import { describe, it, expect, setSystemTime, beforeAll, afterAll } from "bun:test";
import { getVehicleDisplayStatus } from "./utils";
import { Vehicle } from "./api";

describe("getVehicleDisplayStatus", () => {
    beforeAll(() => {
        setSystemTime(new Date("2024-01-01T12:00:10Z")); // Mock Current Time: 12:00:10 UTC
    });

    afterAll(() => {
        setSystemTime(); // Reset
    });

    it("should return Online if heartbeat is recent (<5s)", () => {
        const vehicle: Vehicle = {
            vin: "TEST",
            status: "Online",
            currentVersion: "1.0",
            lastHeartbeat: "2024-01-01T12:00:08", // 2 seconds ago (assuming UTC fix)
            groupId: null
        };
        // The function appends Z -> 12:00:08Z. Diff is 2000ms.
        expect(getVehicleDisplayStatus(vehicle)).toBe("Online");
    });

    it("should return Offline if heartbeat is old (>5s)", () => {
        const vehicle: Vehicle = {
            vin: "TEST",
            status: "Online",
            currentVersion: "1.0",
            lastHeartbeat: "2024-01-01T12:00:04", // 6 seconds ago
            groupId: null
        };
        // The function appends Z -> 12:00:04Z. Diff is 6000ms.
        expect(getVehicleDisplayStatus(vehicle)).toBe("Offline");
    });

    it("should handle already UTC string with Z", () => {
        const vehicle: Vehicle = {
            vin: "TEST",
            status: "Online",
            currentVersion: "1.0",
            lastHeartbeat: "2024-01-01T12:00:09Z", // 1s ago
            groupId: null
        };
        expect(getVehicleDisplayStatus(vehicle)).toBe("Online");
    });

    it("should preserve Updating status even if old heartbeat", () => {
        // Usually updating vehicles might not heartbeat? Or they do. 
        // Logic says: if (displayStatus === 'Online' && diffMs > 5000) -> Offline.
        // If status is 'Updating', it stays 'Updating'.
        const vehicle: Vehicle = {
            vin: "TEST",
            status: "Updating",
            currentVersion: "1.0",
            lastHeartbeat: "2024-01-01T12:00:00", // 10s ago
            groupId: null
        };
        expect(getVehicleDisplayStatus(vehicle)).toBe("Updating");
    });

    it("should handle microsecond precision timestamps", () => {
        // Backend sends 6 digit precision e.g. .991694
        // 2024-01-01T12:00:04.991694 -> 6s ago
        const vehicle: Vehicle = {
            vin: "TEST",
            status: "Online",
            currentVersion: "1.0",
            lastHeartbeat: "2024-01-01T12:00:04.991694",
            groupId: null
        };
        // If it parses correctly, diff is ~6s > 5s -> Offline
        expect(getVehicleDisplayStatus(vehicle)).toBe("Offline");
    });
});