import { describe, expect, it } from "bun:test";
import {
	CURRENCY_MARKET_MAP,
	type ExchangeRates,
	convertPrice,
	getMarketForCurrency,
} from "../../src/server/services/currency.service";

const mockRates: ExchangeRates = {
	base: "EUR",
	date: "2026-04-13",
	rates: {
		EUR: 1,
		USD: 1.08,
		GBP: 0.86,
		JPY: 163.5,
		CAD: 1.47,
		AUD: 1.65,
	},
};

describe("convertPrice", () => {
	it("returns same amount when from === to", () => {
		expect(convertPrice(1000, "EUR", "EUR", mockRates)).toBe(1000);
		expect(convertPrice(2500, "USD", "USD", mockRates)).toBe(2500);
	});

	it("converts EUR to USD correctly", () => {
		// 1000 EUR cents * 1.08 = 1080 USD cents
		expect(convertPrice(1000, "EUR", "USD", mockRates)).toBe(1080);
	});

	it("converts USD to EUR correctly", () => {
		// 1080 USD cents / 1.08 * 1 = 1000 EUR cents
		expect(convertPrice(1080, "USD", "EUR", mockRates)).toBe(1000);
	});

	it("converts between non-EUR currencies via EUR base", () => {
		// 1000 USD cents → EUR: 1000 / 1.08 = 925.926 → GBP: 925.926 * 0.86 = 796.296 → rounded 796
		expect(convertPrice(1000, "USD", "GBP", mockRates)).toBe(796);
	});

	it("rounds to nearest integer", () => {
		// 100 EUR cents * 1.08 = 108 USD cents (exact)
		expect(convertPrice(100, "EUR", "USD", mockRates)).toBe(108);
		// 100 EUR cents * 0.86 = 86 GBP cents (exact)
		expect(convertPrice(100, "EUR", "GBP", mockRates)).toBe(86);
	});

	it("returns original for unknown currency", () => {
		expect(convertPrice(1000, "EUR", "XYZ", mockRates)).toBe(1000);
		expect(convertPrice(1000, "XYZ", "EUR", mockRates)).toBe(1000);
	});
});

describe("CURRENCY_MARKET_MAP", () => {
	it("maps EUR to EU", () => {
		expect(CURRENCY_MARKET_MAP.EUR).toBe("EU");
	});

	it("maps USD to US", () => {
		expect(CURRENCY_MARKET_MAP.USD).toBe("US");
	});

	it("maps GBP to UK", () => {
		expect(CURRENCY_MARKET_MAP.GBP).toBe("UK");
	});

	it("maps all 6 supported currencies", () => {
		expect(Object.keys(CURRENCY_MARKET_MAP)).toHaveLength(6);
		expect(CURRENCY_MARKET_MAP.JPY).toBe("JP");
		expect(CURRENCY_MARKET_MAP.CAD).toBe("CA");
		expect(CURRENCY_MARKET_MAP.AUD).toBe("AU");
	});
});

describe("getMarketForCurrency", () => {
	it("returns mapped market for known currency", () => {
		expect(getMarketForCurrency("EUR")).toBe("EU");
		expect(getMarketForCurrency("USD")).toBe("US");
		expect(getMarketForCurrency("GBP")).toBe("UK");
	});

	it("returns currency itself for unknown currency", () => {
		expect(getMarketForCurrency("XYZ")).toBe("XYZ");
	});
});
