using System.Security.Claims;
using System.Text.Json;
using JobTrackerApi.Controllers;
using JobTrackerApi.Data;
using JobTrackerApi.Models;
using JobTrackerApi.Services;
using JobTrackerApi.Tests.TestSupport;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Data.Sqlite;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Moq;
using Xunit;

namespace JobTrackerApi.Tests;

public sealed class Rd21CareerPersistenceTests
{
    private static JobTrackerContext Context(SqliteConnection connection, IInterceptor? interceptor = null)
    {
        var current = new Mock<ICurrentUserService>();
        current.SetupGet(x => x.UserId).Returns("rd21-owner");
        var options = new DbContextOptionsBuilder<JobTrackerContext>().UseSqlite(connection);
        if (interceptor is not null) options.AddInterceptors(interceptor);
        return new(options.Options, current.Object);
    }

    private static CareerProfileController Controller(JobTrackerContext db, bool identitySucceeds = true)
        => new(Users(db, identitySucceeds).Object, new CareerProfileService(db), db)
        {
            ControllerContext = new() { HttpContext = new DefaultHttpContext() },
        };

    private static Mock<UserManager<ApplicationUser>> Users(JobTrackerContext db, bool identitySucceeds)
    {
        var user = db.Users.Single();
        var users = TestHostFactory.CreateUserManager();
        users.Setup(x => x.GetUserAsync(It.IsAny<ClaimsPrincipal>())).ReturnsAsync(user);
        users.Setup(x => x.UpdateAsync(user)).Returns(async () =>
        {
            if (!identitySucceeds) return IdentityResult.Failed(new IdentityError { Description = "Synthetic Identity failure" });
            await db.SaveChangesAsync();
            return IdentityResult.Success;
        });
        return users;
    }

    private static ProfileCvController ImportController(JobTrackerContext db, bool identitySucceeds = true) =>
        new(Users(db, identitySucceeds).Object, new Mock<ISummarizerService>().Object, db, null!)
        { ControllerContext = new() { HttpContext = new DefaultHttpContext() } };

    private static CareerProfileSaveRequest Request(string title, int? expectedVersion) =>
        JsonSerializer.Deserialize<CareerProfileSaveRequest>(JsonSerializer.Serialize(new
        {
            profile = new StructuredCvProfile { Jobs = { new() { Id = "stable-role", Title = title } } },
            expectedVersion,
        }), new JsonSerializerOptions(JsonSerializerDefaults.Web))!;

    [Fact]
    public async Task Independent_stale_snapshot_cannot_replace_acknowledged_career_edit()
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using (var seed = Context(connection))
        {
            await seed.Database.EnsureCreatedAsync();
            seed.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic" });
            await seed.SaveChangesAsync();
            Assert.IsType<OkObjectResult>((await Controller(seed).Put(Request("Original", 0), default)).Result);
        }
        await using var first = Context(connection);
        await using var stale = Context(connection);
        var staleController = Controller(stale);
        var source = Assert.IsType<CareerProfileDto>(Assert.IsType<OkObjectResult>((await staleController.Get(default)).Result).Value);
        Assert.Equal(1, source.Revision);
        Assert.Equal("Original", source.Profile.Jobs.Single().Title);
        Assert.IsType<OkObjectResult>((await Controller(first).Put(Request("Acknowledged winner", 1), default)).Result);
        var rejected = await staleController.Put(Request("Stale draft", 1), default);
        Assert.IsType<ConflictObjectResult>(rejected.Result);
        await stale.SaveChangesAsync();
        await using var verify = Context(connection);
        Assert.Equal("Acknowledged winner", (await verify.CareerExperiences.SingleAsync()).Title);
        Assert.Equal(2, (await verify.CareerProfiles.SingleAsync()).Version);
        Assert.Equal(2, await verify.CareerProfileVersions.CountAsync());
        Assert.Contains("Acknowledged winner", (await verify.Users.SingleAsync()).ProfileCvStructureJson);
    }

    [Fact]
    public async Task Identity_failure_rolls_back_canonical_children_history_and_projection()
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var db = Context(connection);
        await db.Database.EnsureCreatedAsync();
        db.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic" });
        await db.SaveChangesAsync();
        var result = await Controller(db, false).Put(Request("Must not persist", 0), default);
        Assert.IsType<BadRequestObjectResult>(result.Result);
        await db.SaveChangesAsync();
        await using var verify = Context(connection);
        Assert.Empty(await verify.CareerProfiles.ToListAsync());
        Assert.Empty(await verify.CareerExperiences.ToListAsync());
        Assert.Empty(await verify.CareerProfileVersions.ToListAsync());
        Assert.Null((await verify.Users.SingleAsync()).ProfileCvStructureJson);
    }

    [Fact]
    public async Task Stale_tracked_entity_is_guarded_at_database_update_and_stale_restore_is_rejected()
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var first = Context(connection);
        await first.Database.EnsureCreatedAsync();
        var a = new CareerProfileService(first);
        await a.SaveVersionAsync("rd21-owner", new() { Jobs = { new() { Id = "role", Title = "Original" } } }, "manual", 0, default);
        await using var stale = Context(connection);
        await stale.CareerProfiles.SingleAsync();
        await a.SaveVersionAsync("rd21-owner", new() { Jobs = { new() { Id = "role", Title = "Winner" } } }, "manual", 1, default);
        var b = new CareerProfileService(stale);
        await Assert.ThrowsAsync<DbUpdateConcurrencyException>(() => b.SaveVersionAsync("rd21-owner", new() { Jobs = { new() { Title = "Stale" } } }, "manual", 1, default));
        await stale.SaveChangesAsync();
        await Assert.ThrowsAsync<DbUpdateConcurrencyException>(() => b.RestoreVersionAsync("rd21-owner", 1, 1, default));
        await using var verify = Context(connection);
        Assert.Equal("Winner", (await verify.CareerExperiences.SingleAsync()).Title);
        Assert.Equal(2, await verify.CareerProfileVersions.CountAsync());
        Assert.Equal(0, (await b.LoadSnapshotAsync("another-owner", default)).Revision);
    }

    [Fact]
    public async Task Competing_first_save_sources_have_one_acknowledged_winner()
    {
        var path = Path.Combine(Path.GetTempPath(), $"rd21-first-save-{Guid.NewGuid():N}.db");
        try
        {
            await using (var setupConnection = new SqliteConnection($"Data Source={path};Pooling=False"))
            {
                await setupConnection.OpenAsync();
                await using var setup = Context(setupConnection);
                await setup.Database.EnsureCreatedAsync();
                setup.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic" });
                await setup.SaveChangesAsync();
            }
            using var ready = new Barrier(2);
            async Task<IActionResult?> Save(string title) => await Task.Run(async () =>
            {
                await using var connection = new SqliteConnection($"Data Source={path};Pooling=False");
                await connection.OpenAsync();
                await using var db = Context(connection);
                var controller = Controller(db);
                Assert.Equal(0, Assert.IsType<CareerProfileDto>(Assert.IsType<OkObjectResult>((await controller.Get(default)).Result).Value).Revision);
                Assert.True(ready.SignalAndWait(TimeSpan.FromSeconds(10)));
                return (await controller.Put(Request(title, 0), default)).Result;
            });
            var outcomes = await Task.WhenAll(Save("Candidate A"), Save("Candidate B"));
            Assert.Single(outcomes.OfType<OkObjectResult>());
            Assert.Single(outcomes.OfType<ConflictObjectResult>());
            await using var verifyConnection = new SqliteConnection($"Data Source={path};Pooling=False");
            await verifyConnection.OpenAsync();
            await using var verify = Context(verifyConnection);
            var profile = await verify.CareerProfiles.SingleAsync();
            Assert.Equal(1, profile.Version);
            Assert.Single(await verify.CareerProfileVersions.ToListAsync());
            Assert.Equal(profile.ProfileJson, (await verify.Users.SingleAsync()).ProfileCvStructureJson);
            Assert.Equal(StructuredCvProfileJson.DeserializePersisted(profile.ProfileJson).Jobs.Single().Title, (await verify.CareerExperiences.SingleAsync()).Title);
        }
        finally { File.Delete(path); }
    }

    private sealed class FailAfterChildDeletion : SaveChangesInterceptor
    {
        private int _saves;
        public override ValueTask<InterceptionResult<int>> SavingChangesAsync(DbContextEventData eventData, InterceptionResult<int> result, CancellationToken cancellationToken = default)
        {
            if (++_saves == 3) throw new InvalidOperationException("Synthetic child insert failure");
            return base.SavingChangesAsync(eventData, result, cancellationToken);
        }
    }

    [Fact]
    public async Task Database_failure_after_deletion_restores_children_history_and_revision_and_clears_tracker()
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using (var seed = Context(connection))
        {
            await seed.Database.EnsureCreatedAsync();
            await new CareerProfileService(seed).SaveVersionAsync("rd21-owner", new() { Jobs = { new() { Id = "role", Title = "Original" } } }, "manual", 0, default);
        }
        await using var failed = Context(connection, new FailAfterChildDeletion());
        await Assert.ThrowsAsync<InvalidOperationException>(() => new CareerProfileService(failed).SaveVersionAsync("rd21-owner", new() { Jobs = { new() { Title = "Rejected" } } }, "manual", 1, default));
        Assert.Empty(failed.ChangeTracker.Entries());
        await failed.SaveChangesAsync();
        await using var verify = Context(connection);
        Assert.Equal("Original", (await verify.CareerExperiences.SingleAsync()).Title);
        Assert.Equal(1, (await verify.CareerProfiles.SingleAsync()).Version);
        Assert.Single(await verify.CareerProfileVersions.ToListAsync());
    }

    [Theory]
    [InlineData(null)]
    [InlineData(-1)]
    public async Task Replacement_restore_parse_and_import_fail_closed_without_valid_revision(int? expectedVersion)
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var db = Context(connection);
        await db.Database.EnsureCreatedAsync();
        db.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic" });
        await db.SaveChangesAsync();
        var controller = Controller(db);
        Assert.IsType<BadRequestObjectResult>((await controller.Put(Request("Rejected", expectedVersion), default)).Result);
        Assert.IsType<BadRequestObjectResult>((await controller.Restore(1, new(expectedVersion), default)).Result);
        var imports = ImportController(db);
        Assert.IsType<BadRequestObjectResult>((await imports.Parse(new("# Synthetic", expectedVersion))).Result);
        Assert.IsType<BadRequestObjectResult>(await imports.AcceptRun(1, new(null, expectedVersion)));
        Assert.Empty(await db.CareerProfiles.ToListAsync());
        Assert.Empty(await db.CvExtractionRuns.ToListAsync());
    }

    [Theory]
    [InlineData(true)]
    [InlineData(false)]
    public async Task Reviewed_import_commits_or_rolls_back_canonical_projection_and_application_metadata(bool identitySucceeds)
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var db = Context(connection);
        await db.Database.EnsureCreatedAsync();
        db.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic" });
        var run = new CvExtractionRun
        {
            OwnerUserId = "rd21-owner", Trigger = "upload", Status = "pending_review",
            StructuredProfileJson = StructuredCvProfileJson.Serialize(new() { Jobs = { new() { Id = "imported-role", Title = "Reviewed role" } } }),
        };
        db.CvExtractionRuns.Add(run);
        await db.SaveChangesAsync();
        var result = await ImportController(db, identitySucceeds).AcceptRun(run.Id, new(null, 0));
        if (identitySucceeds) Assert.IsType<OkObjectResult>(result);
        else Assert.IsType<BadRequestObjectResult>(result);
        await db.SaveChangesAsync();
        await using var verify = Context(connection);
        var savedRun = await verify.CvExtractionRuns.SingleAsync();
        var user = await verify.Users.SingleAsync();
        Assert.Equal(identitySucceeds ? "applied" : "pending_review", savedRun.Status);
        Assert.Equal(identitySucceeds, savedRun.AppliedAtUtc.HasValue);
        Assert.Equal(identitySucceeds, user.CurrentCvExtractionRunId.HasValue);
        Assert.Equal(identitySucceeds ? 1 : 0, await verify.CareerProfileVersions.CountAsync());
        Assert.Equal(identitySucceeds ? 1 : 0, await verify.CareerExperiences.CountAsync());
        Assert.Equal(identitySucceeds, user.ProfileCvStructureJson is not null);
    }

    [Fact]
    public async Task Import_acceptance_requires_the_revision_shown_in_its_diff()
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var db = Context(connection);
        await db.Database.EnsureCreatedAsync();
        db.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic" });
        var run = new CvExtractionRun { OwnerUserId = "rd21-owner", Trigger = "upload", Status = "pending_review", StructuredProfileJson = "{}" };
        db.CvExtractionRuns.Add(run);
        await db.SaveChangesAsync();
        var imports = ImportController(db);
        var diff = Assert.IsType<OkObjectResult>(await imports.GetRunDiff(run.Id));
        Assert.Equal(0, JsonSerializer.SerializeToElement(diff.Value).GetProperty("revision").GetInt32());
        Assert.IsType<OkObjectResult>((await Controller(db).Put(Request("Winner", 0), default)).Result);
        Assert.IsType<ConflictObjectResult>(await imports.AcceptRun(run.Id, new(null, 0)));
        await using var verify = Context(connection);
        Assert.Equal("pending_review", (await verify.CvExtractionRuns.SingleAsync()).Status);
        Assert.Equal("Winner", (await verify.CareerExperiences.SingleAsync()).Title);
    }

    [Theory]
    [InlineData(true)]
    [InlineData(false)]
    public async Task Parsing_commits_or_rolls_back_its_entire_import_application(bool identitySucceeds)
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var db = Context(connection);
        await db.Database.EnsureCreatedAsync();
        db.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic" });
        await db.SaveChangesAsync();
        const string text = "# Contact\nSynthetic Person\n\n# Professional Summary\nBuilt APIs.\n\n# Skills\nC#\nSQL";
        var result = await ImportController(db, identitySucceeds).Parse(new(text, 0));
        if (identitySucceeds) Assert.IsType<OkObjectResult>(result.Result);
        else Assert.IsType<BadRequestObjectResult>(result.Result);
        await db.SaveChangesAsync();
        await using var verify = Context(connection);
        Assert.Equal(identitySucceeds ? 1 : 0, await verify.CvExtractionRuns.CountAsync());
        Assert.Equal(identitySucceeds ? 1 : 0, await verify.CareerProfileVersions.CountAsync());
        var user = await verify.Users.SingleAsync();
        Assert.Equal(identitySucceeds, user.CurrentCvExtractionRunId.HasValue);
        Assert.Equal(identitySucceeds, user.ProfileCvStructureJson is not null);
        if (identitySucceeds)
        {
            var profile = await verify.CareerProfiles.SingleAsync();
            Assert.Equal(profile.ProfileJson, user.ProfileCvStructureJson);
            Assert.Equal(profile.ProfileJson, (await verify.CvExtractionRuns.SingleAsync()).StructuredProfileJson);
            Assert.Equal(user.ProfileCvText, (await new CareerProfileService(verify).LoadSnapshotAsync("rd21-owner", default)).CvText);
        }
    }

    [Fact]
    public async Task Editor_snapshot_uses_relational_canonical_source_and_never_writes_during_read()
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var db = Context(connection);
        await db.Database.EnsureCreatedAsync();
        db.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic", ProfileCvText = "Stored source text" });
        var profile = new CareerProfile
        {
            OwnerUserId = "rd21-owner", Version = 7,
            ProfileJson = StructuredCvProfileJson.SerializePersisted(new() { Jobs = { new() { Title = "Outdated projection" } } }),
            LongTailJson = CareerProfileMapper.SerializeLongTail(new() { Summary = { "Canonical summary" } }),
            Experiences = { new() { OwnerUserId = "rd21-owner", ItemKey = "canonical-role", Title = "Canonical role" } },
        };
        db.CareerProfiles.Add(profile);
        await db.SaveChangesAsync();
        db.ChangeTracker.Clear();
        var snapshot = await new CareerProfileService(db).LoadSnapshotAsync("rd21-owner", default);
        Assert.Equal(7, snapshot.Revision);
        Assert.Equal("Canonical role", snapshot.Profile.Jobs.Single().Title);
        Assert.Equal("canonical-role", snapshot.Profile.Jobs.Single().Id);
        Assert.Equal("Canonical summary", snapshot.Profile.Summary.Single());
        Assert.Equal("Stored source text", snapshot.CvText);
        Assert.Empty(db.ChangeTracker.Entries());
        Assert.Equal(7, (await db.CareerProfiles.SingleAsync()).Version);
        Assert.Single(await db.CareerExperiences.ToListAsync());
        Assert.Empty(await db.CareerProfileVersions.ToListAsync());
    }

    [Fact]
    public async Task Empty_canonical_profile_preserves_legacy_raw_text_in_its_revision_zero_snapshot()
    {
        await using var connection = new SqliteConnection("Data Source=:memory:");
        await connection.OpenAsync();
        await using var db = Context(connection);
        await db.Database.EnsureCreatedAsync();
        db.Users.Add(new() { Id = "rd21-owner", UserName = "synthetic", ProfileCvText = "Legacy raw CV text" });
        await db.SaveChangesAsync();
        var response = await Controller(db).Get(default);
        var dto = Assert.IsType<CareerProfileDto>(Assert.IsType<OkObjectResult>(response.Result).Value);
        Assert.Equal(0, dto.Revision);
        Assert.Empty(dto.Profile.Jobs);
        Assert.Equal("Legacy raw CV text", dto.CvText);
        Assert.Empty(await db.CareerProfiles.ToListAsync());
        Assert.Empty(await db.CareerProfileVersions.ToListAsync());
    }
}