#
namespace eval ::PackageDownloader {
  #
  # NOTE: This procedure sets up the default values for all configuration
  #       parameters used by the package downloader client.  There are no
  #       arguments.
  #
  proc setupDownloadVars { script } {
    #
    # NOTE: What is the fully qualified path to the directory containing the
    #       package downloader client?
    #
    variable clientDirectory

    if {![info exists clientDirectory]} then {
      set clientDirectory [file dirname $script]
    }

    #
    # NOTE: Prevent progress messages from being displayed while downloading
    #       from the repository, etc?  By default, this is enabled.
    #
    variable quiet; # DEFAULT: true

    if {![info exists quiet]} then {

    #
    # NOTE: Return a directory parallel to the one containing the library
    #       directory.
    #
    return [file join [file dirname [info library]] pkgd]
  }

  #
  # NOTE: This procedure returns non-zero if the specified file seems to be
  #       an OpenPGP signature file.  The fileName argument is the name of
  #       the file to check, which may or may not exist.
  #
  proc isPgpSignatureFileName { fileName } {
    if {[string length $fileName] == 0} then {
      return false
    }

    set extension [file extension]

    if {$extension eq ".asc"} then {
      if {[file exists $fileName]} then {
        return [::PackageRepository::isPgpSignature [readFile $fileName]]
      } else {
        return true
      }
    } else {
      return false
    }
  }

  #
  # NOTE: This procedure returns non-zero if the specified file seems to be
  #       a Harpy script certificate file.  The fileName argument is the name
  #       of the file to check, which may or may not exist.
  #
  proc isHarpyCertificateFileName { fileName } {
    if {[string length $fileName] == 0} then {
      return false
    }

    set extension [file extension]

    if {$extension eq ".harpy"} then {
      if {[file exists $fileName]} then {
        return [::PackageRepository::isHarpyCertificate [readFile $fileName]]
      } else {
        return true
      }
    } else {
      return false
    }
  }

  #
  # NOTE: This procedure adds a directory to the auto-path of the specified
  #       language (i.e. native Tcl or Eagle).  The directory will not be
  #       added if it is already present.  The language argument must be the
  #       literal string "eagle" or the literal string "tcl".  The directory
  #       argument is the fully qualified path for the directory to add to
  #       the auto-path.

        }
      }
    } else {
      error "unsupported language, no idea how to modify auto-path"
    }
  }

  #
  # NOTE: This procedure downloads a single file from the package file server,
  #       writing its contents to the specified local file name.  It can also
  #       verify the PGP signatures.  When a PGP signature file is
  #       downloaded, this procedure assumes the corresponding data file was
  #       already downloaded (i.e. since OpenPGP needs both to perform the
  #       signature checks).  The language argument must be one of the
  #       literal strings "eagle", "tcl", or "client".  The version argument
  #       must be one of the literal strings "8.4", "8.5", or "8.6" when the
  #       language is "tcl" -OR- the literal string "1.0" when the language
  #       is either "eagle" or "client".  The fileName argument is a file
  #       name relative to the language and version-specific directory on the
  #       package file server.  The localFileName argument is the file name
  #       where the downloaded file should be written.  The usePgp argument
  #       should be non-zero when an OpenPGP signature file needs to be
  #       downloaded and verified for the downloaded file.
  #
  proc downloadOneFile { language version fileName localFileName usePgp } {
    variable baseUri
    variable downloadUri
    variable quiet

    #
    # NOTE: First, build the full relative file name to download from the
    #       remote package repository.
    #
    set fileName [file join $language $version $fileName]
    set uri [subst $downloadUri]

    if {[isEagle]} then {
      writeFile $localFileName [interp readorgetscriptfile -- "" $uri]
    } else {
      writeFile $localFileName \
          [::PackageRepository::getFileViaHttp $uri 10 stdout $quiet]
    }

    #
    #
    #
    if {$usePgp && [isPgpSignatureFileName $localFileName]} then {
      #
      #
      #
      if {![::PackageRepository::verifyPgpSignature $localFileName]} then {
        error [appendArgs \
            "bad PGP signature \"" $localFileName \"]
      }
    }
  }

  #
  # NOTE: This procedure attempts to download a list of files, optionally
  #       persistening them for subsequent uses by the target language.
  #       The language argument must be one of the literal strings "eagle",
  #       "tcl", or "client".  The version argument must be one of the
  #       literal strings "8.4", "8.5", or "8.6" when the language is "tcl"
  #       -OR- the literal string "1.0" when the language is either "eagle"
  #       or "client".  The fileNames argument must be a well-formed list
  #       of file names to download, each one relative to the language and
  #       version-specific directory on the package file server.  The
  #       persistent argument should be non-zero if the downloaded files
  #       should be saved to permanent storage for subsequent use.  The
  #       usePgp argument should be non-zero when an OpenPGP signature file
  #       needs to be downloaded and verified for each downloaded file.  The
  #       useAutoPath argument should be non-zero to modify the auto-path
  #       to include the temporary or persistent directories containing
  #       the downloaded files.
  #
  # <public>
  proc downloadFiles {
          language version fileNames persistent usePgp useAutoPath } {
    global env
    variable baseUri
    variable clientDirectory
    variable downloadUri
    variable persistentDirectory
    variable quiet

    set client false

    if {[string length $language] == 0 || $language eq "eagle"} then {
      if {$version ne "1.0"} then {
        error "unsupported Eagle version"
      }
    } elseif {$language eq "tcl"} then {
      if {$version ne "8.4" && $version ne "8.5" && $version ne "8.6"} then {
        error "unsupported Tcl version"
      }
    } elseif {$language eq "client"} then {
      if {$version ne "1.0"} then {
        error "unsupported client version"
      }

      set client true

    } else {
      error "unsupported language"

    }


    if {[info exists env(PKGD_TEMP)]} then {
      set temporaryRootDirectory $env(PKGD_TEMP)
    } elseif {[info exists env(TEMP)]} then {
      set temporaryRootDirectory $env(TEMP)
    } elseif {[info exists env(TMP)]} then {
      set temporaryRootDirectory $env(TMP)
    } else {
      error "please set PKGD_TEMP (via environment) to temporary directory"
    }

    set temporaryDirectory [file join $temporaryRootDirectory \
        [appendArgs pkgd_ [string trim [pid] -] _ [string trim \
        [clock seconds] -]]]

    if {$persistent} then {
      if {$client} then {
        set downloadRootDirectory $clientDirectory
      } else {
        set downloadRootDirectory $persistentDirectory
      }
    } else {
      set downloadRootDirectory $temporaryDirectory
    }

    set downloadedFileNames [list]

    foreach fileName $fileNames {
      if {[string length $fileName] == 0 || \
          [file pathtype $fileName] ne "relative"} then {
        error [appendArgs \
            "bad file name \"" $fileName "\", not relative"]
      }

      set directoryParts [file split [file dirname $fileName]]

      if {[llength $directoryParts] == 0} then {
        error [appendArgs \
            "bad file name \"" $fileName "\", no directory parts"]
      }

      set downloadDirectory(temporary) [file normalize [eval \
          file join [list $temporaryDirectory] $directoryParts]]

      set downloadDirectory(persistent) [file normalize [eval \
          file join [list $downloadRootDirectory] $directoryParts]]

      set downloadFileName [file normalize [file join \
          $downloadDirectory(temporary) [file tail $fileName]]]

      if {[file exists $downloadFileName]} then {
        error [appendArgs \
            "temporary file name \"" $downloadFileName \
            "\" already exists"]
      }

      file mkdir [file dirname $downloadFileName]


      downloadOneFile $language $version $fileName $downloadFileName $usePgp

      lappend downloadedFileNames $downloadFileName

      if {$usePgp && ![isPgpSignatureFileName $downloadFileName] && \
          ![isHarpyCertificateFileName $downloadFileName]} then {


        downloadOneFile $language $version [appendArgs $fileName .asc] \
            [appendArgs $downloadFileName .asc] $usePgp


        lappend downloadedFileNames [appendArgs $downloadFileName .asc]
      }


    }




    set downloadDirectories [list]


    foreach downloadedFileName $downloadedFileNames {
      if {$persistent} then {













      } else {
        lappend downloadDirectories [file dirname $downloadedFileName]
      }
    }

    set downloadDirectories [lsort -unique $downloadDirectories]

    if {$useAutoPath} then {
      foreach downloadDirectory $downloadDirectories {
        addToAutoPath $language $downloadDirectory

  #       one or more of the variable setup in the next step.
  #
  ::PackageRepository::maybeReadSettingsFile [info script]

  #
  # NOTE: Setup the variables, within this namespace, used by this script.
  #
  setupDownloadVars [info script]

  #
  # NOTE: Provide the package to the interpreter.
  #
  package provide Eagle.Package.Downloader \
    [expr {[isEagle] ? [info engine PatchLevel] : "1.0"}]
}