using System.IO;
using System.Text.Json;
using UtopiaCanteenSystem.Data;
using UtopiaCanteenSystem.Models;

namespace UtopiaCanteenSystem.Services;

/// <summary>
/// Scanner frontend configuration: backend URL, device/site, admin UI. No HRMS/production credentials.
/// </summary>
public sealed class ClientConfigService : IConfigService
{
    private readonly string _configPath;
    private ClientAppConfig _config;

    public ClientConfigService()
    {
        DatabasePath.UseClientStorage();
        _configPath = DatabasePath.GetConfigPath();
        _config = LoadConfig();
    }

    public string GetSyncApiEndpoint() => string.Empty;
    public void SetSyncApiEndpoint(string endpoint) { }

    public bool GetSyncServiceEnabled() => false;
    public void SetSyncServiceEnabled(bool enabled) { }

    public bool GetScannerConnected() => _config.ScannerConnected;
    public void SetScannerConnected(bool connected)
    {
        _config.ScannerConnected = connected;
        SaveConfig();
    }

    public int GetScanIntervalDays() => Math.Clamp(_config.ScanIntervalDays, 0, 365);
    public void SetScanIntervalDays(int value) { _config.ScanIntervalDays = Math.Clamp(value, 0, 365); SaveConfig(); }
    public int GetScanIntervalHours() => Math.Clamp(_config.ScanIntervalHours, 0, 23);
    public void SetScanIntervalHours(int value) { _config.ScanIntervalHours = Math.Clamp(value, 0, 23); SaveConfig(); }
    public int GetScanIntervalMinutes() => Math.Clamp(_config.ScanIntervalMinutes, 0, 59);
    public void SetScanIntervalMinutes(int value) { _config.ScanIntervalMinutes = Math.Clamp(value, 0, 59); SaveConfig(); }
    public int GetScanIntervalSeconds() => Math.Clamp(_config.ScanIntervalSeconds, 0, 59);
    public void SetScanIntervalSeconds(int value) { _config.ScanIntervalSeconds = Math.Clamp(value, 0, 59); SaveConfig(); }

    public TimeSpan GetScanInterval()
    {
        var ts = TimeSpan.FromDays(GetScanIntervalDays()) + TimeSpan.FromHours(GetScanIntervalHours())
            + TimeSpan.FromMinutes(GetScanIntervalMinutes()) + TimeSpan.FromSeconds(GetScanIntervalSeconds());
        return ts > TimeSpan.Zero ? ts : TimeSpan.FromMinutes(1);
    }

    public string GetAdminCardId() => _config.AdminCardId ?? "ADMIN";
    public void SetAdminCardId(string cardId) { _config.AdminCardId = cardId ?? string.Empty; SaveConfig(); }

    public string GetSiteId() => _config.SiteId ?? string.Empty;
    public void SetSiteId(string siteId) { _config.SiteId = siteId ?? string.Empty; SaveConfig(); }

    public void ApplyLocationSiteIdFromAuth(string? locationSiteId)
    {
        if (string.IsNullOrWhiteSpace(locationSiteId))
            return;
        var digits = new string(locationSiteId.Where(char.IsDigit).ToArray());
        if (string.IsNullOrEmpty(digits))
            return;
        _config.SiteId = $"SITE : {digits}";
        SaveConfig();
    }

    public string GetDeviceId()
    {
        if (!string.IsNullOrWhiteSpace(_config.DeviceId))
            return _config.DeviceId.Trim();

        _config.DeviceId = ResolveMachineDeviceId();
        SaveConfig();
        return _config.DeviceId;
    }

    public void SetDeviceId(string deviceId)
    {
        _config.DeviceId = string.IsNullOrWhiteSpace(deviceId)
            ? ResolveMachineDeviceId()
            : deviceId.Trim();
        SaveConfig();
    }

    public bool GetRememberAdminCredentials() => _config.RememberAdminCredentials;
    public void SetRememberAdminCredentials(bool remember) { _config.RememberAdminCredentials = remember; SaveConfig(); }
    public string GetSavedAdminUsername() => _config.SavedAdminUsername ?? string.Empty;
    public void SetSavedAdminUsername(string username) { _config.SavedAdminUsername = username ?? string.Empty; SaveConfig(); }
    public string GetSavedAdminPassword() => DecryptPassword(_config.SavedAdminPasswordProtected ?? string.Empty);
    public void SetSavedAdminPassword(string password) { _config.SavedAdminPasswordProtected = EncryptPassword(password ?? string.Empty); SaveConfig(); }

    public string GetMySqlConnectionString() => string.Empty;
    public void SetMySqlConnectionString(string connectionString) { }

    public string GetHrmsLookupConnectionString() => string.Empty;
    public void SetHrmsLookupConnectionString(string connectionString) { }

    public DateTime? GetLastEmployeeRfidCacheSyncUtc() => null;
    public void SetLastEmployeeRfidCacheSyncUtc(DateTime utc) { }

    public DateTime? GetLastMealMenuCacheSyncUtc() => null;
    public void SetLastMealMenuCacheSyncUtc(DateTime utc) { }

    public AppMode GetAppMode() => AppMode.Client;
    public void SetAppMode(AppMode mode) { }

    public string GetCentralServerBaseUrl() => GetBackendBaseUrl();
    public void SetCentralServerBaseUrl(string url) => SetBackendBaseUrl(url);

    public string GetBackendBaseUrl() => (_config.BackendBaseUrl ?? string.Empty).TrimEnd('/');

    public void SetBackendBaseUrl(string url)
    {
        _config.BackendBaseUrl = (url ?? string.Empty).Trim().TrimEnd('/');
        SaveConfig();
    }

    public string GetLocalServerListenUrls() => string.Empty;
    public void SetLocalServerListenUrls(string urls) { }

    private ClientAppConfig LoadConfig()
    {
        try
        {
            if (!File.Exists(_configPath))
                return new ClientAppConfig { BackendBaseUrl = "http://localhost:5000" };
            var json = File.ReadAllText(_configPath);
            return JsonSerializer.Deserialize<ClientAppConfig>(json) ?? new ClientAppConfig();
        }
        catch
        {
            return new ClientAppConfig();
        }
    }

    private void SaveConfig()
    {
        try
        {
            var json = JsonSerializer.Serialize(_config, new JsonSerializerOptions { WriteIndented = true });
            File.WriteAllText(_configPath, json);
        }
        catch (Exception ex)
        {
            Logger.Log(ex, "ClientConfigService.SaveConfig");
        }
    }

    private static string ResolveMachineDeviceId()
    {
        var machineName = Environment.MachineName;
        return string.IsNullOrWhiteSpace(machineName)
            ? Guid.NewGuid().ToString("N")
            : machineName.Trim();
    }

    private static string EncryptPassword(string plain)
    {
        if (string.IsNullOrEmpty(plain)) return string.Empty;
        try
        {
            var bytes = System.Text.Encoding.UTF8.GetBytes(plain);
            var protectedBytes = System.Security.Cryptography.ProtectedData.Protect(bytes, null, System.Security.Cryptography.DataProtectionScope.CurrentUser);
            return Convert.ToBase64String(protectedBytes);
        }
        catch
        {
            return string.Empty;
        }
    }

    private static string DecryptPassword(string protectedBase64)
    {
        if (string.IsNullOrEmpty(protectedBase64)) return string.Empty;
        try
        {
            var protectedBytes = Convert.FromBase64String(protectedBase64);
            var bytes = System.Security.Cryptography.ProtectedData.Unprotect(protectedBytes, null, System.Security.Cryptography.DataProtectionScope.CurrentUser);
            return System.Text.Encoding.UTF8.GetString(bytes);
        }
        catch
        {
            return string.Empty;
        }
    }

    private sealed class ClientAppConfig
    {
        public string? BackendBaseUrl { get; set; }
        public bool ScannerConnected { get; set; }
        public int ScanIntervalDays { get; set; }
        public int ScanIntervalHours { get; set; }
        public int ScanIntervalMinutes { get; set; }
        public int ScanIntervalSeconds { get; set; } = 5;
        public string? AdminCardId { get; set; }
        public string? SiteId { get; set; }
        public string? DeviceId { get; set; }
        public bool RememberAdminCredentials { get; set; }
        public string? SavedAdminUsername { get; set; }
        public string? SavedAdminPasswordProtected { get; set; }
    }
}