#!/bin/bash
# Assert that a program can be derived from the ASG as expected.
#
# See `./README.md` for more information.

set -euo pipefail

mypath=$(dirname "$0")
. "$mypath/../../conf.sh"

# Performing this check within `<()` below won't cause a failure.
: "${P_XMLLINT?}" # conf.sh

tamer-flag-or-exit-ok wip-asg-derived-xmli

# Derive a program from `src.xml` and verify that it meets our expectations.
#
# This test is inherently fragile, as it will break any time we perform
# certain types of optimizations or change internal representations.  _But
# that is intended._  We want to be well aware of such changes in derivation
# so that we can judge whether it needs adjustment.
test-derive-from-src() {
  echo '# test-derive-from-src'
  "${TAMER_PATH_TAMEC?}" -o "$mypath/out.xmli" --emit xmlo "$mypath/src.xml" || return

  diff <("$P_XMLLINT" --format "$mypath/expected.xml" || echo 'ERR expected.xml') \
       <("$P_XMLLINT" --format "$mypath/out.xmli" || echo 'ERR out.xmli')
}


# Having taken `A` and derived `B`, we should be able to take `B` and derive
# `C`, where `B` and `C` are equivalent programs.
#
# That is, this derivation should be transitively equivalent and reach a
# fixpoint on the second derivation.  This serves as a sanity check to
# ensure that the program we generated makes sense to our own system.
#
# Note that, in the future, we'll have to strip handoff metadata
# (`preproc:*` data) from the output so that it will be accepted by TAMER.
test-fixpoint() {
  echo '# test-fixpoint'
  "${TAMER_PATH_TAMEC?}" -o "$mypath/out-2.xmli" --emit xmlo "$mypath/out.xmli" || return

  diff <("$P_XMLLINT" --format "$mypath/expected.xml" || echo 'ERR expected.xml') \
       <("$P_XMLLINT" --format "$mypath/out-2.xmli" || echo 'ERR out.xmli')
}


main() {
  local fail=

  test-derive-from-src && test-fixpoint || fail=1

  test -z "$fail" || {
      cat << EOF
!!! TEST FAILED
tamec: $TAMER_PATH_TAMEC

note: The compiler output and diff between the expected and given data
      are above.  Both files are formatted with \`xmllint\` automatically.
EOF

      exit 1
    }
}

main "$@"