const http = require('http');
const fs = require('fs');
const path = require('path');
const XLSX = require('xlsx');
const formidable = require('formidable');

const PORT = process.env.PORT || 3000;
const DATA_FILE = path.join(__dirname, 'data.json');

function readData() {
  try {
    return JSON.parse(fs.readFileSync(DATA_FILE, 'utf8'));
  } catch (e) {
    return { employees: [], decrees: [], payments: [], operations: [] };
  }
}

function writeData(data) {
  fs.writeFileSync(DATA_FILE, JSON.stringify(data, null, 2));
}

function parseBody(req) {
  return new Promise((resolve) => {
    let s = '';
    req.on('data', (c) => (s += c));
    req.on('end', () => {
      try {
        resolve(JSON.parse(s || '{}'));
      } catch (_) {
        resolve({});
      }
    });
  });
}

function sendJSON(res, data, status = 200) {
  res.writeHead(status, { 'Content-Type': 'application/json' });
  res.end(JSON.stringify(data));
}

http.createServer(async (req, res) => {
  const url = req.url.split('?')[0];
  
  if (req.method === 'GET' && url === '/api/data') {
    const data = readData();
    return sendJSON(res, data);
  }
  
  if (req.method === 'POST' && url === '/api/data') {
    const body = await parseBody(req);
    writeData(body);
    return sendJSON(res, { ok: true });
  }
  
  if (req.method === 'POST' && url === '/api/upload-sap') {
    const form = formidable({ uploadDir: __dirname, keepExtensions: true });
    form.parse(req, async (err, fields, files) => {
      if (err) {
        return sendJSON(res, { error: err.message }, 400);
      }
      
      const file = files.file && files.file[0];
      if (!file) {
        return sendJSON(res, { error: 'Нет файла' }, 400);
      }
      
      try {
        const wb = XLSX.readFile(file.filepath);
        const sheet = wb.Sheets[wb.SheetNames[0]];
        const data = XLSX.utils.sheet_to_json(sheet);
        
        fs.unlinkSync(file.filepath);
        
        const currentData = readData();
        let imported = 0;
        
        data.forEach(row => {
          const tabNum = row['Табельный номер'] || row['Таб.номер'] || row['tab_num'];
          if (tabNum) {
            const existing = currentData.employees.find(e => e.tabNum === String(tabNum));
            if (existing) {
              existing.name = row['ФИО'] || row['FIO'] || existing.name;
              existing.iin = row['ИИН'] || row['IIN'] || existing.iin;
              existing.salary = parseFloat(row['ЧистыйДоход'] || row['Чистый доход'] || row['salary'] || existing.salary);
            } else {
              currentData.employees.push({
                id: Date.now() + Math.random(),
                tabNum: String(tabNum),
                name: row['ФИО'] || row['FIO'] || 'Не указано',
                iin = row['ИИН'] || row['IIN'] || '',
                salary: parseFloat(row['ЧистыйДоход'] || row['Чистый доход'] || row['salary'] || 0)
              });
              imported++;
            }
          }
        });
        
        writeData(currentData);
        sendJSON(res, { ok: true, imported, total: currentData.employees.length });
      } catch (err) {
        sendJSON(res, { error: err.message }, 400);
      }
    });
    return;
  }
  
  if (req.method === 'POST' && url === '/api/upload-payment') {
    const form = formidable({ uploadDir: __dirname, keepExtensions: true });
    form.parse(req, async (err, fields, files) => {
      if (err) {
        return sendJSON(res, { error: err.message }, 400);
      }
      
      const file = files.file && files.file[0];
      if (!file) {
        return sendJSON(res, { error: 'Нет файла' }, 400);
      }
      
      try {
        const wb = XLSX.readFile(file.filepath);
        const sheet = wb.Sheets[wb.SheetNames[0]];
        const data = XLSX.utils.sheet_to_json(sheet);
        
        fs.unlinkSync(file.filepath);
        
        const currentData = readData();
        let imported = 0;
        
        data.forEach(row => {
          const decreeNumber = row['Номер постановления'] || row['decree_number'];
          if (decreeNumber) {
            const decree = currentData.decrees.find(d => d.number === String(decreeNumber));
            if (decree) {
              currentData.payments.push({
                id: Date.now() + Math.random(),
                decreeId: decree.id,
                decreeNumber: String(decreeNumber),
                amount: parseFloat(row['Сумма'] || row['amount'] || 0),
                date: row['Дата'] || row['date'] || new Date().toISOString().split('T')[0],
                period: fields.period || new Date().toISOString().slice(0, 7)
              });
              
              decree.paidAmount = (decree.paidAmount || 0) + parseFloat(row['Сумма'] || row['amount'] || 0);
              if (decree.paidAmount >= decree.amount) {
                decree.status = 'closed';
              }
              imported++;
            }
          }
        });
        
        writeData(currentData);
        sendJSON(res, { ok: true, imported });
      } catch (err) {
        sendJSON(res, { error: err.message }, 400);
      }
    });
    return;
  }
  
  if (req.method === 'POST' && url === '/api/export-bank') {
    const body = await parseBody(req);
    const data = readData();
    
    const exportData = [];
    data.employees.forEach(emp => {
      const decrees = data.decrees.filter(d => d.employeeId === emp.id && d.status === 'active');
      if (decrees.length > 0) {
        const maxDeduction = emp.salary * 0.5;
        const alimonyDecrees = decrees.filter(d => d.type === 'alimony');
        const otherDecrees = decrees.filter(d => d.type === 'other');
        
        let allocated = 0;
        alimonyDecrees.forEach(d => {
          const remaining = d.amount - (d.paidAmount || 0);
          const amount = Math.min(remaining, maxDeduction * 0.5);
          if (amount > 0) {
            exportData.push({
              'Таб.номер': emp.tabNum,
              'ФИО': emp.name,
              'ИИН': emp.iin,
              'Постановление': d.number,
              'Тип': 'Алименты',
              'Сумма удержания': amount.toFixed(2)
            });
            allocated += amount;
          }
        });
        
        const remainingForOther = maxDeduction - allocated;
        if (remainingForOther > 0 && otherDecrees.length > 0) {
          const perOther = remainingForOther / otherDecrees.length;
          otherDecrees.forEach(d => {
            const remaining = d.amount - (d.paidAmount || 0);
            const amount = Math.min(remaining, perOther);
            if (amount > 0) {
              exportData.push({
                'Таб.номер': emp.tabNum,
                'ФИО': emp.name,
                'ИИН': emp.iin,
                'Постановление': d.number,
                'Тип': 'Штрафы',
                'Сумма удержания': amount.toFixed(2)
              });
            }
          });
        }
      }
    });
    
    if (exportData.length === 0) {
      return sendJSON(res, { error: 'Нет данных' }, 400);
    }
    
    const ws = XLSX.utils.json_to_sheet(exportData);
    const wb = XLSX.utils.book_new();
    XLSX.utils.book_append_sheet(wb, ws, 'Банк');
    
    const filename = `bank_export_${body.period || new Date().toISOString().slice(0, 7)}.xlsx`;
    const filepath = path.join(__dirname, filename);
    XLSX.writeFile(wb, filepath);
    
    sendJSON(res, { ok: true, filename, count: exportData.length });
  }
  
  if (req.method === 'POST' && url === '/api/export-report') {
    const body = await parseBody(req);
    const data = readData();
    
    const exportData = data.decrees.map(d => {
      const emp = data.employees.find(e => e.id === d.employeeId);
      return {
        'Квартал': body.quarter || '',
        'Постановление': d.number,
        'Дата': new Date(d.date).toLocaleDateString('ru-RU'),
        'Сотрудник': emp ? emp.name : '',
        'ИИН': emp ? emp.iin : '',
        'Тип': d.type === 'alimony' ? 'Алименты' : 'Штрафы',
        'Сумма долга': d.amount.toFixed(2),
        'Выплачено': (d.paidAmount || 0).toFixed(2),
        'Остаток': (d.amount - (d.paidAmount || 0)).toFixed(2),
        'Статус': d.status === 'closed' ? 'Закрыто' : 'Активно'
      };
    });
    
    const ws = XLSX.utils.json_to_sheet(exportData);
    const wb = XLSX.utils.book_new();
    XLSX.utils.book_append_sheet(wb, ws, 'Отчёт');
    
    const filename = `report_${body.quarter || new Date().toISOString().slice(0, 7)}.xlsx`;
    const filepath = path.join(__dirname, filename);
    XLSX.writeFile(wb, filepath);
    
    sendJSON(res, { ok: true, filename, count: exportData.length });
  }
  
  if (req.method === 'GET' && url.startsWith('/api/download/')) {
    const filename = decodeURIComponent(url.replace('/api/download/', ''));
    const filepath = path.join(__dirname, filename);
    
    if (fs.existsSync(filepath)) {
      res.writeHead(200, {
        'Content-Type': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
        'Content-Disposition': `attachment; filename="${filename}"`
      });
      fs.createReadStream(filepath).pipe(res);
      
      setTimeout(() => {
        try { fs.unlinkSync(filepath); } catch (e) {}
      }, 60000);
    } else {
      sendJSON(res, { error: 'Файл не найден' }, 404);
    }
    return;
  }
  
  let file = url === '/' ? '/index.html' : url;
  const full = path.join(__dirname, file);
  
  if (fs.existsSync(full) && fs.statSync(full).isFile()) {
    const ext = path.extname(full);
    const type = ext === '.css' ? 'text/css' : ext === '.js' ? 'application/javascript' : 'text/html';
    res.writeHead(200, { 'Content-Type': type + '; charset=utf-8' });
    res.end(fs.readFileSync(full));
  } else {
    res.writeHead(404);
    res.end('Not found');
  }
}).listen(PORT, () => {
  console.log('Сервер запущен на порту ' + PORT);
});