import { describe, expect, it } from "vitest";
import { rollInitiative } from "../roll-initiative.js";
import { isDomainError } from "../types.js";

describe("rollInitiative", () => {
	describe("valid rolls", () => {
		it("normal roll: 15 + modifier 7 = 22", () => {
			expect(rollInitiative(15, 7)).toBe(22);
		});

		it("boundary: roll 1 + modifier 0 = 1", () => {
			expect(rollInitiative(1, 0)).toBe(1);
		});

		it("boundary: roll 20 + modifier 0 = 20", () => {
			expect(rollInitiative(20, 0)).toBe(20);
		});

		it("negative modifier: roll 1 + (−3) = −2", () => {
			expect(rollInitiative(1, -3)).toBe(-2);
		});

		it("zero modifier: roll 10 + 0 = 10", () => {
			expect(rollInitiative(10, 0)).toBe(10);
		});

		it("large positive modifier: roll 20 + 12 = 32", () => {
			expect(rollInitiative(20, 12)).toBe(32);
		});
	});

	describe("invalid dice rolls", () => {
		it("rejects 0", () => {
			const result = rollInitiative(0, 5);
			expect(isDomainError(result)).toBe(true);
			if (isDomainError(result)) {
				expect(result.code).toBe("invalid-dice-roll");
			}
		});

		it("rejects 21", () => {
			const result = rollInitiative(21, 5);
			expect(isDomainError(result)).toBe(true);
			if (isDomainError(result)) {
				expect(result.code).toBe("invalid-dice-roll");
			}
		});

		it("rejects non-integer (3.5)", () => {
			const result = rollInitiative(3.5, 0);
			expect(isDomainError(result)).toBe(true);
		});

		it("rejects negative dice roll", () => {
			const result = rollInitiative(-1, 0);
			expect(isDomainError(result)).toBe(true);
		});

		it("rejects NaN", () => {
			const result = rollInitiative(Number.NaN, 0);
			expect(isDomainError(result)).toBe(true);
		});
	});

	describe("determinism", () => {
		it("same input produces same output", () => {
			expect(rollInitiative(10, 5)).toBe(rollInitiative(10, 5));
		});
	});
});