import React from 'react';
import type { AlertKind } from '../../types';
import { renderProseBody } from './proseBody';
import { InlineMarkdown } from '../InlineMarkdown';
import { parseAlertTitleLine } from '../../utils/alertTitle';

interface AlertBlockProps {
  blockId: string;
  kind: AlertKind;
  body: string;
  onOpenLinkedDoc?: (path: string) => void;
  onOpenCodeFile?: (path: string) => void;
  imageBaseDir?: string;
  onImageClick?: (src: string, alt: string) => void;
  githubRepo?: string;
  repoHost?: string;
  onNavigateAnchor?: (hash: string) => void;
}

const TITLE: Record<AlertKind, string> = {
  note: 'Note',
  tip: 'Tip',
  warning: 'Warning',
  caution: 'Caution',
  important: 'Important',
};

/**
 * Host seam: resolve a named icon from a title line's `<!-- icon: name -->`
 * comment to a React node. Default: null for every name, so the alert keeps
 * the type's own icon exactly as today. A host that ships an icon set (the
 * package deliberately bundles none) registers a renderer once at startup.
 * Returning null for an unknown name falls back to the type's icon.
 */
export type AlertIconRenderer = (name: string) => React.ReactNode | null;

let alertIconRenderer: AlertIconRenderer | null = null;

export function setAlertIconRenderer(renderer: AlertIconRenderer | null): void {
  alertIconRenderer = renderer;
}

export function resetAlertIconRenderer(): void {
  alertIconRenderer = null;
}

const Icon: React.FC<{ kind: AlertKind }> = ({ kind }) => {
  const common = { viewBox: '0 0 16 16', width: '16', height: '16', fill: 'currentColor', 'aria-hidden': true as const };
  switch (kind) {
    case 'note':
      return <svg {...common}><path d="M0 8a8 8 0 1 1 16 0A8 8 0 0 1 0 8Zm8-6.5a6.5 6.5 0 1 0 0 13 6.5 6.5 0 0 0 0-13ZM6.5 7.75A.75.75 0 0 1 7.25 7h1a.75.75 0 0 1 .75.75v2.75h.25a.75.75 0 0 1 0 1.5h-2a.75.75 0 0 1 0-1.5h.25v-2h-.25a.75.75 0 0 1-.75-.75ZM8 6a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"/></svg>;
    case 'tip':
      return <svg {...common}><path d="M8 1.5c-2.363 0-4 1.69-4 3.75 0 .984.424 1.625.984 2.304l.214.253c.223.264.47.556.673.848.284.411.537.896.621 1.49a.75.75 0 0 1-1.484.211c-.04-.282-.163-.547-.37-.847a8.456 8.456 0 0 0-.542-.68c-.084-.1-.173-.205-.268-.32C3.201 7.75 2.5 6.766 2.5 5.25 2.5 2.31 4.863 0 8 0s5.5 2.31 5.5 5.25c0 1.516-.701 2.5-1.328 3.259-.095.115-.184.22-.268.319-.207.245-.383.453-.541.681-.208.3-.33.565-.37.847a.751.751 0 0 1-1.485-.212c.084-.593.337-1.078.621-1.489.203-.292.45-.584.673-.848.075-.088.147-.173.213-.253.561-.679.985-1.32.985-2.304 0-2.06-1.637-3.75-4-3.75ZM5.75 12h4.5a.75.75 0 0 1 0 1.5h-4.5a.75.75 0 0 1 0-1.5ZM6 15.25a.75.75 0 0 1 .75-.75h2.5a.75.75 0 0 1 0 1.5h-2.5a.75.75 0 0 1-.75-.75Z"/></svg>;
    case 'warning':
      return <svg {...common}><path d="M6.457 1.047c.659-1.234 2.427-1.234 3.086 0l6.082 11.378A1.75 1.75 0 0 1 14.082 15H1.918a1.75 1.75 0 0 1-1.543-2.575Zm1.763.707a.25.25 0 0 0-.44 0L1.698 13.132a.25.25 0 0 0 .22.368h12.164a.25.25 0 0 0 .22-.368Zm.53 3.996v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 11a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"/></svg>;
    case 'caution':
      return <svg {...common}><path d="M4.47.22A.749.749 0 0 1 5 0h6c.199 0 .389.079.53.22l4.25 4.25c.141.14.22.331.22.53v6a.749.749 0 0 1-.22.53l-4.25 4.25A.749.749 0 0 1 11 16H5a.749.749 0 0 1-.53-.22L.22 11.53A.749.749 0 0 1 0 11V5c0-.199.079-.389.22-.53Zm.84 1.28L1.5 5.31v5.38l3.81 3.81h5.38l3.81-3.81V5.31L10.69 1.5ZM8 4a.75.75 0 0 1 .75.75v3.5a.75.75 0 0 1-1.5 0v-3.5A.75.75 0 0 1 8 4Zm0 8a1 1 0 1 1 0-2 1 1 0 0 1 0 2Z"/></svg>;
    case 'important':
      return <svg {...common}><path d="M0 1.75C0 .784.784 0 1.75 0h12.5C15.216 0 16 .784 16 1.75v9.5A1.75 1.75 0 0 1 14.25 13H8.06l-2.573 2.573A1.458 1.458 0 0 1 3 14.543V13H1.75A1.75 1.75 0 0 1 0 11.25Zm1.75-.25a.25.25 0 0 0-.25.25v9.5c0 .138.112.25.25.25h2a.75.75 0 0 1 .75.75v2.19l2.72-2.72a.749.749 0 0 1 .53-.22h6.5a.25.25 0 0 0 .25-.25v-9.5a.25.25 0 0 0-.25-.25Zm7 2.25v2.5a.75.75 0 0 1-1.5 0v-2.5a.75.75 0 0 1 1.5 0ZM9 9a1 1 0 1 1-2 0 1 1 0 0 1 2 0Z"/></svg>;
  }
};

export const AlertBlock: React.FC<AlertBlockProps> = ({
  blockId, kind, body, onOpenLinkedDoc, onOpenCodeFile, imageBaseDir, onImageClick, githubRepo, repoHost, onNavigateAnchor,
}) => {
  const proseProps = { imageBaseDir, onImageClick, onOpenLinkedDoc, onOpenCodeFile, onNavigateAnchor, githubRepo, repoHost };

  // A bold-only first line (optionally led by one emoji, optionally trailed by
  // an `<!-- icon: name -->` comment) is the alert's title and rides the icon
  // row in place of the type word; the emoji, or a host-resolved named icon,
  // takes the icon slot. See utils/alertTitle for the exact grammar. A body
  // with no such line renders exactly as before.
  const titleLine = parseAlertTitleLine(body);
  // The emoji wins outright: the host renderer is consulted only for a title
  // line that carries an icon comment and no emoji (the seam contract).
  const icon = titleLine?.emoji
    ? <span aria-hidden="true" className="alert-emoji text-base leading-none">{titleLine.emoji}</span>
    : (titleLine?.icon && alertIconRenderer ? alertIconRenderer(titleLine.icon) : null) ?? <Icon kind={kind} />;

  return (
    <div
      className={`alert alert-${kind} my-4 pl-4 pr-3 py-2 border-l-[3px]`}
      data-block-id={blockId}
      data-block-type="alert"
      data-alert-kind={kind}
    >
      <div className="alert-title flex items-center gap-2 font-semibold mb-1">
        {icon}
        <span>
          {titleLine?.title
            ? (
              <>
                {/* The type word stays part of the accessible name. A visually
                    hidden span is read by every engine; an aria-label on this
                    generic div is prohibited by ARIA and dropped by WebKit.
                    `annotation-exclude` keeps it out of the annotation text
                    stream: without it a drag that starts on the icon quotes
                    the invisible word ("Warning:Named icon title"), which is
                    what the panel shows, what the agent is handed, and a quote
                    no share-link restore can find again. */}
                <span className="sr-only annotation-exclude">{TITLE[kind]}: </span>
                <InlineMarkdown text={titleLine.title} {...proseProps} />
              </>
            )
            : TITLE[kind]}
        </span>
      </div>
      {titleLine
        ? (titleLine.rest.trim()
            // Indent the body by the icon's width plus the row gap so it starts
            // at the title's left edge (16px icon + 8px gap = pl-6).
            ? <div className="alert-body pl-6">{renderProseBody({ body: titleLine.rest, ...proseProps })}</div>
            : null)
        : renderProseBody({ body, ...proseProps })}
    </div>
  );
};