"use strict";

/**
 * UI Logic for Max-Outlier Visualization
 * Handles rendering of table, chart, and filter interactions.
 * Relies on api.js for data fetching.
 */

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

const ui = (() => {
  const tableContainer = document.getElementById('outlier-table');
  const chartContainer = document.getElementById('outlier-chart');
  const filters = document.querySelectorAll('.filter-input');

  /**
   * Render results table from API data.
   * @param {Array<Object>} data
   */
  const renderTable = (data) => {
    if (!tableContainer) return;
    const table = document.createElement('table');
    table.className = 'outlier__table';

    const header = document.createElement('thead');
    header.innerHTML = `
      <tr>
        <th>Run ID</th>
        <th>Parallelism</th>
        <th>Stratum</th>
        <th>Δt</th>
        <th>p95</th>
        <th>p99</th>
        <th>Retry Status</th>
      </tr>
    `;
    table.appendChild(header);

    const body = document.createElement('tbody');
    data.forEach((row) => {
      const tr = document.createElement('tr');
      tr.innerHTML = `
        <td>${row.run_id ?? '-'}</td>
        <td>${row.parallelism ?? '-'}</td>
        <td>${row.stratum ?? '-'}</td>
        <td>${row.delta_t ?? '-'}</td>
        <td>${row.p95 ?? '-'}</td>
        <td>${row.p99 ?? '-'}</td>
        <td>${row.retry_status ?? '-'}</td>
      `;
      body.appendChild(tr);
    });
    table.appendChild(body);

    tableContainer.innerHTML = '';
    tableContainer.appendChild(table);
  };

  /**
   * Render chart for p95/p99 visualization.
   * @param {Array<Object>} data
   */
  const renderChart = (data) => {
    if (!chartContainer) return;
    const ctx = chartContainer.getContext('2d');
    if (!ctx) return;

    const labels = data.map((d) => `${d.run_id}`);
    const p95Values = data.map((d) => d.p95);
    const p99Values = data.map((d) => d.p99);

    if (chartContainer.chartInstance) {
      chartContainer.chartInstance.destroy();
    }

    // Basic chart setup using Chart.js style interface if loaded
    chartContainer.chartInstance = new Chart(ctx, {
      type: 'line',
      data: {
        labels,
        datasets: [
          {
            label: 'p95',
            data: p95Values,
            borderColor: 'var(--primary)',
            backgroundColor: 'rgba(0, 128, 255, 0.2)',
            fill: true,
            tension: 0.2,
          },
          {
            label: 'p99',
            data: p99Values,
            borderColor: 'var(--accent)',
            backgroundColor: 'rgba(255, 64, 64, 0.2)',
            fill: true,
            tension: 0.2,
          },
        ],
      },
      options: {
        responsive: true,
        maintainAspectRatio: false,
        scales: {
          x: {
            title: {
              display: true,
              text: 'Run ID'
            }
          },
          y: {
            title: {
              display: true,
              text: 'Metric Value'
            }
          }
        },
        plugins: {
          legend: {
            position: 'top'
          },
          tooltip: {
            mode: 'index',
            intersect: false
          }
        }
      }
    });
  };

  /**
   * Handle filter input change, fetch new data and re-render views.
   * @param {Event} e
   */
  const handleFilterChange = async (e) => {
    e?.preventDefault();
    const params = {};
    filters.forEach((input) => {
      if (input.value.trim()) {
        params[input.name] = input.value.trim();
      }
    });

    try {
      const results = await fetchMaxOutlierResults(params);
      renderTable(results);
      renderChart(results);
    } catch (err) {
      console.error('Failed to update data:', err);
    }
  };

  // Binding filter events on page load
  const bindFilterEvents = () => {
    filters.forEach((input) => {
      input.addEventListener('change', handleFilterChange);
    });
  };

  // Public API
  return {
    renderTable,
    renderChart,
    handleFilterChange,
    bindFilterEvents
  };
})();

export default ui;