#!/usr/bin/env bash
# Runs as a systemd ExecStartPre for the Sunshine service. Two jobs:
#   1. Make sure exactly one Hyprland headless output exists.
#   2. Sync sunshine.conf's `output_name` to whatever the headless output is
#      currently named — Hyprland's HEADLESS-N counter doesn't reset across
#      session restarts, so pinning to HEADLESS-1 drifts after the first
#      remove/create cycle.
#
# Non-fatal at every step: a stale state can't worsen things by aborting here.

set -uo pipefail

log() { printf '[sunshine-prestart] %s\n' "$*" >&2; }

CONF="$HOME/.config/sunshine/sunshine.conf"

# Recover Hyprland's instance signature when the unit's env didn't propagate it.
if [[ -z "${HYPRLAND_INSTANCE_SIGNATURE:-}" ]]; then
  for sig in "${XDG_RUNTIME_DIR:-/run/user/$(id -u)}"/hypr/*/; do
    [[ -d "$sig" ]] || continue
    export HYPRLAND_INSTANCE_SIGNATURE="$(basename "$sig")"
    break
  done
fi
if [[ -z "${HYPRLAND_INSTANCE_SIGNATURE:-}" ]]; then
  log "Hyprland not running; nothing to prepare."
  exit 0
fi

if ! command -v hyprctl >/dev/null || ! command -v jq >/dev/null; then
  log "hyprctl/jq missing; skipping prestart."
  exit 0
fi

# Reduce to exactly one headless output. Hyprland's HEADLESS-N counter
# increments on every create and never decrements, so previous failed runs
# leave extras laying around. Remove all but the lowest-numbered one (most
# likely to be the one with workspaces bound to it).
mapfile -t headless_outputs < <(hyprctl monitors -j 2>/dev/null \
  | jq -r '.[] | select(.name | startswith("HEADLESS")) | .name' \
  | sort -V)
existing="${headless_outputs[0]:-}"

if [[ -z "$existing" ]]; then
  log "No headless output present; creating one"
  hyprctl output create headless >/dev/null
  for _ in 1 2 3 4 5; do
    existing="$(hyprctl monitors -j 2>/dev/null \
      | jq -r '.[] | select(.name | startswith("HEADLESS")) | .name' \
      | sort -V | head -1)"
    [[ -n "$existing" ]] && break
    sleep 0.1
  done
elif [[ ${#headless_outputs[@]} -gt 1 ]]; then
  log "Found ${#headless_outputs[@]} headless outputs; keeping $existing, removing the rest"
  for extra in "${headless_outputs[@]:1}"; do
    hyprctl output remove "$extra" >/dev/null 2>&1 || true
  done
fi

if [[ -z "$existing" ]]; then
  log "Failed to obtain a headless output; Sunshine will start without one."
  exit 0
fi
log "Headless output present: $existing"

# Sync sunshine.conf's output_name. Only touch the file if it's our managed
# variant (has the management marker) AND the line has actually drifted.
if [[ -f "$CONF" ]] && grep -qF '# managed-by: omarchy-moonlight' "$CONF"; then
  current="$(awk '/^output_name = / {print $3; exit}' "$CONF" 2>/dev/null || true)"
  if [[ "$current" != "$existing" ]]; then
    log "Updating sunshine.conf output_name: ${current:-(unset)} -> $existing"
    if grep -q '^output_name = ' "$CONF"; then
      sed -i "s|^output_name = .*|output_name = $existing|" "$CONF"
    else
      printf '\noutput_name = %s\n' "$existing" >> "$CONF"
    fi
  fi
fi

exit 0