import type { ConditionId } from "./conditions.js";
import { VALID_CONDITION_IDS } from "./conditions.js";
import { creatureId } from "./creature-types.js";
import {
	playerCharacterId,
	VALID_PLAYER_COLORS,
	VALID_PLAYER_ICONS,
} from "./player-character-types.js";
import type { Combatant } from "./types.js";
import { combatantId } from "./types.js";

function validateAc(value: unknown): number | undefined {
	return typeof value === "number" && Number.isInteger(value) && value >= 0
		? value
		: undefined;
}

function validateConditions(value: unknown): ConditionId[] | undefined {
	if (!Array.isArray(value)) return undefined;
	const valid = value.filter(
		(v): v is ConditionId =>
			typeof v === "string" && VALID_CONDITION_IDS.has(v),
	);
	return valid.length > 0 ? valid : undefined;
}

function validateHp(
	rawMaxHp: unknown,
	rawCurrentHp: unknown,
): { maxHp: number; currentHp: number } | undefined {
	if (
		typeof rawMaxHp !== "number" ||
		!Number.isInteger(rawMaxHp) ||
		rawMaxHp < 1
	) {
		return undefined;
	}
	const validCurrentHp =
		typeof rawCurrentHp === "number" &&
		Number.isInteger(rawCurrentHp) &&
		rawCurrentHp >= 0 &&
		rawCurrentHp <= rawMaxHp;
	return {
		maxHp: rawMaxHp,
		currentHp: validCurrentHp ? rawCurrentHp : rawMaxHp,
	};
}

function validateTempHp(value: unknown): number | undefined {
	return typeof value === "number" && Number.isInteger(value) && value >= 0
		? value
		: undefined;
}

function validateInteger(value: unknown): number | undefined {
	return typeof value === "number" && Number.isInteger(value)
		? value
		: undefined;
}

function validateSetMember(
	value: unknown,
	valid: ReadonlySet<string>,
): string | undefined {
	return typeof value === "string" && valid.has(value) ? value : undefined;
}

function validateNonEmptyString(value: unknown): string | undefined {
	return typeof value === "string" && value.length > 0 ? value : undefined;
}

function parseOptionalFields(entry: Record<string, unknown>) {
	return {
		initiative: validateInteger(entry.initiative),
		ac: validateAc(entry.ac),
		conditions: validateConditions(entry.conditions),
		isConcentrating: entry.isConcentrating === true ? true : undefined,
		creatureId: validateNonEmptyString(entry.creatureId)
			? creatureId(entry.creatureId as string)
			: undefined,
		color: validateSetMember(entry.color, VALID_PLAYER_COLORS),
		icon: validateSetMember(entry.icon, VALID_PLAYER_ICONS),
		playerCharacterId: validateNonEmptyString(entry.playerCharacterId)
			? playerCharacterId(entry.playerCharacterId as string)
			: undefined,
		tempHp: validateTempHp(entry.tempHp),
	};
}

export function rehydrateCombatant(raw: unknown): Combatant | null {
	if (typeof raw !== "object" || raw === null || Array.isArray(raw))
		return null;
	const entry = raw as Record<string, unknown>;

	if (typeof entry.id !== "string" || entry.id.length === 0) return null;
	if (typeof entry.name !== "string") return null;

	const shared: Combatant = {
		id: combatantId(entry.id),
		name: entry.name,
		...parseOptionalFields(entry),
	};

	const hp = validateHp(entry.maxHp, entry.currentHp);
	return hp ? { ...shared, ...hp } : shared;
}