using Codex.Dal;
using Codex.Dal.Enums;
using Codex.Dal.Services;
using FluentValidation;
using Microsoft.EntityFrameworkCore;
using OpenHarbor.CQRS.Abstractions;

namespace Codex.CQRS.Commands;

/// <summary>
/// Command to update an existing agent's configuration
/// </summary>
public record UpdateAgentCommand
{
    /// <summary>
    /// ID of the agent to update
    /// </summary>
    public Guid Id { get; init; }

    /// <summary>
    /// Display name of the agent
    /// </summary>
    public string Name { get; init; } = string.Empty;

    /// <summary>
    /// Description of the agent's purpose and capabilities
    /// </summary>
    public string Description { get; init; } = string.Empty;

    /// <summary>
    /// Type of agent (CodeGenerator, CodeReviewer, etc.)
    /// </summary>
    public AgentType Type { get; init; }

    /// <summary>
    /// Model provider name (e.g., "openai", "anthropic", "ollama")
    /// </summary>
    public string ModelProvider { get; init; } = string.Empty;

    /// <summary>
    /// Specific model name (e.g., "gpt-4o", "claude-3.5-sonnet", "codellama:7b")
    /// </summary>
    public string ModelName { get; init; } = string.Empty;

    /// <summary>
    /// Type of provider (CloudApi, LocalEndpoint, Custom)
    /// </summary>
    public ModelProviderType ProviderType { get; init; }

    /// <summary>
    /// Model endpoint URL (required for LocalEndpoint, optional for CloudApi)
    /// </summary>
    public string? ModelEndpoint { get; init; }

    /// <summary>
    /// API key for cloud providers (will be encrypted). Leave null to keep existing key.
    /// </summary>
    public string? ApiKey { get; init; }

    /// <summary>
    /// Temperature parameter for model generation (0.0 to 2.0)
    /// </summary>
    public double Temperature { get; init; } = 0.7;

    /// <summary>
    /// Maximum tokens to generate in response
    /// </summary>
    public int MaxTokens { get; init; } = 4000;

    /// <summary>
    /// System prompt defining agent behavior and instructions
    /// </summary>
    public string SystemPrompt { get; init; } = string.Empty;

    /// <summary>
    /// Whether conversation memory is enabled for this agent
    /// </summary>
    public bool EnableMemory { get; init; } = true;

    /// <summary>
    /// Number of recent messages to include in context (1-100)
    /// </summary>
    public int ConversationWindowSize { get; init; } = 10;

    /// <summary>
    /// Agent status
    /// </summary>
    public AgentStatus Status { get; init; } = AgentStatus.Active;
}

/// <summary>
/// Handler for updating an agent
/// </summary>
public class UpdateAgentCommandHandler(CodexDbContext dbContext, IEncryptionService encryptionService)
    : ICommandHandler<UpdateAgentCommand>
{
    public async Task HandleAsync(UpdateAgentCommand command, CancellationToken cancellationToken = default)
    {
        var agent = await dbContext.Agents
            .FirstOrDefaultAsync(a => a.Id == command.Id && !a.IsDeleted, cancellationToken);

        if (agent == null)
        {
            throw new InvalidOperationException($"Agent with ID {command.Id} not found or has been deleted");
        }

        agent.Name = command.Name;
        agent.Description = command.Description;
        agent.Type = command.Type;
        agent.ModelProvider = command.ModelProvider.ToLowerInvariant();
        agent.ModelName = command.ModelName;
        agent.ProviderType = command.ProviderType;
        agent.ModelEndpoint = command.ModelEndpoint;
        agent.Temperature = command.Temperature;
        agent.MaxTokens = command.MaxTokens;
        agent.SystemPrompt = command.SystemPrompt;
        agent.EnableMemory = command.EnableMemory;
        agent.ConversationWindowSize = command.ConversationWindowSize;
        agent.Status = command.Status;
        agent.UpdatedAt = DateTime.UtcNow;

        // Only update API key if a new one is provided
        if (command.ApiKey != null)
        {
            agent.ApiKeyEncrypted = encryptionService.Encrypt(command.ApiKey);
        }

        await dbContext.SaveChangesAsync(cancellationToken);
    }
}

/// <summary>
/// Validator for UpdateAgentCommand
/// </summary>
public class UpdateAgentCommandValidator : AbstractValidator<UpdateAgentCommand>
{
    private static readonly string[] ValidModelProviders = { "openai", "anthropic", "ollama" };

    public UpdateAgentCommandValidator()
    {
        RuleFor(x => x.Id)
            .NotEmpty().WithMessage("Agent ID is required");

        RuleFor(x => x.Name)
            .NotEmpty().WithMessage("Agent name is required")
            .MaximumLength(200).WithMessage("Agent name must not exceed 200 characters");

        RuleFor(x => x.Description)
            .NotEmpty().WithMessage("Agent description is required")
            .MaximumLength(1000).WithMessage("Agent description must not exceed 1000 characters");

        RuleFor(x => x.ModelProvider)
            .NotEmpty().WithMessage("Model provider is required")
            .MaximumLength(100).WithMessage("Model provider must not exceed 100 characters")
            .Must(provider => ValidModelProviders.Contains(provider.ToLowerInvariant()))
            .WithMessage("Model provider must be one of: openai, anthropic, ollama");

        RuleFor(x => x.ModelName)
            .NotEmpty().WithMessage("Model name is required")
            .MaximumLength(100).WithMessage("Model name must not exceed 100 characters");

        RuleFor(x => x.SystemPrompt)
            .NotEmpty().WithMessage("System prompt is required")
            .MinimumLength(10).WithMessage("System prompt must be at least 10 characters");

        RuleFor(x => x.Temperature)
            .InclusiveBetween(0.0, 2.0).WithMessage("Temperature must be between 0.0 and 2.0");

        RuleFor(x => x.MaxTokens)
            .GreaterThan(0).WithMessage("Max tokens must be greater than 0")
            .LessThanOrEqualTo(100000).WithMessage("Max tokens must not exceed 100,000");

        RuleFor(x => x.ConversationWindowSize)
            .InclusiveBetween(1, 100).WithMessage("Conversation window size must be between 1 and 100");

        // Local endpoints require a valid URL
        RuleFor(x => x.ModelEndpoint)
            .NotEmpty()
            .When(x => x.ProviderType == ModelProviderType.LocalEndpoint)
            .WithMessage("Model endpoint URL is required for local endpoints");

        RuleFor(x => x.ModelEndpoint)
            .Must(BeAValidUrl!)
            .When(x => !string.IsNullOrWhiteSpace(x.ModelEndpoint))
            .WithMessage("Model endpoint must be a valid URL");
    }

    private static bool BeAValidUrl(string url)
    {
        return Uri.TryCreate(url, UriKind.Absolute, out var uriResult)
               && (uriResult.Scheme == Uri.UriSchemeHttp || uriResult.Scheme == Uri.UriSchemeHttps);
    }
}