#!/bin/bash
#
# develop_brew_cask
#

###
### settings
###

set -e               # exit on any uncaught error
set +o histexpand    # don't expand history expressions
shopt -s nocasematch # case-insensitive regular expressions

###
### configurable global variables
###

tap_subdir="Library/Taps/caskroom/homebrew-cask"

###
### functions
###

warn () {
    local message="$@"
    message="${message//\\t/$'\011'}"
    message="${message//\\n/$'\012'}"
    message="${message%"${message##*[![:space:]]}"}"
    printf "%s\n" "$message" 1>&2
}

die () {
    warn "$@"
    exit 1
}

cd_to_project_root () {
    local script_dir="$(/usr/bin/dirname "$0")"
    cd "$script_dir"
    local git_root="$(git rev-parse --show-toplevel)"
    if [[ -z "$git_root" ]]; then
        die "ERROR: Could not find git project root"
    fi
    cd "$git_root"
}

cd_to_version_dir () {
    local cellar_dir="$1"
    local version_dir="$2"
    if [[ -z "$version_dir" ]]; then
        die "ERROR: Could not find version dir under $cellar_dir/"
    fi
    cd "$cellar_dir/$version_dir"
}

not_inside_homebrew () {
    local tap_dir="$1"
    local git_root="$2"
    if [[ "$(/usr/bin/stat -L -f '%i' -- "$tap_dir")" -eq "$(/usr/bin/stat -L -f '%i' -- "$git_root")" ]]; then
        die "\nERROR: Run this script in your private repo, not inside Homebrew.\n"
    fi
}

create_dev_links () {
    local tap_dir="$1"
    local git_root="$2"
    /bin/mv -- rubylib production_rubylib
    /bin/mv -- Casks   production_Casks
    /bin/ln -s -- "$git_root/Casks" .
    /bin/ln -s -- "$git_root/lib"   rubylib
    cd "$tap_dir"
    /bin/mv -- lib   production_lib
    /bin/mv -- Casks production_Casks
    /bin/ln -s -- "$git_root/Casks" .
    /bin/ln -s -- "$git_root/lib"   .
    printf "brew-cask is now in development mode\n"
    printf "Note: it is not safe to run 'brew update' while in development mode\n"
}

###
### main
###

_develop_brew_cask () {

    # initialization
    cd_to_project_root
    local git_root="$(/bin/pwd)"
    local brew_prefix="$(brew --prefix)"
    local cellar_dir="$brew_prefix/Cellar/brew-cask"
    local version_dir="$(/bin/ls -- "$cellar_dir/" | /usr/bin/sort | /usr/bin/tail -1)"
    local tap_dir="$brew_prefix/$tap_subdir"

    # sanity check
    not_inside_homebrew "$tap_dir" "$git_root"

    # action
    cd_to_version_dir "$cellar_dir" "$version_dir"
    if [[ -e "production_rubylib" ]]; then
        die "brew-cask is already set up for development"
    else
        create_dev_links "$tap_dir" "$git_root"
    fi

}

# process args
if [[ $1 =~ ^-+h(elp)?$ ]]; then
    printf "develop_brew_cask

Symlink private repo directories into Homebrew's Cellar, so
that the 'brew cask' command will use code and Casks from
the current development branch in your private repo.

Saves the production Homebrew directories under new names.

You can reverse this operation with 'production_brew_cask'.

Note: it is not safe to run 'brew update' while development
mode is in effect.

"
    exit
fi

# dispatch main
_develop_brew_cask "${@}"

#