using System.Net.Http.Json;
using System.Text.Json;
using Elternbeirat.Contracts;

namespace Elternbeirat.PocketBase;

/// <summary>
/// Reads published content from a PocketBase instance over its REST API.
/// <para>
/// One method per collection (pages, posts, events, faqs). Each returns only
/// records with <c>public = true</c> and lets PocketBase do the filtering and
/// sorting via query parameters. The <see cref="HttpClient"/> is expected to have
/// its <see cref="HttpClient.BaseAddress"/> set to the PocketBase base URL, so it
/// is registered as a typed client via <c>AddHttpClient</c>.
/// </para>
/// </summary>
public sealed class PocketBaseClient(HttpClient http)
{
    private static readonly JsonSerializerOptions JsonOptions = CreateJsonOptions();

    private static JsonSerializerOptions CreateJsonOptions()
    {
        var options = new JsonSerializerOptions
        {
            PropertyNameCaseInsensitive = true,
        };
        options.Converters.Add(new LocalDateTimeConverter());
        options.Converters.Add(new NullableLocalDateTimeConverter());
        return options;
    }

    /// <summary>Gets all public pages, ordered for navigation.</summary>
    public Task<IReadOnlyList<Page>> GetPagesAsync(CancellationToken ct = default)
        => GetRecordsAsync<Page>("pages", "order", ct);

    /// <summary>Gets all public posts, newest first.</summary>
    public Task<IReadOnlyList<Post>> GetPostsAsync(CancellationToken ct = default)
        => GetRecordsAsync<Post>("posts", "-date", ct);

    /// <summary>Gets all public events, earliest start first.</summary>
    public Task<IReadOnlyList<Event>> GetEventsAsync(CancellationToken ct = default)
        => GetRecordsAsync<Event>("events", "start", ct);

    /// <summary>Gets all public FAQ entries.</summary>
    public Task<IReadOnlyList<Faq>> GetFaqsAsync(CancellationToken ct = default)
        => GetRecordsAsync<Faq>("faqs", "topic", ct);

    private async Task<IReadOnlyList<T>> GetRecordsAsync<T>(string collection, string sort, CancellationToken ct)
    {
        // filter=public=true keeps drafts out; perPage is large enough to fetch
        // every record in a single page given the small content volume.
        var url = $"/api/collections/{collection}/records"
                  + $"?perPage=500&filter={Uri.EscapeDataString("public=true")}"
                  + $"&sort={Uri.EscapeDataString(sort)}";

        var result = await http.GetFromJsonAsync<RecordList<T>>(url, JsonOptions, ct);
        return result?.Items ?? [];
    }
}