#!/usr/bin/env bash
# verify-x68000-audio.sh - X68000 audio gate, read off the chips.
#
# Boots a built example on a Human68k floppy pair under headless MAME and
# watches the two sound devices through memory taps, so the checks are on
# what the hardware was actually told, not on a log line:
#
#   1. PPI port C ($E9A005) low nibble. That nibble IS the MSM6258's
#      sample rate (bits 3,2) and channel gating (bits 1,0): the gate
#      wants rate index 2, divider 512, 7812 Hz -- the rate the mixer
#      renders at -- and pan 0, both channels. IOCS's own mode byte does
#      not set these correctly (measured: mode 0x05 leaves 0x01, which is
#      3906 Hz out of the right speaker only), so audioPcm.c writes the
#      register itself and this checks that it stuck.
#   2. Every YM2151 noise write ($E90000 register 0x0F). The low five
#      bits must be a value from kOpmNoiseFreq in src/x68000/audio.c,
#      which is read out of the source here rather than duplicated: a
#      pitch that escapes the table is the bug this gate exists for
#      (a plain `31 - pitch` ran the generator an octave bright).
#   3. The ADPCM byte feed rate WHILE A SOUND IS PLAYING. Two samples per
#      byte at 7812 Hz is 3906 bytes/s; half that means the divider is
#      wrong again and every sample the port plays is an octave low. It
#      is the rate inside one burst of feeding that counts, not the
#      average: the port stops the chip between sounds, so an average
#      over a mostly silent run would say nothing.
#
# Space Taxi is the default because its attract demo exercises the whole
# noise curve (all seventeen distinct table values) and speaks.
#
# Usage:   scripts/verify-x68000-audio.sh [example] [seconds]
# Env:     X68K_DIR   dir holding HUMAN302.XDF + roms/ (default toolchains/x68mame)
# Requires: the example built (make -f make/x68000.mk), MAME with x68000.
set -uo pipefail

prog=${1:-staxi}
seconds=${2:-160}
PROG=$(echo "$prog" | tr '[:lower:]' '[:upper:]')

repo=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
bin=$repo/build/x68000/bin/$PROG.X
x68=${X68K_DIR:-$repo/toolchains/x68mame}
template=$x68/HUMAN302.XDF
source=$repo/src/x68000/audio.c

MAME="${MAME:-$repo/toolchains/cache/mame-mame0264/x68k}"
if [[ ! -x $MAME ]]; then
    MAME="$(command -v mame || true)"
fi
[[ -n ${MAME:-} && -x $MAME ]] || { echo "verify-x68000-audio: no MAME (set MAME=...)" >&2; exit 2; }
[[ -f $bin ]]      || { echo "verify-x68000-audio: $bin not built" >&2; exit 2; }
[[ -f $template ]] || { echo "verify-x68000-audio: missing $template" >&2; exit 2; }

# The noise table, straight out of the port so the two cannot drift apart.
table=$(python3 - "$source" <<'PY'
import re, sys
src = open(sys.argv[1]).read()
m = re.search(r'kOpmNoiseFreq\[32\]\s*=\s*\{(.*?)\}', src, re.S)
if not m:
    sys.exit("kOpmNoiseFreq not found")
print(",".join(v.strip() for v in m.group(1).split(",") if v.strip()))
PY
) || { echo "verify-x68000-audio: cannot read kOpmNoiseFreq from $source" >&2; exit 2; }

work=$(mktemp -d -t joey-x68audio.XXXXXX)
trap 'rm -rf "$work"' EXIT

printf 'B:\r\nB:\\%s.X\r\n\x1a' "$PROG" > "$work/AUTOEXEC.BAT"
cp "$template" "$work/boot.xdf"
cp "$template" "$work/data.xdf"
python3 "$repo/tools/xdftool.py" empty "$work/data.xdf" >/dev/null
for f in USKCG.SYS BEEP.SYS KEY.SYS STARTUP.ENV; do
    python3 "$repo/tools/xdftool.py" delete "$work/boot.xdf" "$f" >/dev/null 2>&1 || true
done
for d in SYS HIS BIN BASIC2 ASK ETC; do
    python3 "$repo/tools/xdftool.py" deltree "$work/boot.xdf" "$d" >/dev/null 2>&1 || true
done
python3 "$repo/tools/xdftool.py" add "$work/boot.xdf" "$work/AUTOEXEC.BAT" AUTOEXEC.BAT >/dev/null
python3 "$repo/tools/xdftool.py" add "$work/data.xdf" "$bin" "$PROG.X" >/dev/null
data_dir=$repo/build/x68000/bin/DATA
if [[ -d $data_dir ]]; then
    while IFS= read -r f; do
        rel=${f#"$data_dir"/}
        python3 "$repo/tools/xdftool.py" add "$work/data.xdf" "$f" \
            "DATA/$(echo "$rel" | tr '[:lower:]' '[:upper:]')" >/dev/null
    done < <(find "$data_dir" -type f | sort)
fi

# The taps keep to arithmetic and file writes: a tap that reads memory
# takes MAME down with it.
cat > "$work/tap.lua" <<LUA
local cpu = manager.machine.devices[":maincpu"]
local mem = cpu.spaces["program"]
local out = io.open("audio.txt", "w")
local sel = -1
local pcmWrites = 0
local burstCount = 0
local burstStart = 0
local burstLast = -1
local bestRate = 0
local stop = $seconds
-- A local tap object is garbage collected and stops firing. Keep globals.
opmTap = mem:install_write_tap(0xE90000, 0xE90003, "opm", function(offset, data, mask)
    local v = data & 0xFF
    if (mask & 0xFF) == 0 then v = (data >> 8) & 0xFF end
    if offset < 0xE90002 then
        sel = v
    elseif sel == 0x0F then
        out:write(string.format("NOISE %02X\\n", v))
    end
    return data
end)
ppiTap = mem:install_write_tap(0xE9A004, 0xE9A005, "ppi", function(offset, data, mask)
    local v = data & 0xFF
    if (mask & 0xFF) == 0 then v = (data >> 8) & 0xFF end
    out:write(string.format("PORTC %02X\\n", v))
    return data
end)
-- The port stops the chip between sounds, so the honest figure is the rate
-- inside one burst of feeding, not an average across the silence. A gap of
-- more than 100 ms ends a burst; bursts shorter than 300 ms are too short to
-- time accurately and are skipped.
local function closeBurst()
    if burstLast > burstStart + 0.3 and burstCount > 0 then
        local r = burstCount / (burstLast - burstStart)
        if r > bestRate then bestRate = r end
    end
    burstCount = 0
end
pcmTap = mem:install_write_tap(0xE92000, 0xE92003, "pcm", function(offset, data, mask)
    local t = manager.machine.time:as_double()
    pcmWrites = pcmWrites + 1
    if burstLast < 0 or (t - burstLast) > 0.1 then
        closeBurst()
        burstStart = t
    end
    burstLast = t
    burstCount = burstCount + 1
    return data
end)
emu.register_frame_done(function()
    local t = manager.machine.time:as_double()
    if t >= stop then
        closeBurst()
        out:write(string.format("PCMTOTAL %d\\n", pcmWrites))
        out:write(string.format("PCMRATE %.0f\\n", bestRate))
        out:write("DONE\\n")
        out:close()
        manager.machine:exit()
    end
end)
LUA

( cd "$work" && SDL_AUDIODRIVER=dummy timeout 1800 "$MAME" x68000 \
    -bios ipl10 -rompath "$x68/roms" \
    -flop1 boot.xdf -flop2 data.xdf \
    -video none -sound none -nothrottle -skip_gameinfo \
    -autoboot_script tap.lua </dev/null >mame.log 2>&1 ) || true

[[ -f $work/audio.txt ]] || { echo "verify-x68000-audio: FAIL (MAME produced no tap output)" >&2; exit 1; }

python3 - "$work/audio.txt" "$table" "$PROG" <<'PY'
import sys
path, table, prog = sys.argv[1], sys.argv[2], sys.argv[3]
allowed = {int(v) for v in table.split(",")}
noise, portc, rate, done = [], [], None, False
for line in open(path):
    p = line.split()
    if not p:
        continue
    if p[0] == "NOISE":
        noise.append(int(p[1], 16))
    elif p[0] == "PORTC":
        portc.append(int(p[1], 16))
    elif p[0] == "PCMRATE":
        rate = float(p[1])
    elif p[0] == "DONE":
        done = True

fails = []
if not done:
    fails.append("the run never reached its time limit")

# 1. The ADPCM rate/pan nibble. The last value written wins; the ROM's own
#    boot value (0x0B) does not count as ours.
ours = [v for v in portc if v != 0x0B]
if not ours:
    fails.append("PPI port C was never programmed, so the ADPCM never played")
else:
    got = ours[-1] & 0x0F
    if got != 0x08:
        fails.append(f"port C low nibble {got:#04x}, want 0x08 "
                     f"(rate index {(got >> 2) & 3} pan {got & 3}; want rate 2 = 7812 Hz, pan 0 = both)")

# 2. Every enabled noise write must name a table entry.
on = {v & 0x1F for v in noise if v & 0x80}
if not on:
    fails.append("no noise writes seen at all")
stray = sorted(on - allowed)
if stray:
    fails.append(f"noise codes outside kOpmNoiseFreq: {stray}")

# 3. Byte feed rate: two samples per byte at 7812 Hz.
if rate is None:
    fails.append("the ADPCM channel was never fed")
elif not (3500.0 <= rate <= 4300.0):
    fails.append(f"ADPCM in-burst feed {rate:.0f} bytes/s, want ~3906 "
                 f"({'half rate, the divider is wrong' if rate < 2600 else 'off rate'})")

portcText = "/".join(f"{v:02X}" for v in ours[-2:]) if ours else "never set"
rateText = f"{rate:.0f} bytes/s in-burst" if rate is not None else "silent"
print(f"verify-x68000-audio: {prog} noise writes {len(noise)} "
      f"({len(on)} distinct codes, {len(allowed - on)} table entries unused), "
      f"port C {portcText}, ADPCM {rateText}")
if fails:
    for f in fails:
        print(f"verify-x68000-audio: FAIL ({f})", file=sys.stderr)
    sys.exit(1)
print("verify-x68000-audio: PASS")
PY