import { SEP, SEP_PATTERN } from "./constants.ts";
import { globrex } from "./globrex.ts";
import { join, normalize } from "./mod.ts";
const { DenoError, ErrorKind } = Deno;

export interface GlobOptions {
  extended?: boolean;
  globstar?: boolean;
}

export interface GlobToRegExpOptions extends GlobOptions {
  flags?: string;
}

/**
 * Generate a regex based on glob pattern and options
 * This was meant to be using the the `fs.walk` function
 * but can be used anywhere else.
 * Examples:
 *
 *     Looking for all the `ts` files:
 *     walkSync(".", {
 *       match: [globToRegExp("*.ts")]
 *     })
 *
 *     Looking for all the `.json` files in any subfolder:
 *     walkSync(".", {
 *       match: [globToRegExp(join("a", "**", "*.json"),{
 *         flags: "g",
 *         extended: true,
 *         globstar: true
 *       })]
 *     })
 *
 * @param glob - Glob pattern to be used
 * @param options - Specific options for the glob pattern
 * @returns A RegExp for the glob pattern
 */
export function globToRegExp(
  glob: string,
  options: GlobToRegExpOptions = {}
): RegExp {
  const result = globrex(glob, { ...options, strict: false, filepath: true });
  return result.path!.regex;
}

/** Test whether the given string is a glob */
export function isGlob(str: string): boolean {
  const chars: Record<string, string> = { "{": "}", "(": ")", "[": "]" };
  /* eslint-disable-next-line max-len */
  const regex = /\\(.)|(^!|\*|[\].+)]\?|\[[^\\\]]+\]|\{[^\\}]+\}|\(\?[:!=][^\\)]+\)|\([^|]+\|[^\\)]+\))/;

  if (str === "") {
    return false;
  }

  let match: RegExpExecArray | null;

  while ((match = regex.exec(str))) {
    if (match[2]) return true;
    let idx = match.index + match[0].length;

    // if an open bracket/brace/paren is escaped,
    // set the index to the next closing character
    const open = match[1];
    const close = open ? chars[open] : null;
    if (open && close) {
      const n = str.indexOf(close, idx);
      if (n !== -1) {
        idx = n + 1;
      }
    }

    str = str.slice(idx);
  }

  return false;
}

/** Like normalize(), but doesn't collapse "**\/.." when `globstar` is true. */
export function normalizeGlob(
  glob: string,
  { globstar = false }: GlobOptions = {}
): string {
  if (!!glob.match(/\0/g)) {
    throw new DenoError(
      ErrorKind.InvalidPath,
      `Glob contains invalid characters: "${glob}"`
    );
  }
  if (!globstar) {
    return normalize(glob);
  }
  const s = SEP_PATTERN.source;
  const badParentPattern = new RegExp(
    `(?<=(${s}|^)\\*\\*${s})\\.\\.(?=${s}|$)`,
    "g"
  );
  return normalize(glob.replace(badParentPattern, "\0")).replace(/\0/g, "..");
}

/** Like join(), but doesn't collapse "**\/.." when `globstar` is true. */
export function joinGlobs(
  globs: string[],
  { extended = false, globstar = false }: GlobOptions = {}
): string {
  if (!globstar || globs.length == 0) {
    return join(...globs);
  }
  if (globs.length === 0) return ".";
  let joined: string | undefined;
  for (const glob of globs) {
    const path = glob;
    if (path.length > 0) {
      if (!joined) joined = path;
      else joined += `${SEP}${path}`;
    }
  }
  if (!joined) return ".";
  return normalizeGlob(joined, { extended, globstar });
}