# -*-eselect-*-  vim: ft=eselect
# Copyright 2005-2012 Gentoo Foundation
# Distributed under the terms of the GNU GPL version 2 or later

inherit portage

DESCRIPTION="Handle configuration file merges"
MAINTAINER="eselect@gentoo.org"

show_extra_help_text() {
	cat <<ENDOFTEXT
This tool can be used to automatically or manually merge configuration files
which have been created by portage.

The 'interactive' action will enter interactive mode.

The 'list' action will show all configuration files which need updating.

The 'accept' action will accept the proposed changes to one or more
configuration files. It accepts one or more parameters, each of which can either
be the names of files to overwrite, a number corresponding to the value shown by
the 'list' action, or two numbers separated by a hyphen -- for example, "3-7" --
which is treated as a range.

The 'reject' action will discard (reject) the proposed changes to one or more
configuration files. It takes parameters in the same way as 'accept'.

The 'display' action shows (as a unified diff) the proposed update for one or
more files.

The 'accept-all' action accepts all proposed changes to all configuration files.
Similarly, 'reject-all' rejects all changes. Use with caution.
ENDOFTEXT
}

config_protect_dirs() {
	if [[ -z ${CONFIG_UPDATE_DIRS} ]] ; then
		export CONFIG_UPDATE_DIRS=$(envvar sys-devel/gcc CONFIG_PROTECT )
	fi
	echo ${CONFIG_UPDATE_DIRS}
}

find_targets() {
	local dir targets
	for dir in $(config_protect_dirs ) ; do
		[[ -d ${dir} ]] || continue
		find ${dir} -iname '._cfg????_*' | \
			sed -e 's,^\(.*\)\._cfg...._\(.*\),\1\2,g' | sort -u
	done
}

generic_handle_one_file() {
	local action_name="${1}" apply_cmd="${2}"
	shift 2

	local targets=( ) has_targets=0

	# check whether we've been given any parameters
	if [[ ${#@} < 1 ]] ; then
		die -q "You should give me at least one file to work with"
	else
		local file_raw file

		# for each parameter...
		for file_raw in "$@" ; do
			[[ -z ${file_raw} ]] && continue

			# do we have a number or a name?
			if is_number "${file_raw}" ; then
				# number. decode
				if [[ ${has_targets} == 0 ]] ; then
					targets=( $(find_targets ) )
					has_targets=1
				fi
				file=${targets[${file_raw} - 1]}
			else
				# name. don't decode
				file=${file_raw}
			fi

			# sanity checks
			[[ -z ${file} ]] && die -q "Sorry, ${file_raw} seems to be invalid"
			[[ -e ${file} ]] || die -q "Sorry, ${file} doesn't seem to exist"

			# find the files to discard
			local cfgname="._cfg????_$(basename "${file}")"
			local dirname="$(canonicalise -f $(dirname ${file} ))"
			local kfiles
			kfiles=( $(find "${dirname}" -maxdepth 1 -type f \
					-iname "${cfgname}") )

			if [[ -n ${kfiles[@]//[[:space:]]} ]] ; then
				# files found. work on them
				${apply_cmd} "${kfiles}"
			else
				# no files found
				write_error_msg "Couldn't find any files to ${action_name}."
				write_error_msg "I was looking in: ${dirname}"
				write_error_msg "For files named:  ${cfgname}"
				die -q "Can't ${action_name} ${file_raw}"
			fi
		done
	fi
}

generic_handle_all() {
	local verb="${1}" action="${2}"
	shift 2

	local targets target
	write_list_start "${verb} changes to configuration files:"
	targets=( $(find_targets ) )
	if [[ ${#targets[@]} > 0 ]] ; then
		for target in ${targets[@]} ; do
			write_kv_list_entry "${target}" ""
			do_action config "${action}" "${target}"
		done
	else
		write_kv_list_entry "No out of date files found"
	fi
}

### list action ###

describe_list() {
	echo "List files which need merging"
}

do_list() {
	targets=( $(find_targets ) )
	write_list_start "Configuration files needing action:"
	if [[ ${#targets[@]} > 0 ]] ; then
		write_numbered_list "${targets[@]}"
	else
		write_kv_list_entry "No out of date files found"
	fi
}

### reject action ###

describe_reject() {
	echo "Reject updates to the specified files"
}

do_reject() {
	generic_handle_one_file "reject" "reject_handler" "$@"
}

reject_handler() {
	rm --interactive "$@"
}

### accept action ###

describe_accept() {
	echo "Accept changes to the specified files"
}

do_accept() {
	generic_handle_one_file "accept" "accept_handler" "$@"
}

accept_handler() {
	local file
	for file in "$@" ; do
		local sfile="${file}" dfile="${file/._cfg????_}"
		echo "Replacing ${dfile} with ${sfile}..."
		mv --interactive "${sfile}" "${dfile}"
	done
}

### reject-all action ###

describe_reject-all() {
	echo "Reject all updates ($(highlight_warning dangerous))"
}

do_reject-all() {
	generic_handle_all "Rejecting" "reject"
}

### accept-all action ###

describe_accept-all() {
	echo "Accept all updates ($(highlight_warning dangerous))"
}

do_accept-all() {
	generic_handle_all "Accepting" "accept"
}

### merge action ###

describe_merge() {
	echo "Interactively merge changes to the specified files"
}

do_merge() {
	generic_handle_one_file "merge" "merge_handler" "$@"
}

merge_handler() {
	local file
	for file in "$@" ; do
		local sfile="${file}" dfile="${file/._cfg????_}"
		echo "Merging ${dfile} with ${sfile}..."
		merge_prog ${dfile} ${sfile}
	done
}

merge_prog() {
	if type vimdiff &>/dev/null ; then
		vimdiff "$@"
	else
		write_error_msg "Couldn't find a suitable merge program."
		write_error_msg "Currently I know how to use 'vimdiff', which you can"
		write_error_msg "get by installing app-editors/vim."
		die -q "No merge program found"
	fi

}

### merge-all action ###

describe_merge-all() {
	echo "Interactively merge all changes"
}

do_merge-all() {
	generic_handle_all "Merging" "merge"
}

### display action ###

describe_display() {
	echo "Display the proposed changes to the specified files"
}

do_display() {
	generic_handle_one_file "display" "display_handler" "$@"
}

display_handler() {
	local file
	for file in "$@" ; do
		local sfile="${file}" dfile="${file/._cfg????_}"
		echo "Proposed changes to ${dfile}:"
		diff_prog -u ${dfile} ${sfile}
	done
}

diff_prog() {
	if type colordiff &>/dev/null ; then
		colordiff "$@"
	else
		diff "$@"
	fi
}
### display-all action ###

describe_display-all() {
	echo "Display all proposed updates"
}

do_display-all() {
	generic_handle_all "Displaying" "display"
}

### interactive action ###

describe_interactive() {
	echo "Enter interactive mode"
}

do_interactive() {
	local targets command show_menu=yes show_list=yes

	config_protect_dirs 1>/dev/null
	while true ; do
		targets=( $(find_targets) )

		# Are we finished?
		if [[ ${#targets[@]} == 0 ]] ; then
			write_list_start "Nothing left to do."
			break
		fi

		# Should we show a file list?
		if [[ -n ${show_list} ]] ; then
			show_list=
			write_list_start "Configuration files needing action:"
			write_numbered_list "${targets[@]}"
			echo
		fi

		# Should we show a menu?
		if [[ -n ${show_menu} ]] ; then
			show_menu=
			write_list_start "Enter command:"
			write_kv_list_entry "<number>" "Work with the specified file"
			write_kv_list_entry "$(highlight d)isplay <number>" "Display proposed change"
			write_kv_list_entry "$(highlight a)ccept <number>"  "Accept proposed change"
			write_kv_list_entry "$(highlight r)eject <number>"  "Reject proposed change"
			write_kv_list_entry "$(highlight m)erge <number>"   "Merge proposed change"
			echo
			write_kv_list_entry "accept-all" \
				"Accept all changes ($(highlight_warning dangerous))"
			write_kv_list_entry "reject-all" \
				"Reject all changes ($(highlight_warning dangerous))"
			echo
			write_kv_list_entry "$(highlight l)ist" "Show file list"
			write_kv_list_entry "$(highlight h)elp" "Show this menu again"
			write_kv_list_entry "$(highlight q)uit" "Exit the program"
			echo
		else
			write_list_start "Enter command ($(highlight h)elp to show menu)"
		fi
		echo -n "> "
		read command

		case ${command%%[[:space:]]*} in
			q|qu|qui|quit)
				break;
				;;
			h|he|hel|help)
				show_menu=yes
				;;
			l|li|lis|list)
				show_list=yes
				;;
			d|di|dis|disp|displ|displa|display)
				local args=${command#*[[:space:]]}
				if [[ -z ${command//[^[:space:]]} ]] ; then
					write_error_msg "You didn't tell me which file to display"
				else
					do_action config display ${command#*[[:space:]]}
				fi
				;;
			a|ac|acc|acce|accep|accept)
				local args=${command#*[[:space:]]}
				if [[ -z ${command//[^[:space:]]} ]] ; then
					write_error_msg "You didn't tell me which file to accept"
				else
					do_action config accept ${command#*[[:space:]]}
				fi
				show_list=yes
				;;
			r|re|rej|reje|rejec|reject)
				local args=${command#*[[:space:]]}
				if [[ -z ${command//[^[:space:]]} ]] ; then
					write_error_msg "You didn't tell me which file to reject"
				else
					do_action config reject ${command#*[[:space:]]}
				fi
				show_list=yes
				;;
			m|me|mer|merg|merge)
				local args=${command#*[[:space:]]}
				if [[ -z ${command//[^[:space:]]} ]] ; then
					write_error_msg "You didn't tell me which file to merge"
				else
					do_action config merge ${command#*[[:space:]]}
				fi
				show_list=yes
				;;
			accept-all)
				do_action config accept-all
				show_list=yes
				;;
			reject-all)
				do_action config reject-all
				show_list=yes
				;;
			+([[:digit:]])*(+([[:space:]])+([[:digit:]])))
				while true ; do
					local item ok=
					for item in ${command} ; do
						[[ -z ${targets[${item}-1]} ]] && continue
						[[ -z ${ok} ]] && write_list_start "Selected files:"
						ok=yes
						write_numbered_list_entry ${item} ${targets[${item}-1]}
					done
					if [[ -z ${ok} ]] ; then
						write_error_msg "Sorry, ${command} not valid"
						show_list=yes
					else
						echo
						write_list_start "Enter subcommand:"
						write_kv_list_entry "$(highlight d)isplay" "Display proposed change"
						write_kv_list_entry "$(highlight a)ccept"  "Accept proposed change"
						write_kv_list_entry "$(highlight r)eject"  "Reject proposed change"
						write_kv_list_entry "$(highlight m)erge"   "Merge proposed change"
						write_kv_list_entry "$(highlight q)uit"    "Return to parent menu"
						echo
						echo -n "> "
						read subcommand
						case ${subcommand} in
							q|qu|qui|quit)
								break;
								;;
							d|di|dis|disp|displ|displa|display)
								do_action config display ${command}
								;;
							a|ac|acc|acce|accep|accept)
								do_action config accept ${command}
								show_list=yes
								break
								;;
							r|re|rej|reje|rejec|reject)
								do_action config reject ${command}
								show_list=yes
								break
								;;
							m|me|mer|merg|merge)
								do_action config reject ${command}
								show_list=yes
								break
								;;
							*)
								write_error_msg "Sorry, ${subcommand} not understood"
								;;
						esac
					fi
				done
				;;
			*)
				write_error_msg "Sorry, ${command} not understood"
				;;
		esac
	done
}