using System;
using System.IO;
using System.Net;

namespace NonaBGS.EDDB {
    public class API {
        private static readonly string EDDB_SYSTEMS_ARCHIVE = "https://eddb.io/archive/v6/systems_populated.json";
        private string cache_folder = null;
        private readonly WebClient client = new WebClient();

        private string systems_file = null;

        public string SystemsFile => systems_file;

        public string Cache {
            get => cache_folder;
            set => cache_folder = value;
        }

        public API(string cache_folder) {
            Initialise(cache_folder);
        }

        private void Initialise(string cache_folder) {
            this.cache_folder = cache_folder;
            systems_file = Path.Combine(this.cache_folder, "systems_populated.json");
            client.DownloadDataCompleted += Client_DownloadDataCompleted;
        }

        private void DownloadFile(string url, string file) {
            client.DownloadFileAsync(new Uri(url), file);
        }

        public void Download(bool force) {
            if (!HaveSystemsFile || force) {
                DownloadFile(EDDB_SYSTEMS_ARCHIVE, systems_file);
            }
        }

        public void Download() {
            Download(false);
        }

        public bool HaveSystemsFile {
            get { return systems_file != null && File.Exists(systems_file); }
        }

        public PopulatedSystems MakePopulatedSystems() {
            if (!HaveSystemsFile) {
                throw new InvalidOperationException("no local systems file downloaded");
            }

            return PopulatedSystems.FromFile(SystemsFile);
        }

        private void Client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e) {
        }
    }
}