#!/bin/sh
# Installs a Homebrew formula as the Mac user who owns Homebrew.
# If Homebrew is missing, the official Homebrew installer is installed first (Apple silicon only).

FORMULA="hello"    # <-- Replace with your target Homebrew formula (e.g. wget, jq, git)

# Pinned official Homebrew installer package
HOMEBREW_PKG_URL="https://github.com/Homebrew/brew/releases/download/7.0.7/Homebrew.pkg"
HOMEBREW_PKG_SHA256="75f699be3059d0068262cab830b5eadce048229aecb469018b5a883b4f3206d7"

WORK_DIR=""
fail() {
    echo "ERROR: $1"
    [ -n "$WORK_DIR" ] && /bin/rm -rf "$WORK_DIR"
    exit 1
}

# 1. Install Homebrew if missing
if [ ! -x /opt/homebrew/bin/brew ] && [ ! -x /usr/local/bin/brew ]; then
    [ "$(/usr/bin/uname -m)" = "arm64" ] || fail "Homebrew is not installed. Automatic install works only on Apple silicon Macs."

    # Identify user who will own Homebrew
    BREW_USER=$(/usr/bin/stat -f %Su /dev/console)
    case "$BREW_USER" in
        ""|root|_*) BREW_USER=$(/usr/bin/defaults read /Library/Preferences/com.apple.loginwindow lastUserName 2>/dev/null) ;;
    esac
    case "$BREW_USER" in
        ""|root|_*) fail "Homebrew is not installed and no active user was found to own it. Will retry later." ;;
    esac
    /usr/bin/id "$BREW_USER" >/dev/null 2>&1 || fail "User $BREW_USER does not exist."

    # Set installer target user
    /bin/rm -f /var/tmp/.homebrew_pkg_user.plist
    /usr/bin/defaults write /var/tmp/.homebrew_pkg_user HOMEBREW_PKG_USER "$BREW_USER"
    /usr/sbin/chown root:wheel /var/tmp/.homebrew_pkg_user.plist
    /bin/chmod 600 /var/tmp/.homebrew_pkg_user.plist

    # Download, verify SHA-256, and install
    echo "Installing Homebrew for user $BREW_USER..."
    WORK_DIR=$(/usr/bin/mktemp -d /tmp/homebrew-install.XXXXXX) || fail "Could not create temporary directory."
    PKG="$WORK_DIR/Homebrew.pkg"
    /usr/bin/curl -fsSL --retry 3 --connect-timeout 30 --max-time 1800 -o "$PKG" "$HOMEBREW_PKG_URL" || fail "Failed to download Homebrew installer."
    [ "$(/usr/bin/shasum -a 256 "$PKG" | /usr/bin/awk '{print $1}')" = "$HOMEBREW_PKG_SHA256" ] || fail "Checksum verification failed for Homebrew installer."
    /usr/sbin/installer -pkg "$PKG" -target / || fail "Homebrew package installation failed."
    /bin/rm -rf "$WORK_DIR"
    WORK_DIR=""
fi

# 2. Locate Homebrew installation path
if [ -x /opt/homebrew/bin/brew ]; then
    PREFIX="/opt/homebrew"
elif [ -x /usr/local/bin/brew ]; then
    PREFIX="/usr/local"
else
    fail "Homebrew is not installed on this Mac."
fi

# 3. Locate the owner of Homebrew
OWNER=$(/usr/bin/stat -L -f %Su "$PREFIX/bin/brew")
case "$OWNER" in
    ""|root) fail "Could not determine the non-root owner of Homebrew." ;;
esac
OWNER_HOME=$(/usr/bin/dscl /Search -read "/Users/$OWNER" NFSHomeDirectory 2>/dev/null | /usr/bin/awk '{print $2}')
[ -n "$OWNER_HOME" ] || fail "Could not find home directory for $OWNER."

# 4. Install formula in clean environment as Homebrew owner
cd /tmp || fail "Could not access /tmp."
exec /usr/bin/sudo -u "$OWNER" /usr/bin/env -i \
    HOME="$OWNER_HOME" USER="$OWNER" LOGNAME="$OWNER" \
    PATH="$PREFIX/bin:/usr/bin:/bin:/usr/sbin:/sbin" \
    HOMEBREW_NO_ANALYTICS=1 HOMEBREW_NO_ENV_HINTS=1 \
    "$PREFIX/bin/brew" install --formula "$FORMULA"

#!/bin/sh
# Install check
#   exit 0 -> Formula missing or older than MIN_VERSION (install/upgrade required)
#   exit 1 -> Formula installed at MIN_VERSION or newer (compliant)
# This script inspects the filesystem directly and does not run brew.

FORMULA="${FORMULA:-hello}"            # <-- Target formula name
MIN_VERSION="${MIN_VERSION:-2.12.3}"   # <-- Increment this value to trigger fleet-wide upgrades

# Semantic version comparison: returns 0 if $1 < $2
version_lt() {
    /usr/bin/awk -v a="$1" -v b="$2" 'BEGIN {
        na = split(a, x, /[._+-]/); nb = split(b, y, /[._+-]/)
        n = (na > nb) ? na : nb
        for (i = 1; i <= n; i++) {
            if (x[i] == y[i]) continue
            if (x[i] ~ /^[0-9]+$/ && y[i] ~ /^[0-9]+$/) exit !(x[i] + 0 < y[i] + 0)
            exit !(x[i] < y[i])
        }
        exit 1
    }'
}

for PREFIX in /opt/homebrew /usr/local; do
    if [ -x "$PREFIX/bin/brew" ]; then
        LINK=$(/usr/bin/readlink "$PREFIX/opt/$FORMULA") || exit 0    # Formula not installed
        INSTALLED=$(/usr/bin/basename "$LINK")                        # Resolves version from Cellar path
        if version_lt "$INSTALLED" "$MIN_VERSION"; then
            exit 0    # Installed version is older than MIN_VERSION
        fi
        exit 1        # Already installed at or above MIN_VERSION
    fi
done

exit 0    # Homebrew not found; proceed to preinstall to bootstrap or report error

#!/bin/sh
# Uninstalls a Homebrew formula as the Mac user who owns Homebrew.

FORMULA="hello"    # <-- Replace with formula to remove

fail() {
    echo "ERROR: $1"
    exit 1
}

# 1. Locate Homebrew installation path
if [ -x /opt/homebrew/bin/brew ]; then
    PREFIX="/opt/homebrew"
elif [ -x /usr/local/bin/brew ]; then
    PREFIX="/usr/local"
else
    fail "Homebrew is not installed on this Mac."
fi

# 2. Locate Homebrew owner
OWNER=$(/usr/bin/stat -L -f %Su "$PREFIX/bin/brew")
case "$OWNER" in
    ""|root) fail "Could not find Homebrew owner." ;;
esac
OWNER_HOME=$(/usr/bin/dscl /Search -read "/Users/$OWNER" NFSHomeDirectory 2>/dev/null | /usr/bin/awk '{print $2}')
[ -n "$OWNER_HOME" ] || fail "Could not find home directory for $OWNER."

# 3. Remove formula in clean environment as Homebrew owner
cd /tmp || fail "Could not access /tmp."
exec /usr/bin/sudo -u "$OWNER" /usr/bin/env -i \
    HOME="$OWNER_HOME" USER="$OWNER" LOGNAME="$OWNER" \
    PATH="$PREFIX/bin:/usr/bin:/bin:/usr/sbin:/sbin" \
    HOMEBREW_NO_ANALYTICS=1 HOMEBREW_NO_ENV_HINTS=1 \
    "$PREFIX/bin/brew" uninstall --formula "$FORMULA"