#!/usr/bin/env bash
set -uo pipefail

LOGTAG=revive-monitor-fix
SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
# Source-tree and installed layouts.
COMMON="$SCRIPT_DIR/../lib/hyprland-hdmi-revive/common.sh"
[[ -f "$COMMON" ]] || COMMON="$SCRIPT_DIR/../lib/common.sh"
# shellcheck source=lib/common.sh
source "$COMMON" || exit 1
load_config || exit 1
require_commands timeout loginctl hyprctl jq sudo flock stat sleep || exit 1
prepare_runtime || exit 1

GRAPHICAL_VT="${1:-}"
if [[ ! "$GRAPHICAL_VT" =~ ^[1-9][0-9]?$ ]] || (( GRAPHICAL_VT > 63 )); then
    log 'No valid graphical VT supplied (expected 1..63)'
    exit 1
fi

exec 9>"$STATE_DIR/fix.lock" || exit 1
flock -n -E 75 9
lock_status=$?
if (( lock_status == 75 )); then
    log 'Recovery already running - skipping'
    exit 0
elif (( lock_status != 0 )); then
    log 'Cannot acquire recovery lock'
    exit 1
fi

SESSION="$(get_active_wayland_session)" || { log 'No active Wayland session - recovery skipped'; exit 0; }
if [[ "${SESSION##*:}" != "$GRAPHICAL_VT" ]]; then
    log 'Requested VT does not belong to the active Wayland session'
    exit 1
fi
if [[ -z "${HYPRLAND_INSTANCE_SIGNATURE:-}" ]]; then
    log 'Missing HYPRLAND_INSTANCE_SIGNATURE; import the Hyprland environment into systemd --user'
    exit 1
fi

monitor_present() {
    timeout 5 hyprctl -j monitors |
        jq -e --arg name "$MONITOR" 'any(.[]; .name == $name)' >/dev/null 2>&1
}

select_dispatch_syntax() {
    local status provider
    DISPATCH_SYNTAX=hyprlang
    # The active config provider, not the version, determines dispatch syntax.
    # Older Hyprland versions do not expose `status`; their dispatch is legacy.
    if status="$(timeout 5 hyprctl -j status 2>/dev/null)" &&
        provider="$(jq -er '.configProvider | select(type == "string")' <<< "$status" 2>/dev/null)"; then
        case "$provider" in
            lua|hyprlang) DISPATCH_SYNTAX="$provider" ;;
            *) log "Unsupported Hyprland config provider: $provider"; return 1 ;;
        esac
    else
        log 'Hyprland config provider unavailable; trying legacy dispatch syntax'
    fi
    log "Using $DISPATCH_SYNTAX dispatch syntax"
}

dispatch_checked() {
    local action="$1" reply status
    shift
    reply="$(timeout 5 hyprctl dispatch "$@" 2>&1)"
    status=$?
    # Some hyprctl versions return exit 0 even for an IPC error response.
    if (( status != 0 )) || [[ "$reply" != ok ]]; then
        log "Hyprland $action failed (exit $status): ${reply:-no response}"
        return 1
    fi
}

refresh_monitor() {
    if [[ "$DISPATCH_SYNTAX" == lua ]]; then
        # MONITOR is restricted to alphanumeric characters, underscores and '-'.
        dispatch_checked DPMS "hl.dsp.dpms({ action = \"on\", monitor = \"$MONITOR\" })" &&
            dispatch_checked focus "hl.dsp.focus({ monitor = \"$MONITOR\" })"
    else
        dispatch_checked DPMS dpms on "$MONITOR" &&
            dispatch_checked focus focusmonitor "$MONITOR"
    fi
}

log "Recovery started for $MONITOR on VT $GRAPHICAL_VT"
sleep "$HDMI_SETTLE_SECONDS" || exit 1
if ! monitor_present; then
    log "Hyprland IPC unavailable or configured output $MONITOR absent - recovery aborted"
    exit 1
fi
select_dispatch_syntax || exit 1
if ! refresh_monitor; then
    log 'Hyprland refresh failed - recovery aborted'
    exit 1
fi

# Recheck after settling/IPC, immediately before the privileged switch.
if [[ "$(get_active_wayland_session)" != "$SESSION" ]]; then
    log 'Active session changed while settling - recovery skipped'
    exit 0
fi
TEMP_VT=1
[[ "$GRAPHICAL_VT" == 1 ]] && TEMP_VT=2
# Check both directions before leaving the desktop (actual sudo can still fail).
for vt in "$TEMP_VT" "$GRAPHICAL_VT"; do
    if ! timeout 5 sudo -n -l /usr/bin/chvt "$vt" >/dev/null 2>&1; then
        log "sudo permission check failed for VT $vt - recovery aborted"
        exit 1
    fi
done

if [[ "$(get_active_wayland_session)" != "$SESSION" ]]; then
    log 'Active session changed during permission checks - recovery skipped'
    exit 0
fi
NEEDS_RETURN=0
cleanup() {
    local status=$?
    trap - EXIT HUP INT TERM
    if (( NEEDS_RETURN )); then
        log "Attempting emergency return to graphical VT $GRAPHICAL_VT"
        if ! timeout 5 sudo -n /usr/bin/chvt "$GRAPHICAL_VT"; then
            log "Emergency return failed; manually switch to VT $GRAPHICAL_VT"
            status=1
        fi
    fi
    exit "$status"
}
trap cleanup EXIT
trap 'exit 129' HUP
trap 'exit 130' INT
trap 'exit 143' TERM

log "VT refresh: $TEMP_VT -> $GRAPHICAL_VT"
# Set before chvt to cover a signal arriving as the command completes.
NEEDS_RETURN=1
if ! timeout 5 sudo -n /usr/bin/chvt "$TEMP_VT"; then
    log "Failed to switch to temporary VT $TEMP_VT"
    exit 1
fi
sleep "$VT_SWITCH_DELAY_SECONDS" || exit 1
if ! timeout 5 sudo -n /usr/bin/chvt "$GRAPHICAL_VT"; then
    log "Failed to return to graphical VT $GRAPHICAL_VT"
    exit 1
fi
NEEDS_RETURN=0
sleep "$VT_RETURN_SETTLE_SECONDS" || exit 1
if ! refresh_monitor; then
    log 'Final Hyprland refresh failed'
    exit 1
fi
log "Recovery completed for $MONITOR"