using File_Watcher.Models;
using System.Collections.ObjectModel;
using System.Net.Mail;

namespace File_Watcher.Helpers;

internal static partial class InfinityQSProjectHelper
{
    private record Record(ReadOnlyCollection<string> FilteredLines,
                          DateTime LastWriteTimeUtc,
                          string Path);

    private static long _LastReview = DateTime.UtcNow.Ticks;
    private static readonly Dictionary<string, Record> _KeyValuePairs = [];

    internal static bool SendEmail(AppSettings appSettings, ILogger<Worker> logger)
    {
        InfinityQSProjectConfiguration configuration = appSettings.InfinityQSProjectConfiguration;
        Clear(logger, configuration);
        ReadOnlyDictionary<string, Record> keyValuePairs = GetKeyValuePairs(logger, configuration);
        SendEmail(logger, configuration, keyValuePairs);
        _LastReview = DateTime.UtcNow.Ticks;
        return true;
    }

    private static void Clear(ILogger<Worker> logger, InfinityQSProjectConfiguration configuration)
    {
        long check = DateTime.UtcNow.AddHours(-configuration.ClearEveryHours).Ticks;
        foreach (KeyValuePair<string, Record> keyValuePair in _KeyValuePairs)
        {
            if (keyValuePair.Value.LastWriteTimeUtc.Ticks < check)
            {
                _ = _KeyValuePairs.Remove(keyValuePair.Key);
                logger.LogDebug("Clear File:{file}", keyValuePair.Key);
            }
        }
    }

    private static ReadOnlyDictionary<string, Record> GetKeyValuePairs(ILogger<Worker> logger, InfinityQSProjectConfiguration configuration)
    {
        bool check;
        Record? record;
        string[] lines;
        FileInfo fileInfo;
        List<string> filtered = [];
        Dictionary<string, Record> results = [];
        string[] files = Directory.GetFiles(configuration.SourceDirectory, configuration.SearchPattern, SearchOption.TopDirectoryOnly);
        foreach (string file in files)
        {
            check = false;
            filtered.Clear();
            fileInfo = new(file);
            if (fileInfo.LastWriteTimeUtc.Ticks < _LastReview)
            {
                logger.LogDebug("Old File:{file}", file);
                continue;
            }
            if (_KeyValuePairs.ContainsKey(fileInfo.FullName))
            {
                logger.LogDebug("Verified File:{file}", file);
                continue;
            }
            lines = File.ReadAllLines(fileInfo.FullName);
            foreach (string line in lines)
            {
                if (!check && line.Contains(configuration.Search))
                {
                    check = true;
                    continue;
                }
                if (check)
                {
                    if (line.StartsWith(configuration.Search[0]))
                        break;
                    filtered.Add(line);
                }
            }
            record = new(FilteredLines: filtered.AsReadOnly(),
                         LastWriteTimeUtc: fileInfo.LastWriteTimeUtc,
                         Path: fileInfo.FullName);
            results.Add(fileInfo.FullName, record);
        }
        return results.AsReadOnly();
    }

    private static void SendEmail(ILogger<Worker> logger, InfinityQSProjectConfiguration configuration, ReadOnlyDictionary<string, Record> keyValuePairs)
    {
        string body;
        foreach (KeyValuePair<string, Record> keyValuePair in keyValuePairs)
        {
            logger.LogDebug("File:{file}", keyValuePair.Key);
            body = $"InfinityQS Project Change Detected{Environment.NewLine}File:{keyValuePair.Key}{Environment.NewLine}LastWriteTimeUtc:{keyValuePair.Value:O}{Environment.NewLine}{string.Join(Environment.NewLine, keyValuePair.Value.FilteredLines)}";
            logger.LogWarning("SendEmail:{body}", body);
            SendEmail(configuration.From, configuration.To, configuration.SimpleMailTransferProtocolServer, configuration.Subject, body);
        }
    }

    private static void SendEmail(string from, string to, string simpleMailTransferProtocolServer, string subject, string body)
    {
        SmtpClient smtpClient = new(simpleMailTransferProtocolServer);
        MailMessage mailMessage = new()
        {
            From = new MailAddress(from),
            Subject = subject,
            Body = body,
            Priority = MailPriority.High
        };
        mailMessage.To.Add(new MailAddress(to));
        smtpClient.Send(mailMessage);
        smtpClient.Dispose();
        mailMessage.Dispose();
    }

}