#compdef gem -P gem[0-9.]#

local curcontext="$curcontext" state line expl ret=1
local -A opt_args def
local -a args cmds helptopics proxy lropts filter
local cmd="unknown"

proxy=(
  '(-p --http-proxy)'{-p,--http-proxy=}'[use HTTP proxy for remote operations]:proxy url:_urls'
)
lropts=( $proxy
  '${def[local]}(-l --local -r --remote -b --both)'{-l,--local}'[restrict operations to the LOCAL domain]'
  '${def[remote]}(-l --local -r --remote -b --both)'{-r,--remote}'[restrict operations to the REMOTE domain]'
  '${def[both]}(-l --local -r --remote -b --both)'{-b,--both}'[allow LOCAL and REMOTE operations]'
  '(-B --bulk-threshold)'{-B,--bulk-threshold=}'[specify threshold for switching to bulk synchronization]:threshold [1000]'
  '--clear-sources[clear the gem sources]'
  \*{-s,--source=}'[append specified URL to list of gem sources]:url:_urls'
)

_arguments -C -s \
  '(* -)'{-h,--help}'[display usage information]' \
  '(* -)'{-v,--version}'[display version information]' \
  '*::command:->command' && ret=0

if [[ $state = command ]]; then
  if (( CURRENT == 1 )); then
    cmd=subcommands
  else
    cmds=(
      build cert check cleanup contents dependency environment fetch
      generate_index help install info list lock mirror open outdated owner
      pristine push query rdoc search server signin signout sources
      specification stale uninstall unpack update which yank
    )
    cmds=( ${(M)cmds:#${words[1]}*} )
    if (( ${#cmds} == 1 )) || [[ $cmds[1] = install ]]; then
      cmd="$cmds[1]"
      curcontext="${curcontext%:*:*}:gem-${cmd}:"
    fi
  fi
  case $cmd in
    help)
      helptopics=(
        'commands:list all gem commands'
        'examples:show some examples of usage'
        'gem_dependencies:gem dependencies file guide'
        'platforms:show information about platforms'
      )
      _describe -t topics 'help topic' helptopics -- && ret=0
    ;&
    subcommands)
      cmds=( ${${${(M)${(f)"$(_call_program commands gem help commands)"}:#    [^ ]*}## #}/ ##/:} )
      _describe -t commands 'gem command' cmds -- && ret=0
      return ret
    ;;
    check|cleanup|contents|dependency|list|open|pristine|rdoc|uninstall|unpack|update)
      args+=( '(--all --skip)*:installed gem:->gems-local' )
    ;|
    fetch|install|lock|owner|search|yank)
      args+=( '*:gem:->gems-remote' )
    ;|
    cleanup|uninstall)
      args+=( '(-D --check-development)'{-D,--check-development}'[check development dependencies while uninstalling]' )
    ;|
    contents|pristine|rdoc)
      args+=( '(*)--all[apply to all installed gems]' )
    ;|
    info|list|query) def[local]='!' ;|
    search) def[remote]='!' ;|
    info|list|query|search)
      args+=( ${(e)lropts}
        '(-a --all)'{-a,--all}'[display all gem versions]'
        '(-e --exact)'{-e,--exact}'[use exact string matching instead of regex]'
        '(-I --no-installed -i --installed)'{-i,--installed}'[check if gem is installed]'
        '(-I --no-installed -i --installed)'{-I,--no-installed}'[check if gem is not installed]'
        '--no-versions[display only gem names]'
      )
    ;|
    list|query|search)
      args+=(
        '(-d --details)'{-d,--details}'[display detailed gem information]'
        '!(-d --details)--no-details'
      )
    ;|
    check|contents|dependency|fetch|install|list|open|pristine|query|rdoc|search|specification|uninstall|unpack|yank)
      args+=( '(-v --version)'{-v,--version=}'[specify version of gem]:version' )
    ;|
    dependency|fetch|install|outdated|specification|uninstall|update|yank)
      args+=( '--platform=[specify the platform of gem]:platform' )
    ;|
    dependency|fetch|install|list|query|search|specification|update)
      args+=( '--prerelease[include prerelease versions of a gem]' '!(--prerelease)--no-prerelease' )
    ;|
    install|unpack|update)
      args+=( '(-P --trust-policy)'{-P,--trust-policy=}'[specify gem trust policy]:policy' )
    ;|
    install|update)
      def[both]='!'
      args+=( ${(e)lropts}
        '(-N --no-document)--document=[generate documentation for installed gems]::documentation type:_sequence compadd - rdoc ri'
        '(-N --no-document --document)'{-N,--no-document}'[disable documentation generation]'
        '--build-root=[specify temporary installation root]:directory:_directories'
        '--vendor[install gem into the vendor directory]'
        '(-f --force)'{-f,--force}'[force gem to install, bypassing dependency checks]'
        "(-w --wrappers)--no-wrappers[don't install bin wrappers]"
        '--format-executable[add matching version suffix on executables to ruby]'
        "--user-install[install in user's home directory]"
        '--development[install additional development dependencies]'
        '--development-all[install development dependencies for all gems]'
        "--conservative[don't attempt to upgrade gems already meeting version requirement]"
        "--minimal-deps[don't upgrade any dependencies that already meet version requirements]"
        '--post-install-message[print post install message]'
        '(-g --file)'{-g,--file=}'[read from a gem dependencies API file and install the listed gems]:file:_files'
        '--without=[omit the named groups when installing gem dependencies]:group'
        "--default[add the gem's full specification to specifications/default and extract only its bin]"
        '--explain[rather than install the gems, indicate which would be installed]'
        "--no-lock[don't create a lock file]"
        '--suggestions[suggest alternates when gems are not found]'
      )
    ;|
    (un|)install|pristine|update)
      args+=(
        '(-n --bindir)'{-n,--bindir=}'[specify directory where binary files are located]:directory:_directories'
      )
    ;|
    (un|)install|update)
      args+=(
        '--ignore-dependencies[ignore dependency requirements]'
        '(-i --install-dir)'{-i,--install-dir=}'[specify gem repository directory to get installed gems]:directory:_directories'
      )
    ;|
    owner|push)
      args+=( $proxy )
    ;|
    owner|push|yank)
      args+=( '(-k --key)'{-k,--key=}'[use specified API key from ~/.gem/credentials]:key name' )
    ;|
    owner|push|signin|yank)
      args+=( '--host=[use another gemcutter-compatible host]:host:_urls' )
    ;|
    owner|push|signin)
      args+=( '--otp=[specify digit code for multifactor authentication]:code' )
    ;|
    install|pristine|update)
      args+=( '(-E --env-shebang)'{-E,--env-shebang}'[rewrite executables with a shebang of /usr/bin/env]' )
    ;|
    build)
      args+=(
        '(--strict)--force[skip validation of the spec]'
        '(--force)--strict[consider warnings as errors when validating the spec]'
        '(-o --output)'{-o+,--output=}'[output gem with the given filename]:file:_files'
        '-C+[run as if specified directory was the current directory]:directory:_directories'
        '1:gemspec file:_files -g "*.gemspec(-.)"'
      )
    ;;
    cert)
      args+=(
        '(-a --add)'{-a,--add=}'[add a trusted certificate.]:certificate' \
        '(-l --list)'{-l,--list=}'[list trusted certificates where the subject contains specified filter]:filter'
        '(-r --remove)'{-r,--remove=}'[remove trusted certificates where the subject contains specified filter]:filter'
        '(-b --build)'{-b,--build=}'[build private key and self-signed certificate for specified email address]:email address:_email_addresses -c'
        '(-C --certificate)'{-C,--certificate=}'[specify signing certificate for --sign]:certificate'
        '(-K --private-key)'{-K,--private-key=}'[specify key for --sign or --build]:key'
        '(-s --sign)'{-s,--sign=}'[sign specified certificate with the key from -K and the certificate from -C]:certificate'
        '(-d --days)'{-d,--days=}'[specify days before certificate expires]:days'
        '(-R --re-sign)'{-R,--re-sign}'[re-sign the certificate]'
      )
    ;;
    check)
      args+=(
        "--no-alien[don't report \"unmanaged\" or rogue files in the gem repository]"
        '--doctor[clean up uninstalled gems and broken specifications]'
        "--dry-run[don't remove files, only report what would be removed]"
        "--no-gems[don't check installed gems for problems]"
      )
    ;;
    cleanup)
      args+=(
        '(-n -d --dryrun)'{-n,-d,--dryrun}"[don't uninstall gems]"
        "--user-install[cleanup in user's home directory instead of GEM_HOME]"
      )
    ;;
    contents)
      args+=(
        '(-s --spec-dir)'{-s,--spec-dir=}'[search for gems in specific paths]:path:_sequence _directories'
        '(-l --lib-only)'{-l,--lib-only}"[only return files in the Gem's lib_dirs]"
        '--no-prefix[include installed path prefix]'
        '--show-install-dir[show only the gem install dir]'
      )
    ;;
    dependency)
      def[local]='!'
      args+=( ${(e)lropts}
        '(-R --reverse-dependencies)'{-R,--reverse-dependencies}'[include reverse dependencies in the output]'
        '--pipe[pipe format]'
      )
    ;;
    environment)
      args+=( '1:information:(packageversion gemdir gempath version remotesources platform)' )
    ;;
    fetch)
      def=( both \! local \! remote \! )
      args+=( ${(e)lropts} )
    ;;
    generate_index)
      args+=(
        '(-d --directory)'{-d,--directory=}'[specify repository base dir containing gems]:directory:_directories'
        '--update[update modern indexes with gems added since the last update]'
      )
    ;;
    lock)
      args+=( '(-s --strict)'{-s,--strict}'[fail if unable to satisfy a dependency]' )
    ;;
    open)
      args+=( '(-e --editor)'{-e,--editor=}'[open gem sources in specified editor]:editor:_command_names -e' )
    ;;
    outdated)
      args+=( ${(e)lropts} )
    ;;
    owner)
      args+=(
        '(-a --add)'{-a,--add=}'[add an owner]:email:_email_addresses -c'
        '(-r --remove)'{-r,--remove=}'[remove an owner]:email:_email_addresses -c'
      )
    ;;
    pristine)
      args+=(
        '(*)*--skip=[with --all, skip specified gem]:installed gem:->gems-local'
        "--no-extensions[don't restore gems with extensions in addition to regular gems]"
        '--only-executables[only restore executables]'
      )
    ;;
    push)
      args+=( '1:gem file:_files -g "*.gem(-.)"' )
    ;;
    query)
      args+=(
        '(-n --name-matches)'{-n,--name-matches=}'[specify regex to match against gem names]:gem name (regex):->gems-local'
      )
    ;;
    rdoc)
      args+=(
        '--rdoc[generate RDoc HTML]'
        '--no-ri[generate RI data]'
        '--overwrite[overwrite installed documents]'
      )
    ;;
    server)
      args+=(
        '(-p --port)'{-p,--port=}'[specify port to listen on]:port [8808]:_ports'
        '(-d --dir)'{-d,--dir=}'[specify directories from which to serve gems]:directory:_directories'
        '--daemon[run as a daemon]'
        '(-b --bind)'{-b,--bind=}'[specify addresses to bind]:host:_sequence _hosts'
        '(-l --launch)'{-l,--launch=}'[launch a browser window]:command:_command_names -e'
      )
    ;;
    sources)
      args+=( $proxy
        '(-a --add)'{-a,--add=}'[add source]:source URI:_urls'
        '(-l --list)'{-l,--list}'[list sources]'
        '(-r --remove)'{-r,--remove=}'[remove source]:source URI:_urls'
        '(-c --clear-all)'{-c,--clear-all}'[remove all sources (clear the cache)]'
        '(-u --update)'{-u,--update}'[update source cache]'
      )
    ;;
    specification)
      def[local]='!'
      args+=( ${(e)lropts}
      '--all[output specifications for all versions of the gem]'
        '!(--ruby --marshal)--yaml' '(--ruby --json)--marshal' '(--marshal --json 2)--ruby'
        '1:gem:->gems-local'
        '2:gemspec field:(name description version platform authors autorequire bindir cert_chain date dependencies email executable executables extensions extra_rdoc_files files homepage licenses metadata post_install_message rdoc_options require_paths required_ruby_version requirements rubyforge_project rubygems_version signing_key specification_version summary test_files)'
      )
    ;;
    uninstall)
      args+=(
        '(-a --all)'{-a,--all}'[uninstall all matching versions]'
        '(-x --executables)'{-x,--executables}'[uninstall applicable executables without confirmation]'
        "--no-user-install[uninstall from user's home directory]"
        "--format-executable[assume executable names match Ruby's prefix and suffix]"
        '--force[uninstall all versions of the named gems ignoring dependencies]'
        '--abort-on-dependent[prevent uninstalling gems that are depended on by other gems]'
        '--vendor[uninstall gem from the vendor directory]'
      )
    ;;
    unpack)
      args+=(
        '--spec[unpack the gem specification]'
        '--target=[specify target directory for unpacking]:directory:_directories'
      )
    ;;
    update)
      args+=( '--system[update the RubyGems system software]::version' )
    ;;
    which)
      args+=(
        '(-a --all)'{-a,--all}'[show all matching files]'
        '(-g --gems-first)'{-g,--gems-first}'[search gems before non-gems]'
        '*:file:_files'
      )
    ;;
  esac
  _arguments -C ${args:-'*: :_default'} \
    '(-)'{-h,--help}'[display usage information]' \
    '(-V --verbose --no-verbose)'{-V,--verbose,--no-verbose}'[set verbose level of output]' \
    '(-q --quiet -V --verbose --no-verbose)'{-q,--quiet}'[silence commands progress meter]' \
    '--silent[silence rubygems output]' \
    '--config-file=[use specified config file]:file:_files' \
    '--backtrace[show stack backtrace on errors]' \
    '--debug[turn on ruby debugging]' \
    '--norc[avoid loading any .gemrc file]' && ret=0

  if [[ $state == gems* ]]; then
    filter=( ${${opt_args[(I)-([lbr]|-local|-remote|-both)]}:-${${(M)state:#*-*}/gems-/--}} )
    _description gems expl gem
    compadd "$expl[@]" ${${(f)"$(_call_program gems gem list $filter -q --no-versions)"}%% *} && ret=0
  fi
fi

return ret