#!/usr/bin/env bash
# Diff Godot's drawing of an exported screen against `sylpheed-cli screen
# render` of the same build -- the P1 gate.
#
#   tools/verify-screen                 # every screen in the manifest
#   tools/verify-screen main_menu title # named screens
#
# Writes <screen>.godot.png, <screen>.ref.png and <screen>.diff.png into
# $OUT (default: a directory under /tmp) and prints, per screen, the largest
# per-channel difference anywhere in the frame.
#
# The two renderers are held to the same inputs on purpose:
#
#  * the REFERENCE CLI is the one built by `build-reference-cli`, from the same
#    `sylpheed-formats` revision the exporter is pinned to. /reborn's own
#    target/ is a live mount of the other agent's checkout and moves mid-run; a
#    pixel disagreement against a moving decoder proves nothing.
#  * `--black` because Godot clears to black and the screen carries its own
#    background. The CLI's default dim slate stands in for a 3D scene behind an
#    in-mission screen, which is not this screen.
#  * `--primitives --animated` because those are what make the CLI draw the same
#    element set. `--focus` is NOT passed: nothing is focused at rest (HANDOFF
#    Q5 measured initial focus as unstable boot to boot, so choosing one is
#    P5's decision).
#  * `--pose=rest` on the Godot side. Since P2 the port's DEFAULT is to play the
#    timeline, and the settled timeline is deliberately NOT what `rest` says --
#    the export's `rest` misses `ptframe1`/`ptframe2` on the main menu, and the
#    running game shows them (docs/DECISIONS.md). Both renderers read `rest`
#    through the same decoder, so asking for it here keeps this a test of the
#    PORT against the reference. It is not the test of whether `rest` is right;
#    that one is the oracle capture, and the port already departs from it.
#
# A difference here is not automatically the port's fault. Say which renderer is
# wrong and why -- do not tune until they match.
set -euo pipefail
cd "${PROJECT_DIR:-/work}"

# `reference-cli/`, not `release/`: the reference binary is built per pinned
# revision so a pin change cannot silently reuse the previous revision's build.
# See docker/bin/build-reference-cli.
CLI="${SYLPHEED_CLI:-${CARGO_TARGET_DIR:-/sylph-home/port/target-container}/reference-cli/sylpheed-cli}"
DISC="${SYLPHEED_DISC:-/disc}"
OUT="${OUT:-${TMPDIR:-/tmp}/verify-screen}"
export DISPLAY="${DISPLAY:-:97}"

[ -x "$CLI" ] || { echo "no reference CLI at $CLI -- run build-reference-cli" >&2; exit 2; }
[ -f export/manifest.json ] || { echo "no export/manifest.json -- run build-export --run" >&2; exit 2; }
mkdir -p "$OUT"

# Godot needs one scan to register the `class_name` globals; without it every
# script fails to parse and the run dies with no frame drawn.
[ -d port/.godot ] || godot --headless --path port --import >/dev/null 2>&1

screens=("$@")
if [ ${#screens[@]} -eq 0 ]; then
  mapfile -t screens < <(python3 -c '
import json; print("\n".join(s["name"] for s in json.load(open("export/manifest.json"))["screens"]))')
fi

status=0
for name in "${screens[@]}"; do
  build=$(python3 -c '
import json,sys
m=json.load(open("export/manifest.json"))
f=next(s["file"] for s in m["screens"] if s["name"]==sys.argv[1])
print(json.load(open("export/"+f))["source"]["build"])' "$name")

  "$CLI" screen render "$DISC/dat/GP_TITLE.pak" "$OUT/$name.ref.png" \
    --build "$build" --black --primitives --animated >/dev/null

  godot --path port --resolution 1280x720 -- \
    "--screen=$name" --pose=rest "--capture=$OUT/$name.godot.png" >"$OUT/$name.log" 2>&1

  convert "$OUT/$name.godot.png" "$OUT/$name.ref.png" \
    -compose difference -composite -colorspace Gray -auto-level "$OUT/$name.diff.png"
  read -r max mean <<<"$(convert "$OUT/$name.godot.png" "$OUT/$name.ref.png" \
    -compose difference -composite -format "%[fx:maxima*255] %[fx:mean*255]" info:)"

  # 3/255 is what integer-truncating compositing in the CLI and float rounding
  # in a GPU differ by. Anything above that is a placement, order or colour
  # disagreement and needs a reason, not a threshold.
  verdict=OK
  awk "BEGIN{exit !($max > 3)}" && { verdict=DIFFERS; status=1; }
  printf '%-16s build %-3s max %-5s mean %-8s %s\n' "$name" "$build" "$max" "${mean:0:6}" "$verdict"
done
echo "artifacts in $OUT"
exit $status