using System.Net.Http.Json;
using ItWorx.KnowledgeHub.Contracts.Knowledge;
using ItWorx.KnowledgeHub.IntegrationTests.Infrastructure;

namespace ItWorx.KnowledgeHub.IntegrationTests.Knowledge;

/// <summary>Backlinks ("what links here") update correctly after link, title, slug and
/// tree changes (docs/27-acceptance-matrix.md, M3-A03).</summary>
[Collection(PostgresTestGroup.Name)]
public sealed class BacklinksTests(PostgresContainerFixture postgres) : OwnerSetupTestBase(postgres)
{
    [Fact]
    public async Task A_page_appears_in_another_pages_backlinks_once_it_links_there_and_disappears_once_the_link_is_removed()
    {
        using var client = Factory.CreateClient();
        await SetupHelper.LoginAsync(client, OwnerEmail, OwnerPassword);

        var targetResponse = await SetupHelper.PostWithCsrfAsync(
            client, "/api/v1/pages", new CreatePageRequest(null, "Doelpagina", "WikiPage", "De doelpagina.", null));
        var target = await targetResponse.Content.ReadFromJsonAsync<PageDetail>();
        Assert.NotNull(target);

        var sourceResponse = await SetupHelper.PostWithCsrfAsync(
            client, "/api/v1/pages", new CreatePageRequest(null, "Bronpagina", "WikiPage", "Zie [[Doelpagina]].", null));
        var source = await sourceResponse.Content.ReadFromJsonAsync<PageDetail>();
        Assert.NotNull(source);

        var backlinks = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{target.Id}/backlinks");
        Assert.NotNull(backlinks);
        Assert.Contains(backlinks.Items, entry => entry.Id == source.Id);

        // Renaming the target must not break the already-resolved backlink relationship.
        var renamedTargetResponse = await SetupHelper.PutWithCsrfAsync(
            client,
            $"/api/v1/pages/{target.Id}",
            new UpdatePageRequest("Doelpagina (hernoemd)", "De doelpagina.", "WikiPage", "Active", null),
            target.ETag);
        Assert.True(renamedTargetResponse.IsSuccessStatusCode);

        var backlinksAfterRename = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{target.Id}/backlinks");
        Assert.NotNull(backlinksAfterRename);
        Assert.Contains(backlinksAfterRename.Items, entry => entry.Id == source.Id);

        // Removing the link from the source page removes the backlink.
        var unlinkedSourceResponse = await SetupHelper.PutWithCsrfAsync(
            client,
            $"/api/v1/pages/{source.Id}",
            new UpdatePageRequest("Bronpagina", "Geen verwijzing meer.", "WikiPage", "Active", null),
            source.ETag);
        Assert.True(unlinkedSourceResponse.IsSuccessStatusCode);

        var backlinksAfterUnlink = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{target.Id}/backlinks");
        Assert.NotNull(backlinksAfterUnlink);
        Assert.DoesNotContain(backlinksAfterUnlink.Items, entry => entry.Id == source.Id);
    }

    [Fact]
    public async Task A_page_with_no_incoming_links_has_an_empty_backlinks_list()
    {
        using var client = Factory.CreateClient();
        await SetupHelper.LoginAsync(client, OwnerEmail, OwnerPassword);

        var response = await SetupHelper.PostWithCsrfAsync(
            client, "/api/v1/pages", new CreatePageRequest(null, "Eenzame pagina", "WikiPage", "Niemand linkt hierheen.", null));
        var page = await response.Content.ReadFromJsonAsync<PageDetail>();
        Assert.NotNull(page);

        var backlinks = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{page.Id}/backlinks");
        Assert.NotNull(backlinks);
        Assert.Empty(backlinks.Items);
    }
}