export function escapeHtml(value) {
  return String(value)
    .replaceAll('&', '&')
    .replaceAll('<', '&lt;')
    .replaceAll('>', '&gt;')
    .replaceAll('"', '&quot;')
    .replaceAll("'", '&#39;');
}

export function formatBytes(bytes) {
  if (bytes === null || bytes === undefined || Number.isNaN(Number(bytes))) {
    return 'Unknown';
  }

  const numeric = Number(bytes);
  if (numeric === 0) {
    return '0 B';
  }

  const units = ['B', 'KB', 'MB', 'GB', 'TB'];
  let value = numeric;
  let unitIndex = 0;

  while (value >= 1024 && unitIndex < units.length - 1) {
    value /= 1024;
    unitIndex += 1;
  }

  return `${value.toFixed(value >= 10 || unitIndex === 0 ? 0 : 1)} ${units[unitIndex]}`;
}

export async function fetchJson(url, options = {}) {
  const response = await fetch(url, options);
  const payload = await response.json().catch(() => ({}));

  if (!response.ok) {
    throw new Error(`${payload.error?.code ?? 'REQUEST_FAILED'}: ${payload.error?.message ?? 'Request failed.'}`);
  }

  return payload;
}

export function requireQueryParam(name) {
  const params = new URLSearchParams(window.location.search);
  const value = params.get(name)?.trim();
  if (!value) {
    throw new Error(`MISSING_${name.toUpperCase()}: Query parameter "${name}" is required.`);
  }

  return value;
}

export function optionalQueryParam(name, fallback = '') {
  const params = new URLSearchParams(window.location.search);
  return params.get(name)?.trim() || fallback;
}

export function createFeedbackController(element) {
  return {
    clear() {
      element.hidden = true;
      element.className = 'feedback';
      element.textContent = '';
    },
    set(kind, message) {
      element.hidden = false;
      element.className = `feedback feedback-${kind}`;
      element.textContent = message;
    }
  };
}

export function linkToSource(sourceId) {
  return `/source.html?sourceId=${encodeURIComponent(sourceId)}`;
}

export function linkToFile(sourceId, fileId) {
  return `/file.html?sourceId=${encodeURIComponent(sourceId)}&id=${encodeURIComponent(fileId)}`;
}

export function inferEnhancementLabel(source) {
  switch (source?.enhancement?.status) {
    case 'ready':
      return '已增强';
    case 'running':
      return '增强中';
    case 'queued':
      return '排队中';
    case 'failed':
      return '增强失败';
    default:
      return '未增强';
  }
}

export function inferEnhancementClass(source) {
  switch (source?.enhancement?.status) {
    case 'ready':
      return 'status-ready';
    case 'running':
    case 'queued':
      return 'status-busy';
    case 'failed':
      return 'status-error';
    default:
      return 'status-idle';
  }
}

export function renderSourceSummaryCard(source, extraActionsHtml = '') {
  const title = escapeHtml(source.displayName || source.originalFilename);
  const originalFilename = escapeHtml(source.originalFilename);
  const matchedHint = source.matchedBackupName ? '任务名来自 Server DB' : '未匹配任务名';
  const progress =
    source.enhancement.totalVolumes > 0
      ? `${source.enhancement.processedVolumes}/${source.enhancement.totalVolumes}`
      : '0/0';

  return `
    <article class="source-card">
      <div class="source-main">
        <div>
          <p class="source-name">${title}</p>
          <p class="source-meta">原始库名: ${originalFilename}</p>
          <p class="source-meta">sourceId: ${escapeHtml(source.id)}</p>
        </div>
        <span class="status-pill ${inferEnhancementClass(source)}">${inferEnhancementLabel(source)}</span>
      </div>

      <div class="summary-chip">${escapeHtml(matchedHint)}</div>

      <div class="card-grid">
        <div class="stat">
          <span>上传大小</span>
          <strong>${formatBytes(source.fileSize)}</strong>
        </div>
        <div class="stat">
          <span>最近快照</span>
          <strong>${escapeHtml(source.latestSnapshot?.timestamp ?? '无快照')}</strong>
        </div>
        <div class="stat">
          <span>目录浏览</span>
          <strong>${source.canBrowse ? '可用' : '不可用'}</strong>
        </div>
        <div class="stat">
          <span>增强进度</span>
          <strong>${escapeHtml(progress)}</strong>
        </div>
      </div>

      ${extraActionsHtml}
    </article>
  `;
}

export function assertBrowserFeature(condition, message) {
  if (!condition) {
    throw new Error(message);
  }
}