jobtrackingapp/JobTrackerApi.Tests/RulesEngineProspectTests.cs

using System;
using JobTrackerApi.Models;
using JobTrackerApi.Services;
using Xunit;

namespace JobTrackerApi.Tests;

/// <summary>
/// Guards the rule that matters most after Phase 0 added pre-application stages: a job the user
/// has not applied to must never be chased for a reply or auto-ghosted. Nothing was submitted,
/// so there is nobody to follow up with and nobody to be ghosted by.
/// </summary>
public sealed class RulesEngineProspectTests
{
    private static readonly RuleSettings AggressiveSettings = new()
    {
        Id = 1,
        AppliedFollowUpDays = 1,
        AppliedGhostDays = 2,
        OfferFollowUpDays = 1,
        OfferGhostDays = 2,
        FeedbackFollowUpDays = 1,
        FeedbackGhostDays = 2,
    };

    private static readonly DateTime Now = new(2026, 7, 17, 12, 0, 0, DateTimeKind.Utc);

    [Theory]
    [InlineData("Saved")]
    [InlineData("Interested")]
    [InlineData("Preparing")]
    public void A_prospect_is_never_followed_up_or_ghosted_however_old(string status)
    {
        // Saved a year ago with thresholds of 1-2 days: an unguarded rule would ghost this.
        var job = new JobApplication
        {
            Status = status,
            DateApplied = null,
            SavedAt = Now.AddDays(-365),
        };

        var decision = RulesEngine.Evaluate(AggressiveSettings, job, Now, lastMessageAt: null);

        Assert.False(decision.NeedsFollowUp);
        Assert.False(decision.ShouldGhost);
    }

    [Fact]
    public void An_applied_job_with_no_applied_date_is_not_ghosted()
    {
        // Shouldn't happen (SyncAppliedDate stamps on the way into Applied), but a null must fail
        // safe rather than be read as "infinitely old" and silently ghost the job.
        var job = new JobApplication
        {
            Status = "Applied",
            DateApplied = null,
            SavedAt = Now.AddDays(-365),
        };

        var decision = RulesEngine.Evaluate(AggressiveSettings, job, Now, lastMessageAt: null);

        Assert.False(decision.NeedsFollowUp);
        Assert.False(decision.ShouldGhost);
    }

    [Fact]
    public void An_applied_job_past_the_threshold_still_ghosts()
    {
        // The guards above must not have disabled the actual rule.
        var job = new JobApplication
        {
            Status = "Applied",
            DateApplied = Now.AddDays(-30),
            SavedAt = Now.AddDays(-31),
        };

        var decision = RulesEngine.Evaluate(AggressiveSettings, job, Now, lastMessageAt: null);

        Assert.True(decision.NeedsFollowUp);
        Assert.True(decision.ShouldGhost);
    }
}