namespace HaCompanion;

class StatisticsHolder
{
    public string name;
    public string url;
    public string requestPath;
    public UptimeStatistics? latestResult;
}

public class UptimePollerService : IHostedService
{
    private readonly int _interval;
    private Timer _timer;
    private List<StatisticsHolder> _uptimeStatistics = new List<StatisticsHolder>();
    private readonly IHttpClientFactory _httpClientFactory;
    private readonly ILogger<UptimePollerService> _logger;
    
    public UptimePollerService(IConfiguration configuration, IHttpClientFactory httpClientFactory, ILogger<UptimePollerService> logger)
    {
        _httpClientFactory = httpClientFactory;
        _logger = logger;
        _interval = configuration.GetRequiredSection("Uptime").GetValue<int>("Period") * 60_000;
        
        var statsEntries = configuration.GetRequiredSection("Uptime").GetRequiredSection("Websites").GetChildren();
        foreach (var entry in statsEntries)
        {
            var holder = new StatisticsHolder()
            {
                name = entry.GetRequiredSection("website").Value!,
                url = entry.GetRequiredSection("BaseUrl").Value!,
                requestPath = entry.GetRequiredSection("RequestUrl").Value!,
                latestResult = null
            };
            
            _logger.LogDebug("Added stats entry {Name}", holder.name);
            
            _uptimeStatistics.Add(holder);
        }
    }
    
    public async Task StartAsync(CancellationToken cancellationToken)
    {
        _logger.LogDebug("Starting async.");
        await OnTimerFiredAsync();
        
        _timer = new Timer(async _ => await OnTimerFiredAsync(),
            null, _interval, Timeout.Infinite);
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        _logger.LogDebug("Stopping async.");
        _timer?.Dispose();
        return Task.CompletedTask;
    }

    public List<UptimeStatistics> GetUptimeStatistics()
    {
        var result = new List<UptimeStatistics>();
        foreach (var statistics in _uptimeStatistics)
        {
            result.Add(statistics.latestResult);
        }

        return result;
    }

    private async Task OnTimerFiredAsync()
    {
        _logger.LogInformation("Executing HTTP status checks.");
        try
        {
            foreach (var holder in _uptimeStatistics)
            {
                _logger.LogDebug("{Name} - Checking uptime.", holder.name);
                try
                {
                    var client = _httpClientFactory.CreateClient(holder.name);
                    var response = await client.GetAsync(holder.requestPath);
                    if (!response.IsSuccessStatusCode)
                    {
                        holder.latestResult = new UptimeStatistics(holder.name, true, false, null);
                        _logger.LogWarning("{Name} - HTTP failed. Status code: {Code}", holder.name, response.StatusCode);
                    }
                    else
                    {
                        holder.latestResult = new UptimeStatistics(holder.name, true, true, true);
                        _logger.LogDebug("{Name} - HTTP success.", holder.name);
                    }
                }
                catch (HttpRequestException he)
                {
                    holder.latestResult = new UptimeStatistics(holder.name, false, null, null);
                    _logger.LogWarning("{Name} - HTTP failed with HttpRequestException. {Ex}", holder.name, he);
                }
                catch (Exception e)
                {
                    holder.latestResult = new UptimeStatistics(holder.name, false, null, null);
                    _logger.LogError("{Name} - HTTP failed with general Exception. {Ex}", holder.name, e);
                }
                
            }
        }
        finally
        {
            _logger.LogDebug("HTTP status checks completed.");
            _timer?.Change(_interval, Timeout.Infinite);
        }
    }
}