#!/usr/bin/env nix-shell
#!nix-shell -i bash -p nix-update

usage() {
  echo "update: update rev/hash for one or more packages"
  echo "usage: update [attr-path]"
  echo ""
  echo "examples:"
  echo "update nixpkgs: update only the nixpkgs input"
  echo "update sane: update every package under the 'sane' attribute"
  echo "update: update everything i know how to update"
}

warn() {
  echo "$@"
}
info() {
  echo "$@"
}

# usage: getPkgs outVar prefix
getPkgs() {
  local -n attrsArr="$1"
  local attrPrefix="$2"
  if [ -z "$attrPrefix" ]; then
    attrPrefix=sane
  fi

  local attrs="$(nix-env -f . --query --available --attr-path --no-name -A $attrPrefix)"
  attrsArr=($attrs)
}

updateOnePkg() {
  local attrPath="$1"
  local updateScript="$(nix eval --raw -f . $attrPath.passthru.updateScript --apply 'builtins.concatStringsSep "'" "'"')"
  if [ -z "$updateScript" ]; then
    warn "don't know how to update '$attrPath'"
    return
  fi
  local UPDATE_NIX_NAME="$(nix eval --raw -f . $attrPath.name)"
  local UPDATE_NIX_PNAME="$(nix eval --raw -f . $attrPath.pname)"
  local UPDATE_NIX_OLD_VERSION="$(nix eval --raw -f . $attrPath.version)"
  info "updating: '$attrPath'"
  # we lose spaces inside the exec args... could `nix eval` without `--raw` to fix that.
  UPDATE_NIX_NAME="$UPDATE_NIX_NAME" UPDATE_NIX_PNAME="$UPDATE_NIX_PNAME" UPDATE_NIX_OLD_VERSION="$UPDATE_NIX_OLD_VERSION" UPDATE_NIX_ATTR_PATH="$attrPath" eval $updateScript
}

pkgsToUpdate=()
getPkgs pkgsToUpdate

for p in "${pkgsToUpdate[@]}"; do
  updateOnePkg "$p"
done