using Microsoft.Extensions.Options;
using Npgsql;
using Tau.Acuvim.Portal.Configuration;
using Tau.Acuvim.Portal.DTOs;

namespace Tau.Acuvim.Portal.Services;

// Captures the DB connection-resolution source at startup so the App-config view
// can show how the running container resolved its DB without re-parsing config.
public sealed class DatabaseResolutionInfo
{
    public DatabaseResolutionInfo(string source) => Source = source;
    public string Source { get; }
    public DateTime StartedAtUtc { get; } = DateTime.UtcNow;
}

public sealed class ConfigOverviewService(
    IOptions<ApplicationOptions> appOptions,
    IOptions<DatabaseOptions> dbOptions,
    IOptions<GrafanaOptions> grafanaOptions,
    IOptions<MonitoringOptions> monitoringOptions,
    IOptions<AuthenticationOptions> authOptions,
    IHostEnvironment env,
    DatabaseResolutionInfo dbResolution)
{
    public ConfigOverviewDto Build()
    {
        var (host, port, database) = ParseConnection(dbOptions.Value.ConnectionString);

        var application = new AppInfoDto(
            appOptions.Value.Name,
            env.EnvironmentName,
            appOptions.Value.PublicUrl);

        var database_ = new DatabaseInfoDto(
            dbOptions.Value.Provider,
            host, port, database,
            dbOptions.Value.MigrateOnStartup,
            dbOptions.Value.AutoProvisionLocalTimescaleDb,
            dbResolution.Source);

        var grafana = new GrafanaInfoDto(
            grafanaOptions.Value.BaseUrl,
            grafanaOptions.Value.InternalUrl,
            grafanaOptions.Value.EmbedPathPrefix,
            grafanaOptions.Value.EmbedMode,
            grafanaOptions.Value.DefaultDashboardUid,
            grafanaOptions.Value.AuthMode,
            grafanaOptions.Value.Dashboards.Count);

        var monitoring = new MonitoringInfoDto(
            monitoringOptions.Value.ChunkTimeInterval,
            monitoringOptions.Value.EnableHourlyAggregates);

        var auth = new AuthInfoDto(
            authOptions.Value.CookieName,
            authOptions.Value.RequireConfirmedEmail,
            authOptions.Value.DefaultAdminEmail);

        var assembly = typeof(ConfigOverviewService).Assembly.GetName();
        var build = new BuildInfoDto(
            assembly.Version?.ToString() ?? "0.0.0",
            Environment.Version.ToString(),
            dbResolution.StartedAtUtc);

        return new ConfigOverviewDto(application, database_, grafana, monitoring, auth, build);
    }

    private static (string Host, int Port, string Database) ParseConnection(string connectionString)
    {
        if (string.IsNullOrWhiteSpace(connectionString)) return ("(unset)", 0, "(unset)");
        try
        {
            var b = new NpgsqlConnectionStringBuilder(connectionString);
            return (b.Host ?? "(unset)", b.Port, b.Database ?? "(unset)");
        }
        catch
        {
            return ("(unparseable)", 0, "(unparseable)");
        }
    }
}