#!/usr/bin/env bash
# Part of JoeyLib, Copyright (c) 2026 Scott Duensing, under the MIT License.
# See LICENSE.md for license information.
# SPDX-License-Identifier: MIT
#
# verify-amiga-palette.sh - the Amiga's palette and SCB changes through the
# copper: fast, and right on the screen.
#
# The Amiga shows each SCB band's palette from one of two band lists of its
# own, which the screen's user copper list (merged by graphics.library once)
# jumps to: a present that changes palettes or the SCB writes the list not
# shown, and the VBL server switches to it with the planes (src/amiga/hal.c,
# bandListUpdate). Before, a band that moved rebuilt and merged the whole
# copper list (MrgCop, LoadView, then a WaitTOF) -- about three frames on an
# A500 -- and a palette change patched the shown list, a frame before its
# pixels. The stage hashes cannot see any of this: they hash the surface,
# not the copper.
#
# PALPROBE (examples/palprobe; make -f make/amiga.mk build/amiga/test/Palprobe)
# runs under FS-UAE on an A500. It logs how many palette changes, and SCB
# changes (bands moving), it presented a second, back to back: each waits
# for the VBL that shows the last, so both rates must be at least MIN_RATE,
# nearly the frame rate (a rebuild a change gave 16). Then it holds a screen
# of four bands after one palette change and one same-layout SCB change,
# and the screenshot's bands must be, top to bottom, red, green, yellow, red.
#
# Usage:   scripts/verify-amiga-palette.sh
# Env:     TIMEOUT  seconds to wait for the probe (default 120)
# Exit:    0 PASS, 1 FAIL, 2 SKIP (FS-UAE or the Kickstart not installed)
set -uo pipefail

repo=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
source "$repo/scripts/lib/joeyEnv.sh"
joeyNeed FSUAE fsuae
source "$repo/scripts/lib/amigaGate.sh"
amigaMachine
timeout_s=${TIMEOUT:-120}
probe=$repo/build/amiga/test/Palprobe
label=verify-amiga-palette
# Changes presented a second, back to back: one a frame is 50 on the PAL
# A500 (16 when every change rebuilt the copper list).
MIN_RATE=45

make -s -f "$repo/make/amiga.mk" "$probe" || {
    echo "$label: FAIL - building Palprobe failed" >&2
    exit 1
}

work=$(mktemp -d -t joeylib-amiga-palette.XXXXXX)
mkdir -p "$work/s"
cp "$probe" "$work/"
printf 'stack 32768\n:Palprobe\n' > "$work/s/startup-sequence"
display=:$((RANDOM % 400 + 1300))
Xvfb "$display" -screen 0 800x600x24 -nolisten tcp > /dev/null 2>&1 &
xvfb_pid=$!
fs_pid=
cleanup() {
    [[ -n $fs_pid ]] && joeyStop "$fs_pid"
    kill "$xvfb_pid" 2>/dev/null || true
    wait 2>/dev/null || true
    rm -rf "$work"
}
trap cleanup EXIT
sleep 0.5

DISPLAY=$display "$FSUAE" "${AMIGA_MACHINE_ARGS[@]}" --fast_memory=2048 \
    --hard_drive_0="$work" --hard_drive_0_label=JOEYLIB \
    --automatic_input_grab=0 \
    --fullscreen=0 --fade_out_duration=0 > "$work/fsuae.log" 2>&1 &
fs_pid=$!

log=$work/joeylog.txt
for ((waited = 0; waited < timeout_s; waited++)); do
    if grep -q "PALPROBE: ready" "$log" 2>/dev/null; then
        break
    fi
    sleep 1
done
if ! grep -q "PALPROBE: ready" "$log" 2>/dev/null; then
    echo "$label: FAIL - the probe never reached its held screen within ${timeout_s}s" >&2
    exit 1
fi
# Two seconds into the hold: the copper has run the patched list.
sleep 2
DISPLAY=$display import -window root "$work/screen.png"
grep "PALPROBE:" "$log"

"$(joeyTool amigaCheck)" palette "$work/screen.png" "$log" "$MIN_RATE" "$label"