using ClaudeDo.Data;
using ClaudeDo.Data.Models;
using ClaudeDo.Ui.ViewModels.Islands;
using Microsoft.EntityFrameworkCore;
using TaskStatus = ClaudeDo.Data.Models.TaskStatus;

namespace ClaudeDo.Ui.Tests.ViewModels;

// ClassifyItems (used by Regroup) additionally mutates every row's chain-display fields via
// ApplyChainGrouping. ClearCompletedAsync only needs section membership/counts, so it goes
// through the pure PartitionItems instead — this must not write ShowAsChainMember/ChainStep/
// ChainAfterLabel as a side effect of counting completed rows.
public class TasksIslandClassifyItemsTests : IDisposable
{
    private readonly string _dbPath;

    public TasksIslandClassifyItemsTests()
    {
        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_ui_classify_{Guid.NewGuid():N}.db");
        using var ctx = NewContext();
        ctx.Database.EnsureCreated();
    }

    public void Dispose()
    {
        try { File.Delete(_dbPath); } catch { }
        try { File.Delete(_dbPath + "-wal"); } catch { }
        try { File.Delete(_dbPath + "-shm"); } catch { }
    }

    private ClaudeDoDbContext NewContext()
    {
        var opts = new DbContextOptionsBuilder<ClaudeDoDbContext>()
            .UseSqlite($"Data Source={_dbPath}")
            .Options;
        return new ClaudeDoDbContext(opts);
    }

    private sealed class TestDbFactory : IDbContextFactory<ClaudeDoDbContext>
    {
        private readonly Func<ClaudeDoDbContext> _create;
        public TestDbFactory(Func<ClaudeDoDbContext> create) => _create = create;
        public ClaudeDoDbContext CreateDbContext() => _create();
    }

    private TasksIslandViewModel BuildViewModel()
    {
        var factory = new TestDbFactory(NewContext);
        return new TasksIslandViewModel(factory, worker: null);
    }

    private static ListNavItemViewModel UserList(string listEntityId, string name) =>
        new() { Id = $"user:{listEntityId}", Kind = ListKind.User, Name = name };

    private static async Task LoadAndWaitAsync(TasksIslandViewModel vm, ListNavItemViewModel list, int expectedCount = 1)
    {
        vm.LoadForList(list);
        var deadline = DateTime.UtcNow.AddSeconds(5);
        while (DateTime.UtcNow < deadline)
        {
            await Task.Delay(25);
            if (vm.Items.Count >= expectedCount) break;
        }
        await Task.Delay(50);
    }

    private async Task SeedAsync(
        params (string Id, TaskStatus Status, string? DependsOnTaskId, int SortOrder)[] tasks)
    {
        await using var db = NewContext();
        db.Lists.Add(new ListEntity { Id = "list1", Name = "Default", CreatedAt = DateTime.UtcNow });
        foreach (var t in tasks)
        {
            db.Tasks.Add(new TaskEntity
            {
                Number = TestTaskNumbers.Next(),
                Id = t.Id,
                ListId = "list1",
                Title = t.Id,
                CreatedAt = DateTime.UtcNow,
                Status = t.Status,
                DependsOnTaskId = t.DependsOnTaskId,
                SortOrder = t.SortOrder,
            });
        }
        await db.SaveChangesAsync();
    }

    [Fact]
    public async Task ClearCompleted_counting_path_leaves_chain_fields_untouched()
    {
        await SeedAsync(
            ("head", TaskStatus.Idle, null, 0),
            ("dep", TaskStatus.Idle, "head", 1));

        var vm = BuildViewModel();
        await LoadAndWaitAsync(vm, UserList("list1", "Default"), expectedCount: 2);

        var dep = vm.Items.Single(r => r.Id == "dep");
        // Sanity: the initial Regroup (during load) computed the chain correctly.
        Assert.True(dep.ShowAsChainMember);
        Assert.Equal(1, dep.ChainStep);

        // Corrupt the row to a sentinel distinguishable from both the correct and default value.
        dep.ShowAsChainMember = false;
        dep.ChainStep = 99;
        dep.ChainAfterLabel = "SENTINEL";

        // Nothing is completed, so ClearCompletedAsync does nothing but count via PartitionItems.
        await vm.ClearCompletedCommand.ExecuteAsync(null);

        Assert.False(dep.ShowAsChainMember);
        Assert.Equal(99, dep.ChainStep);
        Assert.Equal("SENTINEL", dep.ChainAfterLabel);
    }

    [Fact]
    public async Task Regroup_still_recomputes_chain_fields()
    {
        await SeedAsync(
            ("head", TaskStatus.Idle, null, 0),
            ("dep", TaskStatus.Idle, "head", 1));

        var vm = BuildViewModel();
        await LoadAndWaitAsync(vm, UserList("list1", "Default"), expectedCount: 2);

        var dep = vm.Items.Single(r => r.Id == "dep");
        dep.ShowAsChainMember = false;
        dep.ChainStep = 99;
        dep.ChainAfterLabel = "SENTINEL";

        vm.Regroup();

        Assert.True(dep.ShowAsChainMember);
        Assert.Equal(1, dep.ChainStep);
        Assert.Null(dep.ChainAfterLabel);
    }

    [Fact]
    public async Task ClearCompleted_still_deletes_completed_rows_and_reports_count()
    {
        await SeedAsync(
            ("open1", TaskStatus.Idle, null, 0),
            ("done1", TaskStatus.Done, null, 1),
            ("done2", TaskStatus.Done, null, 2));

        var vm = BuildViewModel();
        await LoadAndWaitAsync(vm, UserList("list1", "Default"), expectedCount: 3);
        vm.IsShowingCompleted = true;

        await vm.ClearCompletedCommand.ExecuteAsync(null);

        Assert.DoesNotContain(vm.Items, r => r.Id is "done1" or "done2");
        Assert.Contains(vm.Items, r => r.Id == "open1");
    }
}