#!/bin/sh
set -u

SRC_DIR="$1"
OUT_FILE="$2"

git_ver="unknown"
git_branch="unknown"

if command -v git >/dev/null 2>&1 && [ -d "$SRC_DIR/.git" ]; then
    ver=$(git -C "$SRC_DIR" describe --always --dirty --tags 2>/dev/null | tr -d '\n\r')
    if [ $? -eq 0 ] && [ -n "$ver" ]; then
        git_ver="$ver"
    fi

    branch=$(git -C "$SRC_DIR" symbolic-ref --short -q HEAD 2>/dev/null | tr -d '\n\r')
    if [ -z "$branch" ]; then
        branch="detached"
    fi
    git_branch="$branch"
fi

build_time=$(date '+%Y-%m-%d %H:%M:%S' 2>/dev/null)

mkdir -p "$(dirname "$OUT_FILE")"
TMP="$OUT_FILE.tmp.$$"

cat > "$TMP" <<EOF
#pragma once
static constexpr const char* const SM26_GIT_VERSION = "$git_ver";
static constexpr const char* const SM26_GIT_BRANCH  = "$git_branch";
static constexpr const char* const SM26_BUILD_TIME  = "$build_time";
EOF

if [ ! -f "$OUT_FILE" ] || ! cmp -s "$TMP" "$OUT_FILE"; then
    mv "$TMP" "$OUT_FILE"
else
    rm -f "$TMP"
fi

echo "buildinfo: v$git_ver ($git_branch) @ $build_time"