import { useMemo, useRef, useState } from 'react';
import CloseIcon from '../../icons/close.svg';
import SpinnerIcon from '../../icons/spinner.svg';

import { useKeydown } from '../../hooks/use-keydown';
import { useLoadTopic } from '../../hooks/use-load-topic';
import { useOutsideClick } from '../../hooks/use-outside-click';
import { useToggleTopic } from '../../hooks/use-toggle-topic';
import { httpGet } from '../../lib/http';
import { isLoggedIn } from '../../lib/jwt';
import type { ResourceType } from '../../lib/resource-progress';
import {
  isTopicDone,
  refreshProgressCounters,
  renderTopicProgress,
  updateResourceProgress as updateResourceProgressApi,
} from '../../lib/resource-progress';
import { pageProgressMessage, sponsorHidden } from '../../stores/page';
import { TopicProgressButton } from './TopicProgressButton';
import { ContributionForm } from './ContributionForm';
import { showLoginPopup } from '../../lib/popup';
import { useToast } from '../../hooks/use-toast';
import type {
  AllowedLinkTypes,
  RoadmapContentDocument,
} from '../CustomRoadmap/CustomRoadmap';
import { markdownToHtml } from '../../lib/markdown';
import { cn } from '../../lib/classname';
import { Ban, FileText } from 'lucide-react';
import { getUrlParams } from '../../lib/browser';

type TopicDetailProps = {
  canSubmitContribution: boolean;
};

const linkTypes: Record<AllowedLinkTypes, string> = {
  article: 'bg-yellow-200',
  course: 'bg-green-200',
  opensource: 'bg-blue-200',
  podcast: 'bg-purple-200',
  video: 'bg-pink-200',
  website: 'bg-red-200',
};

export function TopicDetail(props: TopicDetailProps) {
  const { canSubmitContribution } = props;

  const [contributionAlertMessage, setContributionAlertMessage] = useState('');
  const [isActive, setIsActive] = useState(false);
  const [isLoading, setIsLoading] = useState(false);
  const [isContributing, setIsContributing] = useState(false);
  const [error, setError] = useState('');
  const [topicHtml, setTopicHtml] = useState('');
  const [topicTitle, setTopicTitle] = useState('');
  const [links, setLinks] = useState<RoadmapContentDocument['links']>([]);
  const toast = useToast();

  const { secret } = getUrlParams() as { secret: string };
  const isGuest = useMemo(() => !isLoggedIn(), []);
  const topicRef = useRef<HTMLDivElement>(null);

  // Details of the currently loaded topic
  const [topicId, setTopicId] = useState('');
  const [resourceId, setResourceId] = useState('');
  const [resourceType, setResourceType] = useState<ResourceType>('roadmap');

  // Close the topic detail when user clicks outside the topic detail
  useOutsideClick(topicRef, () => {
    setIsActive(false);
    setIsContributing(false);
  });

  useKeydown('Escape', () => {
    setIsActive(false);
    setIsContributing(false);
  });

  // Toggle topic is available even if the component UI is not active
  // This is used on the best practice screen where we have the checkboxes
  // to mark the topic as done/undone.
  useToggleTopic(({ topicId, resourceType, resourceId }) => {
    if (isGuest) {
      showLoginPopup();
      return;
    }

    pageProgressMessage.set('Updating');

    // Toggle the topic status
    isTopicDone({ topicId, resourceId, resourceType })
      .then((oldIsDone) =>
        updateResourceProgressApi(
          {
            topicId,
            resourceId,
            resourceType,
          },
          oldIsDone ? 'pending' : 'done',
        ),
      )
      .then(({ done = [] }) => {
        renderTopicProgress(
          topicId,
          done.includes(topicId) ? 'done' : 'pending',
        );
        refreshProgressCounters();
      })
      .catch((err) => {
        toast.error(err.message);
        console.error(err);
      })
      .finally(() => {
        pageProgressMessage.set('');
      });
  });

  // Load the topic detail when the topic detail is active
  useLoadTopic(({ topicId, resourceType, resourceId, isCustomResource }) => {
    setError('');
    setIsLoading(true);
    setIsActive(true);
    sponsorHidden.set(true);

    setContributionAlertMessage('');
    setTopicId(topicId);
    setResourceType(resourceType);
    setResourceId(resourceId);

    const topicPartial = topicId.replaceAll(':', '/');
    let topicUrl =
      resourceType === 'roadmap'
        ? `/${resourceId}/${topicPartial}`
        : `/best-practices/${resourceId}/${topicPartial}`;

    if (isCustomResource) {
      topicUrl = `${
        import.meta.env.PUBLIC_API_URL
      }/v1-get-node-content/${resourceId}/${topicId}${
        secret ? `?secret=${secret}` : ''
      }`;
    }

    httpGet<string | RoadmapContentDocument>(
      topicUrl,
      {},
      {
        ...(!isCustomResource && {
          headers: {
            Accept: 'text/html',
          },
        }),
      },
    )
      .then(({ response }) => {
        if (!response) {
          setError('Topic not found.');
          setIsLoading(false);
          return;
        }
        let topicHtml = '';
        if (!isCustomResource) {
          // It's full HTML with page body, head etc.
          // We only need the inner HTML of the #main-content
          const node = new DOMParser().parseFromString(
            response as string,
            'text/html',
          );
          topicHtml = node?.getElementById('main-content')?.outerHTML || '';
        } else {
          setLinks((response as RoadmapContentDocument)?.links || []);
          setTopicTitle((response as RoadmapContentDocument)?.title || '');
          topicHtml = markdownToHtml(
            (response as RoadmapContentDocument)?.description || '',
            false,
          );
        }

        setIsLoading(false);
        setTopicHtml(topicHtml);
      })
      .catch((err) => {
        setError('Something went wrong. Please try again later.');
        setIsLoading(false);
      });
  });

  if (!isActive) {
    return null;
  }

  const hasContent = topicHtml?.length > 0 || links?.length > 0 || topicTitle;

  return (
    <div className={'relative z-50'}>
      <div
        ref={topicRef}
        className="fixed right-0 top-0 z-40 h-screen w-full overflow-y-auto bg-white p-4 sm:max-w-[600px] sm:p-6"
      >
        {isLoading && (
          <div className="flex w-full justify-center">
            <img
              src={SpinnerIcon.src}
              alt="Loading"
              className="h-6 w-6 animate-spin fill-blue-600 text-gray-200 sm:h-12 sm:w-12"
            />
          </div>
        )}

        {!isLoading && isContributing && (
          <ContributionForm
            resourceType={resourceType}
            resourceId={resourceId}
            topicId={topicId}
            onClose={(message?: string) => {
              if (message) {
                setContributionAlertMessage(message);
              }

              setIsContributing(false);
            }}
          />
        )}

        {!isContributing && !isLoading && !error && (
          <>
            {/* Actions for the topic */}
            <div className="mb-2">
              <TopicProgressButton
                topicId={topicId}
                resourceId={resourceId}
                resourceType={resourceType}
                onClose={() => {
                  setIsActive(false);
                  setIsContributing(false);
                }}
              />

              <button
                type="button"
                id="close-topic"
                className="absolute right-2.5 top-2.5 inline-flex items-center rounded-lg bg-transparent p-1.5 text-sm text-gray-400 hover:bg-gray-200 hover:text-gray-900"
                onClick={() => {
                  setIsActive(false);
                  setIsContributing(false);
                }}
              >
                <img alt="Close" className="h-5 w-5" src={CloseIcon.src} />
              </button>
            </div>

            {/* Topic Content */}
            {hasContent ? (
              <div className="prose prose-quoteless prose-h1:mb-2.5 prose-h1:mt-7 prose-h2:mb-3 prose-h2:mt-0 prose-h3:mb-[5px] prose-h3:mt-[10px] prose-p:mb-2 prose-p:mt-0 prose-blockquote:font-normal prose-blockquote:not-italic prose-blockquote:text-gray-700 prose-li:m-0 prose-li:mb-0.5">
                {topicTitle && <h1>{topicTitle}</h1>}
                <div
                  id="topic-content"
                  dangerouslySetInnerHTML={{ __html: topicHtml }}
                />
              </div>
            ) : (
              <div className="flex h-[calc(100%-38px)] flex-col items-center justify-center">
                <FileText className="h-16 w-16 text-gray-300" />
                <p className="mt-2 text-lg font-medium text-gray-500">
                  Empty Content
                </p>
              </div>
            )}

            {links.length > 0 && (
              <ul className="mt-6 space-y-1">
                {links.map((link) => {
                  return (
                    <li>
                      <a
                        href={link.url}
                        target="_blank"
                        className="font-medium underline"
                      >
                        <span
                          className={cn(
                            'mr-2 inline-block rounded px-1.5 py-1 text-xs uppercase no-underline',
                            linkTypes[link.type],
                          )}
                        >
                          {link.type.charAt(0).toUpperCase() +
                            link.type.slice(1)}
                        </span>
                        {link.title}
                      </a>
                    </li>
                  );
                })}
              </ul>
            )}

            {/* Contribution */}
            {canSubmitContribution && (
              <div className="mt-8 flex-1 border-t">
                <p className="mb-2 mt-2 text-sm leading-relaxed text-gray-400">
                  Help others learn by submitting links to learn more about this
                  topic{' '}
                </p>
                <button
                  onClick={() => {
                    if (isGuest) {
                      setIsActive(false);
                      showLoginPopup();
                      return;
                    }

                    setIsContributing(true);
                  }}
                  disabled={!!contributionAlertMessage}
                  className="block w-full rounded-md bg-gray-800 p-2 text-sm text-white transition-colors hover:bg-black hover:text-white disabled:bg-green-200 disabled:text-black"
                >
                  {contributionAlertMessage
                    ? contributionAlertMessage
                    : 'Submit a Link'}
                </button>
              </div>
            )}
          </>
        )}

        {/* Error */}
        {!isContributing && !isLoading && error && (
          <>
            <button
              type="button"
              id="close-topic"
              className="absolute right-2.5 top-2.5 inline-flex items-center rounded-lg bg-transparent p-1.5 text-sm text-gray-400 hover:bg-gray-200 hover:text-gray-900"
              onClick={() => {
                setIsActive(false);
                setIsContributing(false);
              }}
            >
              <img alt="Close" className="h-5 w-5" src={CloseIcon.src} />
            </button>
            <div className="flex h-full flex-col items-center justify-center">
              <Ban className="h-16 w-16 text-red-500" />
              <p className="mt-2 text-lg font-medium text-red-500">{error}</p>
            </div>
          </>
        )}
      </div>
      <div className="fixed inset-0 z-30 bg-gray-900 bg-opacity-50 dark:bg-opacity-80"></div>
    </div>
  );
}