(config.clientRoot, companyName, 'Projects', oldName),
        joinPath(config.clientRoot, companyName, 'Projects', newName)
      );
      return json(res, 200, { ok: true, configured: true, ...result });
    }

    if (action === 'ensure-project-folder') {
      const fullPath = joinPath(config.clientRoot, companyName, 'Projects', projectName);
      await ensureDirectory(config, fullPath);
      for (const folderName of PROJECT_DEFAULT_SUBFOLDERS) {
        await ensureDirectory(config, joinPath(fullPath, folderName));
      }
      return json(res, 200, { ok: true, configured: true, path: fullPath });
    }

    const taskTitle = safeName(req.query?.taskTitle || body.taskTitle, '');
    if (!taskTitle) return json(res, 400, { error: 'taskTitle is required.' });
    const fullPath = joinPath(config.clientRoot, companyName, 'Projects', projectName, taskTitle);

    if (action === 'upload-request-file') {
      const bucket = String(body.bucket || 'submissions').trim();
      const storagePath = String(body.storagePath || '').trim();
      const fileName = safeName(body.fileName || req.query?.fileName || req.headers['x-file-name'], '');
      if (!storagePath) return json(res, 400, { error: 'storagePath is required.' });
      if (!fileName) return json(res, 400, { error: 'fileName is required.' });
      const surveyPath = joinPath(fullPath, 'Survey');
      await ensureDirectory(config, surveyPath);
      const { data: downloadedFile, error: downloadError } = await admin.storage.from(bucket).download(storagePath);
      if (downloadError || !downloadedFile) {
        return json(res, 500, { error: downloadError?.message || 'Failed to download request file from storage.' });
      }
      const fileBuffer = Buffer.from(await downloadedFile.arrayBuffer());
      const uploadUrl = `${config.url}/api/resources?source=${FB_SOURCE}&path=${encodeURIComponent(joinPath(surveyPath, fileName))}&override=true`;
      const contentType = String(downloadedFile.type || '').trim() || 'application/octet-stream';
      const response = await fetch(uploadUrl, {
        method: 'POST',
        headers: {
          Authorization: `Bearer ${getToken(config)}`,
          'Content-Type': contentType,
        },
        body: fileBuffer,
      });
      if (!response.ok) {
        const text = await response.text().catch(() => '');
        return json(res, response.status, { error: text || `Upload failed (${response.status})` });
      }
      return json(res, 200, { ok: true, configured: true, path: joinPath(surveyPath, fileName) });
    }

    await ensureDirectory(config, fullPath);
    for (const folderName of REQUEST_DEFAULT_SUBFOLDERS) {
      await ensureDirectory(config, joinPath(fullPath, folderName));
    }
    return json(res, 200, { ok: true, configured: true, path: fullPath });
  } catch (error) {
    return json(res, error?.status || 500, { error: error?.message || 'Failed to ensure request folder.' });
  }
}