#!/bin/sh
# Run an iris example on a machine with no display.
#
#   ./scripts/run-headless.sh tabs
#   ./scripts/run-headless.sh tabs --shot /tmp/tabs.png --seconds 4
#   ./scripts/run-headless.sh tabs --replay taps.touch --shot /tmp/tabs.png
#   ./scripts/run-headless.sh app --dir ../elsewhere --mode 1080x2424@120Hz
#
# `--dir DIR` names the workspace to build in, defaulting to this one, so a
# project that depends on iris can be run through the same rig. `--bin` runs a
# crate binary rather than an example, and takes its own argv from
# `$RUN_HEADLESS_ARGS`, word-split on purpose.
#
# `--mode` sets the output, for running something at a size other than a
# desktop's -- a phone's, say. Set every run rather than only when it changes:
# the compositor is reused between runs, so a default-shaped run after a
# custom one would otherwise inherit the other's output and quietly screenshot
# the wrong size.
#
# `--resize WxH@Hz` changes the output under the app once it is up, then
# screenshots. A resize is its own case: what it has to match is a cold start
# at that size, byte for byte, and nothing in `cargo test` can see it.
#
# `--replay FILE` drives a `.touch` recording into the window through
# `replay-touch`, which reads it with the same parser `iris::harness` uses. A
# recording is `<ms> down|move|up <x> <y>` in the output's own pixels. With
# `--shot` it also writes `<shot>-before.png` from just before the gesture,
# since "it moved" is a claim about two pictures.
#
# What it supplies is a compositor for winit to open a surface on: a headless
# sway, and `grim` to screenshot it. Sway gets its own socket and runtime
# directory rather than joining whatever else is running, because it tiles --
# adding a window to someone else's compositor resizes theirs.
set -eu

need() {
    command -v "$1" >/dev/null 2>&1 || {
        echo "run-headless: $1 is not installed ($2)" >&2
        exit 127
    }
}
need sway "the compositor an example opens its window on"
need swaymsg "sway's control socket"

scripts=$(cd "$(dirname "$0")" && pwd)
root=$(cd "$scripts/.." && pwd)
workdir="$root"
cd "$root"
run="${XDG_RUNTIME_DIR:-/tmp}/iris-headless"
seconds=3
shot=""
replay=""
resize=""
example=""
kind=example
mode=1920x1200@60Hz


while [ $# -gt 0 ]; do
    case "$1" in
        --shot) shot=$2; shift 2 ;;
        --seconds) seconds=$2; shift 2 ;;
        --bin) kind=bin; shift ;;
        --mode) mode=$2; shift 2 ;;
        --resize) resize=$2; shift 2 ;;
        --replay) replay=$2; shift 2 ;;
        --dir) workdir=$(cd "$2" && pwd); shift 2 ;;
        --) shift; break ;;
        *) example=$1; shift ;;
    esac
done
[ -n "$example" ] || { echo "usage: $0 NAME [--bin] [--dir DIR] [--mode WxH@Hz] [--resize WxH@Hz] [--replay TOUCH] [--shot PNG] [--seconds N] [-- cargo args]" >&2; exit 2; }
[ -z "$replay" ] || [ -f "$replay" ] || { echo "run-headless: no touch script at $replay" >&2; exit 2; }
[ -z "$shot" ] || need grim "the screenshot --shot writes"

mkdir -p "$run"
export SWAYSOCK="$run/sway.sock"

# Named rather than left to sway's pid-based default, so a second run reuses
# this compositor instead of starting another beside it.
if ! swaymsg -t get_version >/dev/null 2>&1; then
    rm -f "$SWAYSOCK"
    WLR_BACKENDS=headless WLR_LIBINPUT_NO_DEVICES=1 LIBSEAT_BACKEND=noop \
        setsid sway -c "$scripts/headless.conf" >"$run/sway.log" 2>&1 &
    i=0
    while [ $i -lt 20 ]; do
        swaymsg -t get_version >/dev/null 2>&1 && break
        i=$((i + 1)); sleep 0.5
    done
    swaymsg -t get_version >/dev/null 2>&1 || {
        echo "run-headless: compositor did not start; see $run/sway.log" >&2
        exit 1
    }
fi

rm -f "$run/display"
swaymsg exec -- "sh -c 'printf %s \"\$WAYLAND_DISPLAY\" > $run/display'" >/dev/null
i=0
while [ $i -lt 20 ]; do
    [ -s "$run/display" ] && break
    i=$((i + 1)); sleep 0.5
done
[ -s "$run/display" ] || { echo "run-headless: could not read WAYLAND_DISPLAY" >&2; exit 1; }
WAYLAND_DISPLAY=$(cat "$run/display")
export WAYLAND_DISPLAY

echo "run-headless: $WAYLAND_DISPLAY (sway $(swaymsg -t get_version --raw | sed -n 's/.*"human_readable":"\([^"]*\)".*/\1/p'))" >&2

# The extent `replay-touch` positions against, so a script's coordinates are
# the output's own pixels. Set beside every mode change, since a gesture
# scaled against a mode the output no longer has lands somewhere else and
# still looks like a run that worked.
set_mode() {
    swaymsg output HEADLESS-1 mode "$1" >/dev/null
    out_w=${1%x*}
    out_h=${1#*x}; out_h=${out_h%@*}
}
set_mode "$mode"

# Built before the app starts, so a compile error is not reported as a
# window that failed to move.
[ -z "$replay" ] || (cd "$root" && cargo build --bin replay-touch -p rig-input) >&2

cd "$workdir"
if [ "$kind" = bin ]; then
    cargo build --bin "$example" "$@" >&2
    bin="$workdir/target/debug/$example"
else
    cargo build --example "$example" "$@" >&2
    bin="$workdir/target/debug/examples/$example"
fi

# Deliberately word-split: this is the binary's own argv, not a single path.
# shellcheck disable=SC2086
"$bin" ${RUN_HEADLESS_ARGS:-} >"$run/$example.log" 2>&1 &
pid=$!
trap 'kill "$pid" 2>/dev/null || true' EXIT INT TERM

# Wait for the window to be mapped rather than for a number of seconds. A
# fixed sleep took an all-black screenshot the first time this ran, when sway
# had started in the same invocation and had not composited its output yet --
# which is indistinguishable from an app that draws nothing.
i=0
while [ $i -lt 40 ]; do
    kill -0 "$pid" 2>/dev/null || break
    swaymsg -t get_tree --raw 2>/dev/null | grep -q "\"pid\":$pid," && break
    i=$((i + 1)); sleep 0.25
done

i=0
while [ $i -lt "$((seconds * 2))" ]; do
    kill -0 "$pid" 2>/dev/null || break
    i=$((i + 1)); sleep 0.5
done

if [ -n "$resize" ] && kill -0 "$pid" 2>/dev/null; then
    set_mode "$resize"
    echo "run-headless: resized to $resize" >&2
    sleep 2
fi

if [ -n "$replay" ] && kill -0 "$pid" 2>/dev/null; then
    if [ -n "$shot" ]; then
        grim "${shot%.png}-before.png"
        echo "run-headless: wrote ${shot%.png}-before.png (before the gesture)" >&2
    fi
    "$root/target/debug/replay-touch" "$out_w" "$out_h" "$replay"
    # A fling outlives the finger: the gesture's own last sample is not
    # when the list stops. Long enough for Android's spline to settle
    # (`FlingCalculator::duration` tops out around a second and a half).
    sleep 2
fi

if kill -0 "$pid" 2>/dev/null; then
    [ -n "$shot" ] && grim "$shot" && echo "run-headless: wrote $shot" >&2
    kill "$pid" 2>/dev/null || true
    wait "$pid" 2>/dev/null || true
    status=0
else
    wait "$pid" 2>/dev/null || status=$?
    echo "run-headless: $example exited early (status ${status:-0})" >&2
    status=${status:-1}
fi

echo "--- $example output ---" >&2
cat "$run/$example.log" >&2
exit "$status"