using AutoMapper;
using Marco.Pms.DataAccess.Data;
using Marco.Pms.Model.DocumentManager;
using Marco.Pms.Model.Dtos.ServiceProject;
using Marco.Pms.Model.Employees;
using Marco.Pms.Model.Master;
using Marco.Pms.Model.ServiceProject;
using Marco.Pms.Model.Utilities;
using Marco.Pms.Model.ViewModels.Activities;
using Marco.Pms.Model.ViewModels.DocumentManager;
using Marco.Pms.Model.ViewModels.Master;
using Marco.Pms.Model.ViewModels.Organization;
using Marco.Pms.Model.ViewModels.ServiceProject;
using Marco.Pms.Services.Service.ServiceInterfaces;
using MarcoBMS.Services.Service;
using Microsoft.EntityFrameworkCore;

namespace Marco.Pms.Services.Service
{
    public class ServiceProjectService : IServiceProject
    {

        private readonly IDbContextFactory<ApplicationDbContext> _dbContextFactory;
        private readonly IServiceScopeFactory _serviceScopeFactory;
        private readonly ApplicationDbContext _context; // Keeping this for direct scoped context use where appropriate
        private readonly ILoggingService _logger;
        private readonly S3UploadService _s3Service;
        private readonly IMapper _mapper;

        private readonly Guid NewStatus = Guid.Parse("32d76a02-8f44-4aa0-9b66-c3716c45a918");
        private readonly Guid AssignedStatus = Guid.Parse("cfa1886d-055f-4ded-84c6-42a2a8a14a66");

        public ServiceProjectService(IDbContextFactory<ApplicationDbContext> dbContextFactory,
            IServiceScopeFactory serviceScopeFactory,
            ApplicationDbContext context,
            ILoggingService logger,
            S3UploadService s3Service,
            IMapper mapper)
        {
            _serviceScopeFactory = serviceScopeFactory;
            _context = context;
            _logger = logger;
            _s3Service = s3Service;
            _mapper = mapper;
            _dbContextFactory = dbContextFactory;
        }

        #region =================================================================== Service Project Functions ===================================================================
        public async Task<ApiResponse<object>> GetServiceProjectListAsync(int pageNumber, int pageSize, Employee loggedInEmployee, Guid tenantId)
        {
            try
            {

                var serviceProjectQuery = _context.ServiceProjects
                    .Include(sp => sp.Client)
                    .Include(sp => sp.Status)
                    .Include(sp => sp.CreatedBy).ThenInclude(e => e!.JobRole)
                    .Where(sp => sp.TenantId == tenantId && sp.IsActive);

                var totalEntites = await serviceProjectQuery.CountAsync();
                var totalPages = (int)Math.Ceiling((double)totalEntites / pageSize);

                var serviceProjects = await serviceProjectQuery
                    .OrderByDescending(e => e.CreatedAt)
                    .Skip((pageNumber - 1) * pageSize)
                    .Take(pageSize)
                    .ToListAsync();

                var serviceProjectIds = serviceProjects.Select(sp => sp.Id).ToList();
                var serviceProjectServiceMappings = await _context.ServiceProjectServiceMapping
                    .Include(sps => sps.Service)
                    .Where(sps => serviceProjectIds.Contains(sps.ProjectId) &&
                    sps.Service != null &&
                    sps.TenantId == tenantId)
                    .ToListAsync();

                var serviceProjectVMs = serviceProjects.Select(sp =>
                {
                    var services = serviceProjectServiceMappings.Where(sps => sps.ProjectId == sp.Id).Select(sps => sps.Service!).ToList();
                    var result = _mapper.Map<ServiceProjectVM>(sp);
                    result.Services = _mapper.Map<List<ServiceMasterVM>>(services);
                    return result;
                }).ToList();

                var response = new
                {
                    CurrentPage = pageNumber,
                    TotalPages = totalPages,
                    TotalEntites = totalEntites,
                    Data = serviceProjectVMs,
                };

                _logger.LogInfo("Successfully retrieved a total of {ProjectCount} projects.", serviceProjectVMs.Count);
                return ApiResponse<object>.SuccessResponse(response, "Projects retrieved successfully.", 200);

            }
            catch (Exception ex)
            {
                // --- Step 5: Graceful Error Handling ---
                _logger.LogError(ex, "An unexpected error occurred in GetAllProjects for tenant {TenantId}.", tenantId);
                return ApiResponse<object>.ErrorResponse("An internal server error occurred. Please try again later.", null, 500);
            }

        }
        public async Task<ApiResponse<object>> GetServiceProjectDetailsAsync(Guid id, Employee loggedInEmployee, Guid tenantId)
        {
            var serviceProject = await _context.ServiceProjects
                .Include(sp => sp.Client)
                .Include(sp => sp.Status)
                .Include(sp => sp.CreatedBy).ThenInclude(e => e!.JobRole)
                .Include(sp => sp.UpdatedBy).ThenInclude(e => e!.JobRole)
                .FirstOrDefaultAsync(sp => sp.Id == id && sp.TenantId == tenantId);
            if (serviceProject == null)
            {
                return ApiResponse<object>.ErrorResponse("Service Project not found", "Service Project not found", 404);
            }
            var services = await _context.ServiceProjectServiceMapping
                    .Include(sps => sps.Service)
                    .Where(sps => sps.ProjectId == serviceProject.Id &&
                        sps.Service != null &&
                        sps.TenantId == tenantId)
                    .Select(sps => sps.Service!)
                    .ToListAsync();
            //var numberOfJobs = await _context.JobTickets.Where(jt => jt.ProjectId == serviceProject.Id && jt.TenantId == tenantId).CountAsync();

            var response = _mapper.Map<ServiceProjectDetailsVM>(serviceProject);
            response.Services = _mapper.Map<List<ServiceMasterVM>>(services);
            //response.NumberOfJobs = numberOfJobs;
            response.NumberOfJobs = 0;
            return ApiResponse<object>.SuccessResponse(response, "Service Project Details fetched successfully", 200);
        }
        public async Task<ApiResponse<object>> CreateServiceProjectAsync(ServiceProjectDto model, Employee loggedInEmployee, Guid tenantId)
        {
            var serviceIds = model.Services.Where(s => s.IsActive).Select(s => s.ServiceId).ToList();
            var clientTask = Task.Run(async () =>
            {
                await using var context = await _dbContextFactory.CreateDbContextAsync();
                return await context.Organizations.FirstOrDefaultAsync(o => o.Id == model.ClientId && o.IsActive);
            });
            var serviceTask = Task.Run(async () =>
            {
                await using var context = await _dbContextFactory.CreateDbContextAsync();
                return await context.ServiceMasters.Where(s => serviceIds.Contains(s.Id) && s.TenantId == tenantId && s.IsActive).ToListAsync();
            });
            var statusTask = Task.Run(async () =>
            {
                await using var context = await _dbContextFactory.CreateDbContextAsync();
                return await context.StatusMasters.FirstOrDefaultAsync(s => s.Id == model.StatusId);
            });

            await Task.WhenAll(clientTask, serviceTask, statusTask);

            var client = clientTask.Result;
            var services = serviceTask.Result;
            var status = statusTask.Result;

            if (client == null)
            {
                return ApiResponse<object>.ErrorResponse("Client not found", "Client not found", 404);
            }
            if (status == null)
            {
                return ApiResponse<object>.ErrorResponse("Project Status not found", "Project Status not found", 404);
            }

            var serviceProject = _mapper.Map<ServiceProject>(model);
            serviceProject.Id = Guid.NewGuid();
            serviceProject.CreatedById = loggedInEmployee.Id;
            serviceProject.CreatedAt = DateTime.UtcNow;
            serviceProject.IsActive = true;
            serviceProject.TenantId = tenantId;

            var projectServiceMapping = model.Services.Where(sdto => services.Any(s => s.Id == sdto.ServiceId)).Select(sdto => new ServiceProjectServiceMapping
            {
                ServiceId = sdto.ServiceId,
                ProjectId = serviceProject.Id,
                TenantId = tenantId
            }).ToList();
            try
            {
                _context.ServiceProjects.Add(serviceProject);
                _context.ServiceProjectServiceMapping.AddRange(projectServiceMapping);

                await _context.SaveChangesAsync();

                _logger.LogInfo("Service Project {ProjectId} created successfully for TenantId={TenantId}, by Employee {EmployeeId}.",
                  serviceProject.Id, tenantId, loggedInEmployee);

                var serviceProjectVM = _mapper.Map<ServiceProjectVM>(serviceProject);

                serviceProjectVM.Client = _mapper.Map<BasicOrganizationVm>(client);
                serviceProjectVM.Status = status;

                serviceProjectVM.Services = services.Where(s => serviceIds.Contains(s.Id)).Select(s => _mapper.Map<ServiceMasterVM>(s)).ToList();

                serviceProjectVM.CreatedBy = _mapper.Map<BasicEmployeeVM>(loggedInEmployee);
                return ApiResponse<object>.SuccessResponse(serviceProjectVM, "An Successfullly occurred while saving the project.", 201);

            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "DB Failure: Service Project creation failed for TenantId={TenantId}. Rolling back.", tenantId);
                return ApiResponse<object>.ErrorResponse("An error occurred while saving the project.", ex.Message, 500);
            }


        }
        public async Task<ApiResponse<object>> UpdateServiceProjectAsync(Guid id, ServiceProjectDto model, Employee loggedInEmployee, Guid tenantId)
        {
            try
            {
                var serviceIds = model.Services.Select(s => s.ServiceId).ToList();
                var clientTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.Organizations.FirstOrDefaultAsync(o => o.Id == model.ClientId && o.IsActive);
                });
                var serviceTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.ServiceMasters.Where(s => serviceIds.Contains(s.Id) && s.TenantId == tenantId && s.IsActive).ToListAsync();
                });
                var statusTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.StatusMasters.FirstOrDefaultAsync(s => s.Id == model.StatusId);
                });

                await Task.WhenAll(clientTask, serviceTask, statusTask);

                var client = clientTask.Result;
                var services = serviceTask.Result;
                var status = statusTask.Result;

                if (client == null)
                {
                    return ApiResponse<object>.ErrorResponse("Client not found", "Client not found", 404);
                }
                if (status == null)
                {
                    return ApiResponse<object>.ErrorResponse("Project Status not found", "Project Status not found", 404);
                }

                var serviceProject = await _context.ServiceProjects.Where(sp => sp.Id == id && sp.TenantId == tenantId && sp.IsActive).FirstOrDefaultAsync();

                if (serviceProject == null)
                {
                    _logger.LogWarning("Attempt to update non-existent Service project with ID {ProjectId} by user {UserId}.", id, loggedInEmployee.Id);
                    return ApiResponse<object>.ErrorResponse("Project not found.", $"No project found with ID {id}.", 404);
                }

                _mapper.Map(model, serviceProject);

                serviceProject.UpdatedAt = DateTime.UtcNow;
                serviceProject.UpdatedById = loggedInEmployee.Id;

                var serviceProjectServiceMappings = await _context.ServiceProjectServiceMapping
                    .AsNoTracking()
                    .Where(sps => sps.ProjectId == serviceProject.Id && sps.TenantId == tenantId)
                    .ToListAsync();

                var newMapping = new List<ServiceProjectServiceMapping>();
                var removedMapping = new List<ServiceProjectServiceMapping>();

                foreach (var dto in model.Services)
                {
                    var serviceProjectServiceMapping = serviceProjectServiceMappings
                        .FirstOrDefault(sps => sps.ServiceId == dto.ServiceId);

                    if (dto.IsActive && serviceProjectServiceMapping == null)
                    {
                        newMapping.Add(new ServiceProjectServiceMapping
                        {
                            Id = Guid.NewGuid(),
                            ServiceId = dto.ServiceId,
                            ProjectId = serviceProject.Id,
                            TenantId = tenantId,
                        });
                    }
                    else if (!dto.IsActive && serviceProjectServiceMapping != null)
                    {
                        removedMapping.Add(serviceProjectServiceMapping);
                    }
                }

                _context.ServiceProjectServiceMapping.AddRange(newMapping);
                _context.ServiceProjectServiceMapping.RemoveRange(removedMapping);

                await _context.SaveChangesAsync();

                var serviceProjectTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.ServiceProjects
                        .Include(sp => sp.Client)
                        .Include(sp => sp.Status)
                        .Include(sp => sp.CreatedBy).ThenInclude(e => e!.JobRole)
                        .Where(sp => sp.TenantId == tenantId && sp.IsActive).FirstOrDefaultAsync();
                });

                var servicesTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.ServiceProjectServiceMapping
                        .Include(sps => sps.Service)
                        .Where(sps => sps.ProjectId == serviceProject.Id && sps.Service != null && sps.TenantId == tenantId)
                        .Select(sps => sps.Service!)
                        .ToListAsync();
                });

                await Task.WhenAll(serviceProjectTask, servicesTask);


                serviceProject = serviceProjectTask.Result;
                services = servicesTask.Result;

                ServiceProjectVM serviceProjectVm = _mapper.Map<ServiceProjectVM>(serviceProject);
                serviceProjectVm.Services = _mapper.Map<List<ServiceMasterVM>>(services);

                return ApiResponse<object>.SuccessResponse(serviceProjectVm, "Service Project updated successfully.", 200);

            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "An unexpected error occurred in Updating Service Project for tenant {TenantId}.", tenantId);
                return ApiResponse<object>.ErrorResponse("An internal server error occurred. Please try again later.", null, 500);
            }

        }
        public async Task<ApiResponse<object>> DeActivateServiceProjectAsync(Guid id, bool isActive, Employee loggedInEmployee, Guid tenantId)
        {
            try
            {

                var serviceProject = await _context.ServiceProjects
                    .Where(sp => sp.Id == id && sp.TenantId == tenantId).FirstOrDefaultAsync();

                if (serviceProject == null)
                {
                    _logger.LogWarning("Attempt to de-activate non-existent Service project with ID {ProjectId} by user {UserId}.", id, loggedInEmployee.Id);
                    return ApiResponse<object>.ErrorResponse("Project not found.", $"No project found with ID {id}.", 404);
                }

                serviceProject.IsActive = isActive;

                await _context.SaveChangesAsync();

                _logger.LogInfo("Successfully de-activated service project {ProjectId}", id);
                return ApiResponse<object>.SuccessResponse(new { }, "Projects de-activated successfully.", 200);

            }
            catch (Exception ex)
            {
                // --- Step 5: Graceful Error Handling ---
                _logger.LogError(ex, "An unexpected error occurred in DeActivateServiceProject for tenant {TenantId}.", tenantId);
                return ApiResponse<object>.ErrorResponse("An internal server error occurred. Please try again later.", null, 500);
            }
        }

        #endregion

        #region =================================================================== Expense Functions ===================================================================
        #endregion

        #region =================================================================== Job Tickets Functions ===================================================================

        /// <summary>
        /// Retrieves a paginated, filtered list of job tickets for a tenant, including related project, status, assignees, and tags.
        /// </summary>
        /// <param name="projectId">Optional project filter.</param>
        /// <param name="pageNumber">Page index (1-based).</param>
        /// <param name="pageSize">Page size.</param>
        /// <param name="isActive">Active filter.</param>
        /// <param name="tenantId">Tenant context.</param>
        /// <param name="loggedInEmployee">Employee requesting data.</param>
        /// <returns>Paged list of JobTicketVM plus metadata, or error response.</returns>
        public async Task<ApiResponse<object>> GetJobTicketsListAsync(Guid? projectId, int pageNumber, int pageSize, bool isActive, Employee loggedInEmployee, Guid tenantId)
        {
            if (tenantId == Guid.Empty)
            {
                _logger.LogWarning("TenantId missing for job ticket fetch by employee {EmployeeId}", loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse(
                    "Access Denied",
                    "Missing or invalid tenant context.",
                    403);
            }

            if (pageNumber < 1 || pageSize < 1)
            {
                _logger.LogInfo("Invalid paging parameters for job ticket fetch. PageNumber: {PageNumber}, PageSize: {PageSize}", pageNumber, pageSize);
                return ApiResponse<object>.ErrorResponse(
                    "Bad Request",
                    "Page number and size must be greater than zero.",
                    400);
            }

            try
            {
                // Build filtered query with necessary includes for eager loading
                var jobTicketQuery = _context.JobTickets
                    .Include(jt => jt.Status)
                    .Include(jt => jt.Project)
                    .Include(jt => jt.CreatedBy).ThenInclude(e => e!.JobRole)
                    .AsNoTracking()
                    .Where(jt =>
                        jt.TenantId == tenantId &&
                        jt.IsActive == isActive &&
                        jt.Project != null &&
                        jt.Status != null &&
                        jt.CreatedBy != null &&
                        jt.CreatedBy.JobRole != null);

                // Optionally filter by project
                if (projectId.HasValue)
                {
                    var projectExists = await _context.ServiceProjects
                        .AnyAsync(sp => sp.Id == projectId && sp.TenantId == tenantId && sp.IsActive);

                    if (!projectExists)
                    {
                        _logger.LogWarning("Requested service project not found. ProjectId: {ProjectId}, TenantId: {TenantId}", projectId, tenantId);
                        return ApiResponse<object>.ErrorResponse("Service project not found", "Service project not found for this tenant.", 404);
                    }

                    jobTicketQuery = jobTicketQuery.Where(jt => jt.ProjectId == projectId.Value);
                }

                // Total results and paging
                var totalEntities = await jobTicketQuery.CountAsync();
                var totalPages = (int)Math.Ceiling((double)totalEntities / pageSize);

                // Fetch filtered/paged tickets
                var jobTickets = await jobTicketQuery
                    .OrderByDescending(e => e.CreatedAt)
                    .Skip((pageNumber - 1) * pageSize)
                    .Take(pageSize)
                    .ToListAsync();

                var jobTicketIds = jobTickets.Select(jt => jt.Id).ToList();

                // Fetch assignee and tag mappings concurrently using separate DbContexts for parallel IO
                var assigneeTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.JobEmployeeMappings
                        .Include(jem => jem.Assignee).ThenInclude(e => e!.JobRole)
                        .Where(jem => jobTicketIds.Contains(jem.JobTicketId) && jem.Assignee != null && jem.Assignee.JobRole != null && jem.TenantId == tenantId)
                        .ToListAsync();
                });

                var tagTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.JobTagMappings
                        .Include(jtm => jtm.JobTag)
                        .Where(jtm => jobTicketIds.Contains(jtm.JobTicketId) && jtm.JobTag != null && jtm.TenantId == tenantId)
                        .ToListAsync();
                });

                await Task.WhenAll(assigneeTask, tagTask);

                var assigneeMappings = assigneeTask.Result;
                var tagMappings = tagTask.Result;

                // Map tickets to view models and inject assignees/tags per ticket
                var jobTicketVMs = jobTickets.Select(jt =>
                {
                    var vm = _mapper.Map<JobTicketVM>(jt);
                    vm.Assignees = assigneeMappings
                        .Where(jem => jem.JobTicketId == jt.Id)
                        .Select(jem => _mapper.Map<BasicEmployeeVM>(jem.Assignee))
                        .ToList();
                    vm.Tags = tagMappings
                        .Where(jtm => jtm.JobTicketId == jt.Id)
                        .Select(jtm => _mapper.Map<TagVM>(jtm.JobTag))
                        .ToList();
                    return vm;
                }).ToList();

                var response = new
                {
                    CurrentPage = pageNumber,
                    TotalPages = totalPages,
                    TotalEntities = totalEntities,
                    Data = jobTicketVMs,
                };

                _logger.LogInfo("Job tickets fetched: {Count} tickets for tenant {TenantId}, page {PageNumber}", jobTicketVMs.Count, tenantId, pageNumber);

                return ApiResponse<object>.SuccessResponse(response, $"{jobTicketVMs.Count} job records fetched successfully.", 200);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Exception in fetching job tickets list for tenant {TenantId} by employee {EmployeeId}", tenantId, loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse("Internal Server Error", "Unable to fetch job tickets list. Please try again later.", 500);
            }
        }

        /// <summary>
        /// Retrieves detailed information for a specific job ticket, including assignees, tags, comments, and update logs.
        /// </summary>
        /// <param name="id">Job ticket identifier.</param>
        /// <param name="loggedInEmployee">Employee making the request (for logging/audit).</param>
        /// <param name="tenantId">Tenant identifier for multi-tenant scoping.</param>
        /// <returns>ApiResponse containing detailed job ticket view or error.</returns>
        public async Task<ApiResponse<object>> GetJobTicketDetailsAsync(Guid id, Employee loggedInEmployee, Guid tenantId)
        {
            if (tenantId == Guid.Empty)
            {
                _logger.LogWarning("TenantId is empty for job ticket details request by employee {EmployeeId}", loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse("Access Denied", "Invalid tenant context.", 403);
            }

            try
            {
                _logger.LogInfo("Fetching details for job ticket {JobTicketId} by employee {EmployeeId} in tenant {TenantId}",
                    id, loggedInEmployee.Id, tenantId);

                // Load main job ticket with navigation properties
                var jobTicket = await _context.JobTickets
                    .Include(jt => jt.Status)
                    .Include(jt => jt.Project)
                    .Include(jt => jt.CreatedBy).ThenInclude(e => e!.JobRole)
                    .AsNoTracking()
                    .FirstOrDefaultAsync(jt =>
                        jt.Id == id &&
                        jt.TenantId == tenantId &&
                        jt.IsActive &&
                        jt.Project != null &&
                        jt.Status != null &&
                        jt.CreatedBy != null &&
                        jt.CreatedBy.JobRole != null);

                if (jobTicket == null)
                {
                    _logger.LogWarning("Job ticket not found or inactive. JobTicketId: {JobTicketId}, TenantId: {TenantId}", id, tenantId);
                    return ApiResponse<object>.ErrorResponse("Job not found", "Job ticket not found or inactive.", 404);
                }

                // Load all job statuses for status mappings in logs
                var statusList = await _context.JobStatus.ToListAsync();

                // Use parallel queries with separate DbContexts to optimize IO
                var assigneeTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.JobEmployeeMappings
                        .Include(jem => jem.Assignee).ThenInclude(e => e!.JobRole)
                        .Where(jem => jem.JobTicketId == id && jem.Assignee != null && jem.Assignee.JobRole != null && jem.TenantId == tenantId)
                        .Select(jem => jem.Assignee!)
                        .ToListAsync();
                });

                var tagTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.JobTagMappings
                        .Include(jtm => jtm.JobTag)
                        .Where(jtm => jtm.JobTicketId == id && jtm.JobTag != null && jtm.TenantId == tenantId)
                        .Select(jtm => jtm.JobTag!)
                        .ToListAsync();
                });

                var updateLogTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.StatusUpdateLogs
                        .Include(ul => ul.UpdatedBy).ThenInclude(e => e!.JobRole)
                        .Where(ul => ul.EntityId == id && ul.TenantId == tenantId)
                        .ToListAsync();
                });

                await Task.WhenAll(assigneeTask, tagTask, updateLogTask);

                // Map update logs with status descriptions
                var jobUpdateLogVMs = updateLogTask.Result.Select(ul =>
                {
                    var status = statusList.FirstOrDefault(js => js.Id == ul.StatusId);
                    var nextStatus = statusList.FirstOrDefault(js => js.Id == ul.NextStatusId);
                    return new JobUpdateLogVM
                    {
                        Id = ul.Id,
                        Status = status,
                        NextStatus = nextStatus,
                        Comment = ul.Comment,
                        UpdatedBy = _mapper.Map<BasicEmployeeVM>(ul.UpdatedBy)
                    };
                }).ToList();

                // Map assignees, and tags to their respective viewmodels
                var assigneeVMs = _mapper.Map<List<BasicEmployeeVM>>(assigneeTask.Result);
                var tagVMs = _mapper.Map<List<TagVM>>(tagTask.Result);

                // Map main job ticket DTO and attach related data
                var response = _mapper.Map<JobTicketDetailsVM>(jobTicket);
                response.Assignees = assigneeVMs;
                response.Tags = tagVMs;
                response.UpdateLogs = jobUpdateLogVMs;

                _logger.LogInfo("Job ticket details assembled successfully for JobTicketId: {JobTicketId}", id);

                return ApiResponse<object>.SuccessResponse(response, "Job details fetched successfully", 200);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Failed to fetch job ticket details for JobTicketId: {JobTicketId} in tenant {TenantId}", id, tenantId);
                return ApiResponse<object>.ErrorResponse("Internal Server Error", "Failed to retrieve job details. Please try again later.", 500);
            }
        }

        /// <summary>
        /// Retrieves all job tags associated with the tenant, ordered alphabetically by name.
        /// </summary>
        /// <param name="loggedInEmployee">Employee making the request (for audit/logging).</param>
        /// <param name="tenantId">Tenant identifier for multi-tenant data scoping.</param>
        /// <returns>ApiResponse containing the list of job tag view models or error details.</returns>
        public async Task<ApiResponse<object>> GetJobTagListAsync(Employee loggedInEmployee, Guid tenantId)
        {
            if (tenantId == Guid.Empty)
            {
                _logger.LogWarning("Attempt to fetch job tags with missing tenant context by employee {EmployeeId}", loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse("Access Denied", "Invalid tenant context.", 403);
            }

            try
            {
                _logger.LogInfo("Fetching job tags for tenant {TenantId} requested by employee {EmployeeId}", tenantId, loggedInEmployee.Id);

                // Query job tags via JobTagMappings ensuring tenant isolation
                var tags = await _context.JobTagMappings
                    .AsNoTracking()
                    .Include(jtm => jtm.JobTag)
                    .Where(jtm => jtm.JobTag != null && jtm.TenantId == tenantId)
                    .Select(jtm => jtm.JobTag!)
                    .Distinct() // Avoid duplicates if any tag maps multiple times
                    .OrderBy(jt => jt.Name)
                    .ToListAsync();

                var response = _mapper.Map<List<TagVM>>(tags);

                _logger.LogInfo("{Count} job tags fetched successfully for tenant {TenantId}", response.Count, tenantId);

                return ApiResponse<object>.SuccessResponse(response, $"{response.Count} job tag record(s) fetched successfully.", 200);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Failed to fetch job tags for tenant {TenantId} requested by employee {EmployeeId}", tenantId, loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse("Internal Server Error", "Failed to retrieve job tags. Please try again later.", 500);
            }
        }

        /// <summary>
        /// Creates a new job ticket with optional assignees and tags within a transactional scope.
        /// </summary>
        /// <param name="model">Data transfer object containing job ticket details.</param>
        /// <param name="loggedInEmployee">Employee initiating the creation.</param>
        /// <param name="tenantId">Tenant identifier for multi-tenant context.</param>
        /// <returns>ApiResponse containing the created job ticket view or error details.</returns>
        public async Task<ApiResponse<object>> CreateJobTicketAsync(CreateJobTicketDto model, Employee loggedInEmployee, Guid tenantId)
        {
            await using var transaction = await _context.Database.BeginTransactionAsync();
            try
            {
                _logger.LogInfo("Starting job ticket creation for project {ProjectId} by employee {EmployeeId} in tenant {TenantId}",
                    model.ProjectId, loggedInEmployee.Id, tenantId);

                // Load project and relevant statuses in parallel with separate DbContext instances for concurrency efficiency
                var serviceProjectTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.ServiceProjects.FirstOrDefaultAsync(sp => sp.Id == model.ProjectId && sp.TenantId == tenantId && sp.IsActive);
                });

                var statusTask = Task.Run(async () =>
                {
                    await using var context = await _dbContextFactory.CreateDbContextAsync();
                    return await context.JobStatus.Where(js => js.Id == NewStatus || js.Id == AssignedStatus).ToListAsync();
                });

                await Task.WhenAll(serviceProjectTask, statusTask);

                var serviceProject = serviceProjectTask.Result;
                var statusList = statusTask.Result;

                if (serviceProject == null)
                {
                    _logger.LogWarning("Service project with ID {ProjectId} not found or inactive in tenant {TenantId}", model.ProjectId, tenantId);
                    return ApiResponse<object>.ErrorResponse("Service project not found", "Service project not found or inactive", 404);
                }

                var hasAssignees = model.Assignees?.Any(a => a.IsActive) ?? false;

                // Map DTO to entity
                var jobTicket = _mapper.Map<JobTicket>(model);
                jobTicket.Id = Guid.NewGuid();
                jobTicket.StatusId = hasAssignees ? AssignedStatus : NewStatus;
                jobTicket.CreatedAt = DateTime.UtcNow;
                jobTicket.CreatedById = loggedInEmployee.Id;
                jobTicket.TenantId = tenantId;

                _context.JobTickets.Add(jobTicket);
                await _context.SaveChangesAsync();

                // Handle assignees if any
                List<BasicEmployeeVM> assigneeVMs = new();
                if (hasAssignees)
                {
                    var activeAssigneeIds = model.Assignees!.Where(a => a.IsActive).Select(a => a.EmployeeId).ToList();

                    var assignees = await _context.Employees
                        .Include(e => e.JobRole)
                        .Where(e => activeAssigneeIds.Contains(e.Id) && e.IsActive)
                        .ToListAsync();

                    var jobEmployeeMappings = assignees.Select(e => new JobEmployeeMapping
                    {
                        AssigneeId = e.Id,
                        JobTicketId = jobTicket.Id,
                        TenantId = tenantId
                    }).ToList();

                    _context.JobEmployeeMappings.AddRange(jobEmployeeMappings);
                    assigneeVMs = _mapper.Map<List<BasicEmployeeVM>>(assignees);
                }

                // Handle tags if any
                var jobTags = new List<JobTag>();
                if (model.Tags?.Any(t => t.IsActive) ?? false)
                {
                    var activeTagNames = model.Tags.Where(t => t.IsActive).Select(t => t.Name).Distinct().ToList();

                    var existingTags = await _context.JobTags.Where(jt => activeTagNames.Contains(jt.Name) && jt.TenantId == tenantId).ToListAsync();

                    var newTags = new List<JobTag>();
                    var tagMappings = new List<JobTagMapping>();

                    foreach (var tagDto in model.Tags.Where(t => t.IsActive).DistinctBy(t => t.Name))
                    {
                        var tag = existingTags.FirstOrDefault(jt => jt.Name == tagDto.Name);
                        if (tag == null)
                        {
                            tag = new JobTag
                            {
                                Id = Guid.NewGuid(),
                                Name = tagDto.Name,
                                TenantId = tenantId
                            };
                            newTags.Add(tag);
                        }
                        tagMappings.Add(new JobTagMapping
                        {
                            Id = Guid.NewGuid(),
                            JobTagId = tag.Id,
                            JobTicketId = jobTicket.Id,
                            TenantId = tenantId
                        });
                    }

                    if (newTags.Any()) _context.JobTags.AddRange(newTags);
                    _context.JobTagMappings.AddRange(tagMappings);

                    jobTags.AddRange(existingTags);
                    jobTags.AddRange(newTags);
                }

                // Create job update logs for status change
                var updateLogs = new List<StatusUpdateLog>();

                const string creationMessage = "A new job has been successfully created and added to the system. It is now ready for assignment and further processing.";
                updateLogs.Add(new StatusUpdateLog
                {
                    EntityId = jobTicket.Id,
                    NextStatusId = NewStatus,
                    Comment = creationMessage,
                    UpdatedAt = DateTime.UtcNow,
                    UpdatedById = loggedInEmployee.Id,
                    TenantId = tenantId
                });

                if (hasAssignees)
                {
                    const string assignmentMessage = "The designated assignee(s) have been successfully assigned to the job and are now responsible for managing and completing the associated tasks.";
                    updateLogs.Add(new StatusUpdateLog
                    {
                        EntityId = jobTicket.Id,
                        StatusId = NewStatus,
                        NextStatusId = AssignedStatus,
                        Comment = assignmentMessage,
                        UpdatedAt = DateTime.UtcNow.AddTicks(10), // Small offset to preserve time order
                        UpdatedById = loggedInEmployee.Id,
                        TenantId = tenantId
                    });
                }

                _context.StatusUpdateLogs.AddRange(updateLogs);

                await _context.SaveChangesAsync();

                await transaction.CommitAsync();

                // Prepare response VM
                var currentStatus = statusList.FirstOrDefault(js => js.Id == jobTicket.StatusId);
                var vm = _mapper.Map<JobTicketVM>(jobTicket);
                vm.Status = currentStatus;
                vm.Project = _mapper.Map<BasicServiceProjectVM>(serviceProject);
                vm.Assignees = assigneeVMs;
                vm.CreatedBy = _mapper.Map<BasicEmployeeVM>(loggedInEmployee);
                vm.Tags = _mapper.Map<List<TagVM>>(jobTags.Distinct().ToList());

                _logger.LogInfo("Job ticket {JobTicketId} successfully created with status {StatusId} by employee {EmployeeId} in tenant {TenantId}",
                    jobTicket.Id, jobTicket.StatusId, loggedInEmployee.Id, tenantId);

                return ApiResponse<object>.SuccessResponse(vm, "Job created successfully", 201);
            }
            catch (DbUpdateException dbEx)
            {
                await transaction.RollbackAsync();
                _logger.LogError(dbEx, "Database error while creating job ticket for project {ProjectId} by employee {EmployeeId} in tenant {TenantId}",
                    model.ProjectId, loggedInEmployee.Id, tenantId);
                return ApiResponse<object>.ErrorResponse("Database Error", "An error occurred while saving data to the database.", 500);
            }
            catch (Exception ex)
            {
                await transaction.RollbackAsync();
                _logger.LogError(ex, "Unhandled exception while creating job ticket for project {ProjectId} by employee {EmployeeId} in tenant {TenantId}",
                    model.ProjectId, loggedInEmployee.Id, tenantId);
                return ApiResponse<object>.ErrorResponse("Internal Server Error", "An unexpected error occurred.", 500);
            }
        }

        #endregion
        #region =================================================================== Job Comments Functions ===================================================================

        /// <summary>
        /// Retrieves a paginated list of comments with attachments for a specified job ticket within a tenant context.
        /// </summary>
        /// <param name="jobTicketId">Optional job ticket ID to filter comments.</param>
        /// <param name="pageNumber">Page number (1-based) for pagination.</param>
        /// <param name="pageSize">Page size for pagination.</param>
        /// <param name="loggedInEmployee">Employee making the request (for authorization and logging).</param>
        /// <param name="tenantId">Tenant context ID for multi-tenancy.</param>
        /// <returns>ApiResponse with paged comments, attachments, and metadata, or error details.</returns>
        public async Task<ApiResponse<object>> GetCommentListByJobTicketAsync(Guid? jobTicketId, int pageNumber, int pageSize, Employee loggedInEmployee, Guid tenantId)
        {
            if (tenantId == Guid.Empty)
            {
                _logger.LogWarning("TenantId missing in comment list request by employee {EmployeeId}", loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse("Access Denied", "Invalid tenant context.", 403);
            }

            if (pageNumber < 1 || pageSize < 1)
            {
                _logger.LogInfo("Invalid pagination parameters in comment list request. PageNumber: {PageNumber}, PageSize: {PageSize}", pageNumber, pageSize);
                return ApiResponse<object>.ErrorResponse("Bad Request", "Page number and size must be greater than zero.", 400);
            }

            try
            {
                _logger.LogInfo("Fetching comment list for jobTicketId {JobTicketId} by employee {EmployeeId} in tenant {TenantId}",
                    jobTicketId ?? Guid.Empty, loggedInEmployee.Id, tenantId);

                var commentQuery = _context.JobComments
                    .Include(jc => jc.JobTicket).ThenInclude(jt => jt!.Status)
                    .Include(jc => jc.CreatedBy).ThenInclude(e => e!.JobRole)
                    .Include(jc => jc.UpdatedBy).ThenInclude(e => e!.JobRole)
                    .Where(jc => jc.TenantId == tenantId && jc.JobTicket != null && jc.CreatedBy != null && jc.CreatedBy.JobRole != null);

                // Filter by jobTicketId if provided after verifying existence
                if (jobTicketId.HasValue)
                {
                    var jobTicketExists = await _context.JobTickets.AnyAsync(jt =>
                        jt.Id == jobTicketId && jt.TenantId == tenantId);

                    if (!jobTicketExists)
                    {
                        _logger.LogWarning("Job ticket {JobTicketId} not found in tenant {TenantId} for comment listing", jobTicketId, tenantId);
                        return ApiResponse<object>.ErrorResponse("Job not found", "Job ticket not found.", 404);
                    }

                    commentQuery = commentQuery.Where(jc => jc.JobTicketId == jobTicketId.Value);
                }

                // Calculate total count for pagination
                var totalEntities = await commentQuery.CountAsync();
                var totalPages = (int)Math.Ceiling((double)totalEntities / pageSize);

                // Fetch paged comments ordered by creation date descending
                var comments = await commentQuery
                    .OrderByDescending(jc => jc.CreatedAt)
                    .Skip((pageNumber - 1) * pageSize)
                    .Take(pageSize)
                    .ToListAsync();

                var commentIds = comments.Select(jc => jc.Id).ToList();

                // Fetch attachments for current page comments
                var attachments = await _context.JobAttachments
                    .Include(ja => ja.Document)
                    .Where(ja => ja.JobCommentId.HasValue &&
                                 ja.Document != null &&
                                 commentIds.Contains(ja.JobCommentId.Value) &&
                                 ja.TenantId == tenantId)
                    .ToListAsync();

                // Map comments and attach corresponding documents with pre-signed URLs for access
                var commentVMs = comments.Select(jc =>
                {
                    var relatedDocuments = attachments
                        .Where(ja => ja.JobCommentId == jc.Id)
                        .Select(ja => ja.Document!)
                        .ToList();

                    var mappedComment = _mapper.Map<JobCommentVM>(jc);

                    if (relatedDocuments.Any())
                    {
                        mappedComment.Attachments = relatedDocuments.Select(doc =>
                        {
                            var docVM = _mapper.Map<DocumentVM>(doc);
                            docVM.PreSignedUrl = _s3Service.GeneratePreSignedUrl(doc.S3Key);
                            docVM.ThumbPreSignedUrl = string.IsNullOrWhiteSpace(doc.ThumbS3Key) ?
                                _s3Service.GeneratePreSignedUrl(doc.S3Key) :
                                _s3Service.GeneratePreSignedUrl(doc.ThumbS3Key);
                            return docVM;
                        }).ToList();
                    }

                    return mappedComment;
                }).ToList();

                var response = new
                {
                    CurrentPage = pageNumber,
                    TotalPages = totalPages,
                    TotalEntities = totalEntities,
                    Data = commentVMs
                };

                _logger.LogInfo("{Count} comments fetched successfully for jobTicketId {JobTicketId} by employee {EmployeeId}",
                    commentVMs.Count, jobTicketId ?? Guid.Empty, loggedInEmployee.Id);

                return ApiResponse<object>.SuccessResponse(response, $"{commentVMs.Count} record(s) fetched successfully.", 200);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error fetching comments for jobTicketId {JobTicketId} by employee {EmployeeId} in tenant {TenantId}",
                    jobTicketId ?? Guid.Empty, loggedInEmployee.Id, tenantId);

                return ApiResponse<object>.ErrorResponse("Internal Server Error", "Failed to fetch comments. Please try again later.", 500);
            }
        }

        /// <summary>
        /// Adds a comment with optional attachments to a job ticket within the specified tenant context.
        /// </summary>
        /// <param name="model">DTO containing comment content, job ticket ID, and attachments.</param>
        /// <param name="loggedInEmployee">Employee making the comment (for auditing).</param>
        /// <param name="tenantId">Tenant context for data isolation.</param>
        /// <returns>ApiResponse containing created comment details or relevant error information.</returns>
        public async Task<ApiResponse<object>> AddCommentToJobTicketAsync(JobCommentDto model, Employee loggedInEmployee, Guid tenantId)
        {
            // Validate tenant context
            if (tenantId == Guid.Empty)
            {
                _logger.LogWarning("Add comment attempt with invalid tenant context by employee {EmployeeId}", loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse("Access Denied", "Invalid tenant context.", 403);
            }

            // Validate input DTO
            if (model == null || model.JobTicketId == Guid.Empty || string.IsNullOrWhiteSpace(model.Comment))
            {
                _logger.LogInfo("Invalid comment model provided by employee {EmployeeId}", loggedInEmployee.Id);
                return ApiResponse<object>.ErrorResponse("Bad Request", "Comment data is incomplete or invalid.", 400);
            }

            try
            {
                _logger.LogInfo("Attempting to add comment to job ticket {JobTicketId} by employee {EmployeeId}", model.JobTicketId, loggedInEmployee.Id);

                // Verify the job ticket's existence and load minimal required info
                var jobTicket = await _context.JobTickets
                    .Include(jt => jt.Status)
                    .AsNoTracking()
                    .FirstOrDefaultAsync(jt => jt.Id == model.JobTicketId && jt.TenantId == tenantId);

                if (jobTicket == null)
                {
                    _logger.LogWarning("Job ticket {JobTicketId} not found or inaccessible in tenant {TenantId}", model.JobTicketId, tenantId);
                    return ApiResponse<object>.ErrorResponse("Job Not Found", "Job ticket not found or inaccessible.", 404);
                }

                // Create new comment entity
                var comment = new JobComment
                {
                    Id = Guid.NewGuid(),
                    JobTicketId = jobTicket.Id,
                    Comment = model.Comment.Trim(),
                    IsActive = true,
                    CreatedAt = DateTime.UtcNow,
                    CreatedById = loggedInEmployee.Id,
                    TenantId = tenantId
                };
                _context.JobComments.Add(comment);

                // Handle attachments if provided
                if (model.Attachments?.Any() ?? false)
                {
                    var batchId = Guid.NewGuid();
                    var documents = new List<Document>();
                    var attachments = new List<JobAttachment>();

                    foreach (var attachment in model.Attachments)
                    {
                        string base64 = attachment.Base64Data?.Split(',').LastOrDefault() ?? "";
                        if (string.IsNullOrWhiteSpace(base64))
                        {
                            _logger.LogWarning("Attachment missing base64 data in comment for job ticket {JobTicketId} by employee {EmployeeId}", jobTicket.Id, loggedInEmployee.Id);
                            return ApiResponse<object>.ErrorResponse("Bad Request", "Attachment image data is missing or invalid.", 400);
                        }

                        // Determine content type and generate storage keys
                        var fileType = _s3Service.GetContentTypeFromBase64(base64);
                        var fileName = _s3Service.GenerateFileName(fileType, tenantId, "job");
                        var objectKey = $"tenant-{tenantId}/ServiceProject/{jobTicket.ProjectId}/Job/{jobTicket.Id}/{fileName}";

                        // Upload file asynchronously to S3
                        await _s3Service.UploadFileAsync(base64, fileType, objectKey);

                        // Create document record for uploaded file
                        var document = new Document
                        {
                            Id = Guid.NewGuid(),
                            BatchId = batchId,
                            FileName = attachment.FileName ?? fileName,
                            ContentType = fileType,
                            S3Key = objectKey,
                            FileSize = attachment.FileSize,
                            UploadedAt = DateTime.UtcNow,
                            UploadedById = loggedInEmployee.Id,
                            TenantId = tenantId
                        };
                        documents.Add(document);

                        // Link document as attachment to the comment
                        attachments.Add(new JobAttachment
                        {
                            Id = Guid.NewGuid(),
                            DocumentId = document.Id,
                            StatusId = jobTicket.StatusId,
                            JobCommentId = comment.Id,
                            TenantId = tenantId
                        });
                    }
                    _context.Documents.AddRange(documents);
                    _context.JobAttachments.AddRange(attachments);
                }

                // Persist all inserts in database
                await _context.SaveChangesAsync();

                // Prepare response with mapped comment, creator info, and basic job ticket info
                var response = _mapper.Map<JobCommentVM>(comment);
                response.CreatedBy = _mapper.Map<BasicEmployeeVM>(loggedInEmployee);
                response.JobTicket = _mapper.Map<BasicJobTicketVM>(jobTicket);

                _logger.LogInfo("Successfully added comment {CommentId} to job ticket {JobTicketId} by employee {EmployeeId}",
                    comment.Id, jobTicket.Id, loggedInEmployee.Id);

                return ApiResponse<object>.SuccessResponse(response, "Comment added to job ticket successfully.", 201);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error adding comment to job ticket {JobTicketId} by employee {EmployeeId} in tenant {TenantId}",
                    model.JobTicketId, loggedInEmployee.Id, tenantId);
                return ApiResponse<object>.ErrorResponse("Internal Server Error", "Failed to add comment. Please try again later.", 500);
            }
        }

        #endregion
    }
}