using System;
using System.Linq;
using Xunit;
using ytLive.Models;
using ytLive.Services;

namespace ytLive.Tests;

/// <summary>
/// TASK 39·2 — the three eligibility bars. The rules worth pinning: the view criteria are EITHER/OR (so
/// "2 of 3" can mean eligible), the long-form bar doubles on 2027-02-01, and the threshold table carries a
/// publication date that fails a test when it goes stale — YouTube moves the goalposts and a stale bar
/// must not look current.
/// </summary>
public class YppProgressTests
{
    [Fact]
    public void TwoOfThreeCanBeEligible_BecauseTheViewRoutesAreEitherOr()
    {
        var progress = new YppProgress(
            Subscribers: 1_200, SubscriberTarget: 1_000,
            WatchHours: 4_500, WatchHoursTarget: 4_000,
            ShortsViews: 10_000, ShortsViewsTarget: 10_000_000);

        Assert.Equal(2, progress.CriteriaMet);
        Assert.True(progress.MeetsPublishedRule);
        Assert.Equal("2 of 3 criteria met — YouTube reviews eligibility.", progress.CriteriaMetText);
    }

    [Fact]
    public void SubscribersWithoutEitherViewRoute_IsNotEnough()
    {
        var progress = new YppProgress(2_000, 1_000, 100, 4_000, 5_000, 10_000_000);

        Assert.Equal(1, progress.CriteriaMet);
        Assert.False(progress.MeetsPublishedRule);
        Assert.Equal("1 of 3 criteria met — YouTube reviews eligibility.", progress.CriteriaMetText);
    }

    [Fact]
    public void ShortsAlone_IsAQualifyingRoute()
    {
        var progress = new YppProgress(1_000, 1_000, 0, 4_000, 12_000_000, 10_000_000);

        Assert.Equal(2, progress.CriteriaMet);
        Assert.True(progress.MeetsPublishedRule);
    }

    [Fact]
    public void BarsClampAndNeverOverflow()
    {
        var progress = new YppProgress(5_000, 1_000, 20_000, 4_000, 50_000_000, 10_000_000);

        Assert.Equal(1.0, progress.SubscribersFraction);
        Assert.Equal(1.0, progress.WatchHoursFraction);
        Assert.Equal(1.0, progress.ShortsViewsFraction);
        Assert.Equal(3, progress.CriteriaMet);
    }

    [Fact]
    public void TheLongFormBarDoublesOnTheAnnouncedDate()
    {
        var before = YppThresholds.Tier2For(new DateTime(2027, 1, 31));
        var after = YppThresholds.Tier2For(new DateTime(2027, 2, 1));

        Assert.Equal(4_000, before.WatchHours);
        Assert.Equal(8_000, after.WatchHours);
        Assert.Equal(10_000_000, before.ShortsViews);
        Assert.Equal(20_000_000, after.ShortsViews);
    }

    [Fact]
    public void ThresholdsCarryAPublicationDate_ThatFailsWhenStale()
    {
        // YouTube changes these. If the reading is over 180 days old, the drawer would be presenting a
        // stale bar as current — so the suite refuses to pass until someone re-checks the numbers.
        var age = DateTime.UtcNow - YppThresholds.AsOfUtc;
        Assert.True(age < TimeSpan.FromDays(180),
            $"YPP thresholds were last read on {YppThresholds.AsOfUtc:yyyy-MM-dd} — re-check YouTube's published requirements.");
    }

    [Fact]
    public void AnalyticsResponse_ParsesTheTotal_AndTreatsNoRowsAsNoData()
    {
        Assert.Equal(123_456, YouTubeAnalyticsService.ParseTotal(
            """{"columnHeaders":[{"name":"estimatedMinutesWatched"}],"rows":[[123456]]}"""));

        // A channel with nothing in the window returns no rows: that is "no data", not zero.
        Assert.Null(YouTubeAnalyticsService.ParseTotal("""{"columnHeaders":[]}"""));
        Assert.Null(YouTubeAnalyticsService.ParseTotal("""{"rows":[]}"""));
    }

    [Theory]
    [InlineData(640, "640")]
    [InlineData(12_345, "12.3k")]
    [InlineData(1_234_567, "1.23M")]
    public void ValuesStayCompactAndStableInWidth(long value, string expected)
        => Assert.Equal(expected, YppProgress.Compact(value));
}