import * as cp from "child_process"
import * as crypto from "crypto"
import * as argon2 from "argon2"
import envPaths from "env-paths"
import { promises as fs } from "fs"
import * as net from "net"
import * as os from "os"
import * as path from "path"
import * as util from "util"
import xdgBasedir from "xdg-basedir"
import safeCompare from "safe-compare"
import { logger } from "@coder/logger"

export interface Paths {
  data: string
  config: string
  runtime: string
}

export const paths = getEnvPaths()

/**
 * Gets the config and data paths for the current platform/configuration.
 * On MacOS this function gets the standard XDG directories instead of using the native macOS
 * ones. Most CLIs do this as in practice only GUI apps use the standard macOS directories.
 */
export function getEnvPaths(): Paths {
  const paths = envPaths("code-server", { suffix: "" })
  const append = (p: string): string => path.join(p, "code-server")
  switch (process.platform) {
    case "darwin":
      return {
        // envPaths uses native directories so force Darwin to use the XDG spec
        // to align with other CLI tools.
        data: xdgBasedir.data ? append(xdgBasedir.data) : paths.data,
        config: xdgBasedir.config ? append(xdgBasedir.config) : paths.config,
        // Fall back to temp if there is no runtime dir.
        runtime: xdgBasedir.runtime ? append(xdgBasedir.runtime) : paths.temp,
      }
    case "win32":
      return {
        data: paths.data,
        config: paths.config,
        // Windows doesn't have a runtime dir.
        runtime: paths.temp,
      }
    default:
      return {
        data: paths.data,
        config: paths.config,
        // Fall back to temp if there is no runtime dir.
        runtime: xdgBasedir.runtime ? append(xdgBasedir.runtime) : paths.temp,
      }
  }
}

/**
 * humanPath replaces the home directory in p with ~.
 * Makes it more readable.
 *
 * @param p
 */
export function humanPath(p?: string): string {
  if (!p) {
    return ""
  }
  return p.replace(os.homedir(), "~")
}

export const generateCertificate = async (hostname: string): Promise<{ cert: string; certKey: string }> => {
  const certPath = path.join(paths.data, `${hostname.replace(/\./g, "_")}.crt`)
  const certKeyPath = path.join(paths.data, `${hostname.replace(/\./g, "_")}.key`)

  // Try generating the certificates if we can't access them (which probably
  // means they don't exist).
  try {
    await Promise.all([fs.access(certPath), fs.access(certKeyPath)])
  } catch (error) {
    // Require on demand so openssl isn't required if you aren't going to
    // generate certificates.
    const pem = require("pem") as typeof import("pem")
    const certs = await new Promise<import("pem").CertificateCreationResult>((resolve, reject): void => {
      pem.createCertificate(
        {
          selfSigned: true,
          commonName: hostname,
          config: `
[req]
req_extensions = v3_req

[ v3_req ]
basicConstraints = CA:true
extendedKeyUsage = serverAuth
subjectAltName = @alt_names

[alt_names]
DNS.1 = ${hostname}
`,
        },
        (error, result) => {
          return error ? reject(error) : resolve(result)
        },
      )
    })
    await fs.mkdir(paths.data, { recursive: true })
    await Promise.all([fs.writeFile(certPath, certs.certificate), fs.writeFile(certKeyPath, certs.serviceKey)])
  }

  return {
    cert: certPath,
    certKey: certKeyPath,
  }
}

export const generatePassword = async (length = 24): Promise<string> => {
  const buffer = Buffer.alloc(Math.ceil(length / 2))
  await util.promisify(crypto.randomFill)(buffer)
  return buffer.toString("hex").substring(0, length)
}

/**
 * Used to hash the password.
 */
export const hash = async (password: string): Promise<string> => {
  try {
    return await argon2.hash(password)
  } catch (error) {
    logger.error(error)
    return ""
  }
}

/**
 * Used to verify if the password matches the hash
 */
export const isHashMatch = async (password: string, hash: string) => {
  try {
    return await argon2.verify(hash, password)
  } catch (error) {
    logger.error(error)
    return false
  }
}

/**
 * Used to hash the password using the sha256
 * algorithm. We only use this to for checking
 * the hashed-password set in the config.
 *
 * Kept for legacy reasons.
 */
export const hashLegacy = (str: string): string => {
  return crypto.createHash("sha256").update(str).digest("hex")
}

/**
 * Used to check if the password matches the hash using
 * the hashLegacy function
 */
export const isHashLegacyMatch = (password: string, hashPassword: string) => {
  const hashedWithLegacy = hashLegacy(password)
  return safeCompare(hashedWithLegacy, hashPassword)
}

const passwordMethods = ["SHA256", "ARGON2", "PLAIN_TEXT"] as const
export type PasswordMethod = typeof passwordMethods[number]

/**
 * Used to determine the password method.
 *
 * There are three options for the return value:
 * 1. "SHA256" -> the legacy hashing algorithm
 * 2. "ARGON2" -> the newest hashing algorithm
 * 3. "PLAIN_TEXT" -> regular ol' password with no hashing
 *
 * @returns {PasswordMethod} "SHA256" | "ARGON2" | "PLAIN_TEXT"
 */
export function getPasswordMethod(hashedPassword: string | undefined): PasswordMethod {
  if (!hashedPassword) {
    return "PLAIN_TEXT"
  }

  // This is the new hashing algorithm
  if (hashedPassword.includes("$argon")) {
    return "ARGON2"
  }

  // This is the legacy hashing algorithm
  return "SHA256"
}

type PasswordValidation = {
  isPasswordValid: boolean
  hashedPassword: string
}

type HandlePasswordValidationArgs = {
  /** The PasswordMethod */
  passwordMethod: PasswordMethod
  /** The password provided by the user */
  passwordFromRequestBody: string
  /** The password set in PASSWORD or config */
  passwordFromArgs: string | undefined
  /** The hashed-password set in HASHED_PASSWORD or config */
  hashedPasswordFromArgs: string | undefined
}

/**
 * Checks if a password is valid and also returns the hash
 * using the PasswordMethod
 */
export async function handlePasswordValidation(
  passwordValidationArgs: HandlePasswordValidationArgs,
): Promise<PasswordValidation> {
  const { passwordMethod, passwordFromArgs, passwordFromRequestBody, hashedPasswordFromArgs } = passwordValidationArgs
  // TODO implement
  const passwordValidation = <PasswordValidation>{
    isPasswordValid: false,
    hashedPassword: "",
  }

  switch (passwordMethod) {
    case "PLAIN_TEXT": {
      const isValid = passwordFromArgs ? safeCompare(passwordFromRequestBody, passwordFromArgs) : false
      passwordValidation.isPasswordValid = isValid

      const hashedPassword = await hash(passwordFromRequestBody)
      passwordValidation.hashedPassword = hashedPassword
      break
    }
    case "SHA256": {
      const isValid = isHashLegacyMatch(passwordFromRequestBody, hashedPasswordFromArgs || "")
      passwordValidation.isPasswordValid = isValid

      passwordValidation.hashedPassword = hashedPasswordFromArgs || (await hashLegacy(passwordFromRequestBody))
      break
    }
    case "ARGON2": {
      const isValid = await isHashMatch(passwordFromRequestBody, hashedPasswordFromArgs || "")
      passwordValidation.isPasswordValid = isValid

      passwordValidation.hashedPassword = hashedPasswordFromArgs || ""
      break
    }
    default:
      break
  }

  return passwordValidation
}

export type IsCookieValidArgs = {
  passwordMethod: PasswordMethod
  cookieKey: string
  hashedPasswordFromArgs: string | undefined
  passwordFromArgs: string | undefined
}

/** Checks if a req.cookies.key is valid using the PasswordMethod */
export async function isCookieValid(isCookieValidArgs: IsCookieValidArgs): Promise<boolean> {
  let isValid = false
  const { passwordFromArgs = "", cookieKey, hashedPasswordFromArgs = "" } = isCookieValidArgs
  switch (isCookieValidArgs.passwordMethod) {
    case "PLAIN_TEXT":
      isValid = await isHashMatch(passwordFromArgs, cookieKey)
      break
    case "ARGON2":
    case "SHA256":
      isValid = safeCompare(cookieKey, hashedPasswordFromArgs)
      break
    default:
      break
  }
  return isValid
}

const mimeTypes: { [key: string]: string } = {
  ".aac": "audio/x-aac",
  ".avi": "video/x-msvideo",
  ".bmp": "image/bmp",
  ".css": "text/css",
  ".flv": "video/x-flv",
  ".gif": "image/gif",
  ".html": "text/html",
  ".ico": "image/x-icon",
  ".jpe": "image/jpg",
  ".jpeg": "image/jpg",
  ".jpg": "image/jpg",
  ".js": "application/javascript",
  ".json": "application/json",
  ".m1v": "video/mpeg",
  ".m2a": "audio/mpeg",
  ".m2v": "video/mpeg",
  ".m3a": "audio/mpeg",
  ".mid": "audio/midi",
  ".midi": "audio/midi",
  ".mk3d": "video/x-matroska",
  ".mks": "video/x-matroska",
  ".mkv": "video/x-matroska",
  ".mov": "video/quicktime",
  ".movie": "video/x-sgi-movie",
  ".mp2": "audio/mpeg",
  ".mp2a": "audio/mpeg",
  ".mp3": "audio/mpeg",
  ".mp4": "video/mp4",
  ".mp4a": "audio/mp4",
  ".mp4v": "video/mp4",
  ".mpe": "video/mpeg",
  ".mpeg": "video/mpeg",
  ".mpg": "video/mpeg",
  ".mpg4": "video/mp4",
  ".mpga": "audio/mpeg",
  ".oga": "audio/ogg",
  ".ogg": "audio/ogg",
  ".ogv": "video/ogg",
  ".png": "image/png",
  ".psd": "image/vnd.adobe.photoshop",
  ".qt": "video/quicktime",
  ".spx": "audio/ogg",
  ".svg": "image/svg+xml",
  ".tga": "image/x-tga",
  ".tif": "image/tiff",
  ".tiff": "image/tiff",
  ".txt": "text/plain",
  ".wav": "audio/x-wav",
  ".wasm": "application/wasm",
  ".webm": "video/webm",
  ".webp": "image/webp",
  ".wma": "audio/x-ms-wma",
  ".wmv": "video/x-ms-wmv",
  ".woff": "application/font-woff",
}

export const getMediaMime = (filePath?: string): string => {
  return (filePath && mimeTypes[path.extname(filePath)]) || "text/plain"
}

export const isWsl = async (): Promise<boolean> => {
  return (
    (process.platform === "linux" && os.release().toLowerCase().indexOf("microsoft") !== -1) ||
    (await fs.readFile("/proc/version", "utf8")).toLowerCase().indexOf("microsoft") !== -1
  )
}

/**
 * Try opening a URL using whatever the system has set for opening URLs.
 */
export const open = async (url: string): Promise<void> => {
  const args = [] as string[]
  const options = {} as cp.SpawnOptions
  const platform = (await isWsl()) ? "wsl" : process.platform
  let command = platform === "darwin" ? "open" : "xdg-open"
  if (platform === "win32" || platform === "wsl") {
    command = platform === "wsl" ? "cmd.exe" : "cmd"
    args.push("/c", "start", '""', "/b")
    url = url.replace(/&/g, "^&")
  }
  const proc = cp.spawn(command, [...args, url], options)
  await new Promise<void>((resolve, reject) => {
    proc.on("error", reject)
    proc.on("close", (code) => {
      return code !== 0 ? reject(new Error(`Failed to open with code ${code}`)) : resolve()
    })
  })
}

/**
 * For iterating over an enum's values.
 */
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export const enumToArray = (t: any): string[] => {
  const values = [] as string[]
  for (const k in t) {
    values.push(t[k])
  }
  return values
}

/**
 * For displaying all allowed options in an enum.
 */
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export const buildAllowedMessage = (t: any): string => {
  const values = enumToArray(t)
  return `Allowed value${values.length === 1 ? " is" : "s are"} ${values.map((t) => `'${t}'`).join(", ")}`
}

export const isObject = <T extends object>(obj: T): obj is T => {
  return !Array.isArray(obj) && typeof obj === "object" && obj !== null
}

/**
 * Taken from vs/base/common/charCode.ts. Copied for now instead of importing so
 * we don't have to set up a `vs` alias to be able to import with types (since
 * the alternative is to directly import from `out`).
 */
const enum CharCode {
  Slash = 47,
  A = 65,
  Z = 90,
  a = 97,
  z = 122,
  Colon = 58,
}

/**
 * Compute `fsPath` for the given uri.
 * Taken from vs/base/common/uri.ts. It's not imported to avoid also importing
 * everything that file imports.
 */
export function pathToFsPath(path: string, keepDriveLetterCasing = false): string {
  const isWindows = process.platform === "win32"
  const uri = { authority: undefined, path, scheme: "file" }
  let value: string
  if (uri.authority && uri.path.length > 1 && uri.scheme === "file") {
    // unc path: file://shares/c$/far/boo
    value = `//${uri.authority}${uri.path}`
  } else if (
    uri.path.charCodeAt(0) === CharCode.Slash &&
    ((uri.path.charCodeAt(1) >= CharCode.A && uri.path.charCodeAt(1) <= CharCode.Z) ||
      (uri.path.charCodeAt(1) >= CharCode.a && uri.path.charCodeAt(1) <= CharCode.z)) &&
    uri.path.charCodeAt(2) === CharCode.Colon
  ) {
    if (!keepDriveLetterCasing) {
      // windows drive letter: file:///c:/far/boo
      value = uri.path[1].toLowerCase() + uri.path.substr(2)
    } else {
      value = uri.path.substr(1)
    }
  } else {
    // other path
    value = uri.path
  }
  if (isWindows) {
    value = value.replace(/\//g, "\\")
  }
  return value
}

/**
 * Return a promise that resolves with whether the socket path is active.
 */
export function canConnect(path: string): Promise<boolean> {
  return new Promise((resolve) => {
    const socket = net.connect(path)
    socket.once("error", () => resolve(false))
    socket.once("connect", () => {
      socket.destroy()
      resolve(true)
    })
  })
}

export const isFile = async (path: string): Promise<boolean> => {
  try {
    const stat = await fs.stat(path)
    return stat.isFile()
  } catch (error) {
    return false
  }
}