extends Node

# =============================================================================
# Server Browser — Heartbeat Sender
# =============================================================================
# Periodically POSTs server state to the configured master server so the
# server appears in the public server browser.
#
# Relies on cvars defined by the config system:
#   sv_master_server       — Master server URL (e.g. "http://master.example.com:28961")
#   sv_server_id           — Unique server identifier (auto-generated if empty)
#   sv_heartbeat_interval  — Seconds between heartbeats (default 60, range [10,300])
#   sv_server_tags         — Comma-separated tags for filtering
#   sv_server_password     — Whether the server requires a password
#
# Signals:
#   heartbeat_sent(success: bool, server_id: String, http_code: int)
#   master_connection_failed(error_message: String)
# =============================================================================

signal heartbeat_sent(success: bool, server_id: String, http_code: int)
signal master_connection_failed(error_message: String)

const DEFAULT_HEARTBEAT_INTERVAL: float = 60.0
const MIN_INTERVAL: float = 10.0
const MAX_INTERVAL: float = 300.0
const DEFAULT_MASTER_SERVER: String = "http://127.0.0.1:28961"

# HTTP request node for async requests
var _http: HTTPRequest
var _timer: Timer
var _server_id: String = ""
var _enabled: bool = false


func _ready() -> void:
	# Create HTTP request node
	_http = HTTPRequest.new()
	_http.name = "MasterServerHTTP"
	_http.timeout = 10
	_http.use_threads = true
	add_child(_http)
	_http.request_completed.connect(_on_heartbeat_completed)

	# Create timer for periodic heartbeats
	_timer = Timer.new()
	_timer.name = "HeartbeatTimer"
	_timer.one_shot = false
	add_child(_timer)
	_timer.timeout.connect(_send_heartbeat)


func start() -> void:
	"""Begin the heartbeat loop. Call after cvars are loaded and server is ready."""
	var master_url = _get_cvar_string("sv_master_server", "")
	if master_url.is_empty():
		push_warning("[ServerBrowser] sv_master_server is empty — heartbeat disabled")
		return

	# Strip trailing slash
	master_url = master_url.trim_suffix("/")
	if not master_url.begins_with("http"):
		master_url = "http://" + master_url

	if not master_url.begins_with("http://") and not master_url.begins_with("https://"):
		push_warning("[ServerBrowser] Invalid master server URL: ", master_url)
		return

	_server_id = _get_cvar_string("sv_server_id", "")
	_enabled = true

	var interval = _get_cvar_float("sv_heartbeat_interval", DEFAULT_HEARTBEAT_INTERVAL)
	interval = clamp(interval, MIN_INTERVAL, MAX_INTERVAL)

	_timer.wait_time = interval
	_timer.start()

	print("[ServerBrowser] Heartbeat enabled — master: ", master_url, " interval: ", interval, "s")

	# Send initial heartbeat immediately
	_send_heartbeat()


func stop() -> void:
	"""Stop sending heartbeats."""
	_enabled = false
	_timer.stop()
	print("[ServerBrowser] Heartbeat disabled")


func set_server_id(new_id: String) -> void:
	"""Update the server id (e.g., after first heartbeat response)."""
	_server_id = new_id


func _get_master_url() -> String:
	var raw = _get_cvar_string("sv_master_server", DEFAULT_MASTER_SERVER).trim_suffix("/")
	if raw.is_empty():
		return ""
	if not raw.begins_with("http"):
		raw = "http://" + raw
	return raw


func _send_heartbeat() -> void:
	if not _enabled:
		return

	var master_url = _get_master_url()
	if master_url.is_empty():
		return

	# Build heartbeat payload
	var payload = {
		"server_id": _server_id,
		"name": _get_cvar_string("sv_server_name", "Tactical Shooter Server"),
		"map": _get_cvar_string("sv_map", "unknown"),
		"players": _get_player_count(),
		"max_players": _get_cvar_int("sv_max_players", 16),
		"game_mode": _get_cvar_string("sv_game_mode", "deathmatch"),
		"version": _get_cvar_string("sv_version", "1.0.0"),
		"tags": _get_cvar_string("sv_server_tags", ""),
		"password": _get_cvar_int("sv_server_password", 0) != 0,
		"host": _get_external_ip(),
		"port": _get_cvar_int("sv_port", 0),
		"steam_id": _get_cvar_string("sv_steam_id", ""),
	}

	var json_string = JSON.stringify(payload)
	var headers = ["Content-Type: application/json"]

	var endpoint = master_url + "/api/v1/heartbeat"
	var err = _http.request(endpoint, headers, HTTPClient.METHOD_POST, json_string)
	if err != OK:
		push_error("[ServerBrowser] Failed to send heartbeat: HTTP request error ", err)
		master_connection_failed.emit("HTTP request failed (code " + str(err) + ")")


func _on_heartbeat_completed(result: int, response_code: int, _headers: PackedStringArray, body: PackedByteArray) -> void:
	if result != HTTPRequest.RESULT_SUCCESS:
		var msg = "Heartbeat failed — network error " + str(result)
		push_warning("[ServerBrowser] ", msg)
		master_connection_failed.emit(msg)
		heartbeat_sent.emit(false, _server_id, response_code)
		return

	if response_code != 200:
		var msg = "Heartbeat failed — HTTP " + str(response_code)
		push_warning("[ServerBrowser] ", msg)
		master_connection_failed.emit(msg)
		heartbeat_sent.emit(false, _server_id, response_code)
		return

	# Parse response for server_id (first heartbeat may get one assigned)
	var body_text = body.get_string_from_utf8()
	var json = JSON.new()
	var parse_err = json.parse(body_text)
	if parse_err == OK and json.data is Dictionary:
		if json.data.has("server_id") and not json.data["server_id"].is_empty():
			_server_id = json.data["server_id"]

	heartbeat_sent.emit(true, _server_id, response_code)


# -------------------------------------------------------------------------
# Helper: read cvars from the config system (if available)
# -------------------------------------------------------------------------

func _get_cvar_string(name: String, default_value: String) -> String:
	"""Try the CvarRegistry autoload first, fall back to ProjectSettings."""
	if Engine.has_singleton("CvarRegistry"):
		var reg = Engine.get_singleton("CvarRegistry")
		if reg.has_method("get_string"):
			return reg.get_string(name, default_value)
	# Fallback to ProjectSettings if no cvar registry exists
	if ProjectSettings.has_setting(name):
		return ProjectSettings.get_setting(name)
	return default_value


func _get_cvar_int(name: String, default_value: int) -> int:
	if Engine.has_singleton("CvarRegistry"):
		var reg = Engine.get_singleton("CvarRegistry")
		if reg.has_method("get_int"):
			return reg.get_int(name, default_value)
	if ProjectSettings.has_setting(name):
		return ProjectSettings.get_setting(name)
	return default_value


func _get_cvar_float(name: String, default_value: float) -> float:
	if Engine.has_singleton("CvarRegistry"):
		var reg = Engine.get_singleton("CvarRegistry")
		if reg.has_method("get_float"):
			return reg.get_float(name, default_value)
	if ProjectSettings.has_setting(name):
		return ProjectSettings.get_setting(name)
	return default_value


func _get_player_count() -> int:
	"""Get current connected player count."""
	# Try to read from game's player manager singleton
	if Engine.has_singleton("PlayerManager"):
		var pm = Engine.get_singleton("PlayerManager")
		if pm.has_method("get_player_count"):
			return pm.get_player_count()
	return 0


func _get_external_ip() -> String:
	"""Return our public/external IP if known, or empty for auto-detect."""
	return _get_cvar_string("sv_external_ip", "")