#!/bin/sh

set -eu

SOURCE_DIR=$1
MAJOR=$2
MINOR=$3
PATCH=$4

VER="$MAJOR.$MINOR.$PATCH"

update() {
  file="$SOURCE_DIR/$1"
  expr="$2"

  sed -e "$expr" "$file" > "$file.updated-version"
  if diff "$file" "$file.updated-version"; then
    rm "$file.updated-version"
  else
    # use cat > and rm instead of move to keep file permissions
    cat "$file.updated-version" > "$file"
    rm "$file.updated-version"
  fi
}

update 'configure.ac' 's/AC_INIT(\[tox\], \[.*\])/AC_INIT([tox], ['$VER'])/'

update 'toxcore/tox.api.h' 's/\(const VERSION_MAJOR *= \).*;/\1'$MAJOR';/'
update 'toxcore/tox.api.h' 's/\(const VERSION_MINOR *= \).*;/\1'$MINOR';/'
update 'toxcore/tox.api.h' 's/\(const VERSION_PATCH *= \).*;/\1'$PATCH';/'

#
# calculating the SO version
#
# The SO version reflects changes in the ABI compatibility of the libary [1].
# The general convention on this is that the SO version is a monotonically
# increasing number. The major version reflects breaking changes and the minor
# number reflect non-breaking updates [2].
#
# The SO version for tox libraries consists of two parts: `A.B`.
# - incrementing A reflects an ABI breaking change.
# - incrementing B reflects a non-ABI-breaking update. B is set to 0 when A is incremented.
#
# As the tox versioning scheme directly reflects ABI compatibility, we can use it
# to construct the SO version.
#
# In the `0.y.z` release cycle, breaking changes are allowed in every increment of `y`,
# so we can build the SO version just by taking `y.z`.
# In the `x.y.z` release cycle with `x > 0` the SO version must be calculated by taking
# the major of the tox version and add a hardcoded number that is the last A of the 0.y.z
# release cycle.
#
# References:
#
# [1]: https://autotools.io/libtool/version.html
# [2]: http://www.ibm.com/developerworks/linux/library/l-shlibs/index.html#N1006E
#

# the last major version number from the 0.x release cycle
# this must be constant starting from the 1.0 release
LAST_SOMAJOR=1

if [ $MAJOR -eq 0 ]; then
    SOMAJOR=$MINOR
    SOMINOR=$PATCH

    # update lastmajor above
    update 'other/version-sync' 's/^\(LAST_SOMAJOR=\).*/\1'$SOMAJOR'/'
else
    SOMAJOR=$(expr $MAJOR + $LAST_SOMAJOR)
    SOMINOR=$MINOR
fi

#
# libtool has a quite cryptic implementation of the versioning system, which also
# changes between systems, see https://github.com/lxde/lxqt/issues/488#issuecomment-238084222
#
# .so library version, following the libtool scheme:
#
#            current:revision:age
#
# current:  increment if interfaces have been added, removed or changed
# revision: increment if source code has changed, set to zero if current is
#           incremented
# age:      increment if interfaces have been added, set to zero if
#           interfaces have been removed or changed
#
# For a full reference see:
# https://www.gnu.org/software/libtool/manual/libtool.html#Updating-version-info
#
# Passing such a version string to libtool will generate the following version number
# on the libary binary file on GNU/Linux:
#
# (current - age).(age).(revision)
#
# We do not want to use a separate version numbering for the library because the package versioning is equally good:
#
# Semver non-breaking: 0.y.(z+1) or x.(y+1).0:
#
# This would mean to increment current and age, which leave the major of SOVERSION the same.
# Revision is incremented.
#
# Semver breaking: 0.(y+1).0 or (x+1).0.0:
#
# This would mean to increment current, set age and revision to zero.
#
# Thus to make libtool use our version, we have to pass (major + minor):patch:minor as current:revision:age to get:
#
#     (current - age).(age).(revision)
# <=> (major + minor - minor).minor.patch
# <=> major.minor.patch
#

if [ $MAJOR -eq 0 ]; then
    LIBTOOL_CURRENT=$(expr $SOMAJOR + $SOMINOR)
    LIBTOOL_AGE=$SOMINOR
    LIBTOOL_REVISION=0
else
    LIBTOOL_CURRENT=$(expr $SOMAJOR + $SOMINOR)
    LIBTOOL_AGE=$SOMINOR
    LIBTOOL_REVISION=$PATCH
fi

update 'so.version' 's/^\(CURRENT=\).*/\1'$LIBTOOL_CURRENT'/'
update 'so.version' 's/^\(AGE=\).*/\1'$LIBTOOL_AGE'/'
update 'so.version' 's/^\(REVISION=\).*/\1'$LIBTOOL_REVISION'/'