#!/usr/bin/env bash

unset GREP_OPTIONS

source "$rvm_scripts_path/base"

usage()
{
  printf "%b" "

  Usage:

    rvm migrate {source-ruby} {destination-ruby} [--force]

  Description:

    Moves all gemsets from {source-ruby} ruby to {destination-ruby}.

" >&2
}

confirm()
{
  if (( ${rvm_force_flag:-0} > 0 ))
  then return 0
  fi

  \typeset confirmation_response

  printf "%b" "$1 (Y/n): "

  read -r confirmation_response

  [[ -z "$confirmation_response" ]] ||
    echo "$confirmation_response" | __rvm_grep -i '^y' >/dev/null 2>&1
}

die_with_error()
{
  rvm_error "$1"

  exit "${2:-1}"
}

expand_ruby_name()
{
  "$rvm_scripts_path/tools" strings "$1" | __rvm_awk -F"${rvm_gemset_separator:-"@"}" '{print $1}'
}

migrate_rubies()
{
  \typeset -a origin_gemsets alias_pairs
  \typeset origin_gemset destination_gemset gemset_name migrate_ruby_name \
    migrate_alias_name migrate_new_alias_name binaries origin_wrappers_path \
    full_bin_path expanded_symlink linked_binary_name new_wrapper_destination

  expanded_source="$(expand_ruby_name "$source_ruby")"
  expanded_destination="$(expand_ruby_name "$destination_ruby")"

  migrate_rubies_checks   &&
  migrate_rubies_gemsets  &&
  migrate_rubies_aliases  &&
  migrate_rubies_summary  ||
  return $?
}

migrate_rubies_checks()
{
  if
    [[ -z "$expanded_source" ]]
  then
    die_with_error "Could not expand source ruby '$source_ruby'"
  elif
    [[ -z "$expanded_destination" ]]
  then
    die_with_error "Could not expand destination ruby '$destination_ruby'"
  elif
    [[ "$expanded_destination" == "$expanded_source" ]]
  then
    die_with_error "Source and Destination Ruby are the same ($expanded_destination)"
  elif
    [[ ! -d "$rvm_rubies_path/$expanded_source" ]]
  then
    die_with_error "Ruby '$expanded_source' is not installed - please install it first."
  elif
    [[ ! -d "$rvm_rubies_path/$expanded_destination" ]]
  then
    die_with_error "Ruby '$expanded_destination' is not installed - please install it first."
  fi

  migrate_rubies_checks_required_space
}

migrate_rubies_checks_required_space()
{
  \typeset __used_space __free_space
  __rvm_calculate_space_free "${rvm_gems_path}"
  __rvm_calculate_space_used "$rvm_gems_path/$expanded_source"{,@*}

  if
    (( __used_space > __free_space ))
  then
    die_with_error "Not enough space (${__free_space}MB) to copy gemsets (${__used_space}MB)."
  elif
    (( __used_space*12 > __free_space*10 )) # 20% check
  then
    rvm_warn "You are running low on disk space ${__free_space}MB, required ${__used_space}MB."
  else
    rvm_log "Free disk space ${__free_space}MB, required ${__used_space}MB."
  fi
}

migrate_rubies_gemset_calculate_destination()
{
  destination_gemset="$expanded_destination"
  case "$origin_gemset" in
    (*${rvm_gemset_separator:-@}*)
      gemset_name="${origin_gemset/*${rvm_gemset_separator:-"@"}/}"
      destination_gemset="${destination_gemset}${rvm_gemset_separator:-"@"}${gemset_name}"
    ;;
    (*)
      gemset_name="default"
    ;;
  esac
}

migrate_rubies_gemsets_run_each_ask()
{
  case "$__action" in
    (copy)
      echo "Moving gems from $* to $expanded_destination?"
      ;;
    (merge)
      confirm "Are you sure you wish to Merge gems from $* to $expanded_destination" || return 1
      ;;
    (overwrite)
      echo "Are you sure you wish to MOVE gems from $* to $expanded_destination?"
      confirm "This will overwrite existing gems in $expanded_destination and remove them from $expanded_source" || return 1
      ;;
    (*)
      rvm_error "Unknown action($__action) for migrate_rubies_gemsets_run_each"
      return 204
  esac
}

migrate_rubies_gemset_clean_destination()
{
  case "$__action" in
    (overwrite)
      __rvm_log_command "remove.gemset.$gemset_name" "Removing $destination_gemset" \
        \command \rm -rfv  "${rvm_gems_path:-"$rvm_path/gems"}/$destination_gemset"/* ||
        return $?
      ;;
  esac
}

__migrate_gemset()
{
  \command \mkdir -p "${rvm_gems_path:-"$rvm_path/gems"}/$destination_gemset"/ &&
  \command \mv -v "${rvm_gems_path:-"$rvm_path/gems"}/$1"/* "${rvm_gems_path:-"$rvm_path/gems"}/$2"/ &&
  gemset_reset_env "$2"
}

__merge_gemset()
(
  \typeset __file
  \typeset -a __files
  __files=()
  cd "${rvm_gems_path:-"$rvm_path/gems"}/$1"/
  __rvm_read_lines __files <(
    __rvm_find . -type d
  )
  for __file in "${__files[@]}"
  do
    mkdir -p "${rvm_gems_path:-"$rvm_path/gems"}/$2/${__file#./}"
  done
  __files=()
  __rvm_read_lines __files <(
    __rvm_find . -type f
  )
  for __file in "${__files[@]}"
  do
    \command \mv -v "${__file}" "${rvm_gems_path:-"$rvm_path/gems"}/$2/${__file#./}"
  done
  rm -rf "${rvm_gems_path:-"$rvm_path/gems"}/$1"/
  cd ..
  gemset_reset_env "$2"
)

migrate_rubies_gemsets_run_migration()
{
  case "$__action" in
    (copy|overwrite)
      __rvm_log_command "migrate.gemset.$gemset_name" "Moving $origin_gemset to $destination_gemset" \
        __migrate_gemset "$origin_gemset" "$destination_gemset" ||
        return $?
      ;;
    (merge)
      __rvm_log_command "merge.gemset.$gemset_name" "Merging $origin_gemset to $destination_gemset" \
        __merge_gemset "$origin_gemset" "$destination_gemset" ||
        return $?
      ;;
  esac
}

migrate_rubies_gemsets_run_each()
{
  \typeset __action=$1
  shift
  migrate_rubies_gemsets_run_each_ask "$@" || return $?

  for origin_gemset in "$@"
  do
    migrate_rubies_gemset_calculate_destination
    migrate_rubies_gemset_clean_destination
    migrate_rubies_gemsets_run_migration
    __rvm_gemset_pristine "$destination_gemset"
  done
}

migrate_rubies_gemset_partition()
{
  if
    [[ ! -d "${rvm_gems_path:-"$rvm_path/gems"}/$destination_gemset" ]]
  then
    __list_new+=( "$origin_gemset" )
  elif
    [[ "$gemset_name" == "global" ]]
  then
    __list_global+=( "$origin_gemset" )
  elif
    [[ "$gemset_name" == "default" ]]
  then
    __list_default+=( "$origin_gemset" )
  else
    __list_existing+=( "$origin_gemset" )
  fi
}

migrate_rubies_gemsets_run()
{
  if [[ -n "${__list_global[*]}" ]]
  then migrate_rubies_gemsets_run_each overwrite "${__list_global[@]}"
  fi
  if [[ -n "${__list_default[*]}" ]]
  then migrate_rubies_gemsets_run_each merge "${__list_default[@]}"
  fi
  if [[ -n "${__list_existing[*]}" ]]
  then migrate_rubies_gemsets_run_each overwrite "${__list_existing[@]}"
  fi
  if [[ -n "${__list_new[*]}" ]]
  then migrate_rubies_gemsets_run_each copy "${__list_new[@]}"
  fi
}

migrate_rubies_gemsets()
{
  \typeset origin_gemsets __list_global __list_default __list_existing __list_new
  __list_global=()
  __list_default=()
  __list_existing=()
  __list_new=()
  __rvm_read_lines origin_gemsets <(
    __rvm_list_gemset_strings | __rvm_grep -E "^$expanded_source(@.*)?$"
  )
  for origin_gemset in "${origin_gemsets[@]}"
  do
    migrate_rubies_gemset_calculate_destination
    migrate_rubies_gemset_partition
  done
  rvm_debug "__list_global=  ${__list_global[*]};"
  rvm_debug "__list_default= ${__list_default[*]};"
  rvm_debug "__list_existing=${__list_existing[*]};"
  rvm_debug "__list_new=     ${__list_new[*]};"
  migrate_rubies_gemsets_run
}

migrate_rubies_alias()
{
  "$rvm_scripts_path/alias" delete "$migrate_alias_name"
  "$rvm_scripts_path/alias" create "$migrate_alias_name" "$migrate_new_alias_name"
}

migrate_rubies_aliases()
{
  __rvm_read_lines alias_pairs < "$rvm_path/config/alias"
  aliases=()
  for alias_pair in "${alias_pairs[@]}"
  do
    migrate_alias_name="${alias_pair/=*/}"
    migrate_ruby_name="${alias_pair/*=/}"
    if
      [[ "$migrate_ruby_name" == "$expanded_source" ||
         "$migrate_ruby_name" == "${expanded_source}${rvm_gemset_separator:-"@"}"*
      ]]
    then
      migrate_new_alias_name="${migrate_ruby_name/$expanded_source/$expanded_destination}"
      aliases+=( "$migrate_alias_name=$migrate_new_alias_name" )
    fi
  done
  if
    (( ${#aliases[@]} )) &&
    confirm 'Do you wish to move over aliases?'
  then
    for alias_pair in "${aliases[@]}"
    do
      migrate_alias_name="${alias_pair%%=*}"
      migrate_new_alias_name="${alias_pair#*=}"
      __rvm_log_command "migrate.alias.$migrate_alias_name" \
        "Updating alias $migrate_alias_name to point to $migrate_new_alias_name" \
        migrate_rubies_alias
    done
  fi
  true
}

migrate_rubies_summary()
{
  if confirm "Do you also wish to completely remove $expanded_source (inc. archive)?"
  then __rvm_log_command "rvm.remove" "Removing $expanded_source" __rvm_run_wrapper manage remove "$expanded_source" --archive --gems
  fi

  echo "Successfully migrated $expanded_source to $expanded_destination"
}

source_ruby="$1"
destination_ruby="$2"

if
  [[ -z "$source_ruby" || -z "$destination_ruby" ]]
then
  usage
  exit 1
fi

migrate_rubies