import { useMemo, useState } from 'react';

import jsdocJson from '../../../../../doc.json';
import { Textbox } from '../textbox/Textbox';

const isValid = ({ name, description }) => name && !name.startsWith('_') && !!description;

const availableFunctions = (() => {
  const seen = new Set(); // avoid repetition
  const functions = [];
  for (const doc of jsdocJson.docs) {
    if (!isValid(doc)) continue;
    if (seen.has(doc.name)) continue;
    doc.tags = doc.tags?.filter((t) => t && typeof t === 'string') || [];
    functions.push(doc);
    const synonyms = doc.synonyms || [];
    seen.add(doc.name);
    for (const s of synonyms) {
      if (!s || seen.has(s)) continue;
      seen.add(s);
      // Swap `doc.name` in for `s` in the list of synonyms
      const synonymsWithDoc = [doc.name, ...synonyms].filter((x) => x && x !== s);
      // functions.push({
      //   ...doc,
      //   name: s, // update names for the synonym
      //   longname: s,
      //   synonyms: synonymsWithDoc,
      //   synonyms_text: synonymsWithDoc.join(', '),
      // });
    }
  }
  return functions.sort((a, b) => /* a.meta.filename.localeCompare(b.meta.filename) +  */ a.name.localeCompare(b.name));
})();

const getInnerText = (html) => {
  var div = document.createElement('div');
  div.innerHTML = html;
  return div.textContent || div.innerText || '';
};

const GROUP_DISPLAY_NAMES = {
  external_io: 'External I/O',
  effects: 'Effects',
  untagged: 'Untagged',
  structure: 'Structure',
  transforms: 'Transforms',
};

const GROUP_ORDER = ['effects', 'transforms', 'structure', 'untagged', 'external_io'];

export function Reference() {
  const [search, setSearch] = useState('');
  const [selectedTag, setSelectedTag] = useState(null);

  const toggleTag = (tag) => {
    if (selectedTag === tag) {
      setSelectedTag(null);
    } else {
      setSelectedTag(tag);
    }
  };

  const visibleFunctions = useMemo(() => {
    return availableFunctions.filter((entry) => {
      if (selectedTag) {
        if (!(entry.tags || ['untagged']).includes(selectedTag)) {
          return false;
        }
      }

      if (!search) {
        return true;
      }

      const lowCaseSearch = search.toLowerCase();
      return (
        entry.name.toLowerCase().includes(lowCaseSearch) ||
        (entry.synonyms?.some((s) => s.includes(lowCaseSearch)) ?? false)
      );
    });
  }, [search, selectedTag]);

  const visibleFunctionsByGroup = (() => {
    const groups = {};
    for (const doc of visibleFunctions) {
      const group = (doc.tags || ['untagged'])[0];
      if (!groups[group]) {
        groups[group] = [];
      }
      groups[group].push(doc);
    }
    return groups;
  })();
  // console.log(visibleFunctionsByGroup);

  // Sort and map group entries
  const sortedGroups = Object.entries(visibleFunctionsByGroup).sort(([a], [b]) => {
    const ai = GROUP_ORDER.indexOf(a);
    const bi = GROUP_ORDER.indexOf(b);
    if (ai === -1 && bi === -1) return a.localeCompare(b);
    if (ai === -1) return 1;
    if (bi === -1) return -1;
    return ai - bi;
  });

  const tagCounts = {};
  for (const doc of availableFunctions) {
    (doc.tags || ['untagged']).forEach((t) => {
      if (typeof t === 'string' && t) {
        tagCounts[t] = (tagCounts[t] || 0) + 1;
      }
    });
  }

  return (
    <div className="flex flex-col h-full w-full p-2">
      <div className="w-full  flex flex-col gap-2 h-1/3 mb-2">
        <div className="w-full flex flex-col gap-2">
          <Textbox className="w-full" placeholder="Search" value={search} onChange={setSearch} />
          <div>
            {Object.entries(tagCounts)
              .sort(([a], [b]) => a.localeCompare(b))
              .map(([t, count]) => (
                <span key={t}>
                  <a
                    className={[
                      'select-none text-white border-2 border-gray-500 px-1 py-0.5 my-2 cursor-pointer text-sm/8 rounded-md ',
                      `${selectedTag === t ? 'bg-gray-500 text-black' : ''}`,
                    ].join(' ')}
                    onClick={() => toggleTag(t)}
                  >
                    {t}&nbsp;({count})
                  </a>{' '}
                </span>
              ))}
          </div>
        </div>
        <div className="h-full gap-1.5 bg-background bg-opacity-50 rounded-md overflow-y-auto">
          {visibleFunctions.map((entry, i) => (
            <>
              <a
                key={`entry-${entry.name}`}
                className="cursor-pointer text-foreground flex-none hover:bg-lineHighlight overflow-x-hidden px-1 text-ellipsis"
                onClick={() => {
                  const el = document.getElementById(`doc-${entry.name}`);
                  const container = document.getElementById('reference-container');
                  container.scrollTo(0, el.offsetTop);
                }}
              >
                {entry.name}
              </a>{' '}
            </>
          ))}
        </div>
      </div>
      <div
        className="break-normal flex-col overflow-y-auto overflow-x-hidden p-2 flex relative"
        id="reference-container"
      >
        <div className="prose dark:prose-invert min-w-full px-1 ">
          <h2>API Reference</h2>
          <p>
            This is the long list of functions you can use. Remember that you don't need to remember all of those and
            that you can already make music with a small set of functions!
          </p>
          {visibleFunctions.map((entry, i) => (
            <section key={i} className="font-sans">
              <div className="flex flex-row items-center mt-8 justify-between">
                <h3 className="font-mono my-0" id={`doc-${entry.name}`}>
                  {entry.name}
                </h3>
                {entry.tags && (
                  <span className="ml-2 text-xs text-gray-400 border-2 border-gray-500 rounded-md px-1 py-0.5">
                    {entry.tags.join(', ')}
                  </span>
                )}
              </div>
              {!!entry.synonyms_text && (
                <p>
                  Synonyms: <code>{entry.synonyms_text}</code>
                </p>
              )}
              {/* <small>{entry.meta.filename}</small> */}
              <p dangerouslySetInnerHTML={{ __html: entry.description }}></p>
              <ul>
                {entry.params?.map(({ name, type, description }, i) => (
                  <li key={i}>
                    {name} : {type?.names?.join(' | ')} {description ? <> - {getInnerText(description)}</> : ''}
                  </li>
                ))}
              </ul>
              {entry.examples?.map((example, j) => (
                <pre className="bg-background" key={j}>
                  {example}
                </pre>
              ))}
            </section>
          ))}
        </div>
      </div>
    </div>
  );
}