import { getEmbeddedData as getEmbeddedPageData } from "./embedded-data";

/**
 * Utility functions for the Awesome Copilot website
 */

const REPO_BASE_URL =
  "https://raw.githubusercontent.com/github/awesome-copilot/main";
const REPO_GITHUB_URL = "https://github.com/github/awesome-copilot/blob/main";

/**
 * The GitHub repo identifier used for `gh skills install` commands
 */
export const REPO_IDENTIFIER = "github/awesome-copilot";

// VS Code install URL configurations
const VSCODE_INSTALL_CONFIG: Record<
  string,
  { baseUrl: string; scheme: string }
> = {
  instructions: {
    baseUrl: "https://aka.ms/awesome-copilot/install/instructions",
    scheme: "chat-instructions",
  },
  instruction: {
    baseUrl: "https://aka.ms/awesome-copilot/install/instructions",
    scheme: "chat-instructions",
  },
  agent: {
    baseUrl: "https://aka.ms/awesome-copilot/install/agent",
    scheme: "chat-agent",
  },
};

/**
 * Get the base path for the site
 */
export function getBasePath(): string {
  // In Astro, import.meta.env.BASE_URL is available at build time
  // At runtime, we use a data attribute on the body
  if (typeof document !== "undefined") {
    return document.body.dataset.basePath || "/";
  }
  return "/";
}

/**
 * Fetch JSON data from the data directory
 */
export async function fetchData<T = unknown>(
  filename: string
): Promise<T | null> {
  const embeddedData = getEmbeddedPageData<T>(filename);
  if (embeddedData !== null) return embeddedData;

  try {
    const basePath = getBasePath();
    const response = await fetch(`${basePath}data/${filename}`);
    if (!response.ok) throw new Error(`Failed to fetch ${filename}`);
    return await response.json();
  } catch (error) {
    console.error(`Error fetching ${filename}:`, error);
    return null;
  }
}

let jsZipPromise: Promise<typeof import("./jszip")> | null = null;

/**
 * Lazy-load JSZip only when downloads are requested
 */
export async function loadJSZip() {
  jsZipPromise ??= import("./jszip");
  const { default: JSZip } = await jsZipPromise;
  return JSZip;
}

export interface ZipDownloadFile {
  name: string;
  path: string;
}

function triggerBlobDownload(blob: Blob, filename: string): void {
  const url = URL.createObjectURL(blob);
  const link = document.createElement("a");
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
}

export async function downloadZipBundle(
  bundleName: string,
  files: ZipDownloadFile[]
): Promise<void> {
  if (files.length === 0) {
    throw new Error("No files found for this download.");
  }

  const JSZip = await loadJSZip();
  const zip = new JSZip();
  const folder = zip.folder(bundleName);

  const fetchPromises = files.map(async (file) => {
    try {
      const response = await fetch(getRawGitHubUrl(file.path));
      if (!response.ok) return null;

      return {
        name: file.name,
        content: await response.text(),
      };
    } catch {
      return null;
    }
  });

  const results = await Promise.all(fetchPromises);
  let addedFiles = 0;

  for (const result of results) {
    if (result && folder) {
      folder.file(result.name, result.content);
      addedFiles++;
    }
  }

  if (addedFiles === 0) {
    throw new Error("Failed to fetch any files");
  }

  const blob = await zip.generateAsync({ type: "blob" });
  triggerBlobDownload(blob, `${bundleName}.zip`);
}

/**
 * Fetch raw file content from GitHub
 */
export async function fetchFileContent(
  filePath: string
): Promise<string | null> {
  try {
    const response = await fetch(`${REPO_BASE_URL}/${filePath}`);
    if (!response.ok) throw new Error(`Failed to fetch ${filePath}`);
    return await response.text();
  } catch (error) {
    console.error(`Error fetching file content:`, error);
    return null;
  }
}

/**
 * Copy text to clipboard
 */
export async function copyToClipboard(text: string): Promise<boolean> {
  try {
    await navigator.clipboard.writeText(text);
    return true;
  } catch {
    // Deprecated fallback for older browsers that lack the async clipboard API.
    const textarea = document.createElement("textarea");
    textarea.value = text;
    textarea.style.position = "fixed";
    textarea.style.opacity = "0";
    document.body.appendChild(textarea);
    textarea.select();
    const success = document.execCommand("copy");
    document.body.removeChild(textarea);
    return success;
  }
}

/**
 * Generate VS Code install URL
 * @param type - Resource type (agent, instructions)
 * @param filePath - Path to the file
 * @param insiders - Whether to use VS Code Insiders
 */
export function getVSCodeInstallUrl(
  type: string,
  filePath: string,
  insiders = false
): string | null {
  const config = VSCODE_INSTALL_CONFIG[type];
  if (!config) return null;

  const rawUrl = `${REPO_BASE_URL}/${filePath}`;
  const vscodeScheme = insiders ? "vscode-insiders" : "vscode";
  const innerUrl = `${vscodeScheme}:${
    config.scheme
  }/install?url=${encodeURIComponent(rawUrl)}`;

  return `${config.baseUrl}?url=${encodeURIComponent(innerUrl)}`;
}

/**
 * Get GitHub URL for a file
 */
export function getGitHubUrl(filePath: string): string {
  return `${REPO_GITHUB_URL}/${filePath}`;
}

/**
 * Get raw GitHub URL for a file (for fetching content)
 */
export function getRawGitHubUrl(filePath: string): string {
  return `${REPO_BASE_URL}/${filePath}`;
}

/**
 * Download a file from its path
 */
export async function downloadFile(filePath: string): Promise<boolean> {
  try {
    const response = await fetch(`${REPO_BASE_URL}/${filePath}`);
    if (!response.ok) throw new Error("Failed to fetch file");

    const content = await response.text();
    const filename = filePath.split("/").pop() || "file.md";

    const blob = new Blob([content], { type: "text/markdown" });
    triggerBlobDownload(blob, filename);

    return true;
  } catch (error) {
    console.error("Download failed:", error);
    return false;
  }
}

/**
 * Share/copy link to clipboard (deep link to current page with file hash)
 */
export async function shareFile(filePath: string): Promise<boolean> {
  const deepLinkUrl = `${window.location.origin}${
    window.location.pathname
  }#file=${encodeURIComponent(filePath)}`;
  return copyToClipboard(deepLinkUrl);
}

type QueryParamValue = string | string[] | boolean | null | undefined;

/**
 * Read a single query parameter.
 */
export function getQueryParam(name: string): string {
  if (typeof window === "undefined") return "";
  return new URLSearchParams(window.location.search).get(name)?.trim() ?? "";
}

/**
 * Read repeated query parameter values.
 */
export function getQueryParamValues(name: string): string[] {
  if (typeof window === "undefined") return [];
  const values = new URLSearchParams(window.location.search)
    .getAll(name)
    .map((value) => value.trim())
    .filter(Boolean);
  return Array.from(new Set(values));
}

/**
 * Read a boolean-style query parameter.
 */
export function getQueryParamFlag(name: string): boolean {
  const value = getQueryParam(name).toLowerCase();
  return value === "1" || value === "true" || value === "yes";
}

/**
 * Update query parameters while preserving the current hash.
 */
export function updateQueryParams(
  updates: Record<string, QueryParamValue>
): void {
  if (typeof window === "undefined") return;

  const url = new URL(window.location.href);

  for (const [key, value] of Object.entries(updates)) {
    url.searchParams.delete(key);

    if (Array.isArray(value)) {
      for (const item of value) {
        const normalized = item.trim();
        if (normalized) {
          url.searchParams.append(key, normalized);
        }
      }
      continue;
    }

    if (typeof value === "boolean") {
      if (value) {
        url.searchParams.set(key, "1");
      }
      continue;
    }

    if (typeof value === "string") {
      const normalized = value.trim();
      if (normalized) {
        url.searchParams.set(key, normalized);
      }
    }
  }

  const search = url.searchParams.toString();
  const nextUrl = `${url.pathname}${search ? `?${search}` : ""}${url.hash}`;
  const currentUrl = `${window.location.pathname}${window.location.search}${window.location.hash}`;

  if (nextUrl !== currentUrl) {
    history.replaceState(null, "", nextUrl);
  }
}

/**
 * Show a toast notification
 */
export function showToast(
  message: string,
  type: "success" | "error" = "success"
): void {
  const existing = document.querySelector(".toast");
  if (existing) existing.remove();

  const toast = document.createElement("div");
  toast.className = `toast ${type}`;
  toast.textContent = message;
  document.body.appendChild(toast);

  setTimeout(() => {
    toast.remove();
  }, 3000);
}

/**
 * Debounce function for search input
 */
export function debounce<T extends (...args: unknown[]) => void>(
  func: T,
  wait: number
): (...args: Parameters<T>) => void {
  let timeout: ReturnType<typeof setTimeout>;
  return function executedFunction(...args: Parameters<T>) {
    const later = () => {
      clearTimeout(timeout);
      func(...args);
    };
    clearTimeout(timeout);
    timeout = setTimeout(later, wait);
  };
}

/**
 * Escape HTML to prevent XSS
 */
export function escapeHtml(text: string | string[]): string {
  if (Array.isArray(text)) {
    return text.map(escapeHtml).join(", ");
  }

  return text
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&#39;");
}

/**
 * Validate and sanitize URLs to prevent XSS attacks
 * Only allows http/https protocols, returns '#' for invalid URLs
 */
export function sanitizeUrl(url: string | null | undefined): string {
  if (!url) return "#";
  try {
    const parsed = new URL(url);
    // Only allow http and https protocols
    if (parsed.protocol === "http:" || parsed.protocol === "https:") {
      return url;
    }
  } catch {
    // Invalid URL
  }
  return "#";
}

/**
 * Truncate text with ellipsis
 */
export function truncate(text: string | undefined, maxLength: number): string {
  if (!text || text.length <= maxLength) return text || "";
  return text.slice(0, maxLength).trim() + "...";
}

/**
 * Get resource type from file path
 */
export function getResourceType(filePath: string): string {
  if (filePath.endsWith(".agent.md")) return "agent";
  if (filePath.endsWith(".instructions.md")) return "instruction";
  if (/(^|\/)skills\//.test(filePath)) return "skill";
  if (/(^|\/)hooks\//.test(filePath)) return "hook";
  if (/(^|\/)workflows\//.test(filePath) && filePath.endsWith(".md"))
    return "workflow";
  // Check for plugin directories (e.g., plugins/<id>, plugins/<id>/)
  if (/(^|\/)plugins\/[^/]+\/?$/.test(filePath)) return "plugin";
  // Check for plugin.json files (e.g., plugins/<id>/.github/plugin/plugin.json)
  if (filePath.endsWith("/.github/plugin/plugin.json")) return "plugin";
  return "unknown";
}

/**
 * Format a resource type for display
 */
export function formatResourceType(type: string): string {
  const labels: Record<string, string> = {
    agent: "🤖 Agent",
    instruction: "📋 Instruction",
    skill: "⚡ Skill",
    hook: "🪝 Hook",
    workflow: "⚡ Workflow",
    plugin: "🔌 Plugin",
  };
  return labels[type] || type;
}

/**
 * Get icon for resource type (returns SVG icon name)
 */
export function getResourceIcon(type: string): string {
  const icons: Record<string, string> = {
    agent: "robot",
    instruction: "document",
    skill: "lightning",
    hook: "hook",
    workflow: "workflow",
    plugin: "plug",
  };
  return icons[type] || "document";
}

// Icon definitions with fill/stroke type info
const iconDefs: Record<string, { path: string; fill?: boolean }> = {
  // Agent icon - GitHub Primer's agent-24
  robot: {
    fill: true,
    path: '<path d="M22.5 13.919v-.278a5.097 5.097 0 0 0-4.961-5.086.858.858 0 0 1-.754-.497l-.149-.327A6.414 6.414 0 0 0 10.81 4a6.133 6.133 0 0 0-6.13 6.32l.019.628a.863.863 0 0 1-.67.869A3.263 3.263 0 0 0 1.5 14.996v.108A3.397 3.397 0 0 0 4.896 18.5h1.577a.75.75 0 0 1 0 1.5H4.896A4.896 4.896 0 0 1 0 15.104v-.108a4.761 4.761 0 0 1 3.185-4.493l-.004-.137A7.633 7.633 0 0 1 10.81 2.5a7.911 7.911 0 0 1 7.176 4.58C21.36 7.377 24 10.207 24 13.641v.278a.75.75 0 0 1-1.5 0Z"/><path d="m12.306 11.77 3.374 3.375a.749.749 0 0 1 0 1.061l-3.375 3.375-.057.051a.751.751 0 0 1-1.004-.051.751.751 0 0 1-.051-1.004l.051-.057 2.845-2.845-2.844-2.844a.75.75 0 1 1 1.061-1.061ZM22.5 19.8H18a.75.75 0 0 1 0-1.5h4.5a.75.75 0 0 1 0 1.5Z"/>',
  },
  document: {
    path: '<path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/><path d="M14 2v6h6M16 13H8M16 17H8M10 9H8" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>',
  },
  lightning: {
    path: '<path d="M13 2 4.09 12.11a1.23 1.23 0 0 0 .13 1.72l.16.14a1.23 1.23 0 0 0 1.52 0L13 9.5V22l8.91-10.11a1.23 1.23 0 0 0-.13-1.72l-.16-.14a1.23 1.23 0 0 0-1.52 0L13 14.5V2Z" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>',
  },
  // Hook icon - GitHub Primer's sync-24
  hook: {
    fill: true,
    path: '<path d="M3.38 8A9.502 9.502 0 0 1 12 2.5a9.502 9.502 0 0 1 9.215 7.182.75.75 0 1 0 1.456-.364C21.473 4.539 17.15 1 12 1a10.995 10.995 0 0 0-9.5 5.452V4.75a.75.75 0 0 0-1.5 0V8.5a1 1 0 0 0 1 1h3.75a.75.75 0 0 0 0-1.5H3.38Zm-.595 6.318a.75.75 0 0 0-1.455.364C2.527 19.461 6.85 23 12 23c4.052 0 7.592-2.191 9.5-5.451v1.701a.75.75 0 0 0 1.5 0V15.5a1 1 0 0 0-1-1h-3.75a.75.75 0 0 0 0 1.5h2.37A9.502 9.502 0 0 1 12 21.5c-4.446 0-8.181-3.055-9.215-7.182Z"/>',
  },
  // Workflow icon - GitHub Primer's workflow-24
  workflow: {
    fill: true,
    path: '<path d="M1 3a2 2 0 0 1 2-2h6.5a2 2 0 0 1 2 2v6.5a2 2 0 0 1-2 2H7v4.063C7 16.355 7.644 17 8.438 17H12.5v-2.5a2 2 0 0 1 2-2H21a2 2 0 0 1 2 2V21a2 2 0 0 1-2 2h-6.5a2 2 0 0 1-2-2v-2.5H8.437A2.939 2.939 0 0 1 5.5 15.562V11.5H3a2 2 0 0 1-2-2Zm2-.5a.5.5 0 0 0-.5.5v6.5a.5.5 0 0 0 .5.5h6.5a.5.5 0 0 0 .5-.5V3a.5.5 0 0 0-.5-.5ZM14.5 14a.5.5 0 0 0-.5.5V21a.5.5 0 0 0 .5.5H21a.5.5 0 0 0 .5-.5v-6.5a.5.5 0 0 0-.5-.5Z"/>',
  },
  // Plug icon - GitHub Primer's plug-24
  plug: {
    fill: true,
    path: '<path d="M7 11.5H2.938c-.794 0-1.438.644-1.438 1.437v8.313a.75.75 0 0 1-1.5 0v-8.312A2.939 2.939 0 0 1 2.937 10H7V6.151c0-.897.678-1.648 1.57-1.74l6.055-.626 1.006-1.174A1.752 1.752 0 0 1 16.96 2h1.29c.966 0 1.75.784 1.75 1.75V6h3.25a.75.75 0 0 1 0 1.5H20V14h3.25a.75.75 0 0 1 0 1.5H20v2.25a1.75 1.75 0 0 1-1.75 1.75h-1.29a1.75 1.75 0 0 1-1.329-.611l-1.006-1.174-6.055-.627A1.749 1.749 0 0 1 7 15.348Zm9.77-7.913v.001l-1.201 1.4a.75.75 0 0 1-.492.258l-6.353.657a.25.25 0 0 0-.224.249v9.196a.25.25 0 0 0 .224.249l6.353.657c.191.02.368.112.493.258l1.2 1.401a.252.252 0 0 0 .19.087h1.29a.25.25 0 0 0 .25-.25v-14a.25.25 0 0 0-.25-.25h-1.29a.252.252 0 0 0-.19.087Z"/>',
  },
};

/**
 * Get SVG icon HTML for resource type
 */
export function getResourceIconSvg(type: string, size = 20): string {
  const iconName = getResourceIcon(type);
  const icon = iconDefs[iconName] || iconDefs.document;
  const fill = icon.fill ? 'fill="currentColor"' : 'fill="none"';
  return `<svg viewBox="0 0 24 24" width="${size}" height="${size}" ${fill} aria-hidden="true">${icon.path}</svg>`;
}

/**
 * Generate HTML for install dropdown button
 */
export function getInstallDropdownHtml(
  type: string,
  filePath: string,
  small = false
): string {
  const vscodeUrl = getVSCodeInstallUrl(type, filePath, false);
  const insidersUrl = getVSCodeInstallUrl(type, filePath, true);

  if (!vscodeUrl) return "";

  const sizeClass = small ? "install-dropdown-small" : "";
  const uniqueId = `install-${filePath.replace(/[^a-zA-Z0-9]/g, "-")}`;

  return `
    <div class="install-dropdown ${sizeClass}" id="${uniqueId}" data-install-scope="list">
      <a href="${vscodeUrl}" class="btn btn-primary ${
    small ? "btn-small" : ""
  } install-btn-main" target="_blank" rel="noopener">
        Install
      </a>
      <button type="button" class="btn btn-primary ${
        small ? "btn-small" : ""
      } install-btn-toggle" aria-label="Install options" aria-expanded="false">
        <svg viewBox="0 0 16 16" width="12" height="12" fill="currentColor">
          <path d="M4.427 7.427l3.396 3.396a.25.25 0 00.354 0l3.396-3.396A.25.25 0 0011.396 7H4.604a.25.25 0 00-.177.427z"/>
        </svg>
      </button>
      <div class="install-dropdown-menu">
        <a href="${vscodeUrl}" target="_blank" rel="noopener">
          VS Code
        </a>
        <a href="${insidersUrl}" target="_blank" rel="noopener">
          VS Code Insiders
        </a>
      </div>
    </div>
  `;
}

/**
 * Setup dropdown close handlers for dynamically created dropdowns
 */
export function setupDropdownCloseHandlers(): void {
  if (dropdownHandlersReady) return;
  dropdownHandlersReady = true;

  document.addEventListener(
    "click",
    (e) => {
      const target = e.target as HTMLElement;
      const dropdown = target.closest(
        '.install-dropdown[data-install-scope="list"]'
      );
      const toggle = target.closest(
        ".install-btn-toggle"
      ) as HTMLButtonElement | null;
      const menuLink = target.closest(
        ".install-dropdown-menu a"
      ) as HTMLAnchorElement | null;

      if (dropdown) {
        e.stopPropagation();

        if (toggle) {
          e.preventDefault();
          const isOpen = dropdown.classList.toggle("open");
          toggle.setAttribute("aria-expanded", String(isOpen));
          return;
        }

        if (menuLink) {
          dropdown.classList.remove("open");
          const toggleBtn = dropdown.querySelector<HTMLButtonElement>(
            ".install-btn-toggle"
          );
          toggleBtn?.setAttribute("aria-expanded", "false");
          return;
        }

        return;
      }

      document
        .querySelectorAll('.install-dropdown[data-install-scope="list"].open')
        .forEach((openDropdown) => {
          openDropdown.classList.remove("open");
          const toggleBtn = openDropdown.querySelector<HTMLButtonElement>(
            ".install-btn-toggle"
          );
          toggleBtn?.setAttribute("aria-expanded", "false");
        });
    },
    true
  );
}

/**
 * Generate HTML for action buttons (download, share) in list view
 */
export function getActionButtonsHtml(filePath: string, small = false): string {
  const btnClass = small ? "btn-small" : "";
  const iconSize = small ? 14 : 16;

  return `
    <button class="btn btn-secondary ${btnClass} action-download" data-path="${escapeHtml(
    filePath
  )}" title="Download file">
      <svg viewBox="0 0 16 16" width="${iconSize}" height="${iconSize}" fill="currentColor">
        <path d="M7.47 10.78a.75.75 0 0 0 1.06 0l3.75-3.75a.75.75 0 0 0-1.06-1.06L8.75 8.44V1.75a.75.75 0 0 0-1.5 0v6.69L4.78 5.97a.75.75 0 0 0-1.06 1.06l3.75 3.75ZM3.75 13a.75.75 0 0 0 0 1.5h8.5a.75.75 0 0 0 0-1.5h-8.5Z"/>
      </svg>
    </button>
    <button class="btn btn-secondary ${btnClass} action-share" data-path="${escapeHtml(
    filePath
  )}" title="Copy link">
      <svg viewBox="0 0 16 16" width="${iconSize}" height="${iconSize}" fill="currentColor">
        <path d="M7.775 3.275a.75.75 0 0 0 1.06 1.06l1.25-1.25a2 2 0 1 1 2.83 2.83l-2.5 2.5a2 2 0 0 1-2.83 0 .75.75 0 0 0-1.06 1.06 3.5 3.5 0 0 0 4.95 0l2.5-2.5a3.5 3.5 0 0 0-4.95-4.95l-1.25 1.25zm-.025 5.45a.75.75 0 0 0-1.06-1.06l-1.25 1.25a2 2 0 1 1-2.83-2.83l2.5-2.5a2 2 0 0 1 2.83 0 .75.75 0 0 0 1.06-1.06 3.5 3.5 0 0 0-4.95 0l-2.5 2.5a3.5 3.5 0 0 0 4.95 4.95l1.25-1.25z"/>
      </svg>
    </button>
  `;
}

/**
 * Setup global action handlers for download and share buttons
 */
export function setupActionHandlers(): void {
  if (actionHandlersReady) return;
  actionHandlersReady = true;

  document.addEventListener(
    "click",
    async (e) => {
      const target = (e.target as HTMLElement).closest(
        ".action-download, .action-share"
      ) as HTMLElement | null;
      if (!target) return;

      e.preventDefault();
      e.stopPropagation();

      const path = target.dataset.path;
      if (!path) return;

      if (target.classList.contains("action-download")) {
        const success = await downloadFile(path);
        showToast(
          success ? "Download started!" : "Download failed",
          success ? "success" : "error"
        );
        return;
      }

      const success = await shareFile(path);
      showToast(
        success ? "Link copied!" : "Failed to copy link",
        success ? "success" : "error"
      );
    },
    true
  );
}

let dropdownHandlersReady = false;
let actionHandlersReady = false;

/**
 * Format a date as relative time (e.g., "3 days ago")
 * @param isoDate - ISO 8601 date string
 * @returns Relative time string
 */
export function formatRelativeTime(isoDate: string | null | undefined): string {
  if (!isoDate) return "Unknown";

  const date = new Date(isoDate);
  if (isNaN(date.getTime())) return "Unknown";

  const now = new Date();
  const diffMs = now.getTime() - date.getTime();
  const diffSeconds = Math.floor(diffMs / 1000);
  const diffMinutes = Math.floor(diffSeconds / 60);
  const diffHours = Math.floor(diffMinutes / 60);
  const diffDays = Math.floor(diffHours / 24);
  const diffWeeks = Math.floor(diffDays / 7);
  const diffMonths = Math.floor(diffDays / 30);
  const diffYears = Math.floor(diffDays / 365);

  if (diffDays === 0) {
    if (diffHours === 0) {
      if (diffMinutes === 0) return "just now";
      return diffMinutes === 1 ? "1 minute ago" : `${diffMinutes} minutes ago`;
    }
    return diffHours === 1 ? "1 hour ago" : `${diffHours} hours ago`;
  }
  if (diffDays === 1) return "yesterday";
  if (diffDays < 7) return `${diffDays} days ago`;
  if (diffWeeks === 1) return "1 week ago";
  if (diffWeeks < 4) return `${diffWeeks} weeks ago`;
  if (diffMonths === 1) return "1 month ago";
  if (diffMonths < 12) return `${diffMonths} months ago`;
  if (diffYears === 1) return "1 year ago";
  return `${diffYears} years ago`;
}

/**
 * Format a date for display (e.g., "January 15, 2026")
 * @param isoDate - ISO 8601 date string
 * @returns Formatted date string
 */
export function formatFullDate(isoDate: string | null | undefined): string {
  if (!isoDate) return "Unknown";

  const date = new Date(isoDate);
  if (isNaN(date.getTime())) return "Unknown";

  return date.toLocaleDateString("en-US", {
    year: "numeric",
    month: "long",
    day: "numeric",
  });
}

/**
 * Generate HTML for displaying last updated time with hover tooltip
 * @param isoDate - ISO 8601 date string
 * @returns HTML string with relative time and title attribute
 */
export function getLastUpdatedHtml(isoDate: string | null | undefined): string {
  const relativeTime = formatRelativeTime(isoDate);
  const fullDate = formatFullDate(isoDate);

  if (relativeTime === "Unknown") {
    return `<span class="last-updated">Updated: Unknown</span>`;
  }

  return `<span class="last-updated" title="${escapeHtml(
    fullDate
  )}">Updated ${relativeTime}</span>`;
}
