/*
Copyright 2016 The Kubernetes 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 completion

import (
	"bytes"
	"io"

	"github.com/spf13/cobra"

	cmdutil "k8s.io/kubectl/pkg/cmd/util"
	"k8s.io/kubectl/pkg/util/i18n"
	"k8s.io/kubectl/pkg/util/templates"
)

const defaultBoilerPlate = `
# Copyright 2016 The Kubernetes 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.
`

var (
	completionLong = templates.LongDesc(i18n.T(`
		Output shell completion code for the specified shell (bash or zsh).
		The shell code must be evaluated to provide interactive
		completion of kubectl commands.  This can be done by sourcing it from
		the .bash_profile.

		Detailed instructions on how to do this are available here:
		https://kubernetes.io/docs/tasks/tools/install-kubectl/#enabling-shell-autocompletion

		Note for zsh users: [1] zsh completions are only supported in versions of zsh >= 5.2`))

	completionExample = templates.Examples(i18n.T(`
		# Installing bash completion on macOS using homebrew
		## If running Bash 3.2 included with macOS
		    brew install bash-completion
		## or, if running Bash 4.1+
		    brew install bash-completion@2
		## If kubectl is installed via homebrew, this should start working immediately.
		## If you've installed via other means, you may need add the completion to your completion directory
		    kubectl completion bash > $(brew --prefix)/etc/bash_completion.d/kubectl


		# Installing bash completion on Linux
		## If bash-completion is not installed on Linux, please install the 'bash-completion' package
		## via your distribution's package manager.
		## Load the kubectl completion code for bash into the current shell
		    source <(kubectl completion bash)
		## Write bash completion code to a file and source if from .bash_profile
		    kubectl completion bash > ~/.kube/completion.bash.inc
		    printf "
		      # Kubectl shell completion
		      source '$HOME/.kube/completion.bash.inc'
		      " >> $HOME/.bash_profile
		    source $HOME/.bash_profile

		# Load the kubectl completion code for zsh[1] into the current shell
		    source <(kubectl completion zsh)
		# Set the kubectl completion code for zsh[1] to autoload on startup
		    kubectl completion zsh > "${fpath[1]}/_kubectl"`))
)

var (
	completionShells = map[string]func(out io.Writer, boilerPlate string, cmd *cobra.Command) error{
		"bash": runCompletionBash,
		"zsh":  runCompletionZsh,
	}
)

// NewCmdCompletion creates the `completion` command
func NewCmdCompletion(out io.Writer, boilerPlate string) *cobra.Command {
	shells := []string{}
	for s := range completionShells {
		shells = append(shells, s)
	}

	cmd := &cobra.Command{
		Use:                   "completion SHELL",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Output shell completion code for the specified shell (bash or zsh)"),
		Long:                  completionLong,
		Example:               completionExample,
		Run: func(cmd *cobra.Command, args []string) {
			err := RunCompletion(out, boilerPlate, cmd, args)
			cmdutil.CheckErr(err)
		},
		ValidArgs: shells,
	}

	return cmd
}

// RunCompletion checks given arguments and executes command
func RunCompletion(out io.Writer, boilerPlate string, cmd *cobra.Command, args []string) error {
	if len(args) == 0 {
		return cmdutil.UsageErrorf(cmd, "Shell not specified.")
	}
	if len(args) > 1 {
		return cmdutil.UsageErrorf(cmd, "Too many arguments. Expected only the shell type.")
	}
	run, found := completionShells[args[0]]
	if !found {
		return cmdutil.UsageErrorf(cmd, "Unsupported shell type %q.", args[0])
	}

	return run(out, boilerPlate, cmd.Parent())
}

func runCompletionBash(out io.Writer, boilerPlate string, kubectl *cobra.Command) error {
	if len(boilerPlate) == 0 {
		boilerPlate = defaultBoilerPlate
	}
	if _, err := out.Write([]byte(boilerPlate)); err != nil {
		return err
	}

	return kubectl.GenBashCompletion(out)
}

func runCompletionZsh(out io.Writer, boilerPlate string, kubectl *cobra.Command) error {
	zshHead := "#compdef kubectl\n"

	out.Write([]byte(zshHead))

	if len(boilerPlate) == 0 {
		boilerPlate = defaultBoilerPlate
	}
	if _, err := out.Write([]byte(boilerPlate)); err != nil {
		return err
	}

	zshInitialization := `
__kubectl_bash_source() {
	alias shopt=':'
	alias _expand=_bash_expand
	alias _complete=_bash_comp
	emulate -L sh
	setopt kshglob noshglob braceexpand

	source "$@"
}

__kubectl_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 [ "$1" = "__kubectl_compopt" ]; then
			echo builtin
			return 0
		fi
	fi
	type "$@"
}

__kubectl_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
}

__kubectl_compopt() {
	true # don't do anything. Not supported by bashcompinit in zsh
}

__kubectl_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
}

__kubectl_get_comp_words_by_ref() {
	cur="${COMP_WORDS[COMP_CWORD]}"
	prev="${COMP_WORDS[${COMP_CWORD}-1]}"
	words=("${COMP_WORDS[@]}")
	cword=("${COMP_CWORD[@]}")
}

__kubectl_filedir() {
	local RET OLD_IFS w qw

	__kubectl_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="," __kubectl_debug "RET=${RET[@]} len=${#RET[@]}"

	for w in ${RET[@]}; do
		if [[ ! "${w}" = "${cur}"* ]]; then
			continue
		fi
		if eval "[[ \"\${w}\" = *.$1 || -d \"\${w}\" ]]"; then
			qw="$(__kubectl_quote "${w}")"
			if [ -d "${w}" ]; then
				COMPREPLY+=("${qw}/")
			else
				COMPREPLY+=("${qw}")
			fi
		fi
	done
}

__kubectl_quote() {
    if [[ $1 == \'* || $1 == \"* ]]; then
        # Leave out first character
        printf %q "${1:1}"
    else
	printf %q "$1"
    fi
}

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

__kubectl_convert_bash_to_zsh() {
	sed \
	-e 's/declare -F/whence -w/' \
	-e 's/_get_comp_words_by_ref "\$@"/_get_comp_words_by_ref "\$*"/' \
	-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}/__kubectl_filedir/g" \
	-e "s/${LWORD}_get_comp_words_by_ref${RWORD}/__kubectl_get_comp_words_by_ref/g" \
	-e "s/${LWORD}__ltrim_colon_completions${RWORD}/__kubectl_ltrim_colon_completions/g" \
	-e "s/${LWORD}compgen${RWORD}/__kubectl_compgen/g" \
	-e "s/${LWORD}compopt${RWORD}/__kubectl_compopt/g" \
	-e "s/${LWORD}declare${RWORD}/builtin declare/g" \
	-e "s/\\\$(type${RWORD}/\$(__kubectl_type/g" \
	<<'BASH_COMPLETION_EOF'
`
	out.Write([]byte(zshInitialization))

	buf := new(bytes.Buffer)
	kubectl.GenBashCompletion(buf)
	out.Write(buf.Bytes())

	zshTail := `
BASH_COMPLETION_EOF
}

__kubectl_bash_source <(__kubectl_convert_bash_to_zsh)
_complete kubectl 2>/dev/null
`
	out.Write([]byte(zshTail))
	return nil
}
