using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Jellyfin.Plugin.Floatplane.Api.Models;
using Jellyfin.Plugin.Floatplane.Configuration;
using Microsoft.Extensions.Logging;

namespace Jellyfin.Plugin.Floatplane.Api;

/// <summary>
/// Thin typed client for Floatplane's (unofficial) REST API. See
/// <c>doc/floatplane-api-notes.md</c> for which endpoints are public and which need the
/// session cookie.
/// </summary>
public class FloatplaneApiClient
{
    public const string BaseUrl = "https://www.floatplane.com";

    private readonly IHttpClientFactory _httpClientFactory;
    private readonly ILogger<FloatplaneApiClient> _logger;
    private readonly Func<PluginConfiguration> _config;

    public FloatplaneApiClient(IHttpClientFactory httpClientFactory, ILogger<FloatplaneApiClient> logger)
        : this(httpClientFactory, logger, () => Plugin.Instance?.Configuration ?? new PluginConfiguration())
    {
    }

    /// <summary>Constructor for tests: configuration is supplied explicitly.</summary>
    public FloatplaneApiClient(IHttpClientFactory httpClientFactory, ILogger<FloatplaneApiClient> logger, Func<PluginConfiguration> config)
    {
        _httpClientFactory = httpClientFactory;
        _logger = logger;
        _config = config;
    }

    /// <summary>True when a session cookie is configured (not necessarily valid).</summary>
    public bool HasSession => !string.IsNullOrWhiteSpace(_config().SessionCookie);

    // ───────────────────────────── auth / user ─────────────────────────────

    /// <summary>GET /api/v3/user/self — validates the cookie. Throws <see cref="FloatplaneAuthException"/> if invalid.</summary>
    public Task<UserSelfModel> GetSelfAsync(CancellationToken ct, string? cookieOverride = null)
        => GetAsync<UserSelfModel>("/api/v3/user/self", null, ct, cookieOverride);

    /// <summary>GET /api/v3/user/subscriptions (login required).</summary>
    public Task<List<SubscriptionModel>> GetSubscriptionsAsync(CancellationToken ct, string? cookieOverride = null)
        => GetAsync<List<SubscriptionModel>>("/api/v3/user/subscriptions", new() { ["active"] = "true" }, ct, cookieOverride);

    // ───────────────────────────── creators ─────────────────────────────

    /// <summary>GET /api/v3/creator/named?creatorURL[]= (public).</summary>
    public Task<List<CreatorModel>> GetCreatorsByUrlNameAsync(IEnumerable<string> urlNames, CancellationToken ct)
    {
        var q = new Dictionary<string, string>();
        var i = 0;
        foreach (var n in urlNames)
        {
            q[$"creatorURL[{i++}]"] = n;
        }

        return GetAsync<List<CreatorModel>>("/api/v3/creator/named", q, ct);
    }

    /// <summary>GET /api/v3/creator/info?id= (login required).</summary>
    public Task<CreatorModel> GetCreatorAsync(string creatorId, CancellationToken ct)
        => GetAsync<CreatorModel>("/api/v3/creator/info", new() { ["id"] = creatorId }, ct);

    /// <summary>GET /api/v3/creator/channels/list?ids[]= (public).</summary>
    public Task<List<ChannelModel>> GetCreatorChannelsAsync(IEnumerable<string> creatorIds, CancellationToken ct)
    {
        var q = new Dictionary<string, string>();
        var i = 0;
        foreach (var id in creatorIds)
        {
            q[$"ids[{i++}]"] = id;
        }

        return GetAsync<List<ChannelModel>>("/api/v3/creator/channels/list", q, ct);
    }

    /// <summary>GET /api/v3/content/tags?creatorIds[]= (public) → tag → count.</summary>
    public Task<Dictionary<string, int>> GetTagsAsync(string creatorId, CancellationToken ct)
        => GetAsync<Dictionary<string, int>>("/api/v3/content/tags", new() { ["creatorIds[0]"] = creatorId }, ct);

    // ───────────────────────────── content ─────────────────────────────

    /// <summary>
    /// GET /api/v3/content/creator (public). <c>FetchAfter</c> is an offset
    /// (multiples of <c>Limit</c>); max limit is 20. Returns an empty list at the end.
    /// </summary>
    public Task<List<PostModel>> ListPostsAsync(PostQuery query, CancellationToken ct)
    {
        var q = new Dictionary<string, string>
        {
            ["id"] = query.CreatorId,
            ["limit"] = Math.Clamp(query.Limit, 1, 20).ToString(CultureInfo.InvariantCulture),
            ["fetchAfter"] = query.FetchAfter.ToString(CultureInfo.InvariantCulture),
            ["sort"] = query.SortAscending ? "ASC" : "DESC"
        };
        if (!string.IsNullOrEmpty(query.ChannelId))
        {
            q["channel"] = query.ChannelId;
        }

        if (!string.IsNullOrEmpty(query.Search))
        {
            q["search"] = query.Search;
        }

        if (query.HasVideo)
        {
            q["hasVideo"] = "true";
        }

        if (query.Tags != null)
        {
            var i = 0;
            foreach (var t in query.Tags)
            {
                q[$"tags[{i++}]"] = t;
            }
        }

        if (query.FromDate.HasValue)
        {
            q["fromDate"] = query.FromDate.Value.UtcDateTime.ToString("yyyy-MM-dd'T'HH:mm:ss.fff'Z'", CultureInfo.InvariantCulture);
        }

        if (query.ToDate.HasValue)
        {
            q["toDate"] = query.ToDate.Value.UtcDateTime.ToString("yyyy-MM-dd'T'HH:mm:ss.fff'Z'", CultureInfo.InvariantCulture);
        }

        if (query.FromDurationSeconds.HasValue)
        {
            q["fromDuration"] = query.FromDurationSeconds.Value.ToString(CultureInfo.InvariantCulture);
        }

        if (query.ToDurationSeconds.HasValue)
        {
            q["toDuration"] = query.ToDurationSeconds.Value.ToString(CultureInfo.InvariantCulture);
        }

        return GetAsync<List<PostModel>>("/api/v3/content/creator", q, ct);
    }

    /// <summary>GET /api/v3/content/post?id= (login required) — expands attachments.</summary>
    public Task<PostModel> GetPostAsync(string postId, CancellationToken ct)
        => GetAsync<PostModel>("/api/v3/content/post", new() { ["id"] = postId }, ct);

    /// <summary>GET /api/v3/content/video?id= (login required).</summary>
    public Task<VideoModel> GetVideoAsync(string videoId, CancellationToken ct)
        => GetAsync<VideoModel>("/api/v3/content/video", new() { ["id"] = videoId }, ct);

    /// <summary>GET /api/v3/content/progress?ids[]=&amp;contentType=blogPost (login) → percentage per post.</summary>
    public Task<List<ProgressModel>> GetProgressAsync(IEnumerable<string> postIds, CancellationToken ct)
    {
        var q = new Dictionary<string, string> { ["contentType"] = "blogPost" };
        var i = 0;
        foreach (var id in postIds)
        {
            q[$"ids[{i++}]"] = id;
        }

        return GetAsync<List<ProgressModel>>("/api/v3/content/progress", q, ct);
    }

    /// <summary>POST /api/v3/content/progress {id, contentType:"video", progress:seconds} (login).</summary>
    public async Task PostProgressAsync(string videoId, int seconds, CancellationToken ct)
    {
        var body = JsonSerializer.Serialize(new { id = videoId, contentType = "video", progress = seconds });
        using var request = BuildRequest(HttpMethod.Post, BaseUrl + "/api/v3/content/progress", null, null);
        request.Content = new StringContent(body, Encoding.UTF8, "application/json");
        using var response = await SendAsync(request, ct).ConfigureAwait(false);
        await EnsureSuccessAsync(response, ct).ConfigureAwait(false);
    }

    // ───────────────────────────── delivery ─────────────────────────────

    /// <summary>GET /api/v3/delivery/info?scenario=&amp;entityId= (login; rate-limited ≈2/min).</summary>
    public Task<DeliveryInfoModel> GetDeliveryInfoAsync(string scenario, string entityId, CancellationToken ct)
        => GetAsync<DeliveryInfoModel>("/api/v3/delivery/info", new() { ["scenario"] = scenario, ["entityId"] = entityId }, ct);

    /// <summary>Fetches a (sub)playlist from the CDN. No cookie — the signed token is enough.</summary>
    public async Task<string> GetPlaylistAsync(string url, CancellationToken ct)
    {
        using var request = new HttpRequestMessage(HttpMethod.Get, url);
        request.Headers.Referrer = new Uri(BaseUrl + "/");
        using var response = await SendAsync(request, ct).ConfigureAwait(false);
        await EnsureSuccessAsync(response, ct).ConfigureAwait(false);
        return await response.Content.ReadAsStringAsync(ct).ConfigureAwait(false);
    }

    /// <summary>
    /// Fetches the HLS AES-128 key (<c>/api/video/watchKey?token=</c>). This is the one
    /// playback request that needs the session cookie.
    /// </summary>
    public async Task<byte[]> GetWatchKeyAsync(string keyUrl, CancellationToken ct)
    {
        using var request = BuildRequest(HttpMethod.Get, keyUrl, null, null);
        request.Headers.Referrer = new Uri(BaseUrl + "/");
        using var response = await SendAsync(request, ct).ConfigureAwait(false);
        await EnsureSuccessAsync(response, ct).ConfigureAwait(false);
        return await response.Content.ReadAsByteArrayAsync(ct).ConfigureAwait(false);
    }

    /// <summary>Opens an upstream media request (MP4 relay) with optional Range; caller disposes.</summary>
    public async Task<HttpResponseMessage> OpenMediaAsync(HttpMethod method, string url, RangeHeaderValue? range, CancellationToken ct)
    {
        var request = new HttpRequestMessage(method, url);
        request.Headers.Referrer = new Uri(BaseUrl + "/");
        if (range != null)
        {
            request.Headers.Range = range;
        }

        var client = _httpClientFactory.CreateClient(PluginServiceRegistrator.HttpClientName);
        return await client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, ct).ConfigureAwait(false);
    }

    // ───────────────────────────── plumbing ─────────────────────────────

    internal HttpRequestMessage BuildRequest(HttpMethod method, string url, Dictionary<string, string>? query, string? cookieOverride)
    {
        if (query is { Count: > 0 })
        {
            var sb = new StringBuilder(url);
            sb.Append(url.Contains('?', StringComparison.Ordinal) ? '&' : '?');
            var first = true;
            foreach (var (k, v) in query)
            {
                if (!first)
                {
                    sb.Append('&');
                }

                first = false;
                sb.Append(Uri.EscapeDataString(k)).Append('=').Append(Uri.EscapeDataString(v));
            }

            url = sb.ToString();
        }

        var request = new HttpRequestMessage(method, url);
        var cookie = cookieOverride ?? _config().SessionCookie;
        if (!string.IsNullOrWhiteSpace(cookie))
        {
            request.Headers.TryAddWithoutValidation("Cookie", "sails.sid=" + cookie.Trim());
        }

        request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        return request;
    }

    private async Task<T> GetAsync<T>(string path, Dictionary<string, string>? query, CancellationToken ct, string? cookieOverride = null)
    {
        using var request = BuildRequest(HttpMethod.Get, BaseUrl + path, query, cookieOverride);
        using var response = await SendAsync(request, ct).ConfigureAwait(false);
        await EnsureSuccessAsync(response, ct).ConfigureAwait(false);
        var json = await response.Content.ReadAsStringAsync(ct).ConfigureAwait(false);
        _logger.LogDebug("GET {Url} -> {Status}, {Length} bytes", request.RequestUri, (int)response.StatusCode, json.Length);
        T? result;
        try
        {
            result = JsonSerializer.Deserialize<T>(json, FloatplaneJson.Options);
        }
        catch (JsonException ex)
        {
            _logger.LogError(ex, "Could not parse Floatplane response from {Path}: {Head}", path, json.Length > 300 ? json[..300] : json);
            throw new FloatplaneApiException(response.StatusCode, "parseError", "Unexpected response from " + path);
        }

        return result ?? throw new FloatplaneApiException(response.StatusCode, "emptyResponse", "Empty response from " + path);
    }

    private Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken ct)
    {
        var client = _httpClientFactory.CreateClient(PluginServiceRegistrator.HttpClientName);
        return client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, ct);
    }

    private async Task EnsureSuccessAsync(HttpResponseMessage response, CancellationToken ct)
    {
        if (response.IsSuccessStatusCode)
        {
            return;
        }

        if (response.StatusCode == HttpStatusCode.TooManyRequests)
        {
            var retry = response.Headers.RetryAfter?.Delta ?? TimeSpan.FromSeconds(60);
            _logger.LogWarning("Floatplane rate limit hit on {Url}; retry after {Retry}", response.RequestMessage?.RequestUri, retry);
            throw new FloatplaneRateLimitException(retry, "Floatplane rate limit (429)");
        }

        string body = string.Empty;
        try
        {
            body = await response.Content.ReadAsStringAsync(ct).ConfigureAwait(false);
        }
        catch (Exception ex) when (ex is not OperationCanceledException)
        {
            // ignore – we only need the body for the error name
        }

        ApiErrorModel? error = null;
        if (body.StartsWith('{'))
        {
            try
            {
                error = JsonSerializer.Deserialize<ApiErrorModel>(body, FloatplaneJson.Options);
            }
            catch (JsonException)
            {
                // not an envelope
            }
        }

        var name = error?.Errors.FirstOrDefault()?.Name;
        var message = error?.Message ?? error?.Errors.FirstOrDefault()?.Message ?? $"HTTP {(int)response.StatusCode} from Floatplane";
        var url = response.RequestMessage?.RequestUri?.GetLeftPart(UriPartial.Path);
        _logger.LogDebug("Floatplane error {Status} {Name} on {Url}: {Message}", (int)response.StatusCode, name, url, message);

        if (response.StatusCode is HttpStatusCode.Unauthorized or HttpStatusCode.Forbidden
            || string.Equals(name, "notLoggedInError", StringComparison.OrdinalIgnoreCase)
            || string.Equals(name, "notSubscribedError", StringComparison.OrdinalIgnoreCase))
        {
            throw new FloatplaneAuthException(response.StatusCode, name, message);
        }

        throw new FloatplaneApiException(response.StatusCode, name, message);
    }
}

/// <summary>Parameters of GET /api/v3/content/creator.</summary>
public class PostQuery
{
    public string CreatorId { get; set; } = string.Empty;

    public string? ChannelId { get; set; }

    public int Limit { get; set; } = 20;

    public int FetchAfter { get; set; }

    public string? Search { get; set; }

    public bool HasVideo { get; set; }

    public bool SortAscending { get; set; }

    public IEnumerable<string>? Tags { get; set; }

    public DateTimeOffset? FromDate { get; set; }

    public DateTimeOffset? ToDate { get; set; }

    public int? FromDurationSeconds { get; set; }

    public int? ToDurationSeconds { get; set; }
}