let appData = {
  presets: [],
  history: []
};

let selectedPresetId = null;

async function loadData() {
  try {
    const res = await fetch('/api/data');
    const data = await res.json();
    appData = data;
    
    if (appData.presets.length === 0) {
      appData.presets.push({
        id: Date.now(),
        name: 'Областной',
        variableCosts: 15921.2583,
        avgCapacity: 9.4317,
        fixedCosts: 8129.6707
      });
    }
    
    if (appData.history === undefined) {
      appData.history = [];
    }
    
    saveData();
  } catch (e) {
    console.error('Ошибка загрузки:', e);
    if (appData.presets.length === 0) {
      appData.presets.push({
        id: Date.now(),
        name: 'Областной',
        variableCosts: 15921.2583,
        avgCapacity: 9.4317,
        fixedCosts: 8129.6707
      });
    }
  }
}

async function saveData() {
  try {
    await fetch('/api/data', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(appData)
    });
  } catch (e) {
    console.error('Ошибка сохранения:', e);
  }
}

function formatNumber(num) {
  return num.toLocaleString('ru-RU', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}

function formatNumberFull(num) {
  return num.toLocaleString('ru-RU', { minimumFractionDigits: 4, maximumFractionDigits: 4 });
}

function renderPresetsSelect() {
  const select = document.getElementById('presetSelect');
  select.innerHTML = '';
  
  appData.presets.forEach(preset => {
    const option = document.createElement('option');
    option.value = preset.id;
    option.textContent = preset.name;
    select.appendChild(option);
  });
  
  if (selectedPresetId && appData.presets.find(p => p.id === selectedPresetId)) {
    select.value = selectedPresetId;
  } else if (appData.presets.length > 0) {
    selectedPresetId = appData.presets[0].id;
    select.value = selectedPresetId;
  }
}

function renderPresetsSettings() {
  const container = document.getElementById('presetsContainer');
  container.innerHTML = '';
  
  appData.presets.forEach(preset => {
    const card = document.createElement('div');
    card.className = 'preset-card';
    card.innerHTML = `
      <div class="preset-header">
        <h3>
          <input type="text" value="${preset.name}" data-preset-id="${preset.id}" data-field="name" class="preset-name-input" style="font-size: 16px; font-weight: 600; border: none; background: transparent; width: 200px;">
        </h3>
        <button class="btn-delete" data-preset-id="${preset.id}">Удалить</button>
      </div>
      <div class="preset-inputs">
        <div class="form-group">
          <label>Переменные затраты (₸):</label>
          <input type="number" step="0.0001" value="${preset.variableCosts}" data-preset-id="${preset.id}" data-field="variableCosts">
        </div>
        <div class="form-group">
          <label>Средняя пропускная способность (Мбит/с):</label>
          <input type="number" step="0.0001" value="${preset.avgCapacity}" data-preset-id="${preset.id}" data-field="avgCapacity">
        </div>
        <div class="form-group">
          <label>Постоянные затраты (₸):</label>
          <input type="number" step="0.0001" value="${preset.fixedCosts}" data-preset-id="${preset.id}" data-field="fixedCosts">
        </div>
      </div>
    `;
    container.appendChild(card);
  });
  
  container.querySelectorAll('.btn-delete').forEach(btn => {
    btn.addEventListener('click', (e) => {
      const id = parseInt(e.target.dataset.presetId);
      if (appData.presets.length > 1) {
        appData.presets = appData.presets.filter(p => p.id !== id);
        if (selectedPresetId === id) {
          selectedPresetId = appData.presets[0].id;
        }
        renderPresetsSettings();
      } else {
        alert('Должен остаться хотя бы один тип расчета');
      }
    });
  });
  
  container.querySelectorAll('input').forEach(input => {
    input.addEventListener('input', (e) => {
      const id = parseInt(e.target.dataset.presetId);
      const field = e.target.dataset.field;
      const preset = appData.presets.find(p => p.id === id);
      if (preset) {
        if (field === 'name') {
          preset.name = e.target.value;
        } else {
          preset[field] = parseFloat(e.target.value) || 0;
        }
      }
    });
  });
}

function renderHistory() {
  const tbody = document.querySelector('#historyTable tbody');
  const noHistory = document.getElementById('noHistory');
  
  if (appData.history.length === 0) {
    tbody.innerHTML = '';
    noHistory.style.display = 'block';
    return;
  }
  
  noHistory.style.display = 'none';
  tbody.innerHTML = '';
  
  const reversed = [...appData.history].reverse();
  
  reversed.forEach(record => {
    const row = document.createElement('tr');
    const date = new Date(record.date);
    const dateStr = date.toLocaleDateString('ru-RU');
    
    row.innerHTML = `
      <td>${dateStr}</td>
      <td>${record.presetName}</td>
      <td>${formatNumber(record.speed)} Мбит/с</td>
      <td>${formatNumber(record.result)} ₸</td>
    `;
    tbody.appendChild(row);
  });
}

function calculateCost() {
  const speedInput = document.getElementById('speedInput');
  const speed = parseFloat(speedInput.value);
  
  const preset = appData.presets.find(p => p.id === selectedPresetId);
  if (!preset) {
    showError('Выберите тип расчета');
    return null;
  }
  
  if (isNaN(speed) || speed <= 0) {
    showError('Введите корректное значение скорости (больше 0)');
    return null;
  }
  
  if (preset.avgCapacity <= 0) {
    showError('Средняя пропускная способность должна быть больше 0. Проверьте настройки.');
    return null;
  }
  
  const variablePart = (preset.variableCosts / preset.avgCapacity) * speed;
  const total = variablePart + preset.fixedCosts;
  
  return {
    variablePart,
    fixedPart: preset.fixedCosts,
    total,
    speed,
    preset
  };
}

function showResult(calc) {
  const resultBlock = document.getElementById('resultBlock');
  const resultValue = document.getElementById('resultValue');
  const variablePart = document.getElementById('variablePart');
  const fixedPart = document.getElementById('fixedPart');
  const speedDisplay = document.getElementById('speedDisplay');
  const formulaText = document.getElementById('formulaText');
  
  resultValue.textContent = formatNumber(calc.total) + ' ₸';
  variablePart.textContent = formatNumber(calc.variablePart) + ' ₸';
  fixedPart.textContent = formatNumber(calc.fixedPart) + ' ₸';
  speedDisplay.textContent = formatNumber(calc.speed) + ' Мбит/с';
  
  formulaText.textContent = 
    `(${formatNumberFull(calc.preset.variableCosts)} / ${formatNumberFull(calc.preset.avgCapacity)}) × ${formatNumber(calc.speed)} + ${formatNumberFull(calc.preset.fixedCosts)} = ${formatNumber(calc.total)}`;
  
  resultBlock.style.display = 'block';
}

function showError(message) {
  const existingError = document.querySelector('.error-message');
  if (existingError) {
    existingError.remove();
  }
  
  const errorDiv = document.createElement('div');
  errorDiv.className = 'error-message';
  errorDiv.textContent = message;
  
  const calculatorCard = document.querySelector('.calculator');
  calculatorCard.insertBefore(errorDiv, calculatorCard.firstChild);
  
  setTimeout(() => {
    errorDiv.remove();
  }, 5000);
}

function addToHistory(calc) {
  const record = {
    date: new Date().toISOString(),
    presetId: calc.preset.id,
    presetName: calc.preset.name,
    speed: calc.speed,
    variableCosts: calc.preset.variableCosts,
    avgCapacity: calc.preset.avgCapacity,
    fixedCosts: calc.preset.fixedCosts,
    result: calc.total
  };
  
  appData.history.push(record);
  
  if (appData.history.length > 100) {
    appData.history = appData.history.slice(-100);
  }
  
  saveData();
  renderHistory();
}

document.getElementById('calculateBtn').addEventListener('click', () => {
  const calc = calculateCost();
  if (calc) {
    showResult(calc);
    addToHistory(calc);
  }
});

document.getElementById('speedInput').addEventListener('keypress', (e) => {
  if (e.key === 'Enter') {
    document.getElementById('calculateBtn').click();
  }
});

document.getElementById('settingsBtn').addEventListener('click', () => {
  renderPresetsSettings();
  document.getElementById('settingsModal').classList.add('on');
});

document.getElementById('closeModal').addEventListener('click', () => {
  document.getElementById('settingsModal').classList.remove('on');
});

document.getElementById('saveSettingsBtn').addEventListener('click', () => {
  saveData();
  renderPresetsSelect();
  document.getElementById('settingsModal').classList.remove('on');
});

document.getElementById('addPresetBtn').addEventListener('click', () => {
  const name = prompt('Введите название типа расчета:');
  if (name && name.trim()) {
    appData.presets.push({
      id: Date.now(),
      name: name.trim(),
      variableCosts: 0,
      avgCapacity: 1,
      fixedCosts: 0
    });
    renderPresetsSettings();
  }
});

document.getElementById('clearHistoryBtn').addEventListener('click', () => {
  if (confirm('Вы уверены, что хотите очистить историю расчетов?')) {
    appData.history = [];
    saveData();
    renderHistory();
  }
});

document.getElementById('presetSelect').addEventListener('change', (e) => {
  selectedPresetId = parseInt(e.target.value);
});

document.getElementById('settingsModal').addEventListener('click', (e) => {
  if (e.target === document.getElementById('settingsModal')) {
    document.getElementById('settingsModal').classList.remove('on');
  }
});

async function init() {
  await loadData();
  renderPresetsSelect();
  renderHistory();
  
  const urlParams = new URLSearchParams(window.location.search);
  const speed = urlParams.get('speed');
  if (speed) {
    document.getElementById('speedInput').value = speed;
  }
}

init();