import { describe, expect, it } from "vitest";
import { slotDateTime } from "../../app/lib/time";
import { getAvailability, type SlotTemplateLike } from "../../app/services/scheduling.server";

const ZONE = "America/Toronto";

function now(date: string, minutesFromMidnight: number) {
  return slotDateTime(date, minutesFromMidnight, ZONE);
}

// A simple weekday-only (Mon-Fri) 9-5 template, 1hr cutoff, no extra lead time.
const WEEKDAY_TEMPLATE: SlotTemplateLike[] = [1, 2, 3, 4, 5].map((weekday) => ({
  weekday,
  startMin: 9 * 60,
  endMin: 17 * 60,
  capacity: 5,
  cutoffMin: 60,
  leadTimeMin: 0,
}));

describe("getAvailability", () => {
  it("returns a slot for each weekday template date in range, none for weekends", () => {
    // 2024-03-04 (Mon) .. 2024-03-10 (Sun)
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-10" },
      slotTemplates: WEEKDAY_TEMPLATE,
      now: now("2024-03-01", 0),
    });

    expect(Object.keys(result).sort()).toEqual(["2024-03-04", "2024-03-05", "2024-03-06", "2024-03-07", "2024-03-08"]);
    expect(result["2024-03-04"]).toHaveLength(1);
    expect(result["2024-03-04"][0]).toMatchObject({ startMin: 9 * 60, endMin: 17 * 60, remainingCapacity: 5 });
  });

  it("hides a slot once now is within its cutoff window", () => {
    // Slot is 2024-03-04 09:00, cutoff 60 min -> unavailable from 08:00 on.
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: WEEKDAY_TEMPLATE,
      now: now("2024-03-04", 8 * 60 + 1),
    });
    expect(result["2024-03-04"]).toBeUndefined();
  });

  it("shows a slot exactly at the cutoff boundary", () => {
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: WEEKDAY_TEMPLATE,
      now: now("2024-03-04", 8 * 60), // exactly 60 min before 9:00
    });
    expect(result["2024-03-04"]).toHaveLength(1);
  });

  it("enforces leadTimeMin even when it exceeds cutoffMin", () => {
    const template: SlotTemplateLike[] = [
      { weekday: 1, startMin: 9 * 60, endMin: 17 * 60, capacity: 5, cutoffMin: 60, leadTimeMin: 24 * 60 },
    ];
    // Only 2 hours before slot start — passes the 60-min cutoff but fails the 24h lead time.
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: template,
      now: now("2024-03-04", 7 * 60),
    });
    expect(result["2024-03-04"]).toBeUndefined();
  });

  it("excludes a blacked-out date entirely, even if a template would otherwise apply", () => {
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-05" },
      slotTemplates: WEEKDAY_TEMPLATE,
      blackoutDates: [{ date: "2024-03-04" }],
      now: now("2024-03-01", 0),
    });
    expect(result["2024-03-04"]).toBeUndefined();
    expect(result["2024-03-05"]).toHaveLength(1);
  });

  it("a closed override removes the date even though a template exists", () => {
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: WEEKDAY_TEMPLATE,
      overrides: [{ date: "2024-03-04", closed: true, startMin: null, endMin: null, capacity: null }],
      now: now("2024-03-01", 0),
    });
    expect(result["2024-03-04"]).toBeUndefined();
  });

  it("a non-closed override replaces the day's window/capacity instead of the template's", () => {
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: WEEKDAY_TEMPLATE,
      overrides: [
        { date: "2024-03-04", closed: false, startMin: 12 * 60, endMin: 14 * 60, capacity: 2 },
      ],
      now: now("2024-03-01", 0),
    });
    expect(result["2024-03-04"]).toHaveLength(1);
    expect(result["2024-03-04"][0]).toMatchObject({ startMin: 12 * 60, endMin: 14 * 60, capacity: 2 });
  });

  it("hides a slot once consumed capacity reaches the template capacity", () => {
    const consumed = new Map([[`2024-03-04|${9 * 60}`, 5]]);
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: WEEKDAY_TEMPLATE,
      consumed,
      now: now("2024-03-01", 0),
    });
    expect(result["2024-03-04"]).toBeUndefined();
  });

  it("reduces remainingCapacity but keeps the slot visible when partially consumed", () => {
    const consumed = new Map([[`2024-03-04|${9 * 60}`, 3]]);
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: WEEKDAY_TEMPLATE,
      consumed,
      now: now("2024-03-01", 0),
    });
    expect(result["2024-03-04"][0].remainingCapacity).toBe(2);
  });

  it("computes correct instants for a range spanning the spring-forward DST transition", () => {
    // 2024-03-08 (Fri) and 2024-03-11 (Mon) bracket the 2024-03-10 transition.
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-08", endDate: "2024-03-11" },
      slotTemplates: WEEKDAY_TEMPLATE,
      now: now("2024-03-01", 0),
    });

    const friday = result["2024-03-08"][0];
    const monday = result["2024-03-11"][0];
    expect(friday.start.toUTC().hour).toBe(14); // EST, UTC-5
    expect(monday.start.toUTC().hour).toBe(13); // EDT, UTC-4 — offset already changed
    expect(friday.start.hour).toBe(9);
    expect(monday.start.hour).toBe(9); // still wall-clock 9 AM despite the offset shift
  });

  it("returns multiple slots per day sorted by start time when several templates match", () => {
    const templates: SlotTemplateLike[] = [
      { weekday: 1, startMin: 14 * 60, endMin: 16 * 60, capacity: 3, cutoffMin: 0, leadTimeMin: 0 },
      { weekday: 1, startMin: 9 * 60, endMin: 11 * 60, capacity: 3, cutoffMin: 0, leadTimeMin: 0 },
    ];
    const result = getAvailability({
      timezone: ZONE,
      dateRange: { startDate: "2024-03-04", endDate: "2024-03-04" },
      slotTemplates: templates,
      now: now("2024-03-01", 0),
    });
    expect(result["2024-03-04"].map((s) => s.startMin)).toEqual([9 * 60, 14 * 60]);
  });
});