bump

#!/bin/bash

NL=$'\n'

die() {
    echo "ERROR: $*"
    usage
    exit 1
}

usage() {
    echo "Usage: $(basename "$0") <action> <version>"
    echo
    echo "    Whereas <action> can be:"
    echo "    version     do a version bump"
    echo "    cycle       start a new cycle"
}

_prepend() {
    local name=$1 text=$2
    local tmp
    tmp=$(mktemp)
    echo "$text" >"$tmp"
    [ -f "$name" ] && cat "$name" >>"$tmp"
    mv "$tmp" "$name"
}

# Update version strings in files.
_update_files() {
    if [ -n "$1" ]; then
        VERSION=$1
    else
        die "No version string given."
    fi

    echo "$VERSION" >VERSION

    if [[ "$VERSION" != *.*.0* ]]; then
        git show master:Cargo.lock >Cargo.lock
        git show master:Cargo.toml >Cargo.toml
    fi

    local needle='^version = .+$'
    local replace="version = \"$VERSION\""
    sed -i -E "s/$needle/$replace/" Cargo.toml

    cargo check -p "$(cargo pkgid)"
}

# Update version strings after version change.
#
# This function will be executed after hotfix and release start and finish.
version() {
    if [ -n "$1" ]; then
        VERSION=$1
    else
        die "No version string given."
    fi

    _update_files "$VERSION"

    [ -f CHANGES.md ] && \
        head -n1 CHANGES.md | grep -q "since" && \
        sed -i "1,2d" CHANGES.md

    [[ ! "$VERSION" =~ "SNAPSHOT" ]] && \
        _prepend CHANGES.md "# Changes in $VERSION$NL"
}

# Update files to a new development cycle.
cycle() {
    version "$1"
    _prepend CHANGES.md "# Changes since latest release$NL"
}

# Resolve the merge conflict that naturally appears after hotfixes.
resolve() {
    local cur_version new_version
    cur_version=$(git describe --abbrev=0 --tags develop)
    new_version=$(git describe --abbrev=0 --tags master)

    if [ "$cur_version" = "$new_version" ]; then
        echo "No conflict to resolve."
        exit 0
    fi

    _update_files "$new_version"

    {
        git show develop:CHANGES.md |
            sed --quiet '1,/^#.*'"$cur_version"'$/p' | head -n-1
        git show master:CHANGES.md |
            sed --quiet '/^#.*'"$new_version"'$/,/^#.*'"$cur_version"'$/p'
        git show develop:CHANGES.md |
            sed --quiet '/^#.*'"$cur_version"'$/,$p' | tail -n+2
    } >CHANGES.md

    files | xargs -0 git add
    git commit
}

# Return the files that have been modified by this script.
files() {
    printf '%s\0' CHANGES.md VERSION Cargo.toml Cargo.lock
}

# --- Main --- #

cd "$(dirname "$(readlink -e "$0")")" || die "cd failed."

case "$1" in
    version)
        version "$2"
        ;;
    cycle)
        cycle "$2"
        ;;
    resolve)
        resolve
        ;;
    files)
        files
        ;;
    *)
        die "Unknown action."
        ;;
esac