"use strict";

/**
 * Visualization module for replication analysis dashboard.
 * Responsible for rendering charts and updating tables dynamically.
 */

/**
 * @typedef {Object} RunComparison
 * @property {string} run_id
 * @property {Object} metrics
 * @property {number[]} metrics.bandwidth
 * @property {number[]} metrics.retry_tailp99
 * @property {string[]} segments
 */

/**
 * Render bandwidth chart based on provided run data.
 * @param {RunComparison} data
 */
export function renderBandwidthChart(data) {
  const container = document.getElementById('bandwidth-chart');
  if (!container) return;

  container.innerHTML = '';

  const canvas = document.createElement('canvas');
  canvas.setAttribute('aria-label', 'Bandwidth Chart');
  canvas.setAttribute('role', 'img');
  container.appendChild(canvas);

  const ctx = canvas.getContext('2d');
  const bandwidth = data.metrics?.bandwidth ?? [];
  if (!bandwidth.length) {
    ctx.font = '16px sans-serif';
    ctx.fillText('No bandwidth data available', 10, 30);
    return;
  }

  const spacing = canvas.width / bandwidth.length || 5;
  const maxValue = Math.max(...bandwidth);
  const scale = (canvas.height - 20) / maxValue;

  ctx.strokeStyle = '#3366cc';
  ctx.beginPath();
  bandwidth.forEach((val, i) => {
    const x = i * spacing + 10;
    const y = canvas.height - val * scale - 10;
    if (i === 0) ctx.moveTo(x, y);
    else ctx.lineTo(x, y);
  });
  ctx.stroke();
}

/**
 * Render retry_tailp99 chart as a trend visualization.
 * @param {RunComparison} data
 */
export function renderRetryTailChart(data) {
  const container = document.getElementById('retry-tailp99-chart');
  if (!container) return;

  container.innerHTML = '';

  const canvas = document.createElement('canvas');
  canvas.setAttribute('aria-label', 'Retry Tailp99 Trend');
  canvas.setAttribute('role', 'img');
  container.appendChild(canvas);

  const ctx = canvas.getContext('2d');
  const retries = data.metrics?.retry_tailp99 ?? [];
  if (!retries.length) {
    ctx.font = '16px sans-serif';
    ctx.fillText('No retry_tailp99 data available', 10, 30);
    return;
  }

  const spacing = canvas.width / retries.length || 5;
  const maxValue = Math.max(...retries);
  const scale = (canvas.height - 20) / maxValue;

  ctx.strokeStyle = '#cc3333';
  ctx.beginPath();
  retries.forEach((val, i) => {
    const x = i * spacing + 10;
    const y = canvas.height - val * scale - 10;
    if (i === 0) ctx.moveTo(x, y);
    else ctx.lineTo(x, y);
  });
  ctx.stroke();
}

/**
 * Update results table with latest run metrics.
 * @param {RunComparison} data
 */
export function updateResultsTable(data) {
  const table = document.getElementById('results-table');
  if (!table) return;

  table.innerHTML = '';

  const headerRow = document.createElement('tr');
  ['Segment', 'Bandwidth', 'Retry Tail p99'].forEach(h => {
    const th = document.createElement('th');
    th.textContent = h;
    headerRow.appendChild(th);
  });
  table.appendChild(headerRow);

  const {segments = [], metrics: {bandwidth = [], retry_tailp99 = []} = {}} = data;
  const len = Math.max(segments.length, bandwidth.length, retry_tailp99.length);

  for (let i = 0; i < len; i++) {
    const row = document.createElement('tr');
    const seg = document.createElement('td');
    seg.textContent = segments[i] ?? '-';

    const bw = document.createElement('td');
    bw.textContent = bandwidth[i]?.toFixed(2) ?? '-';

    const rt = document.createElement('td');
    rt.textContent = retry_tailp99[i]?.toFixed(2) ?? '-';

    row.appendChild(seg);
    row.appendChild(bw);
    row.appendChild(rt);
    table.appendChild(row);
  }
}

/**
 * Ensure responsiveness on resize.
 */
window.addEventListener('resize', () => {
  const dataAttr = document.body.dataset.runComparison;
  if (!dataAttr) return;
  try {
    const data = JSON.parse(dataAttr);
    renderBandwidthChart(data);
    renderRetryTailChart(data);
  } catch (err) {
    console.error('Failed to re-render charts on resize:', err);
  }
});