#!/bin/sh
set -eu
compiler=${OCAMLC:-ocamlc}
rewriter=$(cd "$(dirname "$1")" && pwd)/$(basename "$1")
library=$(cd "$2" && pwd)
directory=$(mktemp -d)
trap 'rm -rf "$directory"' EXIT HUP INT TERM

cat > "$directory/unit.mli" <<'ML'
type t = { colour : string; label : string }
val colour : t -> string
val set_colour : string -> t -> t
val _colour : (t -> string) * (string -> t -> t)
ML

cat > "$directory/unit.ml" <<'ML'
type t = { colour : string; label : string } [@@fieldglass generate]
ML

cat > "$directory/client.ml" <<'ML'
let () =
  let original = Unit.{ colour = "grey"; label = "sample" } in
  let changed = Fieldglass.over Unit._colour ~f:String.uppercase_ascii original in
  assert (Unit.colour changed = "GREY");
  assert (changed.Unit.label = original.Unit.label);
  assert (Unit.colour original = "grey")
ML

"$compiler" -c "$directory/unit.mli"
"$compiler" -I "$directory" -ppx "$rewriter" -c "$directory/unit.ml"
"$compiler" -I "$library" -I "$directory" "$library/fieldglass.cma" \
  "$directory/unit.cmo" "$directory/client.ml" -o "$directory/client.byte"
"$directory/client.byte"