using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Sozsoft.Mcp.Dtos;
using Sozsoft.Mcp.Services;
using Sozsoft.Platform.Localization;
using Volo.Abp;
using Volo.Abp.Application.Services;

namespace Sozsoft.Mcp;

/// <summary>
/// MCP uygulama servislerinin ortak tabani. Kullaniciya gorunen metinler platformun
/// <c>PlatformResource</c> kaynagindan okunur; sunucu kaydini cozme ve arac kapisi her
/// serviste ayni davranir.
/// </summary>
public abstract class McpAppService : ApplicationService
{
    protected IMcpServerConfigProvider ServerConfigProvider { get; }

    protected McpAppService(IMcpServerConfigProvider serverConfigProvider)
    {
        ServerConfigProvider = serverConfigProvider;
        LocalizationResource = typeof(PlatformResource);
    }

    /// <summary>Etkin sunucu kaydinin DTO hali; kayit yoksa null.</summary>
    protected async Task<McpServerConfigDto?> ResolveServerConfigAsync()
    {
        var server = await ServerConfigProvider.GetEffectiveServerAsync();
        if (server is null)
        {
            return null;
        }

        return new McpServerConfigDto
        {
            Name = server.Name,
            Url = server.Url,
            DataSourceCode = server.DataSourceCode,
            AllowedTools = [.. ServerConfigProvider.SplitMultiValue(server.AllowedTools)],
            MaxRows = server.MaxRows,
            AllowWrite = server.AllowWrite,
            Description = server.Description,
            TenantName = CurrentTenant.Name
        };
    }

    /// <summary>
    /// Kaydi zorunlu kilan islemler icin. Kayit yoksa istemcinin nedenini gorebilecegi bir
    /// hata atar.
    /// </summary>
    protected async Task<McpServerConfigDto> RequireServerConfigAsync()
        => await ResolveServerConfigAsync()
           ?? throw new UserFriendlyException(L[McpErrorCodes.NoServerRecord]);

    /// <summary>
    /// Kapali bir araca yapilan cagriyi reddeder: arac sunucu kaydinda kapaliysa ya da
    /// kullanicinin uygulamada karsilik gelen yetkisi yoksa. Arac listesini suzmek tek basina
    /// yeterli degildir — istemci listede olmayan bir araci da cagirabilir.
    /// </summary>
    protected async Task<McpServerConfigDto> EnsureToolAllowedAsync(string toolName)
    {
        var config = await RequireServerConfigAsync();

        if (!McpToolPolicy.IsAllowed(true, config.AllowWrite, config.AllowedTools, toolName))
        {
            throw new UserFriendlyException(L[McpErrorCodes.ToolDisabled, toolName, config.Name]);
        }

        if (McpToolNames.RequiredPermissions.TryGetValue(toolName, out var permission))
        {
            await AuthorizationService.CheckAsync(permission);
        }

        return config;
    }

    /// <summary>Istenen satir sayisini sunucu kaydindaki tavana kirpar.</summary>
    protected static int ResolveMaxRows(McpServerConfigDto config, int requested)
    {
        var ceiling = config.MaxRows > 0 ? config.MaxRows : McpConsts.DefaultMaxRows;

        return requested > 0 ? Math.Min(requested, ceiling) : ceiling;
    }
}