#!/bin/sh

# Script to add some local git customizations suitable for working
# with the GCC git repository

ask () {
    question=$1
    default=$2
    var=$3
    echo -n $question "["$default"]? "
    read answer
    if [ "x$answer" = "x" ]
    then
	eval $var=\$default
    else
	eval $var=\$answer
    fi
}

# Add a git command to find the git commit equivalent to legacy SVN revision NNN
git config alias.svn-rev '!f() { rev=$1; shift; git log --all --grep="From-SVN: r\\?$rev\\b" "${@}"; } ; f'

# Add git commands to convert git commit to monotonically increasing revision number
# and vice versa
git config alias.gcc-descr \!"f() { if test \${1:-no} = --full; then c=\${2:-master}; r=\$(git describe --all --abbrev=40 --match 'basepoints/gcc-[0-9]*' \$c | sed -n 's,^\\(tags/\\)\\?basepoints/gcc-,r,p'); expr match \${r:-no} '^r[0-9]\\+\$' >/dev/null && r=\${r}-0-g\$(git rev-parse \${2:-master}); else c=\${1:-master}; r=\$(git describe --all --match 'basepoints/gcc-[0-9]*' \$c | sed -n 's,^\\(tags/\\)\\?basepoints/gcc-\\([0-9]\\+\\)-\\([0-9]\\+\\)-g[0-9a-f]*\$,r\\2-\\3,p;s,^\\(tags/\\)\\?basepoints/gcc-\\([0-9]\\+\\)\$,r\\2-0,p'); fi; if test -n \$r; then o=\$(git config --get gcc-config.upstream); rr=\$(echo \$r | sed -n 's,^r\\([0-9]\\+\\)-[0-9]\\+\\(-g[0-9a-f]\\+\\)\\?\$,\\1,p'); if git rev-parse --verify --quiet \${o:-origin}/releases/gcc-\$rr >/dev/null; then m=releases/gcc-\$rr; else m=master; fi; git merge-base --is-ancestor \$c \${o:-origin}/\$m && \echo \${r}; fi; }; f"
git config alias.gcc-undescr \!"f() { o=\$(git config --get gcc-config.upstream); r=\$(echo \$1 | sed -n 's,^r\\([0-9]\\+\\)-[0-9]\\+\$,\\1,p'); n=\$(echo \$1 | sed -n 's,^r[0-9]\\+-\\([0-9]\\+\\)\$,\\1,p'); test -z \$r && echo Invalid id \$1 && exit 1; h=\$(git rev-parse --verify --quiet \${o:-origin}/releases/gcc-\$r); test -z \$h && h=\$(git rev-parse --verify --quiet \${o:-origin}/master); p=\$(git describe --all --match 'basepoints/gcc-'\$r \$h | sed -n 's,^\\(tags/\\)\\?basepoints/gcc-[0-9]\\+-\\([0-9]\\+\\)-g[0-9a-f]*\$,\\2,p;s,^\\(tags/\\)\\?basepoints/gcc-[0-9]\\+\$,0,p'); git rev-parse --verify \$h~\$(expr \$p - \$n); }; f"

# Make diff on MD files use "(define" as a function marker.
# Use this in conjunction with a .gitattributes file containing
# *.md    diff=md
git config diff.md.xfuncname '^\(define.*$'

set_user=$(git config --get "user.name")
set_email=$(git config --get "user.email")

if [ "x$set_user" = "x" ]
then
    # Try to guess the user's name by looking it up in the password file
    new_user=$(getent passwd $(whoami) | awk -F: '{ print $5 }')
    if [ "x$new_user" = "x" ]
    then
       new_user="(no default)"
    fi
else
    new_user=$set_user
fi
ask "Your name" "${new_user}" new_user
if [ "x$new_user" = "x(no default)" ]
then
    echo "Cannot continue, git needs to record your name against commits"
    exit 1
fi

if [ "x$set_email" = "x" ]
then
    new_email="(no_default)"
else
    new_email=$set_email
fi

ask "Your email address (for git commits)" "${new_email}" new_email
if [ "x$new_email" = "x(no default)" ]
then
    echo "Cannot continue, git needs to record your email address against commits"
    exit 1
fi

if [ "x$set_user" != "x$new_user" ]
then
    git config "user.name" "$new_user"
fi

if [ "x$set_email" != "x$new_email" ]
then
    git config "user.email" "$new_email"
fi

upstream=$(git config --get "gcc-config.upstream")
if [ "x$upstream" = "x" ]
then
    upstream="origin"
fi
ask "Local name for upstream repository" "origin" upstream

v=$(git config --get-all "remote.${upstream}.fetch")
if [ "x$v" = "x" ]
then
    echo "Remote $upstream does not seem to exist as a remote"
    exit 1
fi
git config "gcc-config.upstream" "$upstream"

remote_id=$(git config --get "gcc-config.user")
if [ "x$remote_id" = "x" ]
then
    # See if the url specifies the remote user name.
    url=$(git config --get "remote.$upstream.url")
    if [ "x$url" = "x" ]
    then
	# This is a pure guess, but for many people it might be OK.
	remote_id=$(whoami)
    else
	remote_id=$(echo $url | sed -r "s|^.*ssh://(.+)@gcc.gnu.org.*$|\1|")
	if [ x$remote_id = x$url ]
	then
	    remote_id=$(whoami)
	fi
    fi
fi

ask "Account name on gcc.gnu.org (for your personal branches area)" $remote_id remote_id
git config "gcc-config.user" "$remote_id"

old_pfx=$(git config --get "gcc-config.userpfx")
if [ "x$old_pfx" = "x" ]
then
    old_pfx="me"
fi
echo
echo "Local branch prefix for personal branches you want to share"
echo "(local branches starting <prefix>/ can be pushed directly to your"
ask "personal area on the gcc server)" $old_pfx new_pfx
git config "gcc-config.userpfx" "$new_pfx"

# Scan the existing settings to see if there are any we need to rewrite.
vendors=$(git config --get-all "remote.${upstream}.fetch" "refs/vendors/" | sed -r "s:.*refs/vendors/([^/]+)/.*:\1:" | sort | uniq)
url=$(git config --get "remote.${upstream}.url")
pushurl=$(git config --get "remote.${upstream}.pushurl")
for v in $vendors
do
    echo "Migrating vendor \"$v\" to new remote \"vendors/$v\""
    git config --unset-all "remote.${upstream}.fetch" "refs/vendors/$v/"
    git config --unset-all "remote.${upstream}.push" "refs/vendors/$v/"
    git config "remote.vendors/${v}.url" "${url}"
    if [ "x$pushurl" != "x" ]
    then
	git config "remote.vendors/${v}.pushurl" "${pushurl}"
    fi
    git config --add "remote.vendors/${v}.fetch" "+refs/vendors/$v/heads/*:refs/remotes/vendors/${v}/*"
    git config --add "remote.vendors/${v}.fetch" "+refs/vendors/$v/tags/*:refs/tags/vendors/${v}/*"
done

# Convert the remote 'pfx' to users/pfx to avoid problems with ambiguous refs
# on user branches
old_remote=$(git config --get "remote.${old_pfx}.url")
if [ -n "${old_remote}" ]
then
    echo "Migrating remote \"${old_pfx}\" to new remote \"users/${new_pfx}\""
    # Create a dummy fetch rule that will cause the subsequent prune to remove the old remote refs.
    git config --replace-all "remote.${old_pfx}.fetch" "+refs/empty/*:refs/remotes/${old_pfx}/*"
    # Remove any remotes
    git remote prune ${old_pfx}
    git config --remove-section "remote.${old_pfx}"
    for br in $(git branch --list "${old_pfx}/*")
    do
	old_remote=$(git config --get "branch.${br}.remote")
	if [ "${old_remote}" = "${old_pfx}" ]
	then
	    git config "branch.${br}.remote" "users/${new_pfx}"
	fi
    done
fi

echo "Setting up tracking for personal namespace $remote_id in remotes/users/${new_pfx}"
git config "remote.users/${new_pfx}.url" "${url}"
if [ "x$pushurl" != "x" ]
then
    git config "remote.users/${new_pfx}.pushurl" "${pushurl}"
fi
git config --replace-all "remote.users/${new_pfx}.fetch" "+refs/users/${remote_id}/heads/*:refs/remotes/users/${new_pfx}/*" "refs/users/${remote_id}/heads/"
git config --replace-all "remote.users/${new_pfx}.fetch" "+refs/users/${remote_id}/tags/*:refs/tags/users/${new_pfx}/*" "refs/users/${remote_id}/tags/"
git config --replace-all "remote.users/${new_pfx}.push" "refs/heads/${new_pfx}/*:refs/users/${remote_id}/heads/*" "refs/users/${remote_id}"

if [ "$old_pfx" != "$new_pfx" -a "$old_pfx" != "${upstream}" ]
then
    git config --remove-section "remote.${old_pfx}"
fi

git config --unset-all "remote.${upstream}.fetch" "refs/users/${remote_id}/"
git config --unset-all "remote.${upstream}.push" "refs/users/${remote_id}/"

git fetch "users/${new_pfx}"