import { fetchSensorData } from './api.js';

/**
 * @typedef {Object} SensorData
 * @property {string} timestamp
 * @property {string} location_id
 * @property {number} temperature
 * @property {number} humidity
 * @property {number} light
 */

let allData = [];
let chartInstances = {};

/**
 * Initialisiert UI-Elemente, ruft Daten ab und rendert Diagramme.
 * Wird beim Laden des Fensters aufgerufen.
 */
export async function initApp() {
  try {
    const data = await fetchSensorData();
    if (!Array.isArray(data)) {
      console.error('Ungültige Datenstruktur von /data');
      return;
    }
    allData = data;
    initializeFilters();
    renderCharts(data);
  } catch (error) {
    console.error('Fehler beim Initialisieren der Anwendung:', error);
  }
}

/**
 * Initialisiert Datumsauswahl- und Filter-Events.
 */
function initializeFilters() {
  const startInput = document.getElementById('filter-start');
  const endInput = document.getElementById('filter-end');

  [startInput, endInput].forEach((input) => {
    if (input) {
      input.addEventListener('change', () => {
        const startDate = new Date(startInput?.value);
        const endDate = new Date(endInput?.value);
        const filtered = filterDataByDate(allData, startDate, endDate);
        updateCharts(filtered);
      });
    }
  });
}

/**
 * Filtert Daten basierend auf Start- und Enddatum.
 * @param {SensorData[]} data
 * @param {Date} start
 * @param {Date} end
 * @returns {SensorData[]}
 */
function filterDataByDate(data, start, end) {
  if (!(start instanceof Date) || !(end instanceof Date)) return data;
  return data.filter(({ timestamp }) => {
    const t = new Date(timestamp);
    return t >= start && t <= end;
  });
}

/**
 * Rendert initiale Diagramme.
 * @param {SensorData[]} data
 */
function renderCharts(data) {
  const ctxTemp = document.getElementById('chart-temperature');
  const ctxHum = document.getElementById('chart-humidity');
  const ctxLight = document.getElementById('chart-light');

  const timestamps = data.map(d => new Date(d.timestamp).toLocaleTimeString());

  chartInstances.temperature = new Chart(ctxTemp, {
    type: 'line',
    data: {
      labels: timestamps,
      datasets: [{
        label: 'Temperatur (°C)',
        data: data.map(d => d.temperature),
        borderColor: '#FF5733',
        backgroundColor: 'rgba(255, 87, 51, 0.1)',
        tension: 0.3,
      }]
    },
    options: baseChartOptions('Temperaturverlauf')
  });

  chartInstances.humidity = new Chart(ctxHum, {
    type: 'line',
    data: {
      labels: timestamps,
      datasets: [{
        label: 'Feuchtigkeit (%)',
        data: data.map(d => d.humidity),
        borderColor: '#33A1FF',
        backgroundColor: 'rgba(51, 161, 255, 0.1)',
        tension: 0.3,
      }]
    },
    options: baseChartOptions('Feuchtigkeitsverlauf')
  });

  chartInstances.light = new Chart(ctxLight, {
    type: 'line',
    data: {
      labels: timestamps,
      datasets: [{
        label: 'Lichtintensität (lx)',
        data: data.map(d => d.light),
        borderColor: '#FFC300',
        backgroundColor: 'rgba(255, 195, 0, 0.1)',
        tension: 0.3,
      }]
    },
    options: baseChartOptions('Lichtintensität')
  });
}

/**
 * Options-Vorlage für Diagramme.
 * @param {string} title
 * @returns {object}
 */
function baseChartOptions(title) {
  return {
    responsive: true,
    maintainAspectRatio: false,
    interaction: { mode: 'index', intersect: false },
    plugins: {
      title: { display: true, text: title },
      tooltip: { enabled: true },
      legend: { display: true }
    },
    scales: {
      x: { display: true, title: { display: true, text: 'Zeit' } },
      y: { display: true }
    }
  };
}

/**
 * Aktualisiert Diagramme auf Basis neuer Filter oder Daten.
 * @param {SensorData[]} filteredData
 */
export function updateCharts(filteredData) {
  const timestamps = filteredData.map(d => new Date(d.timestamp).toLocaleTimeString());

  if (chartInstances.temperature) {
    chartInstances.temperature.data.labels = timestamps;
    chartInstances.temperature.data.datasets[0].data = filteredData.map(d => d.temperature);
    chartInstances.temperature.update();
  }

  if (chartInstances.humidity) {
    chartInstances.humidity.data.labels = timestamps;
    chartInstances.humidity.data.datasets[0].data = filteredData.map(d => d.humidity);
    chartInstances.humidity.update();
  }

  if (chartInstances.light) {
    chartInstances.light.data.labels = timestamps;
    chartInstances.light.data.datasets[0].data = filteredData.map(d => d.light);
    chartInstances.light.update();
  }
}

window.addEventListener('load', initApp);