// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
// Copyright the Browserify authors. MIT License.
// Ported from https://github.com/browserify/path-browserify/
// This module is browser compatible.

import type { FormatInputPathObject } from "./_interface.ts";
import {
  CHAR_BACKWARD_SLASH,
  CHAR_DOT,
  CHAR_FORWARD_SLASH,
  CHAR_LOWERCASE_A,
  CHAR_LOWERCASE_Z,
  CHAR_UPPERCASE_A,
  CHAR_UPPERCASE_Z,
} from "./_constants.ts";

export function assertPath(path: string) {
  if (typeof path !== "string") {
    throw new TypeError(
      `Path must be a string. Received ${JSON.stringify(path)}`,
    );
  }
}

export function isPosixPathSeparator(code: number): boolean {
  return code === CHAR_FORWARD_SLASH;
}

export function isPathSeparator(code: number): boolean {
  return isPosixPathSeparator(code) || code === CHAR_BACKWARD_SLASH;
}

export function isWindowsDeviceRoot(code: number): boolean {
  return (
    (code >= CHAR_LOWERCASE_A && code <= CHAR_LOWERCASE_Z) ||
    (code >= CHAR_UPPERCASE_A && code <= CHAR_UPPERCASE_Z)
  );
}

// Resolves . and .. elements in a path with directory names
export function normalizeString(
  path: string,
  allowAboveRoot: boolean,
  separator: string,
  isPathSeparator: (code: number) => boolean,
): string {
  let res = "";
  let lastSegmentLength = 0;
  let lastSlash = -1;
  let dots = 0;
  let code: number | undefined;
  for (let i = 0, len = path.length; i <= len; ++i) {
    if (i < len) code = path.charCodeAt(i);
    else if (isPathSeparator(code!)) break;
    else code = CHAR_FORWARD_SLASH;

    if (isPathSeparator(code!)) {
      if (lastSlash === i - 1 || dots === 1) {
        // NOOP
      } else if (lastSlash !== i - 1 && dots === 2) {
        if (
          res.length < 2 ||
          lastSegmentLength !== 2 ||
          res.charCodeAt(res.length - 1) !== CHAR_DOT ||
          res.charCodeAt(res.length - 2) !== CHAR_DOT
        ) {
          if (res.length > 2) {
            const lastSlashIndex = res.lastIndexOf(separator);
            if (lastSlashIndex === -1) {
              res = "";
              lastSegmentLength = 0;
            } else {
              res = res.slice(0, lastSlashIndex);
              lastSegmentLength = res.length - 1 - res.lastIndexOf(separator);
            }
            lastSlash = i;
            dots = 0;
            continue;
          } else if (res.length === 2 || res.length === 1) {
            res = "";
            lastSegmentLength = 0;
            lastSlash = i;
            dots = 0;
            continue;
          }
        }
        if (allowAboveRoot) {
          if (res.length > 0) res += `${separator}..`;
          else res = "..";
          lastSegmentLength = 2;
        }
      } else {
        if (res.length > 0) res += separator + path.slice(lastSlash + 1, i);
        else res = path.slice(lastSlash + 1, i);
        lastSegmentLength = i - lastSlash - 1;
      }
      lastSlash = i;
      dots = 0;
    } else if (code === CHAR_DOT && dots !== -1) {
      ++dots;
    } else {
      dots = -1;
    }
  }
  return res;
}

export function _format(
  sep: string,
  pathObject: FormatInputPathObject,
): string {
  const dir: string | undefined = pathObject.dir || pathObject.root;
  const base: string = pathObject.base ||
    (pathObject.name || "") + (pathObject.ext || "");
  if (!dir) return base;
  if (base === sep) return dir;
  if (dir === pathObject.root) return dir + base;
  return dir + sep + base;
}

const WHITESPACE_ENCODINGS: Record<string, string> = {
  "\u0009": "%09",
  "\u000A": "%0A",
  "\u000B": "%0B",
  "\u000C": "%0C",
  "\u000D": "%0D",
  "\u0020": "%20",
};

export function encodeWhitespace(string: string): string {
  return string.replaceAll(/[\s]/g, (c) => {
    return WHITESPACE_ENCODINGS[c] ?? c;
  });
}

export function lastPathSegment(
  path: string,
  isSep: (char: number) => boolean,
  start = 0,
): string {
  let matchedNonSeparator = false;
  let end = path.length;

  for (let i = path.length - 1; i >= start; --i) {
    if (isSep(path.charCodeAt(i))) {
      if (matchedNonSeparator) {
        start = i + 1;
        break;
      }
    } else if (!matchedNonSeparator) {
      matchedNonSeparator = true;
      end = i + 1;
    }
  }

  return path.slice(start, end);
}

export function stripTrailingSeparators(
  segment: string,
  isSep: (char: number) => boolean,
): string {
  if (segment.length <= 1) {
    return segment;
  }

  let end = segment.length;

  for (let i = segment.length - 1; i > 0; i--) {
    if (isSep(segment.charCodeAt(i))) {
      end = i;
    } else {
      break;
    }
  }

  return segment.slice(0, end);
}

export function stripSuffix(name: string, suffix: string): string {
  if (suffix.length >= name.length) {
    return name;
  }

  const lenDiff = name.length - suffix.length;

  for (let i = suffix.length - 1; i >= 0; --i) {
    if (name.charCodeAt(lenDiff + i) !== suffix.charCodeAt(i)) {
      return name;
    }
  }

  return name.slice(0, -suffix.length);
}