/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

/* eslint-disable jsx-a11y/no-noninteractive-tabindex */

import React, { useEffect, useState, useRef } from "react";
import classnames from "classnames";
import Highlight, { defaultProps } from "prism-react-renderer";
import Prism from "prism-react-renderer/prism";
import darkTheme from "./dracula";
import lightTheme from "./github";
import Clipboard from "clipboard";
import rangeParser from "parse-numeric-range";
import useDocusaurusContext from "@docusaurus/useDocusaurusContext";
import useThemeContext from "@theme/hooks/useThemeContext";

import styles from "./styles.module.css";

const highlightLinesRangeRegex = /{([\d,-]+)}/;
const getHighlightDirectiveRegex = (
  languages = ["js", "jsBlock", "jsx", "python", "html"]
) => {
  // supported types of comments
  const comments = {
    js: {
      start: "\\/\\/",
      end: "",
    },
    jsBlock: {
      start: "\\/\\*",
      end: "\\*\\/",
    },
    jsx: {
      start: "\\{\\s*\\/\\*",
      end: "\\*\\/\\s*\\}",
    },
    python: {
      start: "#",
      end: "",
    },
    html: {
      start: "<!--",
      end: "-->",
    },
  };
  // supported directives
  const directives = [
    "highlight-next-line",
    "highlight-start",
    "highlight-end",
  ].join("|");
  // to be more reliable, the opening and closing comment must match
  const commentPattern = languages
    .map(
      (lang) =>
        `(?:${comments[lang].start}\\s*(${directives})\\s*${comments[lang].end})`
    )
    .join("|");
  // white space is allowed, but otherwise it should be on it's own line
  return new RegExp(`^\\s*(?:${commentPattern})\\s*$`);
};
// select comment styles based on language
const highlightDirectiveRegex = (lang) => {
  switch (lang) {
    case "js":
    case "javascript":
    case "ts":
    case "typescript":
      return getHighlightDirectiveRegex(["js", "jsBlock"]);

    case "jsx":
    case "tsx":
      return getHighlightDirectiveRegex(["js", "jsBlock", "jsx"]);

    case "html":
      return getHighlightDirectiveRegex(["js", "jsBlock", "html"]);

    case "python":
    case "py":
      return getHighlightDirectiveRegex(["python"]);

    default:
      // all comment types
      return getHighlightDirectiveRegex();
  }
};
const codeBlockTitleRegex = /title=".*"/;

export default ({ children, className: languageClassName, metastring }) => {
  (typeof global !== "undefined" ? global : window).Prism = Prism;
  require("prismjs/components/prism-shell-session");
  require("prismjs/components/prism-nginx");
  const {
    siteConfig: {
      themeConfig: { prism = {} },
    },
  } = useDocusaurusContext();

  const [showCopied, setShowCopied] = useState(false);
  const [mounted, setMounted] = useState(false);
  // The Prism theme on SSR is always the default theme but the site theme
  // can be in a different mode. React hydration doesn't update DOM styles
  // that come from SSR. Hence force a re-render after mounting to apply the
  // current relevant styles. There will be a flash seen of the original
  // styles seen using this current approach but that's probably ok. Fixing
  // the flash will require changing the theming approach and is not worth it
  // at this point.
  useEffect(() => {
    setMounted(true);
  }, []);

  const target = useRef(null);
  const button = useRef(null);
  let highlightLines = [];
  let codeBlockTitle = "";

  const { isDarkTheme } = useThemeContext();
  const lightModeTheme = prism.theme || lightTheme || darkTheme;
  const darkModeTheme = prism.darkTheme || darkTheme || lightTheme;
  const prismTheme = isDarkTheme ? darkModeTheme : lightModeTheme;

  if (metastring && highlightLinesRangeRegex.test(metastring)) {
    const highlightLinesRange = metastring.match(highlightLinesRangeRegex)[1];
    highlightLines = rangeParser
      .parse(highlightLinesRange)
      .filter((n) => n > 0);
  }

  if (metastring && codeBlockTitleRegex.test(metastring)) {
    codeBlockTitle = metastring
      .match(codeBlockTitleRegex)[0]
      .split("title=")[1]
      .replace(/"+/g, "");
  }

  useEffect(() => {
    let clipboard;

    if (button.current) {
      clipboard = new Clipboard(button.current, {
        target: () => target.current,
      });
    }

    return () => {
      if (clipboard) {
        clipboard.destroy();
      }
    };
  }, [button.current, target.current]);

  let language =
    languageClassName && languageClassName.replace(/language-/, "");

  if (!language && prism.defaultLanguage) {
    language = prism.defaultLanguage;
  }

  // only declaration OR directive highlight can be used for a block
  let code = children.replace(/\n$/, "");
  if (highlightLines.length === 0 && language !== undefined) {
    let range = "";
    const directiveRegex = highlightDirectiveRegex(language);
    // go through line by line
    const lines = children.replace(/\n$/, "").split("\n");
    let blockStart;
    // loop through lines
    for (let index = 0; index < lines.length; ) {
      const line = lines[index];
      // adjust for 0-index
      const lineNumber = index + 1;
      const match = line.match(directiveRegex);
      if (match !== null) {
        const directive = match
          .slice(1)
          .reduce((final, item) => final || item, undefined);
        switch (directive) {
          case "highlight-next-line":
            range += `${lineNumber},`;
            break;

          case "highlight-start":
            blockStart = lineNumber;
            break;

          case "highlight-end":
            range += `${blockStart}-${lineNumber - 1},`;
            break;

          default:
            break;
        }
        lines.splice(index, 1);
      } else {
        // lines without directives are unchanged
        index += 1;
      }
    }
    highlightLines = rangeParser.parse(range);
    code = lines.join("\n");
  }

  const handleCopyCode = () => {
    window.getSelection().empty();
    setShowCopied(true);

    setTimeout(() => setShowCopied(false), 2000);
  };

  return (
    <Highlight
      {...defaultProps}
      key={mounted}
      theme={prismTheme}
      code={code}
      language={language}
    >
      {({ className, style, tokens, getLineProps, getTokenProps }) => (
        <>
          {codeBlockTitle && (
            <div style={style} className={styles.codeBlockTitle}>
              {codeBlockTitle}
            </div>
          )}
          <div className={styles.codeBlockContent}>
            {/* <button
              ref={button}
              type="button"
              aria-label="Copy code to clipboard"
              className={classnames(styles.copyButton, {
                [styles.copyButtonWithTitle]: codeBlockTitle,
              })}
              onClick={handleCopyCode}>
              {showCopied ? 'Copied' : 'Copy'}
            </button> */}
            <div
              tabIndex="0"
              className={classnames(className, styles.codeBlock, {
                [styles.codeBlockWithTitle]: codeBlockTitle,
              })}
            >
              <div ref={target} className={styles.codeBlockLines} style={style}>
                {tokens.map((line, i) => {
                  if (line.length === 1 && line[0].content === "") {
                    line[0].content = "\n"; // eslint-disable-line no-param-reassign
                  }

                  const lineProps = getLineProps({ line, key: i });

                  if (highlightLines.includes(i + 1)) {
                    lineProps.className = `${lineProps.className} docusaurus-highlight-code-line`;
                  }

                  return (
                    <div key={i} {...lineProps}>
                      {line.map((token, key) => (
                        <span key={key} {...getTokenProps({ token, key })} />
                      ))}
                    </div>
                  );
                })}
              </div>
            </div>
          </div>
        </>
      )}
    </Highlight>
  );
};