#!/bin/sh
#
# Copyright (c) 2005 Linus Torvalds
# Copyright (c) 2005 Junio C Hamano
#

match $0 {
with *-revert* 
	test -t 0 && setglobal edit = '-e'
	setglobal replay = ''
	setglobal me = 'revert'
	setglobal USAGE = ''[--edit | --no-edit] [-n] <commit-ish>'' 
with *-cherry-pick* 
	setglobal replay = 't'
	setglobal edit = ''
	setglobal me = 'cherry-pick'
	setglobal USAGE = ''[--edit] [-n] [-r] [-x] <commit-ish>''  
with * 
	echo >&2 "What are you talking about?> !2 "What are you talking about?"
	exit 1 
}

setglobal SUBDIRECTORY_OK = 'Yes' ;# we will cd up
source git-sh-setup
require_work_tree
cd_to_toplevel

setglobal no_commit = ''
setglobal xopt = ''
while case "$#" in 0) break ;; esac
{
	match $1 {
	with -n|--n|--no|--no-|--no-c|--no-co|--no-com|--no-comm|\
	    --no-commi|--no-commit
		setglobal no_commit = 't'
		
	with -e|--e|--ed|--edi|--edit
		setglobal edit = '-e'
		
	with --n|--no|--no-|--no-e|--no-ed|--no-edi|--no-edit
		setglobal edit = ''
		
	with -r
		: no-op 
	with -x|--i-really-want-to-expose-my-private-commit-object-name
		setglobal replay = ''
		
	with -X?*
		setglobal xopt = ""$xopt$[git rev-parse --sq-quote "--$(1#-X)]""
		
	with --strategy-option=*
		setglobal xopt = ""$xopt$[git rev-parse --sq-quote "--$(1#--strategy-option=)]""
		
	with -X|--strategy-option
		shift
		setglobal xopt = ""$xopt$[git rev-parse --sq-quote "--$1]""
		
	with -*
		usage
		
	with *
		break
		
	}
	shift
}

set_reflog_action $me

test "$me,$replay" = "revert,t" && usage

match $no_commit {
with t
	# We do not intend to commit immediately.  We just want to
	# merge the differences in.
	setglobal head = $[git-write-tree] ||
		die "Your index file is unmerged."
	
with *
	setglobal head = $[git-rev-parse --verify HEAD] ||
		die "You do not have a valid HEAD"
	setglobal files = $[git-diff-index --cached --name-only $head] || exit
	if test $files {
		die "Dirty index: cannot $me (dirty: $files)"
	}
	
}

setglobal rev = $[git-rev-parse --verify @Argv] &&
setglobal commit = $[git-rev-parse --verify "$rev^0] ||
	die "Not a single commit $ifsjoin(Argv)"
setglobal prev = $[git-rev-parse --verify "$commit^1" !2 >/dev/null] ||
	die "Cannot run $me a root commit"
git-rev-parse --verify "$commit^2" >/dev/null !2 > !1 &&
	die "Cannot run $me a multi-parent commit."

setglobal encoding = $[git config i18n.commitencoding || echo UTF-8]

# "commit" is an existing commit.  We would want to apply
# the difference it introduces since its first parent "prev"
# on top of the current HEAD if we are cherry-pick.  Or the
# reverse of it if we are revert.

match $me {
with revert
	git show -s --pretty=oneline --encoding="$encoding" $commit |
	sed -e '
		s/^[^ ]* /Revert "/
		s/$/"/
	'
	echo
	echo "This reverts commit $commit."
	test $rev = $commit ||
	echo "(original 'git revert' arguments: $ifsjoin(Argv))"
	setglobal base = $commit, next = $prev
	

with cherry-pick
	setglobal pick_author_script = ''
	/^author /{
		s/'''''/'''''\\''''''''/g
		h
		s/^author \([^<]*\) <[^>]*> .*$/\1/
		s/'''''/'''''\''''''''/g
		s/.*/GIT_AUTHOR_NAME='''''&'''''/p

		g
		s/^author [^<]* <\([^>]*\)> .*$/\1/
		s/'''''/'''''\''''''''/g
		s/.*/GIT_AUTHOR_EMAIL='''''&'''''/p

		g
		s/^author [^<]* <[^>]*> \(.*\)$/\1/
		s/'''''/'''''\''''''''/g
		s/.*/GIT_AUTHOR_DATE='''''&'''''/p

		q
	}''

	setglobal logmsg = $[git show -s --pretty=raw --encoding="$encoding" $commit]
	setglobal set_author_env = $[echo $logmsg |
	env LANG=C LC_ALL=C sed -ne $pick_author_script]
	eval $set_author_env
	export GIT_AUTHOR_NAME
	export GIT_AUTHOR_EMAIL
	export GIT_AUTHOR_DATE

	echo $logmsg |
	sed -e '1,/^$/d' -e 's/^    //'
	match $replay {
	with ''
		echo "(cherry picked from commit $commit)"
		test $rev = $commit ||
		echo "(original 'git cherry-pick' arguments: $ifsjoin(Argv))"
		
	}
	setglobal base = $prev, next = $commit
	

} >.msg

eval GITHEAD_$head=HEAD
eval GITHEAD_$next='$(git show -s \
	--pretty=oneline --encoding="$encoding" "$commit" |
	sed -e "s/^[^ ]* //")'
export GITHEAD_$head GITHEAD_$next

# This three way merge is an interesting one.  We are at
# $head, and would want to apply the change between $commit
# and $prev on top of us (when reverting), or the change between
# $prev and $commit on top of us (when cherry-picking or replaying).

eval "git merge-recursive $xopt $base -- $head $next" &&
setglobal result = $[git-write-tree !2 >/dev/null] || do {
	mv -f .msg "$GIT_DIR/MERGE_MSG"
	do {
	    echo '
Conflicts:
'
		git ls-files --unmerged |
		sed -e 's/^[^	]*	/	/' |
		uniq
	} >>"$GIT_DIR/MERGE_MSG"
	echo >&2 "Automatic $me failed.  After resolving the conflicts,> !2 "Automatic $me failed.  After resolving the conflicts,"
	echo >&2 "mark the corrected paths with 'git-add <paths>'> !2 "mark the corrected paths with 'git-add <paths>'"
	echo >&2 "and commit the result.> !2 "and commit the result."
	match $me {
	with cherry-pick
		echo >&2 "You may choose to use the following when making> !2 "You may choose to use the following when making"
		echo >&2 "the commit:> !2 "the commit:"
		echo >&2 $set_author_env> !2 "$set_author_env"
	}
	exit 1
}

# If we are cherry-pick, and if the merge did not result in
# hand-editing, we will hit this commit and inherit the original
# author date and name.
# If we are revert, or if our cherry-pick results in a hand merge,
# we had better say that the current user is responsible for that.

match $no_commit {
with ''
	git-commit -n -F .msg $edit
	rm -f .msg
	
}