#!/usr/bin/env bash

set -f # remove wildcard

# first param Trait name
# second param function trait name
# third param function operator trait
# fourth is the operator "/" or "+"

trait="


"

gen_tuple() {
  r="("
  for i in $(seq 1 $1); do
    if test $i -eq $1; then
      r="$r $2"
    else
      r="$r $2,"
    fi
  done
  r="$r)"
  echo $r
}

gen_cast_from() {
  echo "("
  for v in $(seq 0 $(($1 - 1))); do
    echo "$3::from($2.$v),"
  done
  echo ")"
}

gen_cast_into() {
  echo "("
  for v in $(seq 0 $(($1 - 1))); do
    echo "$2.$v.into(),"
  done
  echo ")"
}

gen_impl_from() {
  #
  for i in $(seq 2 16); do
    echo "
    impl<T, Too> CastOneToOne<Too> for $(gen_tuple $i T)
      where Too: From<T>
      {
        type Ret = $(gen_tuple $i Too);
        fn cast(self) -> Self::Ret {
          $(gen_cast_from $i self Too)
      }
    }
    "
  done
}

gen_impl_into() {
  #
  for i in $(seq 1 16); do
    echo "
    impl<T, Too> CastOneToOne<Too> for $(gen_tuple $i T)
      where T: Into<Too>
      {
        type Ret = $(gen_tuple $i Too);
        fn cast(self) -> Self::Ret {
          $(gen_cast_into $i self)
      }
    }
    "
  done
}

echo "
pub trait CastOneToOne<Too> {
    type Ret;
    fn cast(self) -> Self::Ret;
}
"

# test
gen_impl_from