using Microsoft.Extensions.Configuration;
using ZA.CoreService.ESBCertificateManager.Models;

namespace ZA.CoreService.ESBCertificateManager.Configuration;

public static class AppSettingsLoader
{
    public static AppSettings Load()
    {
        string basePath = Directory.Exists(AppContext.BaseDirectory)
            ? AppContext.BaseDirectory
            : Directory.GetCurrentDirectory();

        string settingsPath = Path.Combine(basePath, "appsettings.json");

        if (!File.Exists(settingsPath))
        {
            string cwdPath = Path.Combine(
                Directory.GetCurrentDirectory(),
                "appsettings.json");

            if (File.Exists(cwdPath))
            {
                basePath = Directory.GetCurrentDirectory();
            }
            else
            {
                throw new FileNotFoundException(
                    "Die Datei appsettings.json wurde nicht gefunden.",
                    settingsPath);
            }
        }

        IConfigurationRoot configuration = new ConfigurationBuilder()
            .SetBasePath(basePath)
            .AddJsonFile(
                "appsettings.json",
                optional: false,
                reloadOnChange: false)
            .Build();

        AppSettings settings = new();
        configuration.Bind(settings);

        Validate(settings);

        return settings;
    }

    private static void Validate(
        AppSettings settings)
    {
        if (string.IsNullOrWhiteSpace(settings.EnvironmentCode))
        {
            throw new InvalidOperationException(
                "EnvironmentCode fehlt in appsettings.json.");
        }

        settings.EnvironmentCode =
            settings.EnvironmentCode
                .Trim()
                .ToUpperInvariant();

        string[] allowedEnvironmentCodes =
        [
            "DEV",
        "TEST",
        "PROD"
        ];

        if (!allowedEnvironmentCodes.Contains(
                settings.EnvironmentCode,
                StringComparer.OrdinalIgnoreCase))
        {
            throw new InvalidOperationException(
                $"EnvironmentCode '{settings.EnvironmentCode}' ist ungültig. " +
                "Erlaubt sind DEV, TEST und PROD.");
        }

        if (string.IsNullOrWhiteSpace(
                settings.Database.ConnectionString))
        {
            throw new InvalidOperationException(
                "Database:ConnectionString fehlt in appsettings.json.");
        }

        if (string.IsNullOrWhiteSpace(
                settings.Runtime.JavaExecutablePath))
        {
            throw new InvalidOperationException(
                "Runtime:JavaExecutablePath fehlt in appsettings.json.");
        }

        if (string.IsNullOrWhiteSpace(
                settings.Runtime.SonicClientLibraryPath))
        {
            throw new InvalidOperationException(
                "Runtime:SonicClientLibraryPath fehlt in appsettings.json.");
        }

        if (string.IsNullOrWhiteSpace(
                settings.AlwaysEncrypted.CertificateThumbprint))
        {
            throw new InvalidOperationException(
                "AlwaysEncrypted:CertificateThumbprint fehlt.");
        }
    }
}