#pragma warning disable CS8618
using System;
using System.Linq;
using System.Net.Http.Json;
using Ical.Net;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Xml;
using HtmlAgilityPack;
using System.Diagnostics;
using Newtonsoft.Json;

namespace newsletter
{
    class Program
    {
        static async Task Main(string[] args)
        {
            var conf = Configure();
            if (conf == null) return;

            var reports = await CollectReports(CollectReporters(conf));

            var fullHtml = AssembleHTML(reports.Select(r => r.ReportContent));

            fullHtml.Save(conf.ExportPath);
        }

        static Configuration Configure(string configurationPath = "appsettings.json")
        {
            if (!File.Exists(configurationPath))
            {
                Console.Error.WriteLine($"could not find configuration at {configurationPath}! copying sample to that spot.");
                File.Copy("sample-appsettings.json", configurationPath); //and you know what, if that explodes at the OS level, the OS should give you an error
                return null;
            }
            var fileContents = File.ReadAllText(configurationPath);
            if (string.IsNullOrWhiteSpace(fileContents))
            {
                Console.Error.WriteLine($"configuration file at {configurationPath} was empty! overwriting with sample settings.");
                File.Copy("sample-appsettings.json", configurationPath, true);
                return null;
            }

            var conf = JsonConvert.DeserializeObject<Configuration>(fileContents);

            if (conf == null)
            {
                Console.Error.WriteLine($"configuration file at {configurationPath} was empty! overwriting with sample settings.");
                File.Copy("sample-appsettings.json", configurationPath, true);
                return null;
            }

            return conf;
        }

        static List<Task<Report>> CollectReporters(Configuration conf)
        {
            var toReturn = new List<Task<Report>>();

            var reporterTypes = AppDomain.CurrentDomain.GetAssemblies()
              .SelectMany(domainAssembly => domainAssembly.GetTypes())
              .Where(type => type.IsSubclassOf(typeof(newsletter.Reporters.Reporter)) && !type.IsAbstract)
              .ToList();
            var skipPortionInName = "newsletter.Reporters.".Length;


            foreach(var discoveredConfType in conf.Reporters.Select(r => r.ReporterClass))
            {
                Console.WriteLine($"{discoveredConfType} configuration type discovered");
            }
            foreach (var reporterType in reporterTypes)
            {
                Console.WriteLine($"{reporterType.ToString().Substring(skipPortionInName).ToLower()} reporter class discovered");
                Func<Configuration.Reporter, bool> predicate = r => r.ReporterClass == reporterType.ToString().Substring(skipPortionInName).ToLower();
                if (!conf.Reporters.Any(predicate))
                {
                    Console.WriteLine($"no configurations for it");
                }
                else
                {
                    var configurationsFor = conf.Reporters.Where(predicate);
                    Console.WriteLine($"{configurationsFor.Count()} configurations for it");
                    
                    foreach (var confFor in configurationsFor)
                    {
                         var instance = (newsletter.Reporters.Reporter) Activator.CreateInstance(reporterType);
                        toReturn.Add(instance.Report(confFor));
                    }
                }
            }

            return toReturn;
        }

        static async Task<List<Report>> CollectReports(List<Task<Report>> tasks)
        {
            var results = new List<Report>();
            foreach (var task in tasks)
            {
                var rep = await task;
                results.Add(rep);
            }
            return results;
        }

        static HtmlDocument AssembleHTML(IEnumerable<HtmlNode> reportSections)
        {
            //TODO
            Console.WriteLine($"assembling {reportSections.Count()} sections");
            throw new NotImplementedException();
        }

    }
}