// 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, ParsedPath } from "./_interface.ts";
import { CHAR_DOT } from "./_constants.ts";

import {
  _format,
  assertPath,
  encodeWhitespace,
  isPosixPathSeparator,
  lastPathSegment,
  normalizeString,
  stripSuffix,
  stripTrailingSeparators,
} from "./_util.ts";

export const sep = "/";
export const delimiter = ":";

// path.resolve([from ...], to)
/**
 * Resolves `pathSegments` into an absolute path.
 * @param pathSegments an array of path segments
 */
export function resolve(...pathSegments: string[]): string {
  let resolvedPath = "";
  let resolvedAbsolute = false;

  for (let i = pathSegments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
    let path: string;

    if (i >= 0) path = pathSegments[i];
    else {
      // deno-lint-ignore no-explicit-any
      const { Deno } = globalThis as any;
      if (typeof Deno?.cwd !== "function") {
        throw new TypeError("Resolved a relative path without a CWD.");
      }
      path = Deno.cwd();
    }

    assertPath(path);

    // Skip empty entries
    if (path.length === 0) {
      continue;
    }

    resolvedPath = `${path}/${resolvedPath}`;
    resolvedAbsolute = isPosixPathSeparator(path.charCodeAt(0));
  }

  // 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 path
  resolvedPath = normalizeString(
    resolvedPath,
    !resolvedAbsolute,
    "/",
    isPosixPathSeparator,
  );

  if (resolvedAbsolute) {
    if (resolvedPath.length > 0) return `/${resolvedPath}`;
    else return "/";
  } else if (resolvedPath.length > 0) return resolvedPath;
  else return ".";
}

/**
 * Normalize the `path`, resolving `'..'` and `'.'` segments.
 * Note that resolving these segments does not necessarily mean that all will be eliminated.
 * A `'..'` at the top-level will be preserved, and an empty path is canonically `'.'`.
 * @param path to be normalized
 */
export function normalize(path: string): string {
  assertPath(path);

  if (path.length === 0) return ".";

  const isAbsolute = isPosixPathSeparator(path.charCodeAt(0));
  const trailingSeparator = isPosixPathSeparator(
    path.charCodeAt(path.length - 1),
  );

  // Normalize the path
  path = normalizeString(path, !isAbsolute, "/", isPosixPathSeparator);

  if (path.length === 0 && !isAbsolute) path = ".";
  if (path.length > 0 && trailingSeparator) path += "/";

  if (isAbsolute) return `/${path}`;
  return path;
}

/**
 * Verifies whether provided path is absolute
 * @param path to be verified as absolute
 */
export function isAbsolute(path: string): boolean {
  assertPath(path);
  return path.length > 0 && isPosixPathSeparator(path.charCodeAt(0));
}

/**
 * Join all given a sequence of `paths`,then normalizes the resulting path.
 * @param paths to be joined and normalized
 */
export function join(...paths: string[]): string {
  if (paths.length === 0) return ".";
  let joined: string | undefined;
  for (let i = 0, len = paths.length; i < len; ++i) {
    const path = paths[i];
    assertPath(path);
    if (path.length > 0) {
      if (!joined) joined = path;
      else joined += `/${path}`;
    }
  }
  if (!joined) return ".";
  return normalize(joined);
}

/**
 * Return the relative path from `from` to `to` based on current working directory.
 * @param from path in current working directory
 * @param to path in current working directory
 */
export function relative(from: string, to: string): string {
  assertPath(from);
  assertPath(to);

  if (from === to) return "";

  from = resolve(from);
  to = resolve(to);

  if (from === to) return "";

  // Trim any leading backslashes
  let fromStart = 1;
  const fromEnd = from.length;
  for (; fromStart < fromEnd; ++fromStart) {
    if (!isPosixPathSeparator(from.charCodeAt(fromStart))) break;
  }
  const fromLen = fromEnd - fromStart;

  // Trim any leading backslashes
  let toStart = 1;
  const toEnd = to.length;
  for (; toStart < toEnd; ++toStart) {
    if (!isPosixPathSeparator(to.charCodeAt(toStart))) break;
  }
  const toLen = toEnd - toStart;

  // Compare paths to find the longest common path from root
  const length = fromLen < toLen ? fromLen : toLen;
  let lastCommonSep = -1;
  let i = 0;
  for (; i <= length; ++i) {
    if (i === length) {
      if (toLen > length) {
        if (isPosixPathSeparator(to.charCodeAt(toStart + i))) {
          // We get here if `from` is the exact base path for `to`.
          // For example: from='/foo/bar'; to='/foo/bar/baz'
          return to.slice(toStart + i + 1);
        } else if (i === 0) {
          // We get here if `from` is the root
          // For example: from='/'; to='/foo'
          return to.slice(toStart + i);
        }
      } else if (fromLen > length) {
        if (isPosixPathSeparator(from.charCodeAt(fromStart + i))) {
          // We get here if `to` is the exact base path for `from`.
          // For example: from='/foo/bar/baz'; to='/foo/bar'
          lastCommonSep = i;
        } else if (i === 0) {
          // We get here if `to` is the root.
          // For example: from='/foo'; to='/'
          lastCommonSep = 0;
        }
      }
      break;
    }
    const fromCode = from.charCodeAt(fromStart + i);
    const toCode = to.charCodeAt(toStart + i);
    if (fromCode !== toCode) break;
    else if (isPosixPathSeparator(fromCode)) lastCommonSep = i;
  }

  let out = "";
  // Generate the relative path based on the path difference between `to`
  // and `from`
  for (i = fromStart + lastCommonSep + 1; i <= fromEnd; ++i) {
    if (i === fromEnd || isPosixPathSeparator(from.charCodeAt(i))) {
      if (out.length === 0) out += "..";
      else out += "/..";
    }
  }

  // Lastly, append the rest of the destination (`to`) path that comes after
  // the common path parts
  if (out.length > 0) return out + to.slice(toStart + lastCommonSep);
  else {
    toStart += lastCommonSep;
    if (isPosixPathSeparator(to.charCodeAt(toStart))) ++toStart;
    return to.slice(toStart);
  }
}

/**
 * Resolves path to a namespace path
 * @param path to resolve to namespace
 */
export function toNamespacedPath(path: string): string {
  // Non-op on posix systems
  return path;
}

/**
 * Return the directory path of a `path`.
 * @param path - path to extract the directory from.
 */
export function dirname(path: string): string {
  if (path.length === 0) return ".";

  let end = -1;
  let matchedNonSeparator = false;

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

  // No matches. Fallback based on provided path:
  //
  // - leading slashes paths
  //     "/foo" => "/"
  //     "///foo" => "/"
  // - no slash path
  //     "foo" => "."
  if (end === -1) {
    return isPosixPathSeparator(path.charCodeAt(0)) ? "/" : ".";
  }

  return stripTrailingSeparators(
    path.slice(0, end),
    isPosixPathSeparator,
  );
}

/**
 * Return the last portion of a `path`.
 * Trailing directory separators are ignored, and optional suffix is removed.
 *
 * @param path - path to extract the name from.
 * @param [suffix] - suffix to remove from extracted name.
 */
export function basename(path: string, suffix = ""): string {
  assertPath(path);

  if (path.length === 0) return path;

  if (typeof suffix !== "string") {
    throw new TypeError(
      `Suffix must be a string. Received ${JSON.stringify(suffix)}`,
    );
  }

  const lastSegment = lastPathSegment(path, isPosixPathSeparator);
  const strippedSegment = stripTrailingSeparators(
    lastSegment,
    isPosixPathSeparator,
  );
  return suffix ? stripSuffix(strippedSegment, suffix) : strippedSegment;
}

/**
 * Return the extension of the `path` with leading period.
 * @param path with extension
 * @returns extension (ex. for `file.ts` returns `.ts`)
 */
export function extname(path: string): string {
  assertPath(path);
  let startDot = -1;
  let startPart = 0;
  let end = -1;
  let matchedSlash = true;
  // Track the state of characters (if any) we see before our first dot and
  // after any path separator we find
  let preDotState = 0;
  for (let i = path.length - 1; i >= 0; --i) {
    const code = path.charCodeAt(i);
    if (isPosixPathSeparator(code)) {
      // If we reached a path separator that was not part of a set of path
      // separators at the end of the string, stop now
      if (!matchedSlash) {
        startPart = i + 1;
        break;
      }
      continue;
    }
    if (end === -1) {
      // We saw the first non-path separator, mark this as the end of our
      // extension
      matchedSlash = false;
      end = i + 1;
    }
    if (code === CHAR_DOT) {
      // If this is our first dot, mark it as the start of our extension
      if (startDot === -1) startDot = i;
      else if (preDotState !== 1) preDotState = 1;
    } else if (startDot !== -1) {
      // We saw a non-dot and non-path separator before our dot, so we should
      // have a good chance at having a non-empty extension
      preDotState = -1;
    }
  }

  if (
    startDot === -1 ||
    end === -1 ||
    // We saw a non-dot character immediately before the dot
    preDotState === 0 ||
    // The (right-most) trimmed path component is exactly '..'
    (preDotState === 1 && startDot === end - 1 && startDot === startPart + 1)
  ) {
    return "";
  }
  return path.slice(startDot, end);
}

/**
 * Generate a path from `FormatInputPathObject` object.
 * @param pathObject with path
 */
export function format(pathObject: FormatInputPathObject): string {
  if (pathObject === null || typeof pathObject !== "object") {
    throw new TypeError(
      `The "pathObject" argument must be of type Object. Received type ${typeof pathObject}`,
    );
  }
  return _format("/", pathObject);
}

/**
 * Return a `ParsedPath` object of the `path`.
 * @param path to process
 */
export function parse(path: string): ParsedPath {
  assertPath(path);

  const ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };
  if (path.length === 0) return ret;
  const isAbsolute = isPosixPathSeparator(path.charCodeAt(0));
  let start: number;
  if (isAbsolute) {
    ret.root = "/";
    start = 1;
  } else {
    start = 0;
  }
  let startDot = -1;
  let startPart = 0;
  let end = -1;
  let matchedSlash = true;
  let i = path.length - 1;

  // Track the state of characters (if any) we see before our first dot and
  // after any path separator we find
  let preDotState = 0;

  // Get non-dir info
  for (; i >= start; --i) {
    const code = path.charCodeAt(i);
    if (isPosixPathSeparator(code)) {
      // If we reached a path separator that was not part of a set of path
      // separators at the end of the string, stop now
      if (!matchedSlash) {
        startPart = i + 1;
        break;
      }
      continue;
    }
    if (end === -1) {
      // We saw the first non-path separator, mark this as the end of our
      // extension
      matchedSlash = false;
      end = i + 1;
    }
    if (code === CHAR_DOT) {
      // If this is our first dot, mark it as the start of our extension
      if (startDot === -1) startDot = i;
      else if (preDotState !== 1) preDotState = 1;
    } else if (startDot !== -1) {
      // We saw a non-dot and non-path separator before our dot, so we should
      // have a good chance at having a non-empty extension
      preDotState = -1;
    }
  }

  if (
    startDot === -1 ||
    end === -1 ||
    // We saw a non-dot character immediately before the dot
    preDotState === 0 ||
    // The (right-most) trimmed path component is exactly '..'
    (preDotState === 1 && startDot === end - 1 && startDot === startPart + 1)
  ) {
    if (end !== -1) {
      if (startPart === 0 && isAbsolute) {
        ret.base = ret.name = path.slice(1, end);
      } else {
        ret.base = ret.name = path.slice(startPart, end);
      }
    }
    // Fallback to '/' in case there is no basename
    ret.base = ret.base || "/";
  } else {
    if (startPart === 0 && isAbsolute) {
      ret.name = path.slice(1, startDot);
      ret.base = path.slice(1, end);
    } else {
      ret.name = path.slice(startPart, startDot);
      ret.base = path.slice(startPart, end);
    }
    ret.ext = path.slice(startDot, end);
  }

  if (startPart > 0) {
    ret.dir = stripTrailingSeparators(
      path.slice(0, startPart - 1),
      isPosixPathSeparator,
    );
  } else if (isAbsolute) ret.dir = "/";

  return ret;
}

/**
 * Converts a file URL to a path string.
 *
 * ```ts
 *      import { fromFileUrl } from "https://deno.land/std@$STD_VERSION/path/posix.ts";
 *      fromFileUrl("file:///home/foo"); // "/home/foo"
 * ```
 * @param url of a file URL
 */
export function fromFileUrl(url: string | URL): string {
  url = url instanceof URL ? url : new URL(url);
  if (url.protocol != "file:") {
    throw new TypeError("Must be a file URL.");
  }
  return decodeURIComponent(
    url.pathname.replace(/%(?![0-9A-Fa-f]{2})/g, "%25"),
  );
}

/**
 * Converts a path string to a file URL.
 *
 * ```ts
 *      import { toFileUrl } from "https://deno.land/std@$STD_VERSION/path/posix.ts";
 *      toFileUrl("/home/foo"); // new URL("file:///home/foo")
 * ```
 * @param path to convert to file URL
 */
export function toFileUrl(path: string): URL {
  if (!isAbsolute(path)) {
    throw new TypeError("Must be an absolute path.");
  }
  const url = new URL("file:///");
  url.pathname = encodeWhitespace(
    path.replace(/%/g, "%25").replace(/\\/g, "%5C"),
  );
  return url;
}