using System.Collections.ObjectModel;
using System.ComponentModel;
using ClaudeDo.Data;
using ClaudeDo.Data.Models;
using ClaudeDo.Ui.Services;
using ClaudeDo.Ui.ViewModels.Islands;
using Microsoft.EntityFrameworkCore;
using TaskStatus = ClaudeDo.Data.Models.TaskStatus;

namespace ClaudeDo.Ui.Tests.ViewModels;

public class DetailsIslandPlanningTests : IDisposable
{
    private readonly string _dbPath;

    public DetailsIslandPlanningTests()
    {
        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_details_test_{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 sealed class FakeWorkerClient : IWorkerClient
    {
        public event PropertyChangedEventHandler? PropertyChanged;
        public event Action<string, string, DateTime>? TaskStartedEvent;
        public event Action<string, string, string, DateTime>? TaskFinishedEvent;
        public event Action<string>? TaskUpdatedEvent;
        public event Action<string>? WorktreeUpdatedEvent;
        public event Action<string, string>? TaskMessageEvent;
        public event Action<string, string>? PlanningMergeStartedEvent;
        public event Action<string, string>? PlanningSubtaskMergedEvent;
        public event Action<string, string, IReadOnlyList<string>>? PlanningMergeConflictEvent;
        public event Action<string>? PlanningMergeAbortedEvent;
        public event Action<string>? PlanningCompletedEvent;

        public bool IsConnected => false;
        public MergeTargetsDto? MergeTargetsResult { get; set; }

        public Task WakeQueueAsync() => Task.CompletedTask;
        public Task RunNowAsync(string taskId) => Task.CompletedTask;
        public Task ContinueTaskAsync(string taskId, string followUpPrompt) => Task.CompletedTask;
        public Task ResetTaskAsync(string taskId) => Task.CompletedTask;
        public Task CancelTaskAsync(string taskId) => Task.CompletedTask;
        public Task<List<AgentInfo>> GetAgentsAsync() => Task.FromResult(new List<AgentInfo>());
        public Task<ListConfigDto?> GetListConfigAsync(string listId) => Task.FromResult<ListConfigDto?>(null);
        public Task UpdateTaskAgentSettingsAsync(UpdateTaskAgentSettingsDto dto) => Task.CompletedTask;
        public Task StartPlanningSessionAsync(string taskId, CancellationToken ct = default) => Task.CompletedTask;
        public Task ResumePlanningSessionAsync(string taskId, CancellationToken ct = default) => Task.CompletedTask;
        public Task DiscardPlanningSessionAsync(string taskId, CancellationToken ct = default) => Task.CompletedTask;
        public Task FinalizePlanningSessionAsync(string taskId, bool queueAgentTasks = true, CancellationToken ct = default) => Task.CompletedTask;
        public Task<int> GetPendingDraftCountAsync(string taskId, CancellationToken ct = default) => Task.FromResult(0);
        public Task<MergeTargetsDto?> GetMergeTargetsAsync(string taskId) => Task.FromResult(MergeTargetsResult);
        public Task<IReadOnlyList<SubtaskDiffDto>> GetPlanningAggregateAsync(string planningTaskId) =>
            Task.FromResult<IReadOnlyList<SubtaskDiffDto>>(Array.Empty<SubtaskDiffDto>());
        public Task<CombinedDiffResultDto?> BuildPlanningIntegrationBranchAsync(string planningTaskId, string targetBranch) =>
            Task.FromResult<CombinedDiffResultDto?>(null);
        public Task MergeAllPlanningAsync(string planningTaskId, string targetBranch) => Task.CompletedTask;
        public Task ContinuePlanningMergeAsync(string planningTaskId) => Task.CompletedTask;
        public Task AbortPlanningMergeAsync(string planningTaskId) => Task.CompletedTask;
    }

    private sealed class NullServiceProvider : IServiceProvider
    {
        public object? GetService(Type serviceType) => null;
    }

    private DetailsIslandViewModel BuildVm(FakeWorkerClient worker)
    {
        var factory = new TestDbFactory(NewContext);
        return new DetailsIslandViewModel(factory, worker, new NullServiceProvider());
    }

    private static SubtaskRowViewModel MakeSubtask(TaskStatus status, WorktreeState wt = WorktreeState.Active) =>
        new() { Id = Guid.NewGuid().ToString(), Title = "t", Status = status, WorktreeState = wt };

    // ── CanMergeAll tests exercising the real VM ─────────────────────────────

    [Fact]
    public void CanMergeAll_AllChildrenDoneActiveWorktrees_True()
    {
        var vm = BuildVm(new FakeWorkerClient());
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Active));
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Active));

        vm.RecomputeCanMergeAll();

        Assert.True(vm.CanMergeAll);
        Assert.Null(vm.MergeAllDisabledReason);
    }

    [Fact]
    public void CanMergeAll_AnyChildNotDone_FalseWithReason()
    {
        var vm = BuildVm(new FakeWorkerClient());
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Active));
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Active));
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Running, WorktreeState.Active));

        vm.RecomputeCanMergeAll();

        Assert.False(vm.CanMergeAll);
        Assert.NotNull(vm.MergeAllDisabledReason);
        Assert.Contains("1 subtask", vm.MergeAllDisabledReason, StringComparison.OrdinalIgnoreCase);
        Assert.Contains("not done", vm.MergeAllDisabledReason, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public void CanMergeAll_AnyChildDiscarded_FalseWithReason()
    {
        var vm = BuildVm(new FakeWorkerClient());
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Active));
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Discarded));

        vm.RecomputeCanMergeAll();

        Assert.False(vm.CanMergeAll);
        Assert.NotNull(vm.MergeAllDisabledReason);
        Assert.True(
            vm.MergeAllDisabledReason!.Contains("discarded", StringComparison.OrdinalIgnoreCase) ||
            vm.MergeAllDisabledReason.Contains("kept", StringComparison.OrdinalIgnoreCase));
    }

    [Fact]
    public void CanMergeAll_AnyChildKept_FalseWithReason()
    {
        var vm = BuildVm(new FakeWorkerClient());
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Active));
        vm.Subtasks.Add(MakeSubtask(TaskStatus.Done, WorktreeState.Kept));

        vm.RecomputeCanMergeAll();

        Assert.False(vm.CanMergeAll);
        Assert.NotNull(vm.MergeAllDisabledReason);
        Assert.True(
            vm.MergeAllDisabledReason!.Contains("kept", StringComparison.OrdinalIgnoreCase) ||
            vm.MergeAllDisabledReason.Contains("discarded", StringComparison.OrdinalIgnoreCase));
    }

    // ── Branch-load test exercising the VM via Bind ──────────────────────────

    [Fact]
    public async Task MergeTargetBranches_LoadedFromWorkerOnPlanningParent()
    {
        // Seed a Planning parent with one child that has a worktree
        const string parentId = "parent-1";
        const string childId  = "child-1";
        const string listId   = "list-1";

        await using (var ctx = NewContext())
        {
            ctx.Lists.Add(new ListEntity { Id = listId, Name = "L", CreatedAt = DateTime.UtcNow });
            ctx.Tasks.Add(new TaskEntity
            {
                Id = parentId, ListId = listId, Title = "Parent",
                Status = TaskStatus.Planning, CreatedAt = DateTime.UtcNow,
            });
            ctx.Tasks.Add(new TaskEntity
            {
                Id = childId, ListId = listId, Title = "Child",
                Status = TaskStatus.Done, ParentTaskId = parentId, CreatedAt = DateTime.UtcNow,
            });
            ctx.Set<WorktreeEntity>().Add(new WorktreeEntity
            {
                TaskId = childId, Path = "/tmp/wt", BranchName = "branch",
                BaseCommit = "abc", CreatedAt = DateTime.UtcNow,
            });
            await ctx.SaveChangesAsync();
        }

        var fake = new FakeWorkerClient
        {
            MergeTargetsResult = new MergeTargetsDto("main", new[] { "main", "dev" }),
        };

        var vm = BuildVm(fake);

        // Bind triggers BindAsync → LoadPlanningChildrenAsync → GetMergeTargetsAsync
        var parentRow = new TaskRowViewModel { Id = parentId };
        parentRow.Status = TaskStatus.Planning;
        vm.Bind(parentRow);

        // Wait for the background load to settle
        var deadline = DateTime.UtcNow.AddSeconds(5);
        while (DateTime.UtcNow < deadline && vm.MergeTargetBranches.Count == 0)
            await Task.Delay(20);

        Assert.Contains("main", vm.MergeTargetBranches);
        Assert.Contains("dev",  vm.MergeTargetBranches);
        Assert.Equal("main", vm.SelectedMergeTarget);
    }
}