using FluentAssertions;
using NovelSoftware.Application;
using NovelSoftware.Application.Dtos;
using NovelSoftware.Application.Services;
using NovelSoftware.Domain;

namespace NovelSoftware.Tests;

public class OutlineServiceTests : IDisposable
{
    private readonly TestDatabase _db = new();
    private readonly OutlineService _outlines;
    private readonly Guid _projectId;

    public OutlineServiceTests()
    {
        _outlines = new OutlineService(_db.Context);
        _projectId = new ProjectService(_db.Context)
            .CreateAsync(new CreateProjectRequest("The Salt Road")).Result.Id;
    }

    [Fact]
    public async Task Nested_nodes_come_back_as_a_tree()
    {
        var act = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest(
            "Act One", OutlineNodeType.Act));

        await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest(
            "She finds the map", OutlineNodeType.Beat, ParentId: act.Id));
        await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest(
            "The harbour burns", OutlineNodeType.Beat, ParentId: act.Id));

        var tree = await _outlines.GetTreeAsync(_projectId);

        tree.Should().ContainSingle();
        tree[0].Title.Should().Be("Act One");
        tree[0].Children.Select(c => c.Title)
            .Should().Equal("She finds the map", "The harbour burns");
    }

    [Fact]
    public async Task Sibling_order_follows_sort_order_not_insertion_order()
    {
        await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Third", SortOrder: 30));
        await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("First", SortOrder: 10));
        await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Second", SortOrder: 20));

        var tree = await _outlines.GetTreeAsync(_projectId);

        tree.Select(n => n.Title).Should().Equal("First", "Second", "Third");
    }

    [Fact]
    public async Task Moving_a_node_under_its_own_descendant_is_rejected()
    {
        var act = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Act One"));
        var sequence = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest(
            "Sequence", ParentId: act.Id));
        var beat = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest(
            "Beat", ParentId: sequence.Id));

        var move = async () => await _outlines.MoveAsync(act.Id, new MoveOutlineNodeRequest(beat.Id, 1));

        await move.Should().ThrowAsync<InvalidOperationException>()
            .WithMessage("*beneath its own descendant*");
    }

    [Fact]
    public async Task A_node_cannot_be_its_own_parent()
    {
        var node = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Act One"));

        var move = async () => await _outlines.MoveAsync(node.Id, new MoveOutlineNodeRequest(node.Id, 1));

        await move.Should().ThrowAsync<InvalidOperationException>()
            .WithMessage("*its own parent*");
    }

    [Fact]
    public async Task Moving_to_the_root_detaches_from_the_old_parent()
    {
        var act = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Act One"));
        var beat = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest(
            "Beat", ParentId: act.Id));

        await _outlines.MoveAsync(beat.Id, new MoveOutlineNodeRequest(null, 2));

        var tree = await _outlines.GetTreeAsync(_projectId);
        tree.Should().HaveCount(2);
        tree.Single(n => n.Title == "Act One").Children.Should().BeEmpty();
    }

    [Fact]
    public async Task Deleting_a_node_takes_its_whole_subtree()
    {
        var act = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Act One"));
        var sequence = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest(
            "Sequence", ParentId: act.Id));
        await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Beat", ParentId: sequence.Id));
        var survivor = await _outlines.CreateAsync(_projectId, new CreateOutlineNodeRequest("Act Two"));

        await _outlines.DeleteAsync(act.Id);

        var tree = await _outlines.GetTreeAsync(_projectId);
        tree.Should().ContainSingle().Which.Id.Should().Be(survivor.Id);

        using var verification = _db.CreateContext();
        verification.OutlineNodes.Should().ContainSingle();
    }

    [Fact]
    public async Task Creating_under_a_missing_parent_reports_not_found()
    {
        var create = async () => await _outlines.CreateAsync(_projectId,
            new CreateOutlineNodeRequest("Orphan", ParentId: Guid.NewGuid()));

        await create.Should().ThrowAsync<NotFoundException>();
    }

    public void Dispose() => _db.Dispose();
}