completion.go

// Copyright © 2017 The Kubicorn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package cmd

import (
	"bytes"
	"fmt"
	"os"

	"github.com/kris-nova/kubicorn/cutil/logger"

	"github.com/spf13/cobra"
)

const license = `# Copyright © 2017 The Kubicorn Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

`

// CompletionCmd represents the completion command
func CompletionCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "completion",
		Short: "Generate completion code for bash and zsh shells.",
		Long: `completion is used to output completion code for bash and zsh shells.
	
	Before using completion features, you have to source completion code
	from your .profile. This is done by adding following line to one of above files:
		source <(kubicorn completion SHELL)
	Valid arguments for SHELL are: "bash" and "zsh".
	Notes:
	1) zsh completions requires zsh 5.2 or newer.
		
	2) macOS users have to install bash-completion framework to utilize
	completion features. This can be done using homebrew:
		brew install bash-completion
	Once installed, you must load bash_completion by adding following
	line to your .profile or .bashrc/.zshrc:
		source $(brew --prefix)/etc/bash_completion`,
		RunE: func(cmd *cobra.Command, args []string) error {
			if logger.Fabulous {
				cmd.SetOutput(logger.FabulousWriter)
			}
			if os.Getenv("KUBICORN_TRUECOLOR") != "" {
				cmd.SetOutput(logger.FabulousWriter)
			}

			if len(args) != 1 {
				return fmt.Errorf("shell argument is not specified")
			}
			shell := args[0]

			if shell == "bash" {
				return RunBashGeneration()
			} else if shell == "zsh" {
				return RunZshGeneration()
			} else {
				return fmt.Errorf("invalid shell argument")
			}
		},
	}
}

func RunBashGeneration() error {
	var buf bytes.Buffer

	_, err := buf.Write([]byte(license))
	if err != nil {
		return fmt.Errorf("error while generating bash completion: %v", err)
	}

	err = RootCmd.GenBashCompletion(&buf)
	if err != nil {
		return fmt.Errorf("error generating bash completion: %v", err)
	}

	fmt.Printf("%s", buf.String())

	return nil
}

func RunZshGeneration() error {
	var buf bytes.Buffer

	// zshInit converts appropriate bash to zsh code.
	zshInit := `
__kubicorn_bash_source() {
	alias shopt=':'
	alias _expand=_bash_expand
	alias _complete=_bash_comp
	emulate -L sh
	setopt kshglob noshglob braceexpand
	source "$@"
}
__kubicorn_type() {
	# -t is not supported by zsh
	if [ "$1" == "-t" ]; then
		shift
		# fake Bash 4 to disable "complete -o nospace". Instead
		# "compopt +-o nospace" is used in the code to toggle trailing
		# spaces. We don't support that, but leave trailing spaces on
		# all the time
		if [ "$1" = "__kubicorn_compopt" ]; then
			echo builtin
			return 0
		fi
	fi
	type "$@"
}
__kubicorn_compgen() {
	local completions w
	completions=( $(compgen "$@") ) || return $?
	# filter by given word as prefix
	while [[ "$1" = -* && "$1" != -- ]]; do
		shift
		shift
	done
	if [[ "$1" == -- ]]; then
		shift
	fi
	for w in "${completions[@]}"; do
		if [[ "${w}" = "$1"* ]]; then
			echo "${w}"
		fi
	done
}
__kubicorn_compopt() {
	true # don't do anything. Not supported by bashcompinit in zsh
}
__kubicorn_declare() {
	if [ "$1" == "-F" ]; then
		whence -w "$@"
	else
		builtin declare "$@"
	fi
}
__kubicorn_ltrim_colon_completions()
{
	if [[ "$1" == *:* && "$COMP_WORDBREAKS" == *:* ]]; then
		# Remove colon-word prefix from COMPREPLY items
		local colon_word=${1%${1##*:}}
		local i=${#COMPREPLY[*]}
		while [[ $((--i)) -ge 0 ]]; do
			COMPREPLY[$i]=${COMPREPLY[$i]#"$colon_word"}
		done
	fi
}
__kubicorn_get_comp_words_by_ref() {
	cur="${COMP_WORDS[COMP_CWORD]}"
	prev="${COMP_WORDS[${COMP_CWORD}-1]}"
	words=("${COMP_WORDS[@]}")
	cword=("${COMP_CWORD[@]}")
}
__kubicorn_filedir() {
	local RET OLD_IFS w qw
	__debug "_filedir $@ cur=$cur"
	if [[ "$1" = \~* ]]; then
		# somehow does not work. Maybe, zsh does not call this at all
		eval echo "$1"
		return 0
	fi
	OLD_IFS="$IFS"
	IFS=$'\n'
	if [ "$1" = "-d" ]; then
		shift
		RET=( $(compgen -d) )
	else
		RET=( $(compgen -f) )
	fi
	IFS="$OLD_IFS"
	IFS="," __debug "RET=${RET[@]} len=${#RET[@]}"
	for w in ${RET[@]}; do
		if [[ ! "${w}" = "${cur}"* ]]; then
			continue
		fi
		if eval "[[ \"\${w}\" = *.$1 || -d \"\${w}\" ]]"; then
			qw="$(__kubicorn_quote "${w}")"
			if [ -d "${w}" ]; then
				COMPREPLY+=("${qw}/")
			else
				COMPREPLY+=("${qw}")
			fi
		fi
	done
}
__kubicorn_quote() {
    if [[ $1 == \'* || $1 == \"* ]]; then
        # Leave out first character
        printf %q "${1:1}"
    else
    	printf %q "$1"
    fi
}
autoload -U +X compinit && compinit
autoload -U +X bashcompinit && bashcompinit
# use word boundary patterns for BSD or GNU sed
LWORD='[[:<:]]'
RWORD='[[:>:]]'
if sed --help 2>&1 | grep -q GNU; then
	LWORD='\<'
	RWORD='\>'
fi
__kubicorn_convert_bash_to_zsh() {
	sed \
	-e 's/declare -F/whence -w/' \
	-e 's/local \([a-zA-Z0-9_]*\)=/local \1; \1=/' \
	-e 's/flags+=("\(--.*\)=")/flags+=("\1"); two_word_flags+=("\1")/' \
	-e 's/must_have_one_flag+=("\(--.*\)=")/must_have_one_flag+=("\1")/' \
	-e "s/${LWORD}_filedir${RWORD}/__kubicorn_filedir/g" \
	-e "s/${LWORD}_get_comp_words_by_ref${RWORD}/__kubicorn_get_comp_words_by_ref/g" \
	-e "s/${LWORD}__ltrim_colon_completions${RWORD}/__kubicorn_ltrim_colon_completions/g" \
	-e "s/${LWORD}compgen${RWORD}/__kubicorn_compgen/g" \
	-e "s/${LWORD}compopt${RWORD}/__kubicorn_compopt/g" \
	-e "s/${LWORD}declare${RWORD}/__kubicorn_declare/g" \
	-e "s/\\\$(type${RWORD}/\$(__kubicorn_type/g" \
	<<'BASH_COMPLETION_EOF'
`

	// zshFinalize is code going to the end of completion file.
	// It that calls conversion bash to zsh.
	zshFinalize := `
BASH_COMPLETION_EOF
}
__kubicorn_bash_source <(__kubicorn_convert_bash_to_zsh)
	`

	_, err := buf.Write([]byte(license))
	if err != nil {
		return fmt.Errorf("error while generating zsh completion: %v", err)
	}

	_, err = buf.Write([]byte(zshInit))

	err = RootCmd.GenBashCompletion(&buf)
	if err != nil {
		return fmt.Errorf("error wheil generating zsh completion: %v", err)
	}

	_, err = buf.Write([]byte(zshFinalize))
	if err != nil {
		return fmt.Errorf("error while generating zsh completion: %v", err)
	}

	fmt.Printf("%s", buf.String())

	return nil
}