using CsvHelper;
using CsvHelper.Configuration;
using CsvHelper.Configuration.Attributes;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    public class Program
    {
        private readonly string[] SOURCE_FILES = new string[]
        {
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\deces-2018.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\deces-2019.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\deces-2020-m01.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M02.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M03.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M04.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M05.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M06.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M07.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M08.csv"),
            Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\Deces_2020_M09.csv"),
        };
        private readonly string DESTINATION_FILE = Environment.ExpandEnvironmentVariables(@"%USERPROFILE%\Downloads\deaths\output.csv");

        public static async Task Main(string[] args)
        {
            Console.WriteLine("Starting");
            try
            {
                var program = new Program();
                await program.Run();
            }
            catch (Exception ex)
            {
                Console.WriteLine("ERROR");
                Console.WriteLine(ex.ToString());
            }
            Console.WriteLine("Stopping");
        }

        public Task Run()
        {
            var csvConfig = new CsvConfiguration(CultureInfo.InvariantCulture)
            {
                Delimiter = ";",
                HasHeaderRecord = true
            };

            // Read input data
            var records = new List<InputEntry>();
            foreach (string sourceFile in SOURCE_FILES)
            {
                using var reader = new StreamReader(sourceFile);
                using var csvReader = new CsvReader(reader, csvConfig);
                IEnumerable<InputEntry> entries = csvReader.GetRecords<InputEntry>();
                records.AddRange(entries);
            }

            // Compute stats
            var stats = new Dictionary<string, Dictionary<int, int>>();
            foreach (InputEntry record in records)
            {
                Match match = Regex.Match(record.DeathDate, @"(20\d\d)(\d\d)(\d\d)");
                if (match.Success)
                {
                    int year = int.Parse(match.Groups[1].Value);
                    int month = int.Parse(match.Groups[2].Value);
                    int day = int.Parse(match.Groups[3].Value);
                    string date = $"{month:00}-{day:00}";

                    if (!stats.ContainsKey(date))
                    {
                        stats[date] = new Dictionary<int, int>();
                    }
                    Dictionary<int, int> stat = stats[date];
                    if (!stat.ContainsKey(year))
                    {
                        stat[year] = 1;
                    }
                    else
                    {
                        stat[year]++;
                    }
                }
            }

            // Write output data
            var outEntries = new List<OutputEntry>();
            foreach (KeyValuePair<string, Dictionary<int, int>> stat in stats.OrderBy(x => x.Key))
            {
                var outEntry = new OutputEntry()
                {
                    Day = stat.Key,
                    Year2018 = stat.Value.GetValueOrDefault(2018, 0),
                    Year2019 = stat.Value.GetValueOrDefault(2019, 0),
                    Year2020 = stat.Value.GetValueOrDefault(2020, 0)
                };
                outEntries.Add(outEntry);
            }
            using var writer = new StreamWriter(DESTINATION_FILE, append: false, encoding: Encoding.UTF8);
            using var csvWriter = new CsvWriter(writer, csvConfig);
            csvWriter.WriteRecords(outEntries);

            return Task.CompletedTask;
        }
    }

    public class InputEntry
    {
        [Name("nomprenom")]
        public string Name { get; set; }
        [Name("sexe")]
        public string Gender { get; set; }
        [Name("datenaiss")]
        public string BirthDate { get; set; }
        [Name("lieunaiss")]
        public string BirthPlace { get; set; }
        [Name("commnaiss")]
        public string BirthCity { get; set; }
        [Name("paysnaiss")]
        public string BirthCountry { get; set; }
        [Name("datedeces")]
        public string DeathDate { get; set; }
        [Name("lieudeces")]
        public string DeathPlace { get; set; }
        [Name("actedeces")]
        public string DeathCertificate { get; set; }
    }

    public class OutputEntry
    {
        [Name("day")]
        public string Day { get; set; }
        [Name("2018")]
        public int Year2018 { get; set; }
        [Name("2019")]
        public int Year2019 { get; set; }
        [Name("2020")]
        public int Year2020 { get; set; }
    }
}