using Jiaowu.Api.Domain.Academic;
using Jiaowu.Api.Infrastructure.CourseSelection;

namespace Jiaowu.Api.Tests;

public sealed class CourseSelectionRulesTests
{
    [Fact]
    public void Selection_requires_open_status_and_active_window()
    {
        var now = new DateTime(2026, 7, 24, 8, 0, 0, DateTimeKind.Utc);
        var round = CreateRound(now.AddHours(-1), now.AddHours(1));

        Assert.True(CourseSelectionRules.IsSelectionOpen(round, now));

        round.Status = CourseSelectionRoundStatus.Closed;
        Assert.False(CourseSelectionRules.IsSelectionOpen(round, now));

        round.Status = CourseSelectionRoundStatus.Open;
        Assert.False(CourseSelectionRules.IsSelectionOpen(round, now.AddHours(2)));
    }

    [Fact]
    public void Withdrawal_respects_deadline()
    {
        var now = new DateTime(2026, 7, 24, 8, 0, 0, DateTimeKind.Utc);
        var round = CreateRound(now.AddDays(-1), now.AddDays(1));
        round.WithdrawalEndsAt = now.AddMinutes(30);

        Assert.True(CourseSelectionRules.CanWithdraw(round, now));
        Assert.False(CourseSelectionRules.CanWithdraw(round, now.AddHours(1)));
    }

    [Fact]
    public void Schedule_conflict_detects_overlapping_weeks_and_periods()
    {
        var selected = CreateEntry(1, 1, 2, 1, 16, WeekPattern.All);
        var overlapping = CreateEntry(1, 2, 2, 1, 16, WeekPattern.All);

        Assert.True(CourseSelectionRules.HasScheduleConflict(
            [overlapping],
            [selected]));
    }

    [Fact]
    public void Odd_and_even_week_entries_do_not_conflict()
    {
        var selected = CreateEntry(3, 5, 2, 1, 16, WeekPattern.Odd);
        var candidate = CreateEntry(3, 5, 2, 1, 16, WeekPattern.Even);

        Assert.False(CourseSelectionRules.HasScheduleConflict(
            [candidate],
            [selected]));
    }

    [Theory]
    [InlineData(CourseNature.GeneralRequired, true)]
    [InlineData(CourseNature.GeneralElective, false)]
    [InlineData(CourseNature.MajorRequired, false)]
    [InlineData(CourseNature.MajorElective, false)]
    [InlineData(CourseNature.Practice, false)]
    public void Proxy_enrollment_is_limited_to_general_required_courses(
        CourseNature nature,
        bool expected)
    {
        Assert.Equal(expected, CourseSelectionRules.SupportsProxyEnrollment(nature));
    }

    private static CourseSelectionRound CreateRound(DateTime startsAt, DateTime endsAt) =>
        new()
        {
            Name = "第一轮选课",
            StartsAt = startsAt,
            EndsAt = endsAt,
            WithdrawalEndsAt = endsAt.AddDays(1),
            Status = CourseSelectionRoundStatus.Open
        };

    private static ScheduleEntry CreateEntry(
        int dayOfWeek,
        int startPeriod,
        int periodCount,
        int startWeek,
        int endWeek,
        WeekPattern weekPattern) =>
        new()
        {
            DayOfWeek = dayOfWeek,
            StartPeriod = startPeriod,
            PeriodCount = periodCount,
            StartWeek = startWeek,
            EndWeek = endWeek,
            WeekPattern = weekPattern
        };
}