using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Json;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

namespace Beam.Api; 
    public class ApiCall(HttpClient client, string uri, HttpMethod method, KeyValuePair<string, string[]>[] headers, object? requestData, object? body, params HashSet<HttpStatusCode> successCodes) {
        public HttpClient Client { get; } = client;
        public object? RequestData { get; } = requestData;
        public object? Body { get; }
        public string Uri { get; } = uri;
        public HttpMethod Method { get; } = method;
        public KeyValuePair<string, string[]>[] Headers { get; private set; } = headers;
        public HashSet<HttpStatusCode> SuccessCodes { get; } = successCodes;

        private string? ContentType = "application/json";

        public async Task<ApiResponse> GetResponse(ILogger<ApiResponse>? logger, (int @try, int max)? tries = null, bool readToBuffer = true, CancellationToken ct = default) {
            SanitizeHeaders();
            
            var request = new HttpRequestMessage(Method, Uri);
            request.Content = body is null ? request.Content :
                body is string stringBody ? new StringContent(stringBody) : JsonContent.Create(body);

            if (request.Content is not null)
                request.Content.Headers.ContentType = ContentType is null ? null : new System.Net.Http.Headers.MediaTypeHeaderValue(ContentType);

            foreach (var header in Headers)
                request.Headers.Add(header.Key, header.Value);
            
            logger?.LogInformation("Fetching '{}' with method '{}', content-type '{}', and headers '{}'", Uri, Method, ContentType, JsonSerializer.Serialize(request.Headers.ToDictionary()));
            var response = await Client.SendAsync(request, ct);

            if (tries is not null && tries?.@try < tries?.max && !SuccessCodes.Contains(response.StatusCode)) {
                await Task.Delay((int)Math.Min(Math.Pow(2, tries.Value.@try), 60) * 1000, ct);
                return await GetResponse(logger, (tries.Value.@try + 1, tries.Value.max), readToBuffer, ct);
            }

            return await ApiResponse.CreateAsync(response, logger, RequestData, readToBuffer, ct);
        }

        private void SanitizeHeaders() {
            Dictionary<string, string[]> headers = [];
            foreach(var kvp in Headers) {
                if (kvp.Value.Length == 0)
                    continue;

                if (kvp.Key == "Content-Type") {
                    ContentType = kvp.Value[0];
                } else {
                    headers[kvp.Key] = kvp.Value;
                }
            }

            Headers = headers.ToArray();
        }

        public static async Task<ApiResponse> Get(HttpClient client, string url, ILoggerFactory factory)
            => await new ApiCall(client, url, HttpMethod.Get, [], null, null).GetResponse(factory.CreateLogger<ApiResponse>());
    }