// ABOUTME: Unit tests for the MonthView component.
// ABOUTME: Tests calendar grid rendering, phase display, navigation, and day cell integration.
import { fireEvent, render, screen } from "@testing-library/react";
import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";

import { MonthView } from "./month-view";

describe("MonthView", () => {
  // Fixed date for consistent testing: January 2026
  const baseProps = {
    year: 2026,
    month: 0, // January (0-indexed)
    lastPeriodDate: new Date("2026-01-01"),
    cycleLength: 28,
    onMonthChange: vi.fn(),
  };

  beforeEach(() => {
    vi.clearAllMocks();
    // Mock Date.now to return Jan 15, 2026
    vi.useFakeTimers();
    vi.setSystemTime(new Date("2026-01-15"));
  });

  afterEach(() => {
    vi.useRealTimers();
  });

  describe("header rendering", () => {
    it("renders the month and year in header", () => {
      render(<MonthView {...baseProps} />);

      expect(screen.getByText("January 2026")).toBeInTheDocument();
    });

    it("renders day-of-week headers", () => {
      render(<MonthView {...baseProps} />);

      expect(screen.getByText("Sun")).toBeInTheDocument();
      expect(screen.getByText("Mon")).toBeInTheDocument();
      expect(screen.getByText("Tue")).toBeInTheDocument();
      expect(screen.getByText("Wed")).toBeInTheDocument();
      expect(screen.getByText("Thu")).toBeInTheDocument();
      expect(screen.getByText("Fri")).toBeInTheDocument();
      expect(screen.getByText("Sat")).toBeInTheDocument();
    });
  });

  describe("calendar grid", () => {
    it("renders all days of the month", () => {
      render(<MonthView {...baseProps} />);

      // January 2026 has 31 days
      for (let day = 1; day <= 31; day++) {
        expect(screen.getByText(day.toString())).toBeInTheDocument();
      }
    });

    it("renders day cells with cycle day information", () => {
      render(<MonthView {...baseProps} />);

      // With lastPeriodDate = Jan 1 and cycleLength = 28:
      // Day 1 appears twice (Jan 1 = Day 1, Jan 29 = Day 1 due to cycle rollover)
      // Day 15 appears once (Jan 15)
      const day1Elements = screen.getAllByText("Day 1");
      expect(day1Elements.length).toBeGreaterThanOrEqual(1);
      expect(screen.getByText("Day 15")).toBeInTheDocument();
    });

    it("highlights today's date", () => {
      render(<MonthView {...baseProps} />);

      // Jan 15 is "today" - aria-label includes date, cycle day, and phase
      // For 28-day cycle, day 15 is EARLY_LUTEAL (days 15-21)
      const todayCell = screen.getByRole("button", {
        name: /January 15, 2026 - Cycle day 15 - Early Luteal phase \(today\)/i,
      });
      expect(todayCell).toHaveClass("ring-2", "ring-black");
    });

    it("does not highlight non-today dates", () => {
      render(<MonthView {...baseProps} />);

      // Jan 1 is not today - aria-label includes date, cycle day, and phase
      const otherCell = screen.getByRole("button", {
        name: /January 1, 2026 - Cycle day 1 - Menstrual phase$/i,
      });
      expect(otherCell).not.toHaveClass("ring-2");
    });
  });

  describe("phase colors", () => {
    it("applies menstrual phase color to days 1-3", () => {
      render(<MonthView {...baseProps} />);

      // Days 1-3 are MENSTRUAL (bg-blue-100)
      const day1 = screen.getByRole("button", {
        name: /January 1, 2026 - Cycle day 1 - Menstrual phase/i,
      });
      expect(day1).toHaveClass("bg-blue-100");
    });

    it("applies follicular phase color to days 4-12", () => {
      render(<MonthView {...baseProps} />);

      // For 28-day cycle, FOLLICULAR is days 4-12
      const day5 = screen.getByRole("button", {
        name: /January 5, 2026 - Cycle day 5 - Follicular phase/i,
      });
      expect(day5).toHaveClass("bg-green-100");
    });

    it("applies ovulation phase color to days 13-14", () => {
      render(<MonthView {...baseProps} />);

      // For 28-day cycle, OVULATION is days 13-14
      const day13 = screen.getByRole("button", {
        name: /January 13, 2026 - Cycle day 13 - Ovulation phase/i,
      });
      expect(day13).toHaveClass("bg-purple-100");
    });

    it("applies early luteal phase color to days 15-21", () => {
      render(<MonthView {...baseProps} />);

      // For 28-day cycle, EARLY_LUTEAL is days 15-21
      const day18 = screen.getByRole("button", {
        name: /January 18, 2026 - Cycle day 18 - Early Luteal phase/i,
      });
      expect(day18).toHaveClass("bg-yellow-100");
    });

    it("applies late luteal phase color to days 22-28", () => {
      render(<MonthView {...baseProps} />);

      // For 28-day cycle, LATE_LUTEAL is days 22-28
      const day25 = screen.getByRole("button", {
        name: /January 25, 2026 - Cycle day 25 - Late Luteal phase/i,
      });
      expect(day25).toHaveClass("bg-red-100");
    });
  });

  describe("navigation", () => {
    it("renders previous month button", () => {
      render(<MonthView {...baseProps} />);

      expect(
        screen.getByRole("button", { name: /previous month/i }),
      ).toBeInTheDocument();
    });

    it("renders next month button", () => {
      render(<MonthView {...baseProps} />);

      expect(
        screen.getByRole("button", { name: /next month/i }),
      ).toBeInTheDocument();
    });

    it("renders Today button", () => {
      render(<MonthView {...baseProps} />);

      expect(
        screen.getByRole("button", { name: /^today$/i }),
      ).toBeInTheDocument();
    });

    it("calls onMonthChange with previous month when clicking previous", () => {
      const onMonthChange = vi.fn();
      render(<MonthView {...baseProps} onMonthChange={onMonthChange} />);

      const prevButton = screen.getByRole("button", {
        name: /previous month/i,
      });
      fireEvent.click(prevButton);

      expect(onMonthChange).toHaveBeenCalledWith(2025, 11); // December 2025
    });

    it("calls onMonthChange with next month when clicking next", () => {
      const onMonthChange = vi.fn();
      render(<MonthView {...baseProps} onMonthChange={onMonthChange} />);

      const nextButton = screen.getByRole("button", { name: /next month/i });
      fireEvent.click(nextButton);

      expect(onMonthChange).toHaveBeenCalledWith(2026, 1); // February 2026
    });

    it("calls onMonthChange with current month when clicking Today", () => {
      const onMonthChange = vi.fn();
      // Render a different month than current (March 2026)
      render(
        <MonthView
          {...baseProps}
          year={2026}
          month={2}
          onMonthChange={onMonthChange}
        />,
      );

      const todayButton = screen.getByRole("button", { name: /^today$/i });
      fireEvent.click(todayButton);

      // Should navigate to January 2026 (month of mocked "today")
      expect(onMonthChange).toHaveBeenCalledWith(2026, 0);
    });
  });

  describe("phase legend", () => {
    it("renders phase legend", () => {
      render(<MonthView {...baseProps} />);

      expect(screen.getByText(/menstrual/i)).toBeInTheDocument();
      expect(screen.getByText(/follicular/i)).toBeInTheDocument();
      expect(screen.getByText(/ovulation/i)).toBeInTheDocument();
      expect(screen.getByText(/early luteal/i)).toBeInTheDocument();
      expect(screen.getByText(/late luteal/i)).toBeInTheDocument();
    });
  });

  describe("cycle rollover", () => {
    it("handles cycle rollover correctly", () => {
      // Last period was Dec 5, 2025 with 28-day cycle
      // Jan 1, 2026 = day 28 of cycle
      // Jan 2, 2026 = day 1 of new cycle
      render(
        <MonthView
          {...baseProps}
          lastPeriodDate={new Date("2025-12-05")}
          cycleLength={28}
        />,
      );

      // Jan 1 should be day 28 (late luteal)
      // Button now has aria-label with full date, cycle day, and phase
      const jan1 = screen.getByRole("button", {
        name: /January 1, 2026 - Cycle day 28 - Late Luteal phase/i,
      });
      expect(jan1).toHaveClass("bg-red-100"); // LATE_LUTEAL

      // Jan 2 should be day 1 (menstrual)
      const jan2 = screen.getByRole("button", {
        name: /January 2, 2026 - Cycle day 1 - Menstrual phase/i,
      });
      expect(jan2).toHaveClass("bg-blue-100"); // MENSTRUAL
    });
  });

  describe("different month displays", () => {
    it("renders February 2026 correctly", () => {
      render(<MonthView {...baseProps} month={1} />);

      expect(screen.getByText("February 2026")).toBeInTheDocument();
      // February 2026 has 28 days (not a leap year)
      expect(screen.getByText("28")).toBeInTheDocument();
      expect(screen.queryByText("29")).not.toBeInTheDocument();
    });

    it("renders leap year February correctly", () => {
      render(<MonthView {...baseProps} year={2024} month={1} />);

      expect(screen.getByText("February 2024")).toBeInTheDocument();
      // February 2024 has 29 days (leap year)
      expect(screen.getByText("29")).toBeInTheDocument();
    });
  });

  describe("keyboard navigation", () => {
    // For 28-day cycle:
    // MENSTRUAL: 1-3, FOLLICULAR: 4-12, OVULATION: 13-14, EARLY_LUTEAL: 15-21, LATE_LUTEAL: 22-28
    it("moves focus to next day when pressing ArrowRight", () => {
      render(<MonthView {...baseProps} />);

      // Focus on Jan 15 (today) - for 28-day cycle, day 15 is EARLY_LUTEAL
      const jan15 = screen.getByRole("button", {
        name: /January 15, 2026 - Cycle day 15 - Early Luteal phase \(today\)/i,
      });
      jan15.focus();

      // Press ArrowRight to move to Jan 16 - day 16 is EARLY_LUTEAL
      fireEvent.keyDown(jan15, { key: "ArrowRight" });

      const jan16 = screen.getByRole("button", {
        name: /January 16, 2026 - Cycle day 16 - Early Luteal phase$/i,
      });
      expect(document.activeElement).toBe(jan16);
    });

    it("moves focus to previous day when pressing ArrowLeft", () => {
      render(<MonthView {...baseProps} />);

      // Focus on Jan 15 (today) - for 28-day cycle, day 15 is EARLY_LUTEAL
      const jan15 = screen.getByRole("button", {
        name: /January 15, 2026 - Cycle day 15 - Early Luteal phase \(today\)/i,
      });
      jan15.focus();

      // Press ArrowLeft to move to Jan 14 - day 14 is OVULATION
      fireEvent.keyDown(jan15, { key: "ArrowLeft" });

      const jan14 = screen.getByRole("button", {
        name: /January 14, 2026 - Cycle day 14 - Ovulation phase$/i,
      });
      expect(document.activeElement).toBe(jan14);
    });

    it("moves focus to same day next week when pressing ArrowDown", () => {
      render(<MonthView {...baseProps} />);

      // Focus on Jan 15 (today) - for 28-day cycle, day 15 is EARLY_LUTEAL
      const jan15 = screen.getByRole("button", {
        name: /January 15, 2026 - Cycle day 15 - Early Luteal phase \(today\)/i,
      });
      jan15.focus();

      // Press ArrowDown to move to Jan 22 (7 days later) - day 22 is LATE_LUTEAL
      fireEvent.keyDown(jan15, { key: "ArrowDown" });

      const jan22 = screen.getByRole("button", {
        name: /January 22, 2026 - Cycle day 22 - Late Luteal phase$/i,
      });
      expect(document.activeElement).toBe(jan22);
    });

    it("moves focus to same day previous week when pressing ArrowUp", () => {
      render(<MonthView {...baseProps} />);

      // Focus on Jan 15 (today) - for 28-day cycle, day 15 is EARLY_LUTEAL
      const jan15 = screen.getByRole("button", {
        name: /January 15, 2026 - Cycle day 15 - Early Luteal phase \(today\)/i,
      });
      jan15.focus();

      // Press ArrowUp to move to Jan 8 (7 days earlier) - day 8 is FOLLICULAR
      fireEvent.keyDown(jan15, { key: "ArrowUp" });

      const jan8 = screen.getByRole("button", {
        name: /January 8, 2026 - Cycle day 8 - Follicular phase$/i,
      });
      expect(document.activeElement).toBe(jan8);
    });

    it("calls onMonthChange when navigating past end of month with ArrowRight", () => {
      const onMonthChange = vi.fn();
      render(<MonthView {...baseProps} onMonthChange={onMonthChange} />);

      // Focus on Jan 31 (last day of month)
      // With lastPeriod Jan 1, cycleLength 28: Jan 31 = cycle day 3 (MENSTRUAL)
      const jan31 = screen.getByRole("button", {
        name: /January 31, 2026 - Cycle day 3 - Menstrual phase$/i,
      });
      jan31.focus();

      // Press ArrowRight - should trigger month change to February
      fireEvent.keyDown(jan31, { key: "ArrowRight" });

      expect(onMonthChange).toHaveBeenCalledWith(2026, 1);
    });

    it("calls onMonthChange when navigating before start of month with ArrowLeft", () => {
      const onMonthChange = vi.fn();
      render(<MonthView {...baseProps} onMonthChange={onMonthChange} />);

      // Focus on Jan 1 (first day of month)
      const jan1 = screen.getByRole("button", {
        name: /January 1, 2026 - Cycle day 1 - Menstrual phase$/i,
      });
      jan1.focus();

      // Press ArrowLeft - should trigger month change to December 2025
      fireEvent.keyDown(jan1, { key: "ArrowLeft" });

      expect(onMonthChange).toHaveBeenCalledWith(2025, 11);
    });

    it("wraps focus at row boundaries for Home and End keys", () => {
      render(<MonthView {...baseProps} />);

      // Focus on Jan 15 - for 28-day cycle, day 15 is EARLY_LUTEAL
      const jan15 = screen.getByRole("button", {
        name: /January 15, 2026 - Cycle day 15 - Early Luteal phase \(today\)/i,
      });
      jan15.focus();

      // Press Home to move to first day of month
      fireEvent.keyDown(jan15, { key: "Home" });

      const jan1 = screen.getByRole("button", {
        name: /January 1, 2026 - Cycle day 1 - Menstrual phase$/i,
      });
      expect(document.activeElement).toBe(jan1);
    });

    it("moves focus to last day when pressing End key", () => {
      render(<MonthView {...baseProps} />);

      // Focus on Jan 15 - for 28-day cycle, day 15 is EARLY_LUTEAL
      const jan15 = screen.getByRole("button", {
        name: /January 15, 2026 - Cycle day 15 - Early Luteal phase \(today\)/i,
      });
      jan15.focus();

      // Press End to move to last day of month
      fireEvent.keyDown(jan15, { key: "End" });

      // With lastPeriod Jan 1, cycleLength 28: Jan 31 = cycle day 3 (MENSTRUAL)
      const jan31 = screen.getByRole("button", {
        name: /January 31, 2026 - Cycle day 3 - Menstrual phase$/i,
      });
      expect(document.activeElement).toBe(jan31);
    });

    it("calendar grid has proper role for accessibility", () => {
      render(<MonthView {...baseProps} />);

      expect(screen.getByRole("grid")).toBeInTheDocument();
    });
  });
});