/* eslint-disable functional/no-let */
/* eslint-disable no-useless-escape */
import _process from "process";

import { normalizeArray, trimArray } from "./utils";
import type { PathObject } from "./utils";
// Regex to split a windows path into three parts: [*, device, slash,
// tail] windows-only
const splitDeviceRe =
  /^([a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/]+[^\\\/]+)?([\\\/])?([\s\S]*?)$/;

// Regex to split the tail part of the above into [*, dir, basename, ext]
const splitTailRe =
  /^([\s\S]*?)((?:\.{1,2}|[^\\\/]+?|)(\.[^.\/\\]*|))(?:[\\\/]*)$/;

// Function to split a filename into [root, dir, basename, ext]
function win32SplitPath(
  filename: string
): readonly [string, string, string, string] {
  // Separate device+slash from tail
  const result = splitDeviceRe.exec(filename),
    device = (result?.[1] || "") + (result?.[2] || ""),
    tail = result?.[3] || "";
  // Split the tail into dir, basename and extension
  const result2 = splitTailRe.exec(tail),
    dir = result2?.[1] ?? "",
    basename = result2?.[2] ?? "",
    ext = result2?.[3] ?? "";
  return [device, dir, basename, ext];
}

function win32StatPath(path: string): {
  readonly device: string;
  readonly isUnc: boolean;
  readonly isAbsolute: boolean;
  readonly tail: string;
} {
  const result = splitDeviceRe.exec(path),
    device = result?.[1] || "",
    isUnc = !!device && device[1] !== ":";
  return {
    device,
    isUnc,
    isAbsolute: isUnc || !!result?.[2], // UNC paths are always absolute
    tail: result?.[3] ?? "",
  };
}

function normalizeUNCRoot(device: string): string {
  return `\\\\${device.replace(/^[\\\/]+/, "").replace(/[\\\/]+/g, "\\")}`;
}

export const sep = "\\";
export const delimiter = ";";
// eslint-disable-next-line functional/functional-parameters
export function resolve(...args: readonly string[]): string {
  let resolvedDevice = "",
    resolvedTail = "",
    resolvedAbsolute = false,
    isUnc = false;

  // eslint-disable-next-line functional/no-loop-statement
  for (let i = args.length - 1; i >= -1; i--) {
    let path: string;
    if (i >= 0) {
      path = args[i];
    } else if (!resolvedDevice) {
      path = _process.cwd();
    } else {
      // Windows has the concept of drive-specific current working
      // directories. If we've resolved a drive letter but not yet an
      // absolute path, get cwd for that drive. We're sure the device is not
      // an unc path at this points, because unc paths are always absolute.
      path = _process.env[`=${resolvedDevice}`];
      // Verify that a drive-local cwd was found and that it actually points
      // to our drive. If not, default to the drive's root.
      if (
        !path ||
        path.substr(0, 3).toLowerCase() !== `${resolvedDevice.toLowerCase()}\\`
      ) {
        path = `${resolvedDevice}\\`;
      }
    }

    // Skip empty and invalid entries
    if (typeof path !== "string") {
      // eslint-disable-next-line functional/no-throw-statement
      throw new TypeError("Arguments to path.resolve must be strings");
    } else if (!path) {
      continue;
    }

    const result = win32StatPath(path);
    const device = result.device;
    isUnc = result.isUnc;
    const isAbsolute = result.isAbsolute;
    const tail = result.tail;

    if (
      device &&
      resolvedDevice &&
      device.toLowerCase() !== resolvedDevice.toLowerCase()
    ) {
      // This path points to another device so it is not applicable
      continue;
    }

    if (!resolvedDevice) {
      resolvedDevice = device;
    }
    if (!resolvedAbsolute) {
      resolvedTail = `${tail}\\${resolvedTail}`;
      resolvedAbsolute = isAbsolute;
    }

    if (resolvedDevice && resolvedAbsolute) {
      break;
    }
  }

  // Convert slashes to backslashes when `resolvedDevice` points to an UNC
  // root. Also squash multiple slashes into a single one where appropriate.
  if (isUnc) {
    resolvedDevice = normalizeUNCRoot(resolvedDevice);
  }

  // At this point the path should be resolved to a full absolute path,
  // but handle relative paths to be safe (might happen when process.cwd()
  // fails)

  // Normalize the tail path
  resolvedTail = normalizeArray(
    resolvedTail.split(/[\\\/]+/),
    !resolvedAbsolute
  ).join("\\");

  return resolvedDevice + (resolvedAbsolute ? "\\" : "") + resolvedTail || ".";
}
export function normalize(path: string): string {
  const result = win32StatPath(path);
  const isUnc = result.isUnc;
  const isAbsolute = result.isAbsolute;

  let { device, tail } = result;

  const trailingSlash = /[\\\/]$/.test(tail);

  // Normalize the tail path

  tail = normalizeArray(tail.split(/[\\\/]+/), !isAbsolute).join("\\");

  if (!tail && !isAbsolute) {
    tail = ".";
  }
  if (tail && trailingSlash) {
    tail += "\\";
  }

  // Convert slashes to backslashes when `device` points to an UNC root.
  // Also squash multiple slashes into a single one where appropriate.
  if (isUnc) {
    device = normalizeUNCRoot(device);
  }

  return device + (isAbsolute ? "\\" : "") + tail;
}
export function isAbsolute(path: string): boolean {
  return win32StatPath(path).isAbsolute;
}
// eslint-disable-next-line functional/functional-parameters
export function join(...args: readonly string[]): string {
  const paths = [];

  // eslint-disable-next-line functional/no-loop-statement
  for (const arg of args) {
    if (typeof arg !== "string") {
      // eslint-disable-next-line functional/no-throw-statement
      throw new TypeError("Arguments to path.join must be strings");
    }
    if (arg) {
      // eslint-disable-next-line functional/immutable-data
      paths.push(arg);
    }
  }

  let joined = paths.join("\\");

  // Make sure that the joined path doesn't start with two slashes, because
  // normalize() will mistake it for an UNC path then.
  //
  // This step is skipped when it is very clear that the user actually
  // intended to point at an UNC path. This is assumed when the first
  // non-empty string arguments starts with exactly two slashes followed by
  // at least one more non-slash character.
  //
  // Note that for normalize() to treat a path as an UNC path it needs to
  // have at least 2 components, so we don't filter for that here.
  // This means that the user can use join to construct UNC paths from
  // a server name and a share name; for example:
  //   path.join('//server', 'share') -> '\\\\server\\share\')
  if (!/^[\\\/]{2}[^\\\/]/.test(paths[0])) {
    joined = joined.replace(/^[\\\/]{2,}/, "\\");
  }

  return normalize(joined);
}
export function relative(from: string, to: string): string {
  from = resolve(from);
  to = resolve(to);

  // windows is not case sensitive
  const lowerFrom = from.toLowerCase();
  const lowerTo = to.toLowerCase();

  const toParts = trimArray(to.split("\\"));

  const lowerFromParts = trimArray(lowerFrom.split("\\"));
  const lowerToParts = trimArray(lowerTo.split("\\"));

  const length = Math.min(lowerFromParts.length, lowerToParts.length);
  let samePartsLength = length;
  // eslint-disable-next-line functional/no-loop-statement
  for (let i = 0; i < length; i++) {
    if (lowerFromParts[i] !== lowerToParts[i]) {
      samePartsLength = i;
      break;
    }
  }

  if (samePartsLength == 0) {
    return to;
  }

  let outputParts = [];
  // eslint-disable-next-line functional/no-loop-statement
  for (let i = samePartsLength; i < lowerFromParts.length; i++) {
    // eslint-disable-next-line functional/immutable-data
    outputParts.push("..");
  }

  outputParts = outputParts.concat(toParts.slice(samePartsLength));

  return outputParts.join("\\");
}
export function _makeLong(path: string): string {
  // Note: this will *probably* throw somewhere.
  if (typeof path !== "string") return path;

  if (!path) {
    return "";
  }

  const resolvedPath = resolve(path);

  if (/^[a-zA-Z]\:\\/.test(resolvedPath)) {
    // path is local filesystem path, which needs to be converted
    // to long UNC path.
    return `\\\\?\\${resolvedPath}`;
  } else if (/^\\\\[^?.]/.test(resolvedPath)) {
    // path is network UNC path, which needs to be converted
    // to long UNC path.
    return `\\\\?\\UNC\\${resolvedPath.substring(2)}`;
  }

  return path;
}
export function dirname(path: string): string {
  const result = win32SplitPath(path);
  const root = result[0];
  let dir = result[1];

  if (!root && !dir) {
    // No dirname whatsoever
    return ".";
  }

  if (dir) {
    // It has a dirname, strip trailing slash
    dir = dir.substr(0, dir.length - 1);
  }

  return root + dir;
}
export function basename(path: string, ext?: string): string {
  let f = win32SplitPath(path)[2];
  // TODO: make this comparison case-insensitive on windows?
  if (ext && f.substr(-1 * ext.length) === ext) {
    f = f.substr(0, f.length - ext.length);
  }
  return f;
}
export function extname(path: string): string {
  return win32SplitPath(path)[3];
}
export function format(pathObject: PathObject): string {
  if (pathObject == null || typeof pathObject !== "object") {
    // eslint-disable-next-line functional/no-throw-statement
    throw new TypeError(
      `Parameter 'pathObject' must be an object, not ${typeof pathObject}`
    );
  }

  const root = pathObject.root || "";

  if (typeof root !== "string") {
    // eslint-disable-next-line functional/no-throw-statement
    throw new TypeError(
      `'pathObject.root' must be a string or undefined, not ${typeof pathObject.root}`
    );
  }

  const dir = pathObject.dir;
  const base = pathObject.base || "";
  if (!dir) {
    return base;
  }
  if (dir[dir.length - 1] === sep) {
    return dir + base;
  }
  return dir + sep + base;
}
export function parse(pathString: string): PathObject {
  if (typeof pathString !== "string") {
    // eslint-disable-next-line functional/no-throw-statement
    throw new TypeError(
      `Parameter 'pathString' must be a string, not ${typeof pathString}`
    );
  }
  const allParts = win32SplitPath(pathString);
  if (!allParts || allParts.length !== 4) {
    // eslint-disable-next-line functional/no-throw-statement
    throw new TypeError(`Invalid path '${pathString}'`);
  }
  return {
    root: allParts[0],
    dir: allParts[0] + allParts[1].slice(0, -1),
    base: allParts[2],
    ext: allParts[3],
    name: allParts[2].slice(0, allParts[2].length - allParts[3].length),
  };
}