using TaskTracker.Api.Pages;
using TaskTracker.Core.Entities;
using TaskTracker.Core.Enums;
using Xunit;

namespace TaskTracker.Tests;

public class BoardUpcomingTasksTests
{
    [Fact]
    public void SelectUpcomingTasks_excludes_completed_abandoned_and_tasks_without_a_deadline()
    {
        var dueAt = DateTimeOffset.Parse("2026-08-14T09:00:00Z");
        var tasks = new[]
        {
            Task("pending", WorkTaskStatus.Pending, dueAt),
            Task("completed", WorkTaskStatus.Completed, dueAt.AddHours(-1)),
            Task("abandoned", WorkTaskStatus.Abandoned, dueAt.AddHours(1)),
            Task("no deadline", WorkTaskStatus.Active),
        };

        var upcoming = BoardModel.SelectUpcomingTasks(tasks, category: null, hasSubtasks: false);

        var task = Assert.Single(upcoming);
        Assert.Equal("pending", task.Title);
    }

    [Fact]
    public void SelectUpcomingTasks_includes_top_level_tasks_and_subtasks_in_due_date_order()
    {
        var parent = Task("top level", WorkTaskStatus.Pending, DateTimeOffset.Parse("2026-08-14T12:00:00Z"));
        var subtask = Task("subtask", WorkTaskStatus.Active, DateTimeOffset.Parse("2026-08-14T10:00:00Z"), parentTaskId: 1);
        var later = Task("later", WorkTaskStatus.Paused, DateTimeOffset.Parse("2026-08-14T14:00:00Z"));

        var upcoming = BoardModel.SelectUpcomingTasks([parent, subtask, later], category: null, hasSubtasks: false);

        Assert.Equal(["subtask", "top level", "later"], upcoming.Select(task => task.Title));
    }

    [Fact]
    public void SelectUpcomingTasks_limits_results_to_eight_earliest_deadlines()
    {
        var start = DateTimeOffset.Parse("2026-08-14T09:00:00Z");
        var tasks = Enumerable.Range(0, 9)
            .Select(index => Task($"task {index}", WorkTaskStatus.Pending, start.AddHours(index)))
            .ToList();

        var upcoming = BoardModel.SelectUpcomingTasks(tasks, category: null, hasSubtasks: false);

        Assert.Equal(8, upcoming.Count);
        Assert.DoesNotContain(upcoming, task => task.Title == "task 8");
    }

    [Fact]
    public void SelectUpcomingTasks_honors_active_category_and_has_subtasks_filters()
    {
        var dueAt = DateTimeOffset.Parse("2026-08-14T09:00:00Z");
        var developmentParent = Task("development parent", WorkTaskStatus.Pending, dueAt, category: "Development");
        developmentParent.SubTasks.Add(Task("development child", WorkTaskStatus.Pending, dueAt.AddHours(1), parentTaskId: 1, category: "Development"));
        var developmentLeaf = Task("development leaf", WorkTaskStatus.Pending, dueAt.AddHours(2), category: "Development");
        var researchParent = Task("research parent", WorkTaskStatus.Pending, dueAt.AddHours(-1), category: "Research");
        researchParent.SubTasks.Add(Task("research child", WorkTaskStatus.Pending, dueAt, parentTaskId: 2, category: "Research"));

        var upcoming = BoardModel.SelectUpcomingTasks(
            [developmentParent, developmentParent.SubTasks[0], developmentLeaf, researchParent, researchParent.SubTasks[0]],
            category: "development",
            hasSubtasks: true);

        var task = Assert.Single(upcoming);
        Assert.Equal("development parent", task.Title);
    }

    private static WorkTask Task(string title, WorkTaskStatus status, DateTimeOffset? dueAt = null, int? parentTaskId = null, string? category = null) =>
        new()
        {
            Title = title,
            Status = status,
            DueAt = dueAt,
            ParentTaskId = parentTaskId,
            Category = category,
        };
}