using System.Text.Json;
using System.Threading.Tasks;
using Uwaa.HTTP;
using Uwaa.Pleroma.API;

namespace Uwaa.Pleroma;

/// <summary>
/// A pleroma client.
/// </summary>
public class Pleroma
{
    static readonly JsonSerializerOptions SerializerOptions = new()
    {
        PropertyNameCaseInsensitive = true,
        NumberHandling = System.Text.Json.Serialization.JsonNumberHandling.AllowReadingFromString,
    };

    static readonly MIMEType JsonMIMEType = new("application", "json");


    /// <summary>
    /// The hostname of the pleroma instance.
    /// </summary>
    public string Host;

    /// <summary>
    /// The full token, including the "Bearer" string.
    /// </summary>
    public string Authorization;

    /// <summary>
    /// The user agent string.
    /// </summary>
    public string UserAgent = "Uwaa.Pleroma/0.0";

    public Pleroma(string host, string authorization)
    {
        Host = host;
        Authorization = authorization;
    }

    async Task<T?> RequestJSON<T>(HttpRequest req) where T : class
    {
        req.Fields.UserAgent = UserAgent;
        req.Fields.Authorization = Authorization;

        HttpResponse res = await HttpClient.Request(Host, true, req);

        if (res.StatusCode == 404)
            return null;

        if (!res.Fields.ContentType.HasValue || !res.Fields.ContentType.Value.Match(JsonMIMEType))
            throw new HttpException("Server did not respond with JSON" + (res.Content.HasValue ? ", got: " + res.Content.Value.AsText : null));

        if (!res.Content.HasValue)
            throw new HttpException("Server responded with no content");

        string text = res.Content.Value.AsText;

        if (res.StatusCode is >= 400 and < 600)
        {
            try
            {
                PleromaException? err = JsonSerializer.Deserialize<PleromaException>(text, SerializerOptions);
                if (err != null && err.Text != null)
                    throw err;
            }
            catch (JsonException)
            {
                //Not an error
            }
        }

        if (res.StatusCode is >= 200 and < 300)
            return JsonSerializer.Deserialize<T>(text, SerializerOptions) ?? throw new HttpException("Couldn't deserialize response");
        else
            throw new HttpException("Unknown error occurred");
    }

    /// <summary>
    /// Posts a status.
    /// </summary>
    /// <param name="status">The status data to send, including the content, visibility, etc.</param>
    /// <returns>The status, if posting was successful.</returns>
    public Task<Status> PostStatus(PublishStatus status)
    {
        HttpRequest req = new HttpRequest(HttpMethod.POST, "/api/v1/statuses");
        req.Content = new HttpContent(JsonMIMEType, JsonSerializer.SerializeToUtf8Bytes(status, SerializerOptions));
        req.Fields.Accept = [JsonMIMEType];
        return RequestJSON<Status>(req)!;
    }

    /// <summary>
    /// Fetches the latest statuses from the public timeline.
    /// </summary>
    public Task<Status[]> GetTimeline()
    {
        //TODO: Parameters and selecting different timelines (home, public, bubble)
        HttpRequest req = new HttpRequest(HttpMethod.GET, "/api/v1/timelines/public");
        req.Fields.Accept = [ JsonMIMEType ];
        return RequestJSON<Status[]>(req)!;
    }

    /// <summary>
    /// Fetches the latest statuses from a user's timeline.
    /// </summary>
    public Task<Status[]> GetTimeline(Account account)
        => GetTimeline(account.ID);

    /// <summary>
    /// Fetches the latest statuses from a user's timeline.
    /// </summary>
    public Task<Status[]> GetTimeline(string account_id)
    {
        HttpRequest req = new HttpRequest(HttpMethod.GET, $"/api/v1/accounts/{account_id}/statuses");
        req.Fields.Accept = [JsonMIMEType];
        return RequestJSON<Status[]>(req)!;
    }

    /// <summary>
    /// Fetches the account of the pleroma client.
    /// </summary>
    public Task<Account> GetAccount()
    {
        HttpRequest req = new HttpRequest(HttpMethod.GET, "/api/v1/accounts/verify_credentials");
        req.Fields.Accept = [JsonMIMEType];
        return RequestJSON<Account>(req)!;
    }

    /// <summary>
    /// Fetches an account.
    /// </summary>
    public Task<Account?> GetAccount(string id)
    {
        HttpRequest req = new HttpRequest(HttpMethod.GET, $"/api/v1/accounts/{id}");
        req.Fields.Accept = [JsonMIMEType];
        return RequestJSON<Account>(req);
    }

    /// <summary>
    /// Fetches the context of a status.
    /// </summary>
    public Task<Context?> GetContext(Status status)
        => GetContext(status.ID);

    /// <summary>
    /// Fetches the context of a status.
    /// </summary>
    public Task<Context?> GetContext(string status_id)
    {
        HttpRequest req = new HttpRequest(HttpMethod.GET, $"/api/v1/statuses/{status_id}/context");
        req.Fields.Accept = [JsonMIMEType];
        return RequestJSON<Context>(req);
    }
}