using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using FrameworkDAL.CustomCode.GOP;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.DTO.GOP;
using GB5Shared.Resource.Response;
using Microsoft.Extensions.Logging;

namespace FrameworkBLL.GOP
{
    // ============================================================
    // GopExecutionMonitorBLL — read-only view of GOP runtime data.
    //
    // This BLL is intentionally thin: it delegates to IGopQueueDAL
    // and IGopFlowDAL without adding business logic.
    // The only write operation here is ResolveRemediation, which marks a
    // remediation item Resolved -- it does NOT re-queue/resubmit the original
    // failed execution (there is no automatic link back to it). To actually
    // retry a failed execution, call ReplayGopExecution (GopQueueBLL) with its
    // ExecutionId separately.
    // ============================================================
    public class GopExecutionMonitorBLL : IGopExecutionMonitorBLL
    {
        private readonly IGopQueueDAL                     _QueueDal;
        private readonly ILogger<GopExecutionMonitorBLL>  _Logger;

        public GopExecutionMonitorBLL(
            IGopQueueDAL                     queueDal,
            ILogger<GopExecutionMonitorBLL>  logger)
        {
            _QueueDal = queueDal;
            _Logger   = logger;
        }

        // ── Execution ─────────────────────────────────────────────────────────────

        public async Task<IEnumerable<GopExecutionHeaderDTO>> GetExecutionList(
            string? status, int page, int pageSize,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            int safePageSize = Math.Clamp(pageSize, 1, 200);
            int safePage     = Math.Max(1, page);

            return await _QueueDal.GetExecutionsByStatus(
                loginDTO.ClientId, status, safePage, safePageSize, loginDTO);
        }

        public async Task<GopExecutionHeaderDTO?> GetExecutionDetail(
            int executionId, LoginDTO loginDTO, CancellationToken ct = default)
        {
            return await _QueueDal.GetExecutionById(loginDTO.ClientId, executionId, loginDTO);
        }

        public async Task<IEnumerable<GopExecutionNodeLogDTO>> GetExecutionNodeLogs(
            int executionId, LoginDTO loginDTO, CancellationToken ct = default)
        {
            return await _QueueDal.GetNodeLogsByExecution(loginDTO.ClientId, executionId, loginDTO);
        }

        public async Task<IEnumerable<GopExecutionStateLogDTO>> GetExecutionStateLogs(
            int executionId, LoginDTO loginDTO, CancellationToken ct = default)
        {
            return await _QueueDal.GetStateLogsByExecution(loginDTO.ClientId, executionId, loginDTO);
        }

        // ── Dead Letter Queue ─────────────────────────────────────────────────────

        public async Task<IEnumerable<GopDeadLetterDTO>> GetDeadLetterList(
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            return await _QueueDal.GetDeadLetters(loginDTO.ClientId, loginDTO);
        }

        // ── Remediation ───────────────────────────────────────────────────────────

        public async Task<IEnumerable<GopRemediationDTO>> GetOpenRemediations(
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            return await _QueueDal.GetOpenRemediations(loginDTO.ClientId, loginDTO);
        }

        public async Task<string> ResolveRemediation(
            int remediationId, string resolutionNotes,
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            if (remediationId == 0)
                throw new ArgumentException("RemediationId is required.");
            if (string.IsNullOrWhiteSpace(resolutionNotes))
                throw new ArgumentException("ResolutionNotes are required.");

            await _QueueDal.UpdateRemediation(
                loginDTO.ClientId,
                remediationId,
                "Resolved",
                resolutionNotes,
                loginDTO.UserId.ToString(),
                loginDTO);

            _Logger.LogInformation(
                "GopExecutionMonitorBLL: remediation {RemediationId} resolved by user {UserId}",
                remediationId, loginDTO.UserId);

            return $"{SuccessResponse.UpdateSuccessMessage} {remediationId}";
        }

        // ── Dashboard ─────────────────────────────────────────────────────────────

        public async Task<IEnumerable<GopQueueDashboardDTO>> GetQueueDashboard(
            LoginDTO loginDTO, CancellationToken ct = default)
        {
            return await _QueueDal.GetQueueDashboard(loginDTO.ClientId, loginDTO);
        }
    }
}