extends Control

const CLIENT_BUILD := "dev"
const PROTOCOL_VERSION := 1
const HEARTBEAT_SECONDS := 10.0
const RECOVERY_POLL_SECONDS := 2.0

@onready var playlist_dropdown: OptionButton = %PlaylistDropdown
@onready var status_label: Label = %StatusLabel
@onready var detail_label: Label = %DetailLabel
@onready var ranked_profile_label: Label = %RankedProfileLabel
@onready var queue_button: Button = %QueueButton
@onready var cancel_button: Button = %CancelButton
@onready var accept_button: Button = %AcceptButton
@onready var decline_button: Button = %DeclineButton
@onready var back_button: Button = %BackButton

var _elapsed_seconds := 0.0
var _heartbeat_seconds := 0.0
var _recovery_poll_seconds := 0.0
# Regions still awaiting RTT evidence, and the queue request deferred until at
# least one lands. The matcher ignores a ticket with no predicted RTT, so
# queueing before probing produces a search that can never match.
var _pending_probe_regions: Array[String] = []
var _probed_regions: Array[String] = []
var _deferred_queue := {}
var _web_api_ticket_handle := 0


func _ready() -> void:
	AudioManager.bind_tree_buttons(self)
	playlist_dropdown.add_item("Casual")
	playlist_dropdown.set_item_metadata(0, "casual")
	playlist_dropdown.add_item("Ranked")
	playlist_dropdown.set_item_metadata(1, "ranked")
	playlist_dropdown.item_selected.connect(_on_playlist_selected)
	ControlPlaneClient.state.changed.connect(_on_state_changed)
	ControlPlaneClient.request_failed.connect(_on_request_failed)
	ControlPlaneClient.request_succeeded.connect(_on_request_succeeded)
	ControlPlaneClient.session_expired.connect(_on_session_expired)
	ControlPlaneClient.probe_challenge_received.connect(_on_probe_challenge_received)
	ControlPlaneClient.probe_recorded.connect(_on_probe_recorded)
	_ensure_signed_in()
	_refresh_ranked_profile()
	_render(ControlPlaneClient.state.snapshot())


# Matchmaking previously opened with an empty token against a loopback default,
# so every request failed ERR_UNAUTHORIZED before reaching the network. Point
# the client at its configured endpoint and complete Steam sign-in first.
func _ensure_signed_in() -> void:
	if ControlPlaneClient.has_session():
		return
	if not ControlPlaneClient.configure(ControlPlaneClient.configured_base_url(), ""):
		_on_local_error("Matchmaking endpoint is not configured")
		return
	if not SteamBootstrap.supports_web_api_ticket():
		# Deliberately explicit rather than silently presenting a search that
		# can never start: online matchmaking requires a verified identity.
		_on_local_error("Sign-in requires the Steam build: %s" % SteamBootstrap.unavailable_reason())
		return
	var steam := Engine.get_singleton("Steam")
	if not steam.get_auth_ticket_for_web_api.is_connected(_on_web_api_ticket):
		steam.get_auth_ticket_for_web_api.connect(_on_web_api_ticket)
	_web_api_ticket_handle = SteamBootstrap.request_web_api_ticket()
	if _web_api_ticket_handle <= 0:
		_on_local_error("Could not request a Steam authentication ticket")
		return
	ControlPlaneClient.state.set_notice("Signing in...")


func _on_web_api_ticket(_handle: int, result: int, ticket: PackedByteArray) -> void:
	# Steam reports k_EResultOK as 1; anything else means no usable ticket.
	if result != 1 or ticket.is_empty():
		_on_local_error("Steam declined to issue an authentication ticket")
		return
	var encoded := SteamBootstrap.encode_web_api_ticket(ticket)
	if encoded.is_empty():
		_on_local_error("Steam returned an unusable authentication ticket")
		return
	var err := ControlPlaneClient.login_steam(encoded)
	if err != OK:
		_on_local_error("Could not sign in: %s" % error_string(err))


func _exit_tree() -> void:
	# The ticket handle is a Steam resource; releasing it avoids leaking one
	# per visit to this screen.
	if _web_api_ticket_handle > 0:
		SteamBootstrap.cancel_web_api_ticket(_web_api_ticket_handle)
		_web_api_ticket_handle = 0


func _process(delta: float) -> void:
	if ControlPlaneClient.state.phase in [MatchmakingState.QUEUED, MatchmakingState.PROPOSED, MatchmakingState.ACCEPTED, MatchmakingState.ALLOCATING]:
		_elapsed_seconds += delta
		_heartbeat_seconds += delta
		_recovery_poll_seconds += delta
		if _recovery_poll_seconds >= RECOVERY_POLL_SECONDS:
			_recovery_poll_seconds = 0.0
			var recovery_err := ControlPlaneClient.recover_proposal(ControlPlaneClient.state.proposal_id) if ControlPlaneClient.state.has_open_proposal() else ControlPlaneClient.recover_queue(ControlPlaneClient.state.ticket_id)
			if recovery_err != OK and recovery_err != ERR_BUSY:
				_on_local_error("State recovery unavailable: %s" % error_string(recovery_err))
		if ControlPlaneClient.state.phase == MatchmakingState.QUEUED and _heartbeat_seconds >= HEARTBEAT_SECONDS:
			_heartbeat_seconds = 0.0
			var err := ControlPlaneClient.heartbeat(ControlPlaneClient.state.ticket_id, ControlPlaneClient.state.revision)
			if err != OK:
				_on_local_error("Heartbeat unavailable: %s" % error_string(err))
	_render(ControlPlaneClient.state.snapshot())


func _on_queue_pressed() -> void:
	if not ControlPlaneClient.has_session():
		# Queueing without a session would fail at the first request guard.
		_ensure_signed_in()
		return
	if ControlPlaneClient.can_retry_queue_create():
		var retry_err := ControlPlaneClient.retry_queue_create()
		if retry_err != OK:
			_on_local_error("Could not retry matchmaking: %s" % error_string(retry_err))
		return
	if ControlPlaneClient.can_retry_last_mutation():
		var mutation_err := ControlPlaneClient.retry_last_mutation()
		if mutation_err != OK:
			_on_local_error("Could not retry matchmaking action: %s" % error_string(mutation_err))
		return
	if not _can_start_new_search(ControlPlaneClient.state.phase):
		return
	_elapsed_seconds = 0.0
	_heartbeat_seconds = 0.0
	_recovery_poll_seconds = 0.0
	var playlist := String(playlist_dropdown.get_selected_metadata())
	var ticket_id := "ticket-%s-%s" % [str(Time.get_ticks_usec()), str(randi())]
	# A ticket with no regional RTT evidence is invisible to the matcher, so
	# collect it first and queue once the first region reports.
	if _probed_regions.is_empty():
		_deferred_queue = {"ticket_id": ticket_id, "playlist": playlist}
		_start_probe_collection()
		return
	var err := ControlPlaneClient.queue_create(ticket_id, playlist, CLIENT_BUILD, PROTOCOL_VERSION)
	if err != OK:
		_on_local_error("Could not start matchmaking: %s" % error_string(err))


func _start_probe_collection() -> void:
	_pending_probe_regions = []
	for region in ControlPlaneClient.PROBE_REGIONS:
		_pending_probe_regions.append(String(region))
	ControlPlaneClient.state.set_notice("Measuring connection quality...")
	_request_next_probe()


# One request at a time: the client serialises HTTP through a single
# HTTPRequest, so a second call would return ERR_BUSY.
func _request_next_probe() -> void:
	if _pending_probe_regions.is_empty():
		_finish_probe_collection()
		return
	var region := _pending_probe_regions[0]
	var err := ControlPlaneClient.request_probe_challenge(region)
	if err != OK and err != ERR_BUSY:
		# A region we cannot probe is not fatal; placement just uses the
		# regions that did respond.
		_pending_probe_regions.remove_at(0)
		_request_next_probe()


func _on_probe_challenge_received(region: String, nonce_base64: String) -> void:
	var err := ControlPlaneClient.submit_probe_answer(region, nonce_base64, ControlPlaneClient.opaque_location_payload())
	if err != OK:
		_drop_pending_probe(region)


func _on_probe_recorded(region: String, _server_rtt_ms: int) -> void:
	if not _probed_regions.has(region):
		_probed_regions.append(region)
	_drop_pending_probe(region)


func _drop_pending_probe(region: String) -> void:
	var index := _pending_probe_regions.find(region)
	if index >= 0:
		_pending_probe_regions.remove_at(index)
	_request_next_probe()


func _finish_probe_collection() -> void:
	if _deferred_queue.is_empty():
		return
	var queued := _deferred_queue
	_deferred_queue = {}
	if _probed_regions.is_empty():
		# Queueing now would create a ticket the matcher can never select.
		_on_local_error("Could not measure connection quality to any region; matchmaking is unavailable")
		return
	var err := ControlPlaneClient.queue_create(String(queued["ticket_id"]), String(queued["playlist"]), CLIENT_BUILD, PROTOCOL_VERSION)
	if err != OK:
		_on_local_error("Could not start matchmaking: %s" % error_string(err))


func _on_cancel_pressed() -> void:
	if not ControlPlaneClient.state.can_cancel():
		return
	var err := ControlPlaneClient.cancel_queue(ControlPlaneClient.state.ticket_id, ControlPlaneClient.state.revision)
	if err != OK:
		_on_local_error("Could not cancel matchmaking: %s" % error_string(err))


func _on_accept_pressed() -> void:
	var err := ControlPlaneClient.respond_to_proposal(ControlPlaneClient.state.proposal_id, true, ControlPlaneClient.state.proposal_revision)
	if err != OK:
		_on_local_error("Could not accept proposal: %s" % error_string(err))


func _on_decline_pressed() -> void:
	var err := ControlPlaneClient.respond_to_proposal(ControlPlaneClient.state.proposal_id, false, ControlPlaneClient.state.proposal_revision)
	if err != OK:
		_on_local_error("Could not decline proposal: %s" % error_string(err))


func _on_playlist_selected(_index: int) -> void:
	_refresh_ranked_profile()


func _refresh_ranked_profile() -> void:
	var ranked := String(playlist_dropdown.get_selected_metadata()) == "ranked"
	ranked_profile_label.visible = ranked
	if not ranked:
		return
	var err := ControlPlaneClient.fetch_ranked_profile()
	if err != OK and err != ERR_BUSY:
		ranked_profile_label.text = "Ranked profile unavailable: %s" % error_string(err)


func _on_back_pressed() -> void:
	if ControlPlaneClient.state.can_cancel():
		status_label.text = "Cancel the active search before leaving"
		return
	get_tree().change_scene_to_file(ScenePaths.MAIN_MENU)


func _on_state_changed(snapshot: Dictionary) -> void:
	_render(snapshot)


func _on_request_succeeded(_operation: String, _payload: Dictionary) -> void:
	ranked_profile_label.text = ControlPlaneClient.ranked_profile.display_text()
	_render(ControlPlaneClient.state.snapshot())


func _on_request_failed(_operation: String, _http_code: int, detail: String) -> void:
	detail_label.text = detail
	ranked_profile_label.text = ControlPlaneClient.ranked_profile.display_text()
	_render(ControlPlaneClient.state.snapshot())


func _on_session_expired() -> void:
	status_label.text = "Session expired"
	detail_label.text = "Sign in again before searching for a match"
	queue_button.disabled = true


func _on_local_error(detail: String) -> void:
	detail_label.text = detail


static func phase_label(phase: String) -> String:
	match phase:
		MatchmakingState.IDLE:
			return "Ready to search"
		MatchmakingState.QUEUED:
			return "Searching for players"
		MatchmakingState.PROPOSED:
			return "Match found — confirm"
		MatchmakingState.ACCEPTED:
			return "Match accepted — preparing server"
		MatchmakingState.ALLOCATING:
			return "Preparing match server"
		MatchmakingState.PROCESS_READY:
			return "Match server started"
		MatchmakingState.ASSIGNMENT_READY:
			return "Match assigned"
		MatchmakingState.CONNECTING:
			return "Connecting to match"
		MatchmakingState.LIVE:
			return "Match in progress"
		MatchmakingState.RESULT_PENDING:
			return "Recording match result"
		MatchmakingState.COMPLETED:
			return "Match complete"
		MatchmakingState.ASSIGNED:
			return "Match assigned"
		MatchmakingState.CANCELLED:
			return "Search cancelled"
		MatchmakingState.EXPIRED:
			return "Search expired"
		MatchmakingState.FAILED:
			return "Matchmaking unavailable"
		_:
			return "Recovering matchmaking state"


func _render(snapshot: Dictionary) -> void:
	var phase := String(snapshot.get("phase", MatchmakingState.IDLE))
	status_label.text = phase_label(phase)
	if String(snapshot.get("message", "")) != "":
		detail_label.text = String(snapshot["message"])
	elif phase == MatchmakingState.QUEUED:
		var waited := _elapsed_seconds
		if int(snapshot.get("enqueued_at_unix", 0)) > 0:
			waited = float(ControlPlaneClient.state.waited_seconds(int(Time.get_unix_time_from_system())))
		detail_label.text = queue_wait_detail_text(int(waited), int(snapshot.get("revision", 0)))
	elif phase == MatchmakingState.PROPOSED:
		detail_label.text = proposal_countdown_text(int(snapshot.get("expires_at_unix", 0)), int(Time.get_unix_time_from_system()))
	elif phase == MatchmakingState.ACCEPTED:
		detail_label.text = phase_detail_label(phase)
	elif phase in [MatchmakingState.ALLOCATING, MatchmakingState.PROCESS_READY, MatchmakingState.ASSIGNMENT_READY, MatchmakingState.ASSIGNED]:
		detail_label.text = phase_detail_label(phase)
	elif phase in [MatchmakingState.CONNECTING, MatchmakingState.LIVE]:
		detail_label.text = "%s · %s" % [phase_detail_label(phase), latency_detail_text(NetworkManager.rtt_ms)]
	elif phase == MatchmakingState.RESULT_PENDING:
		detail_label.text = "The server is confirming the final result"
	elif phase == MatchmakingState.COMPLETED:
		detail_label.text = "The match result has been recorded"
	elif phase == MatchmakingState.IDLE:
		detail_label.text = "Choose a playlist to begin"
	cancel_button.visible = ControlPlaneClient.state.can_cancel()
	accept_button.visible = phase == MatchmakingState.PROPOSED
	decline_button.visible = phase == MatchmakingState.PROPOSED
	var retry_search := ControlPlaneClient.can_retry_queue_create()
	var retry_mutation := ControlPlaneClient.can_retry_last_mutation()
	queue_button.disabled = ControlPlaneClient.auth_expired or not (_can_start_new_search(phase) or retry_search or retry_mutation)
	queue_button.text = "Retry Search" if retry_search else ("Retry Request" if retry_mutation else "Search")


static func _is_terminal(phase: String) -> bool:
	return phase in [MatchmakingState.CANCELLED, MatchmakingState.EXPIRED, MatchmakingState.FAILED, MatchmakingState.LIVE, MatchmakingState.COMPLETED]


static func phase_detail_label(phase: String) -> String:
	match phase:
		MatchmakingState.ACCEPTED:
			return "All players accepted; preparing the match server"
		MatchmakingState.ALLOCATING:
			return "Finding a dedicated match server"
		MatchmakingState.PROCESS_READY:
			return "Match server started; preparing player assignments"
		MatchmakingState.ASSIGNMENT_READY:
			return "Player assignments are ready"
		MatchmakingState.ASSIGNED:
			return "Your match server is ready"
		MatchmakingState.CONNECTING:
			return "Connecting to the match server"
		MatchmakingState.LIVE:
			return "Match in progress"
		_:
			return ""


static func proposal_countdown_text(expires_at_unix: int, now_unix: int) -> String:
	if expires_at_unix <= 0:
		return "Review the proposal before the countdown expires"
	return "Review proposal · %ds remaining" % maxi(0, expires_at_unix - now_unix)


static func queue_wait_detail_text(waited_seconds: int, revision: int) -> String:
	var waited := maxi(0, waited_seconds)
	var suffix := "looking for compatible players"
	if waited >= 30:
		suffix = "widening skill range while keeping latency limits"
	elif waited >= 10:
		suffix = "matching nearby skill and latency"
	return "Waiting %ds · %s · revision %d" % [waited, suffix, maxi(0, revision)]


static func latency_detail_text(rtt_ms: float) -> String:
	if not is_finite(rtt_ms) or rtt_ms < 0.0:
		return "Latency: measuring"
	var rounded := int(round(rtt_ms))
	if rtt_ms <= 50.0:
		return "Latency: %dms · excellent" % rounded
	if rtt_ms <= 100.0:
		return "Latency: %dms · good" % rounded
	return "Latency: %dms · high" % rounded


static func _can_start_new_search(phase: String) -> bool:
	return phase == MatchmakingState.IDLE or phase in [MatchmakingState.CANCELLED, MatchmakingState.EXPIRED, MatchmakingState.FAILED, MatchmakingState.COMPLETED]