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

namespace LazyBear.Confluence;

public static class ConfluenceClientFactory
{
    public static HttpClient CreateClient(string baseUrl, HttpClientHandler? handler = null)
    {
        handler ??= new HttpClientHandler();
        
        return new HttpClient(handler)
        {
            BaseAddress = new Uri(baseUrl.TrimEnd('/')),
            DefaultRequestHeaders =
            {
                HttpHeaders
                {
                    ["User-Agent"] = "LazyBear-Confluence-MCP/1.0",
                    ["Accept"] = "application/json"
                }
            }
        };
    }

    public static ConfluenceHttpClientProvider CreateProvider(string baseUrl, string? token = null, HttpClientHandler? handler = null)
    {
        var httpHandler = handler ?? new HttpClientHandler();
        var httpClient = CreateClient(baseUrl, httpHandler);
        
        return new ConfluenceHttpClientProvider(httpClient, baseUrl, token);
    }
}

public sealed class ConfluenceHttpClientProvider
{
    public HttpClient Client { get; }
    public string BaseUrl => HttpBaseAddress?.Root ?? string.Empty;
    public string? AccessToken { get; }
    public string? InitializationError { get; }

    private Uri? HttpBaseAddress;

    public ConfluenceHttpClientProvider(HttpClient client, string baseUrl, string? token = null)
    {
        Client = client;
        HttpBaseAddress = new Uri(baseUrl.TrimEnd('/'));
        AccessToken = token;
    }

    public ConcurrentDictionary<string, JsonElement> Cache { get; } = new();

    public async Task<T?> GetJsonAsync<T>(HttpRequestMessage request) where T : class
    {
        using var response = await Client.SendAsync(request).ConfigureAwait(false);

        if (!response.IsSuccessStatusCode)
        {
            if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
            {
                return default;
            }

            var errorBody = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
            throw new HttpRequestException($"[{request.RequestMethod}] {request.RequestUri}: {response.StatusCode} {errorBody}");
        }

        return await JsonSerializer.DeserializeAsync<T>(response.Content, request, JsonDefaults.DefaultSerializerOptions)
            .ConfigureAwait(false);
    }

    public async Task<JsonElement?> GetJsonAsync(HttpRequestMessage request)
    {
        if (Cache.TryGetValue(request.RequestUri!.ToString(), out var cached))
        {
            return cached;
        }

        using var response = await Client.SendAsync(request).ConfigureAwait(false);

        if (!response.IsSuccessStatusCode)
        {
            if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
            {
                return null;
            }

            var errorBody = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
            throw new HttpRequestException($"[{request.RequestMethod}] {request.RequestUri}: {response.StatusCode} {errorBody}");
        }

        var json = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
        var element = JsonDocument.Parse(json).RootElement;

        Cache[request.RequestUri!.ToString()] = element;
        return element;
    }

    public HttpRequestMessage CreateGetRequest(string resource)
    {
        return new HttpRequestMessage(HttpMethod.Get, HttpBaseAddress + resource);
    }

    public HttpRequestMessage CreatePostRequest(string resource, object? body = null)
    {
        var request = new HttpRequestMessage(HttpMethod.Post, HttpBaseAddress + resource);
        request.Content = new StringContent(JsonSerializer.Serialize(body), System.Text.Encoding.UTF8, "application/json");
        return request;
    }

    public HttpRequestMessage CreatePutRequest(string resource, object? body = null)
    {
        var request = new HttpRequestMessage(HttpMethod.Put, HttpBaseAddress + resource);
        request.Content = new StringContent(JsonSerializer.Serialize(body), System.Text.Encoding.UTF8, "application/json");
        return request;
    }

    public HttpRequestMessage CreateDeleteRequest(string resource)
    {
        return new HttpRequestMessage(HttpMethod.Delete, HttpBaseAddress + resource);
    }

    public void SetAccessToken(string token)
    {
        AccessToken = token;
    }

    public void SetRequestHeaders(HttpHeaders headers)
    {
        var cloned = Client.DefaultRequestHeaders.Clone();
        foreach (var header in headers)
        {
            cloned.Add(header.Key, header.Value);
        }
        Client.DefaultRequestHeaders = cloned;
    }

    public void AddRequestHeader(string name, params string[] values)
    {
        foreach (var value in values)
        {
            Client.DefaultRequestHeaders.Add(name, value);
        }
    }

    private class JsonDefaults
    {
        public static readonly JsonSerializerOptions DefaultSerializerOptions = new()
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
            Converters = { new JsonStringEnumConverter() }
        };
    }
}