Factor Package Manager Preview

Work has been keeping me quite busy lately, but I use my spare tie to write a package manager for Factor. This post provides an extremely early preview of the code so far. The following code is just for the
pkg-install command. Currently implemented is a really bare-bones pkg-install command that will be used to install a package. Any comments / suggestions are welcome (as always).

USING: kernel http.client system sequences splitting io io.files io.launcher
       crypto.md5 ;

IN: packages

<PRIVATE

: factor-base-dir ( -- path )
    vm "/" last-split1 drop  ;

: base-dir ( -- path )
    ! push the full path of the package/ dir onto the stack
    factor-base-dir "/extra/packages" append ;

: pkg-download ( url -- ? )
    ! download a package from a remote repo (using the specified URL) to the
    ! local package cache
    dup download-name base-dir "/data/pkg-cache/" rot 3append
    download-to
    t ;

: pkg-in-cache? ( name -- ? )
    ! check if a package with the specified name exists in the local package
    ! cache
    base-dir "/data/pkg-cache" append directory
    [ first over ".fpkg" append = ] contains? nip ;

: registry-to-lines ( -- seq )
    ! converts the pkg-registry file to a sequence of lines so it can be
    ! read / parsed
    base-dir "/data/pkg-registry" append <file-reader> lines ;

: pkg-installed? ( name -- ? )
    ! check if a package is installed by reading the pkg-registry file
    registry-to-lines [ over = ] contains? nip ;

: pkg-extract ( name -- ? )
    ! extracts the files from the package tarball into the data/tmp/ dir
    cwd >r
    "tar -xjf " base-dir "/data/pkg-cache/" 3append swap ".fpkg" 3append
    base-dir "/data/tmp" append cd
    run-process drop r> cd
    t ;

: (pkg-valid?) ( path -- ? )
    cd cwd directory
    [
        dup second
        [ first (pkg-valid?) ".." cd ]
        [ first cwd "/" rot 3append dup file>md5str " :: " rot 3append print ] if
    ] each ;

: pkg-valid? ( name -- ? )
    ! verify the integrity of the package and return the result
    cwd swap base-dir "/data/tmp/" rot 3append (pkg-valid?) cd t ;
    
: (pkg-install) ( name -- )
    ! moves the extracted package files to the extra/ dir in the local Factor
    ! installation
    dup base-dir "/data/tmp/" rot 3append dup
    rot factor-base-dir "/extra/" rot 3append
    copy-tree delete-tree ;

PRIVATE>

: pkg-install ( name -- )
    dup pkg-installed? [
        ">> The package is already installed.\n" write
    ] [
        ! sync the local & remote index for the repo

        ! check the cached repo index for the latest version of the package

        ! check if that version is cached in the local package cache

        ! check dependencies of the package to install

        ! Prompt user if he would like to continue installation
        "Would you like to continue the install? [y/n]: " write readln
        "n" = [
            ">> Nothing was installed" print
        ] [
            ! download the required packages from the remote repo
            ">> downloading required packages" print
            dup "http://zenhackers.net/files/" swap append ".fpkg" append pkg-download
            drop ! drop result of pkg-download word, we should use this result to test for errors

            ! extract files from packages into their separate directories
            ">> extracting packages to temporary directory" print
            dup pkg-extract drop

            ! verify integrity of downloaded packages using checksums
            ">> verifying integrity of packages" print
            dup pkg-valid? [
                
                ! install the package in the extra/ directory
                ">> installing packages" print
                (pkg-install)
                ">> install completed" print
                
                
            ] [
                ">> The package integrity check FAILED !!!" print
            ] if
            
        ] if

    ] if ;