import ReactMarkdown, { type Components } from "react-markdown";
import remarkGfm from "remark-gfm";

/**
 * Server-rendered markdown for SOPs and the SOP README.
 *
 * The WFDASH app doesn't depend on `@tailwindcss/typography`, so we
 * hand-style the elements that show up in the SOPs (headings,
 * paragraphs, lists, tables, code blocks, blockquotes, hr).
 *
 * The `components` map below is the single source of truth for those
 * styles. If a new markdown shape shows up in an SOP, add a class
 * here rather than introducing the typography plugin.
 */
export function Markdown({ children }: { children: string }) {
  return (
    <ReactMarkdown remarkPlugins={[remarkGfm]} components={components}>
      {children}
    </ReactMarkdown>
  );
}

const components: Components = {
  h1: ({ children, ...props }) => (
    <h1
      className="text-2xl font-semibold tracking-tight font-heading-theme mt-6 mb-3 first:mt-0"
      {...props}
    >
      {children}
    </h1>
  ),
  h2: ({ children, ...props }) => (
    <h2
      className="text-lg font-semibold tracking-tight mt-8 mb-3 pb-2 border-b"
      {...props}
    >
      {children}
    </h2>
  ),
  h3: ({ children, ...props }) => (
    <h3 className="text-base font-semibold mt-6 mb-2" {...props}>
      {children}
    </h3>
  ),
  h4: ({ children, ...props }) => (
    <h4 className="text-sm font-semibold mt-4 mb-1.5" {...props}>
      {children}
    </h4>
  ),
  p: ({ children, ...props }) => (
    <p className="text-sm leading-relaxed my-3" {...props}>
      {children}
    </p>
  ),
  ul: ({ children, ...props }) => (
    <ul
      className="text-sm leading-relaxed my-3 ml-6 list-disc space-y-1.5"
      {...props}
    >
      {children}
    </ul>
  ),
  ol: ({ children, ...props }) => (
    <ol
      className="text-sm leading-relaxed my-3 ml-6 list-decimal space-y-1.5"
      {...props}
    >
      {children}
    </ol>
  ),
  li: ({ children, ...props }) => (
    <li className="pl-0.5" {...props}>
      {children}
    </li>
  ),
  a: ({ children, href, ...props }) => (
    <a
      href={href}
      className="text-primary underline underline-offset-2 hover:no-underline"
      target={href?.startsWith("http") ? "_blank" : undefined}
      rel={href?.startsWith("http") ? "noopener noreferrer" : undefined}
      {...props}
    >
      {children}
    </a>
  ),
  blockquote: ({ children, ...props }) => (
    <blockquote
      className="my-4 border-l-4 border-muted-foreground/30 bg-muted/40 px-4 py-2 text-sm italic text-muted-foreground"
      {...props}
    >
      {children}
    </blockquote>
  ),
  hr: (props) => (
    <hr className="my-6 border-border" {...props} />
  ),
  // GFM tables. The Markdown plugin emits these as a `table` element
  // with thead/tbody/tr/th/td children. Wrap in a scrollable container
  // so wide KPI tables don't blow out the layout.
  table: ({ children, ...props }) => (
    <div className="my-4 overflow-x-auto rounded-md border">
      <table className="w-full text-sm" {...props}>
        {children}
      </table>
    </div>
  ),
  thead: ({ children, ...props }) => (
    <thead className="bg-muted/50" {...props}>
      {children}
    </thead>
  ),
  tbody: ({ children, ...props }) => (
    <tbody className="divide-y" {...props}>
      {children}
    </tbody>
  ),
  tr: ({ children, ...props }) => (
    <tr {...props}>{children}</tr>
  ),
  th: ({ children, ...props }) => (
    <th
      className="px-3 py-2 text-left font-medium text-foreground text-xs uppercase tracking-wider"
      {...props}
    >
      {children}
    </th>
  ),
  td: ({ children, ...props }) => (
    <td
      className="px-3 py-2 align-top text-sm text-foreground/90"
      {...props}
    >
      {children}
    </td>
  ),
  code: ({ children, className, ...props }) => {
    // `react-markdown` puts fenced code blocks in a <pre><code> pair
    // and inline code in a bare <code>. The presence of a `className`
    // (set by `react-markdown` for fenced blocks, e.g. "language-ts")
    // is the discriminator. For inline code we just style the chip.
    const isBlock = typeof className === "string" && className.length > 0;
    if (isBlock) {
      return (
        <code className={className} {...props}>
          {children}
        </code>
      );
    }
    return (
      <code
        className="rounded bg-muted px-1.5 py-0.5 font-mono text-[0.85em] text-foreground/90"
        {...props}
      >
        {children}
      </code>
    );
  },
  pre: ({ children, ...props }) => (
    <pre
      className="my-4 overflow-x-auto rounded-md border bg-muted/30 p-3 text-xs leading-relaxed"
      {...props}
    >
      {children}
    </pre>
  ),
  strong: ({ children, ...props }) => (
    <strong className="font-semibold text-foreground" {...props}>
      {children}
    </strong>
  ),
  em: ({ children, ...props }) => (
    <em className="italic" {...props}>
      {children}
    </em>
  ),
  input: ({ type, checked, disabled, ...props }) => {
    // GFM task-list checkboxes render as disabled checkboxes. Just
    // pass them through — we don't need a custom checkbox component,
    // the default browser style is fine and conveys "completed task".
    if (type === "checkbox") {
      return (
        <input
          type="checkbox"
          checked={checked}
          disabled={disabled}
          readOnly
          className="mr-1.5 align-middle"
          {...props}
        />
      );
    }
    return <input type={type} {...props} />;
  },
};