#!/usr/bin/env bash
# verify-dos-input.sh - Headless typed-character acceptance gate for the
# DOS port. Runs KEYS.EXE in DOSBox Staging under Xvfb, types the
# RetroNet definition-of-done string with xdotool (real X key events,
# shift and all, so ':' exercises the INT 9 shift path), takes a RAW
# native-resolution screenshot, and decodes the example's verification
# scanline (row 198) from the exact VGA DAC colors. KEYS gives all 16
# palette entries distinct colors precisely so this decode is exact.
#
# Usage:   scripts/verify-dos-input.sh
# Requires: dosbox (staging), Xvfb, xdotool, python3 + PIL;
#           build/dos/bin/KEYS.EXE (make dos).
set -euo pipefail

repo=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
bin_dir=$repo/build/dos/bin
conf=$repo/scripts/dosbox-386sx16.conf

target="192.168.1.10:6510"

[ -f "$bin_dir/KEYS.EXE" ] || { echo "verify-dos-input: build KEYS.EXE first (make dos)" >&2; exit 2; }

work=$(mktemp -d -t joeylib-dos-input.XXXXXX)
display_num=$((RANDOM % 500 + 300))
cleanup() {
    [ -n "${dosbox_pid:-}" ] && kill "$dosbox_pid" 2>/dev/null
    [ -n "${xvfb_pid:-}" ]   && kill "$xvfb_pid" 2>/dev/null
    rm -rf "$work"
}
trap cleanup EXIT

Xvfb ":$display_num" -screen 0 1024x768x24 >/dev/null 2>&1 &
xvfb_pid=$!
sleep 1

DISPLAY=":$display_num" dosbox \
    -conf "$conf" \
    -set "capture capture_dir=$work" \
    -set "capture default_image_capture_formats=raw" \
    -c "C:" -c "KEYS.EXE" \
    "$bin_dir" >/dev/null 2>&1 &
dosbox_pid=$!

# Let DOS boot and KEYS reach its poll loop on the simulated 386SX-16.
sleep 12

# Staging titles its window "<PROG> - <n> cycles/ms"; it is the only
# client on this private display, so match any named window.
win=$(DISPLAY=":$display_num" xdotool search --name -- "." | head -1)
if [ -z "$win" ]; then
    echo "verify-dos-input: FAIL - DOSBox window not found" >&2
    exit 1
fi
DISPLAY=":$display_num" xdotool windowactivate --sync "$win" 2>/dev/null || true
DISPLAY=":$display_num" xdotool type --window "$win" --delay 150 -- "$target"
sleep 2
# Ctrl+F5 = DOSBox screenshot hotkey.
DISPLAY=":$display_num" xdotool key --window "$win" ctrl+F5
sleep 2

png=$(ls "$work"/*.png 2>/dev/null | head -1)
if [ -z "$png" ]; then
    echo "verify-dos-input: FAIL - no screenshot captured" >&2
    exit 1
fi

python3 - "$png" "$target" <<'PY'
import sys
from PIL import Image

png, target = sys.argv[1], sys.argv[2]
img = Image.open(png).convert("RGB")
w, h = img.size
# Raw capture is native 320x200; tolerate an integer upscale.
sx, sy = w // 320, h // 200
if sx < 1 or sy < 1 or w % 320 or h % 200:
    print(f"verify-dos-input: FAIL - unexpected screenshot size {w}x{h}")
    sys.exit(1)

def dac8(c4):
    v6 = ((c4 << 2) | (c4 >> 2)) & 0x3F
    return (v6 << 2) | (v6 >> 4)

# KEYS palette 0 (see buildPalette): gray ramp with the four demo
# colors and red at 15. 12-bit 0x0RGB -> exact 8-bit via the port's
# 6-bit DAC expansion.
pal12 = [(i << 8) | (i << 4) | i for i in range(16)]
pal12[0], pal12[1], pal12[2], pal12[3] = 0x000, 0x333, 0x0F0, 0xFFF
pal12[15] = 0xF00
# Nearest-color match: emulators differ in how they scale the 6-bit
# DAC to 8-bit (bit-replication vs rounding), but the palette entries
# sit ~17 units apart per channel, so nearest is unambiguous.
palRgb = [(dac8((v >> 8) & 0xF), dac8((v >> 4) & 0xF), dac8(v & 0xF)) for v in pal12]

def pix(px):
    r, g, b = img.getpixel((px * sx, 198 * sy))
    best, bestDist = 0, 1 << 30
    for n, (pr, pg, pb) in enumerate(palRgb):
        d = (r - pr) ** 2 + (g - pg) ** 2 + (b - pb) ** 2
        if d < bestDist:
            best, bestDist = n, d
    if bestDist > 3 * 8 ** 2:
        print(f"verify-dos-input: FAIL - pixel {px} color {(r, g, b)} too far from any palette entry")
        sys.exit(1)
    return best

row = bytes((pix(2 * i) << 4) | pix(2 * i + 1) for i in range(40))
expect = bytes([0xA5, 0xA5, len(target), 0x00]) + target.encode("ascii")
got = row[: len(expect)]
print("VERIFY-DOS-INPUT row=" + row.hex().upper())
if got == expect:
    print(f'verify-dos-input: PASS (typed "{target}", all {len(target)} chars arrived via jlInputGetChar)')
else:
    print(f"verify-dos-input: FAIL\n  expected: {expect.hex().upper()}\n  got:      {got.hex().upper()}")
    sys.exit(1)
PY