#!/bin/bash

# Fail fast with concise message when not using bash
# Single brackets is needed here for POSIX compatibility
# shellcheck disable=SC2292
if [ -z "${BASH_VERSION:-}" ]
then
  echo "Error: Bash is required to run brew." >&2
  exit 1
fi

set +o posix # as we are using bash now

# Fail fast with concise message when cwd does not exist
if ! [[ -d "${PWD}" ]]
then
  echo "Error: The current working directory doesn't exist, cannot proceed." >&2
  exit 1
fi

quiet_cd() {
  cd "$@" &>/dev/null || return
}

symlink_target_directory() {
  local target target_dirname
  target="$(readlink "$1")"
  target_dirname="$(dirname "${target}")"
  local directory="$2"
  quiet_cd "${directory}" && quiet_cd "${target_dirname}" && pwd -P
}

# Enable and use default Bash builtins rather than user-defined functions
builtin enable compgen unset
for cmd in $(builtin compgen -A builtin)
do
  builtin unset -f "${cmd}"
  builtin enable "${cmd}"
done
unset cmd

BREW_FILE_DIRECTORY="$(quiet_cd "${0%/*}/" && pwd -P)"
HOMEBREW_BREW_FILE="${BREW_FILE_DIRECTORY%/}/${0##*/}"
HOMEBREW_PREFIX="${HOMEBREW_BREW_FILE%/*/*}"

# Default to / prefix if unset or the bin/brew file.
if [[ -z "${HOMEBREW_PREFIX}" || "${HOMEBREW_PREFIX}" = "${HOMEBREW_BREW_FILE}" ]]
then
  HOMEBREW_PREFIX="/"
fi

HOMEBREW_REPOSITORY="${HOMEBREW_PREFIX}"

# Resolve the bin/brew symlink to find Homebrew's repository
if [[ -L "${HOMEBREW_BREW_FILE}" ]]
then
  BREW_FILE_DIRECTORY="$(symlink_target_directory "${HOMEBREW_BREW_FILE}" "${BREW_FILE_DIRECTORY}")"
  HOMEBREW_REPOSITORY="${BREW_FILE_DIRECTORY%/*}"
fi

# Try to find a /usr/local HOMEBREW_PREFIX where possible (for bottles)
if [[ -L "/usr/local/bin/brew" && ! -L "${HOMEBREW_PREFIX}/Cellar" ]]
then
  USR_LOCAL_BREW_FILE_DIRECTORY="$(symlink_target_directory "/usr/local/bin/brew" "/usr/local/bin")"
  USR_LOCAL_HOMEBREW_REPOSITORY="${USR_LOCAL_BREW_FILE_DIRECTORY%/*}"
  if [[ "${HOMEBREW_REPOSITORY}" = "${USR_LOCAL_HOMEBREW_REPOSITORY}" ]]
  then
    HOMEBREW_PREFIX="/usr/local"
  fi
fi

# If the location of HOMEBREW_LIBRARY changes
# keg_relocate.rb, formula_cellar_checks.rb, and test/global_spec.rb need to change.
HOMEBREW_LIBRARY="${HOMEBREW_REPOSITORY}/Library"

# Copy and export all HOMEBREW_* variables previously mentioned in
# manpage or used elsewhere by Homebrew.
for VAR in BROWSER DISPLAY EDITOR NO_COLOR PATH TMUX DBUS_SESSION_BUS_ADDRESS
do
  # Skip if variable value is empty.
  [[ -z "${!VAR}" ]] && continue

  VAR_NEW="HOMEBREW_${VAR}"
  # Skip if existing HOMEBREW_* variable is set.
  [[ -n "${!VAR_NEW}" ]] && continue
  export "${VAR_NEW}"="${!VAR}"
done
unset VAR VAR_NEW

export HOMEBREW_BREW_FILE
export HOMEBREW_PREFIX
export HOMEBREW_REPOSITORY
export HOMEBREW_LIBRARY

# set from user environment
# shellcheck disable=SC2154
# Use VISUAL if HOMEBREW_EDITOR and EDITOR are unset.
if [[ -z "${HOMEBREW_EDITOR}" && -n "${VISUAL}" ]]
then
  export HOMEBREW_EDITOR="${VISUAL}"
fi

# set from user environment
# shellcheck disable=SC2154
# Set CI variable for Azure Pipelines and Jenkins
# (Set by default on GitHub Actions, Circle and Travis CI)
if [[ -z "${CI}" ]] && [[ -n "${TF_BUILD}" || -n "${JENKINS_HOME}" ]]
then
  export CI="1"
fi

# set from user environment
# shellcheck disable=SC2154
if [[ -z "${HOMEBREW_NO_ENV_FILTERING}" ]]
then
  PATH="/usr/bin:/bin:/usr/sbin:/sbin"

  FILTERED_ENV=()
  ENV_VAR_NAMES=(
    HOME SHELL PATH TERM TERMINFO COLUMNS DISPLAY LOGNAME USER CI SSH_AUTH_SOCK SUDO_ASKPASS
    http_proxy https_proxy ftp_proxy no_proxy all_proxy HTTPS_PROXY FTP_PROXY ALL_PROXY
    GITHUB_ACTIONS GITHUB_WORKSPACE GITHUB_ACTIONS_HOMEBREW_MACOS_SELF_HOSTED
    GITHUB_REPOSITORY GITHUB_RUN_ID GITHUB_SHA GITHUB_HEAD_REF GITHUB_BASE_REF GITHUB_REF
  )
  # Filter all but the specific variables.
  for VAR in "${ENV_VAR_NAMES[@]}" "${!HOMEBREW_@}"
  do
    # Skip if variable value is empty.
    [[ -z "${!VAR}" ]] && continue

    FILTERED_ENV+=("${VAR}=${!VAR}")
  done
  unset VAR ENV_VAR_NAMES

  exec /usr/bin/env -i "${FILTERED_ENV[@]}" /bin/bash "${HOMEBREW_LIBRARY}/Homebrew/brew.sh" "$@"
else
  echo "Warning: HOMEBREW_NO_ENV_FILTERING is undocumented, deprecated and will be removed in a future Homebrew release (because it breaks many things)!" >&2

  source "${HOMEBREW_LIBRARY}/Homebrew/brew.sh"
fi
