using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using YarpGateway.Data;
using YarpGateway.Models;

namespace YarpGateway.Controllers;

[ApiController]
[Route("api/gateway/pending-services")]
[Authorize] // 要求所有管理 API 都需要认证
public class PendingServicesController : ControllerBase
{
    private readonly IDbContextFactory<GatewayDbContext> _dbContextFactory;
    private readonly ILogger<PendingServicesController> _logger;

    public PendingServicesController(
        IDbContextFactory<GatewayDbContext> dbContextFactory,
        ILogger<PendingServicesController> logger)
    {
        _dbContextFactory = dbContextFactory;
        _logger = logger;
    }

    [HttpGet]
    public async Task<IActionResult> GetPendingServices(
        [FromQuery] int page = 1,
        [FromQuery] int pageSize = 10,
        [FromQuery] int? status = null)
    {
        await using var db = _dbContextFactory.CreateDbContext();
        var query = db.PendingServiceDiscoveries.Where(p => !p.IsDeleted);

        if (status.HasValue)
        {
            query = query.Where(p => p.Status == status.Value);
        }

        var total = await query.CountAsync();
        var items = await query
            .OrderByDescending(p => p.DiscoveredAt)
            .Skip((page - 1) * pageSize)
            .Take(pageSize)
            .Select(p => new
            {
                p.Id,
                p.K8sServiceName,
                p.K8sNamespace,
                p.K8sClusterIP,
                DiscoveredPorts = System.Text.Json.JsonSerializer.Deserialize<List<int>>(p.DiscoveredPorts) ?? new List<int>(),
                Labels = System.Text.Json.JsonSerializer.Deserialize<Dictionary<string, string>>(p.Labels) ?? new Dictionary<string, string>(),
                p.PodCount,
                Status = (PendingServiceStatus)p.Status,
                p.AssignedClusterId,
                p.AssignedBy,
                p.AssignedAt,
                p.DiscoveredAt
            })
            .ToListAsync();

        return Ok(new { items, total, page, pageSize });
    }

    [HttpGet("{id}")]
    public async Task<IActionResult> GetPendingService(long id)
    {
        await using var db = _dbContextFactory.CreateDbContext();
        var service = await db.PendingServiceDiscoveries.FindAsync(id);

        if (service == null || service.IsDeleted)
        {
            return NotFound(new { message = "Pending service not found" });
        }

        return Ok(new
        {
            service.Id,
            service.K8sServiceName,
            service.K8sNamespace,
            service.K8sClusterIP,
            DiscoveredPorts = System.Text.Json.JsonSerializer.Deserialize<List<int>>(service.DiscoveredPorts) ?? new List<int>(),
            Labels = System.Text.Json.JsonSerializer.Deserialize<Dictionary<string, string>>(service.Labels) ?? new Dictionary<string, string>(),
            service.PodCount,
            Status = (PendingServiceStatus)service.Status,
            service.AssignedClusterId,
            service.AssignedBy,
            service.AssignedAt,
            service.DiscoveredAt
        });
    }

    [HttpPost("{id}/assign")]
    public async Task<IActionResult> AssignService(long id, [FromBody] AssignServiceRequest request)
    {
        await using var db = _dbContextFactory.CreateDbContext();
        
        var pendingService = await db.PendingServiceDiscoveries.FindAsync(id);
        if (pendingService == null || pendingService.IsDeleted)
        {
            return NotFound(new { message = "Pending service not found" });
        }

        if (pendingService.Status != (int)PendingServiceStatus.Pending)
        {
            return BadRequest(new { message = $"Service is already {((PendingServiceStatus)pendingService.Status)}, cannot assign" });
        }

        if (string.IsNullOrEmpty(request.ClusterId))
        {
            return BadRequest(new { message = "ClusterId is required" });
        }

        var existingCluster = await db.ServiceInstances
            .AnyAsync(i => i.ClusterId == request.ClusterId && !i.IsDeleted);

        if (!existingCluster)
        {
            return BadRequest(new { message = $"Cluster '{request.ClusterId}' does not exist. Please create the cluster first." });
        }

        var discoveredPorts = System.Text.Json.JsonSerializer.Deserialize<List<int>>(pendingService.DiscoveredPorts) ?? new List<int>();
        var primaryPort = discoveredPorts.FirstOrDefault() > 0 ? discoveredPorts.First() : 80;

        var instanceNumber = await db.ServiceInstances
            .CountAsync(i => i.ClusterId == request.ClusterId && !i.IsDeleted);

        var newInstance = new GwServiceInstance
        {
            ClusterId = request.ClusterId,
            DestinationId = $"{pendingService.K8sServiceName}-{instanceNumber + 1}",
            Address = $"http://{pendingService.K8sClusterIP}:{primaryPort}",
            Health = 1,
            Weight = 100,
            Status = 1,
            CreatedTime = DateTime.UtcNow,
            Version = 1
        };

        db.ServiceInstances.Add(newInstance);

        pendingService.Status = (int)PendingServiceStatus.Approved;
        pendingService.AssignedClusterId = request.ClusterId;
        pendingService.AssignedBy = "admin";
        pendingService.AssignedAt = DateTime.UtcNow;
        pendingService.Version++;

        await db.SaveChangesAsync();

        _logger.LogInformation("Service {ServiceName} assigned to cluster {ClusterId} by admin",
            pendingService.K8sServiceName, request.ClusterId);

        return Ok(new
        {
            success = true,
            message = $"Service '{pendingService.K8sServiceName}' assigned to cluster '{request.ClusterId}'",
            instanceId = newInstance.Id
        });
    }

    [HttpPost("{id}/reject")]
    public async Task<IActionResult> RejectService(long id)
    {
        await using var db = _dbContextFactory.CreateDbContext();

        var pendingService = await db.PendingServiceDiscoveries.FindAsync(id);
        if (pendingService == null || pendingService.IsDeleted)
        {
            return NotFound(new { message = "Pending service not found" });
        }

        if (pendingService.Status != (int)PendingServiceStatus.Pending)
        {
            return BadRequest(new { message = $"Service is already {((PendingServiceStatus)pendingService.Status)}, cannot reject" });
        }

        pendingService.Status = (int)PendingServiceStatus.Rejected;
        pendingService.AssignedBy = "admin";
        pendingService.AssignedAt = DateTime.UtcNow;
        pendingService.Version++;

        await db.SaveChangesAsync();

        _logger.LogInformation("Service {ServiceName} rejected by admin", pendingService.K8sServiceName);

        return Ok(new { success = true, message = $"Service '{pendingService.K8sServiceName}' rejected" });
    }

    [HttpGet("clusters")]
    public async Task<IActionResult> GetClusters()
    {
        await using var db = _dbContextFactory.CreateDbContext();
        
        var clusters = await db.ServiceInstances
            .Where(i => !i.IsDeleted)
            .GroupBy(i => i.ClusterId)
            .Select(g => new
            {
                ClusterId = g.Key,
                InstanceCount = g.Count(),
                HealthyCount = g.Count(i => i.Health == 1)
            })
            .ToListAsync();

        return Ok(clusters);
    }
}

public class AssignServiceRequest
{
    public string ClusterId { get; set; } = string.Empty;
}