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 RequestJSON(HttpRequest req)
    {
        req.Fields.UserAgent = UserAgent;
        req.Fields.Authorization = Authorization;
        while (true)
        {
            HttpResponse res = await HttpClient.Request(Host, true, req);

            if (res.StatusCode == 404)
                return;

            if (res.Content.HasValue)
            {
                if (res.Fields.ContentType.HasValue && !res.Fields.ContentType.Value.Match(JsonMIMEType))
                    throw new HttpException(res.Content.Value.AsText);

                if (res.StatusCode is >= 400 and < 600)
                {
                    try
                    {
                        string text = res.Content.Value.AsText;
                        PleromaException? err = JsonSerializer.Deserialize<PleromaException>(text, SerializerOptions);
                        if (err != null && err.Text != null)
                        {
                            if (err.Text == "Throttled")
                            {
                                await Task.Delay(5000);
                                continue; //Retry
                            }
                            else
                            {
                                throw err;
                            }
                        }
                    }
                    catch (JsonException)
                    {
                        //Not an error
                    }
                }
            }

            if (res.StatusCode is not >= 200 or not < 300)
                throw new HttpException("Unknown error occurred");
        }
    }

    async Task<T?> RequestJSON<T>(HttpRequest req) where T : class
    {
        req.Fields.UserAgent = UserAgent;
        req.Fields.Authorization = Authorization;
        req.Fields.Accept = [JsonMIMEType];
        while (true)
        {
            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)
                    {
                        if (err.Text == "Throttled")
                        {
                            await Task.Delay(5000);
                            continue; //Retry
                        }
                        else
                        {
                            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>
    /// <exception cref="HttpException">Thrown if something goes wrong while uploading the status.</exception>
    /// <returns>The status if posting was successful.</returns>
    public async 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];
        Status result = (await RequestJSON<Status>(req))!;
        status.OnPublish?.Invoke();
        return result;
    }

    /// <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);
    }

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

    /// <summary>
    /// Deletes a status.
    /// </summary>
    public Task Delete(Status status)
        => Delete(status.ID);

    /// <summary>
    /// Deletes a status by ID.
    /// </summary>
    public Task Delete(string status_id)
    {
        HttpRequest req = new HttpRequest(HttpMethod.DELETE, $"/api/v1/statuses/{status_id}");
        req.Fields.Accept = [JsonMIMEType];
        return RequestJSON(req);
    }

    /// <summary>
    /// Searches for an accounts, hashtags, and/or statuses.
    /// </summary>
    /// <param name="query">What to search for</param>
    /// <param name="account_id">If provided, statuses returned will be authored only by this account</param>
    /// <param name="type">Search type</param>
    /// <param name="resolve">Attempt WebFinger lookup</param>
    /// <param name="following">Only include accounts that the user is following</param>
    /// <param name="max_id">Return items older than this ID</param>
    /// <param name="min_id">Return the oldest items newer than this ID</param>
    /// <param name="since_id">Return the newest items newer than this ID</param>
    /// <param name="offset">Return items past this number of items</param>
    /// <param name="limit">Maximum number of items to return. Will be ignored if it's more than 40</param>
    /// <returns></returns>
    public Task<SearchResults> Search(string query,
                                      string? account_id = null,
                                      SearchType type = SearchType.All,
                                      bool resolve = false,
                                      bool following = false,
                                      string? max_id = null,
                                      string? min_id = null,
                                      string? since_id = null,
                                      int offset = 0,
                                      int limit = 20)
    {
        HttpRequest req = new HttpRequest(HttpMethod.GET, $"/api/v2/search");
        req.Fields.Accept = [JsonMIMEType];
        req.Query["q"] = query;
        if (account_id != null) req.Query["account_id"] = account_id;
        if (type != SearchType.All) req.Query["type"] = type.ToString().ToLowerInvariant();
        if (resolve) req.Query["resolve"] = "true";
        if (following) req.Query["following"] = "true";
        if (max_id != null) req.Query["max_id"] = max_id;
        if (min_id != null) req.Query["min_id"] = min_id;
        if (since_id != null) req.Query["since_id"] = since_id;
        if (offset > 0) req.Query["offset"] = offset.ToString();
        if (limit != 20) req.Query["limit"] = limit.ToString();
        return RequestJSON<SearchResults>(req)!;
    }
}