using Campaign_Tracker.Server.ExtensionData;
using Campaign_Tracker.Server.LegacyData;
using Campaign_Tracker.Server.LegacyData.Models;

namespace Campaign_Tracker.Server.Tests;

public sealed class LegacyLinkIntegrityServiceTests
{
    private static readonly DateTimeOffset FixedNow =
        new(2026, 5, 6, 12, 0, 0, TimeSpan.Zero);

    private static LegacyLinkIntegrityService BuildSut(
        ILegacyDataAccess data,
        params ILegacyLinkedRecordProvider[] providers)
    {
        var validator = new LegacyLinkValidator(data);
        var time = new FakeTimeProvider(FixedNow);
        return new LegacyLinkIntegrityService(providers, validator, time);
    }

    // ── AC #4 — nightly integrity check with no extension records ────────────

    [Fact]
    public async Task CheckAsync_NoProviders_ReturnsFullyConsistentReport_AC4()
    {
        var sut = BuildSut(new InMemoryLegacyDataAccess());

        var report = await sut.CheckAsync();

        Assert.True(report.IsConsistent);
        Assert.Equal(0, report.TotalRecords);
        Assert.Equal(0, report.FailedRecords);
        Assert.Equal(100.0, report.ConsistencyPercentage);
        Assert.Empty(report.Failures);
        Assert.Equal(FixedNow, report.CheckedAt);
    }

    // ── AC #4 — consistent records produce clean report ──────────────────────

    [Fact]
    public async Task CheckAsync_AllValidLinks_Reports100PercentConsistency_AC4()
    {
        var data = new InMemoryLegacyDataAccess(
            jurisdictions: [new("FAIR01", "Fairview", null, null, null, null)]);

        var provider = new StubProvider(
        [
            new StubRecord("MunicipalityProfile", "mp-001", LegacyLinkReference.ForJurisdiction("FAIR01")),
            new StubRecord("MunicipalityProfile", "mp-002", LegacyLinkReference.ForJurisdiction("FAIR01")),
        ]);

        var sut = BuildSut(data, provider);
        var report = await sut.CheckAsync();

        Assert.True(report.IsConsistent);
        Assert.Equal(2, report.TotalRecords);
        Assert.Equal(2, report.ConsistentRecords);
        Assert.Equal(0, report.FailedRecords);
        Assert.Equal(100.0, report.ConsistencyPercentage);
        Assert.Empty(report.Failures);
    }

    // ── AC #4 — failing links are flagged with descriptive reason ────────────

    [Fact]
    public async Task CheckAsync_InvalidLink_FlagsRecordWithReason_AC4()
    {
        var data = new InMemoryLegacyDataAccess(jurisdictions: []);

        var provider = new StubProvider(
        [
            new StubRecord("MunicipalityProfile", "mp-ghost", LegacyLinkReference.ForJurisdiction("GONE01")),
        ]);

        var sut = BuildSut(data, provider);
        var report = await sut.CheckAsync();

        Assert.False(report.IsConsistent);
        Assert.Equal(1, report.TotalRecords);
        Assert.Equal(0, report.ConsistentRecords);
        Assert.Equal(1, report.FailedRecords);
        Assert.Single(report.Failures);

        var failure = report.Failures[0];
        Assert.Equal("MunicipalityProfile", failure.RecordType);
        Assert.Equal("mp-ghost", failure.RecordId);
        Assert.Equal(LegacyLinkType.JurisdictionJCode, failure.Reference.Type);
        Assert.Equal("GONE01", failure.Reference.Value);
        Assert.Contains("GONE01", failure.Reason);
    }

    [Fact]
    public async Task CheckAsync_MixedValidity_ReportsCorrectConsistencyPercentage_AC4()
    {
        var data = new InMemoryLegacyDataAccess(
            jurisdictions: [new("GOOD01", "Good", null, null, null, null)]);

        var provider = new StubProvider(
        [
            new StubRecord("MunicipalityProfile", "mp-good", LegacyLinkReference.ForJurisdiction("GOOD01")),
            new StubRecord("MunicipalityProfile", "mp-bad",  LegacyLinkReference.ForJurisdiction("MISSING")),
        ]);

        var sut = BuildSut(data, provider);
        var report = await sut.CheckAsync();

        Assert.False(report.IsConsistent);
        Assert.Equal(2, report.TotalRecords);
        Assert.Equal(1, report.ConsistentRecords);
        Assert.Equal(1, report.FailedRecords);
        Assert.Equal(50.0, report.ConsistencyPercentage);
    }

    // ── AC #4 — multiple providers aggregate correctly ───────────────────────

    [Fact]
    public async Task CheckAsync_MultipleProviders_AggregatesAllRecords_AC4()
    {
        var data = new InMemoryLegacyDataAccess(
            jurisdictions: [new("FAIR01", "Fairview", null, null, null, null)],
            kits: [new LegacyKit(101, "FAIR01", null, null, null, null, false, false, null, null, null, null, null, null)]);

        var providerA = new StubProvider(
        [
            new StubRecord("MunicipalityProfile", "mp-001", LegacyLinkReference.ForJurisdiction("FAIR01")),
        ]);
        var providerB = new StubProvider(
        [
            new StubRecord("ElectionJob", "ej-001", LegacyLinkReference.ForKit(101)),
        ]);

        var sut = BuildSut(data, providerA, providerB);
        var report = await sut.CheckAsync();

        Assert.True(report.IsConsistent);
        Assert.Equal(2, report.TotalRecords);
        Assert.Equal(0, report.FailedRecords);
    }

    // ── Helpers ───────────────────────────────────────────────────────────────

    private sealed class StubRecord(string recordType, string recordId, LegacyLinkReference link)
        : ILegacyLinkedRecord
    {
        public string RecordType => recordType;
        public string RecordId => recordId;
        public LegacyLinkReference LegacyLink => link;
    }

    private sealed class StubProvider(IReadOnlyList<ILegacyLinkedRecord> records)
        : ILegacyLinkedRecordProvider
    {
        public Task<IReadOnlyList<ILegacyLinkedRecord>> GetAllAsync(CancellationToken cancellationToken = default)
            => Task.FromResult(records);
    }

    private sealed class FakeTimeProvider(DateTimeOffset utcNow) : TimeProvider
    {
        public override DateTimeOffset GetUtcNow() => utcNow;
    }
}