class_name Main
extends Node
## The single home for the game's screen sequence: Title → Creation → Shell.
## Script-first by design — a pure coordinator with no Control layout, so ADR 0001's
## editor-first rule does not apply (that rule governs layout scenes). It owns one
## ContentDB + one DmService and swaps screens via instantiate → inject → add_child,
## the injection seam change_scene_to_file cannot provide.
##
## §2: the flow carries only plain data; NewGame.construct re-rolls the character
## from the creation seed itself. ⛨ saga: _show_creation and _start_campaign are
## separate, so a fourth entry path is an added arm, not surgery on existing edges.

const HttpTransport = preload("res://scripts/net/http_transport.gd")

const TITLE := preload("res://scenes/title/TitleScreen.tscn")
const CREATION := preload("res://scenes/creation/CharacterCreation.tscn")
const SHELL := preload("res://scenes/shell/MainWindowShell.tscn")

# Injection seams — set BETWEEN instantiate() and add_child(), as the shell/creation
# do for their own deps. _ready builds the real ones when nothing was supplied.
var world: ContentDB = null
var service: DmService = null
var origin: Dictionary = {}

var _current: Node = null
var _http: HTTPRequest


func _ready() -> void:
	if world == null:
		world = ContentDB.new()
		world.load_from(ContentDB.default_content_root())
	if origin.is_empty():
		origin = ContentDB.load_json(ContentDB.origin_path("deserter"))
	if service == null:
		_http = HTTPRequest.new()
		add_child(_http)
		service = DmService.new(HttpTransport.new(_http), FallbackLibrary.new())
	_show_title()


func _show(next: PackedScene, inject: Callable) -> void:
	## The one swap primitive. inject runs after instantiate() (which does NOT run
	## _ready) and before add_child (which does) — the injection window. The outgoing
	## screen is queue_free'd (deferred): a signal handler must never free the node
	## still executing up its own call stack.
	var old := _current
	var screen := next.instantiate()
	inject.call(screen)
	_current = screen
	add_child(screen)
	if old != null:
		old.queue_free()


func _show_title() -> void:
	_show(TITLE, func(s): s.menu_activated.connect(_on_menu))


func _show_creation() -> void:
	_show(CREATION, func(s):
		s.world = world
		s.origin = origin
		s.creation_confirmed.connect(_start_campaign))


func _show_shell(log: CanonLog, state: GameState) -> void:
	_show(SHELL, func(s):
		s.service = service
		s.injected_log = log
		s.injected_state = state)


func _on_menu(id: StringName) -> void:
	match id:
		&"new_game":
			_show_creation()
		&"quit":
			get_tree().quit()
		_:
			pass  # continue / load land in later milestones (M9); inert for now


func _start_campaign(creation: Dictionary) -> void:
	## Takes a plain Dictionary — does NOT assume it came from the creation screen, so
	## a saga can synthesize one and call this directly (skipping creation).
	var result := NewGame.construct(origin, world, creation)
	if not result.get("ok", false):
		# Unreachable via the UI (the CTA gates on validate), but §2 forbids trusting
		# the caller and §13 forbids surfacing an error. Log and stay put.
		push_error("Main: construct rejected a creation: %s" % str(result.get("errors", [])))
		return
	_show_shell(result["log"], result["state"])