#!/bin/bash
# MKit - simple install helper
# See LICENSE file for copyright and license details.

mkit_import ini

git_bool() {
    #
    # Get git bool (ie. exit status counts) $1
    #
    local bool_name=$1      # name of boolean to get
    git_present || warn "can't give bool outside git repo: $bool_name"
    case "$bool_name" in
        dirty_files)
            git diff-files | grep -qm 1 .
            ;;
        dirty_index)
            git diff-index HEAD | grep -qm 1 .
            ;;
        dirty)
            git_bool dirty_files || git_bool dirty_index
            ;;
        *)
            warn "unknown git bool asked: $bool_name"
            return 2
            ;;
    esac
}

git_fact() {
    #
    # Get git fact $1
    #
    local fact_name=$1      # name of fact to get
    git_present || warn "can't give fact outside git repo: $fact_name"
    case "$fact_name" in
        latest_tag)
            git log --format="%d" \
              | sed 's/,/\n/g' \
              | sed 's/^[[:blank:]]*//' \
              | grep -E '^\(?tag' \
              | tr -cd '[[:digit:]].v\n' \
              | grep . -m 1
            ;;
        latest_version)
            git_fact latest_tag | git_tag2ver
            ;;
        current_branch)
            git rev-parse --abbrev-ref HEAD
            ;;
        reldiff)
            git log --oneline "$(git_fact latest_tag)..HEAD" --name-only
            ;;
        latest_sha)
            git log -1 --pretty=format:%h HEAD
            ;;
        latest_cdate)
            git log -1 --format=%ct HEAD
            ;;
        *)
            warn "unknown git fact asked: $fact_name"
            ;;
    esac
}

git_present() {
    #
    # True if we're in a git repo
    #
    git rev-parse HEAD >&/dev/null
}

git_tag2ver() {
    #
    # Convert tag to version
    #
    sed s/^v//
}

git_ver2tag() {
    #
    # Convert version to tag
    #
    sed s/^/v/
}

git_lasthash() {
    #
    # Show last commit hash (with .dirty suffix if needed)
    #
    # We can't do it outside git repo (or without git) but we should
    # not be asked to; targets that don't require git should make use
    # of cache built by dist target.
    #
    local last_hash     # last commit hash
    git_present || {
        echo UNKNOWN_HASH
        warn "no git present; could not determine last hash"
        return 3
    }
    last_hash=$(git rev-parse HEAD)
    echo -n "$last_hash"
    git_bool dirty && echo -n ".dirty"
}

semver() {
    #
    # Build proper SemVer version string
    #
    # Build version string from available info using following
    # logic:
    #
    #  1. Use version from last git tag (or mkit.ini if there is no
    #     tag, which is possible on new project)
    #  2. if set, add project:prerl (from mkit.ini) as pre-release ID
    #     (afer dash)
    #  3. if we are at a later commit than the last tag, add branch
    #     name and commit sha1 to build metadata (after plus sign)
    #  4. if the tree is "dirty", i.e. has uncommited changes,
    #     add "dirty" to build metadata
    #
    # The version is compatible with SemVer 2.0.0.
    #
    # Examples:
    #
    #     foo v1.0.7                            # all clear; proper release
    #     foo v1.0.7-beta                       # mkit.ini: project:prerl="beta"
    #     foo v1.0.7-beta+g1aef811.master       # ^^ + some commits after
    #     foo v1.0.7-beta+gf14fc4f.api2         # ^^ + on a feature branch
    #     foo v1.0.7-beta+gf14fc4f.api2.dirty   # ^^ + tree edited
    #     foo v1.0.7-beta+dirty                 # tag OK but tree edited
    #     foo v1.0.7+dirty                      # ^^ but no pre-release id
    #
    # Note that versions with "dirty" should be perceived as kind of
    # dangerous outside developer's own machine.  Versions with sha1 are
    # safer but must not be released.
    #
    # FIXME:  Using project:prerl for release IDs may not be compatible with
    #         release strategy implemented in release.sh
    #
    local xyz           # base version string
    local prerl         # pre-release keyword (from mkit.ini, eg. 'beta')
    local latest_tag    # latest git tag
    local brname        # current branch name
    local ghash         # current commit short hash
    local is_tagged=T   # T if tagged (clean, no metadata), F if devel
    local is_dirty=F    # F if dirty, T if clean
    local stamp         # timestamp or nothing (see $MKIT_TSTAMP)
    local suffix        # version suffix
    prerl=$(ini 1value project:prerl)
    case $MKIT_TSTAMP in
        none)   stamp= ;;
        btime)  stamp=$(date -u +%Y%m%d%H%M%S) ;;
        ctime)  stamp=$(date -d @"$(git_fact latest_cdate)" -u +%Y%m%d%H%M%S) ;;
    esac
    grep ":" <<<"$prerl" \
     && warn "colon in project:prerl may corrupt version data: $prerl"
    git_present || {
        echo UNKNOWN_VERSION
        warn "no git present; could not determine SemVer"
        return 3
    }
    latest_tag=$(git_fact latest_tag)
    case $latest_tag in
        v*) xyz=${latest_tag:1} ;;
        "") warn "no tags, using base version from mkit.ini (ok for new project)"
            xyz=$(ini 1value project:version) ;;
        *)  warn "bad form of last tag, using base version from mkit.ini: tag is '$latest_tag'"
            xyz=$(ini 1value project:version) ;;
    esac
    if ! git describe --tags --exact-match HEAD >&/dev/null;
    then    # we are at a later commit than the last tag
        is_tagged=F
        brname=$(git_fact current_branch)
        ghash=$(git_fact latest_sha)
    fi
    git_bool dirty && is_dirty=T
    case "$is_dirty:$is_tagged:$stamp" in
        F:T:*)  suffix=""                                 ;;
        T:T:)   suffix="+dirty"                           ;;
        T:T:*)  suffix="+t$stamp.dirty"                   ;;
        F:F:)   suffix="+$brname.g$ghash"                 ;;
        F:F:*)  suffix="+t$stamp.$brname.g$ghash"         ;;
        T:F:)   suffix="+$brname.g$ghash.dirty"           ;;
        T:F:*)  suffix="+t$stamp.$brname.g$ghash.dirty"   ;;
        *)      suffix=MKIT_BUG
                warn "MKIT_BUG: bad dirt/commit detection" ;;
    esac
    test -n "$prerl" && suffix="-$prerl$suffix"
    echo "$xyz$suffix"
}