#!/bin/bash -e

# Based on article http://davidwalsh.name/git-remove-submodule

MODULE_PATH="${1:?You must speicify the module path}"

determinePaths(){
  [ -d "${MODULE_PATH}" ] || die "Module directory does not exist: ${MODULE_PATH}"
  MODULE_PATH="$( cd "${MODULE_PATH}"; pwd )"
  GIT_ROOT="$( cd "$( dirname "${MODULE_PATH}" )"; git rev-parse --show-toplevel )"
  MODULE_PATH="${MODULE_PATH#"${GIT_ROOT}/"}"
}

changeDirToGitRoot(){
  cd "${GIT_ROOT}"
}

editGitModulesFile(){
  local search="$( escapeForSearch "submodule \"${MODULE_PATH}\"" )"
  local file=".gitmodules"
  sed -i '/\['"${search}"'\]/,/^\[/ {
    /\['"${search}"'\]/ d
    /^\s/ d
    /^\[/ n     
  }' "${file}"
  git add "${file}"
}

editGitConfig(){
  local search="$( escapeForSearch "submodule \"${MODULE_PATH}\"" )"
  sed -i '/\['"${search}"'\]/,/^\[/ {
    /\['"${search}"'\]/ d
    /^\s/ d
    /^\[/ n     
  }' ".git/config"
}

removeFromGit(){
  git rm --cached "${MODULE_PATH}"
  rm -rf ".git/modules/${MODULE_PATH}"
  rm -rf "${MODULE_PATH}"
}

die(){
  local msg="$1"
  echo "${msg}" >&2
  exit 1
}

escapeForSearch(){
  local str="$1"
  echo "${str}" | sed -e 's/[\/&]/\\&/g'
}

determinePaths
changeDirToGitRoot
editGitModulesFile
editGitConfig
removeFromGit