class_name CreationDraft
extends RefCounted
## The creation screen's whole brain. Pure, node-free, headlessly testable.
##
## Stores exactly the seven things a creation Dictionary is made of, and nothing
## derived. It CARRIES A SEED, NOT A STAT BLOCK — the screen shows the roll by
## calling NewGame.roll_attributes(seed), the same function construct calls, so
## the numbers on screen are the numbers the player gets and the screen still
## never hands a number to anything (§2).
##
## It owns no rules of its own: errors() delegates to NewGame.validate. A second
## copy of the rules is a second thing to keep in sync, and it would lose.
##
## §7: LCK is not here. Not a field, not an accessor, not a key. It is rolled
## inside construct off the same seed, immediately after MAG, and never surfaces.

const NewGame = preload("res://scripts/newgame/new_game.gd")
const POOL := 3   # mirrors NewGame.SPEND_POOL; validate() is the authority

var name: String = ""
var race_id: String = ""
var calling_id: String = ""
var spend: Dictionary = {}      # {stat: int} — additive only
var skills: Array = []          # the player's picks (NOT the race's grants)
var bonus_skill: String = ""    # human only

## NOT named `seed` — `seed()` is a global GDScript function and a member that
## shadows it reads as a bug (and warns). The creation Dictionary's KEY is still
## "seed"; only the GDScript identifier differs.
var character_seed: int = 0


static func fresh() -> CreationDraft:
	## The ONE place non-determinism enters the entire pipeline — and what it
	## produces is a seed, which is thereafter the character's anchor forever.
	var d := CreationDraft.new()
	d.character_seed = new_seed()
	return d


static func new_seed() -> int:
	var rng := RandomNumberGenerator.new()
	rng.randomize()
	return int(rng.randi())


# ---------------------------------------------------------------- the numbers

func rolled() -> Dictionary:
	return NewGame.roll_attributes(character_seed)


func final() -> Dictionary:
	var out := rolled()
	for stat in spend:
		out[stat] = int(out[stat]) + int(spend[stat])
	return out


func spent_total() -> int:
	var total := 0
	for stat in spend:
		total += int(spend[stat])
	return total


func points_left() -> int:
	return POOL - spent_total()


func can_increment(stat: String) -> bool:
	return Attributes.exists(stat) and points_left() > 0


func increment(stat: String) -> void:
	if not can_increment(stat):
		return
	spend[stat] = int(spend.get(stat, 0)) + 1


func can_decrement(stat: String) -> bool:
	## Removes only what YOU spent. "Additive only" is a rule about where the number
	## can END UP — never below the roll — not about whether a mis-click is
	## recoverable. Those are different things.
	return int(spend.get(stat, 0)) > 0


func decrement(stat: String) -> void:
	if not can_decrement(stat):
		return
	var left := int(spend[stat]) - 1
	if left <= 0:
		spend.erase(stat)
	else:
		spend[stat] = left


func reroll() -> void:
	## A re-roll IS a new seed. Nothing else. The spend clears because points spent
	## against a roll that no longer exists are meaningless; race, calling, skills
	## and name survive because none of them came from the die.
	##
	## Note what the player is NOT told: the seed drives the five visible attributes
	## AND the hidden Luck roll. Chase a 16 and you re-roll your Luck, blind, every
	## time. That is §7 working exactly as designed. Say nothing.
	character_seed = new_seed()
	spend = {}


# ---------------------------------------------------------------- the choices

func set_race(id: String) -> void:
	race_id = id
	# A pick the new race GRANTS now buys nothing, and construct rejects it by name.
	# Drop it here rather than let the player press a button into a 422.
	var granted: Array = Races.granted_skills(id)
	var kept: Array = []
	for s in skills:
		if s not in granted:
			kept.append(s)
	skills = kept
	if not Races.wants_bonus_skill(id):
		bonus_skill = ""


func set_calling(id: String) -> void:
	# The pool changed underneath the picks. Keeping them leaves the player holding
	# an invalid draft he did not cause and cannot see.
	if id != calling_id:
		skills = []
	calling_id = id


func skill_pool() -> Array:
	return Callings.skill_pool(calling_id)


func picks_needed() -> int:
	return Callings.skill_count(calling_id)


func picks_left() -> int:
	return picks_needed() - skills.size()


func is_granted(skill: String) -> bool:
	return skill in Races.granted_skills(race_id)


func is_picked(skill: String) -> bool:
	return skill in skills


func can_pick(skill: String) -> bool:
	if is_granted(skill):
		return false
	if skill not in skill_pool():
		return false
	return picks_left() > 0


func toggle_skill(skill: String) -> void:
	if is_picked(skill):
		skills.erase(skill)
		return
	if can_pick(skill):
		skills.append(skill)


func wants_bonus_skill() -> bool:
	return Races.wants_bonus_skill(race_id)


func can_take_bonus(skill: String) -> bool:
	if not wants_bonus_skill():
		return false
	if not Skills.exists(skill):
		return false
	return not is_granted(skill) and not is_picked(skill)


func set_bonus_skill(skill: String) -> void:
	if bonus_skill == skill:
		bonus_skill = ""
		return
	if can_take_bonus(skill):
		bonus_skill = skill


# ---------------------------------------------------------------- the contract

func to_creation() -> Dictionary:
	## The plain Dictionary NewGame.construct takes. A saga (later) synthesizes one
	## of these and skips this screen entirely — so it stays a plain Dictionary, and
	## this scene must never become the only thing that can produce it.
	return {
		"name": name.strip_edges(),
		"race_id": race_id,
		"calling_id": calling_id,
		"seed": character_seed,     # the DICT key stays "seed" — the contract is unchanged
		"spend": spend.duplicate(),
		"skills": skills.duplicate(),
		"bonus_skill": bonus_skill,
	}


func errors(origin: Dictionary, world: ContentDB) -> Array:
	## Delegates. The screen owns no second copy of the rules — it asks construct's
	## validator what is wrong, and shows the answer.
	return NewGame.validate(origin, world, to_creation())


func is_complete(origin: Dictionary, world: ContentDB) -> bool:
	return errors(origin, world).is_empty()