using Data.SeaHavenIndustries;
using FluentValidation;
using SeaHaven.DataServices.Interfaces;
using SeaHaven.Services.DTOs;
using SeaHaven.Services.Interfaces;
using SeaHaven.Services.Validation;

namespace SeaHaven.Services.Implementation
{
    /// <summary>
    /// Follow-Up service implementation
    /// Contains business logic, validation, and orchestration for Follow-Up operations
    /// </summary>
    public class FollowUpService : IFollowUpService
    {
        private readonly IFollowUpDataService _followUpDataService;
        private readonly ICreateFollowUpValidation _createValidator;
        private readonly IUpdateFollowUpValidation _updateValidator;

        public FollowUpService(
            IFollowUpDataService followUpDataService,
            ICreateFollowUpValidation createValidator,
            IUpdateFollowUpValidation updateValidator)
        {
            _followUpDataService = followUpDataService;
            _createValidator = createValidator;
            _updateValidator = updateValidator;
        }

        public async Task<FollowUpDTO?> GetFollowUpByIdAsync(int id)
        {
            var followUp = await _followUpDataService.GetByIdAsync(id);
            return followUp == null ? null : MapToDTO(followUp);
        }

        public async Task<FollowUpDTO?> GetFollowUpByIdWithDetailsAsync(int id)
        {
            var followUp = await _followUpDataService.GetByIdWithDetailsAsync(id);
            return followUp == null ? null : MapToDTO(followUp);
        }

        public async Task<IEnumerable<FollowUpDTO>> GetAllFollowUpsAsync()
        {
            var followUps = await _followUpDataService.GetAllAsync();
            return followUps.Select(MapToDTO);
        }

        public async Task<IEnumerable<FollowUpDTO>> GetFollowUpsByWorkOrderIdAsync(int workOrderId)
        {
            var followUps = await _followUpDataService.GetByWorkOrderIdAsync(workOrderId);
            return followUps.Select(MapToDTO);
        }

        public async Task<PagedResult<FollowUpDTO>> GetFollowUpsPagedAsync(int page, int pageSize, string? search = null, string? status = null)
        {
            var (items, totalCount) = await _followUpDataService.GetPagedAsync(page, pageSize, search);

            var filteredItems = items.AsEnumerable();
            if (!string.IsNullOrWhiteSpace(status))
            {
                filteredItems = filteredItems.Where(f => f.Status == status);
            }

            return new PagedResult<FollowUpDTO>
            {
                Items = filteredItems.Select(MapToDTO).ToList(),
                TotalCount = totalCount,
                Page = page,
                PageSize = pageSize
            };
        }

        public async Task<FollowUpDTO> CreateFollowUpAsync(CreateFollowUpDTO dto, string userId)
        {
            var validationResult = await _createValidator.ValidateAsync(dto);
            if (!validationResult.IsValid)
            {
                throw new ValidationException(validationResult.Errors);
            }

            var followUp = new FollowUps
            {
                Reason = dto.Reason,
                ScheduleDate = dto.ScheduleDate,
                ScheduleStartTime = dto.ScheduleStartTime,
                Status = dto.Status,
                EmployeeId = dto.EmployeeId,
                WorkOrderId = dto.WorkOrderId,
                AccountId = dto.AccountId,
                LocationId = dto.LocationId,
                CreatedDate = DateTime.UtcNow,
                createdby = userId
            };

            var created = await _followUpDataService.AddAsync(followUp);
            return MapToDTO(created);
        }

        public async Task<FollowUpDTO> UpdateFollowUpAsync(int id, UpdateFollowUpDTO dto, string userId)
        {
            var validationResult = await _updateValidator.ValidateAsync(dto);
            if (!validationResult.IsValid)
            {
                throw new ValidationException(validationResult.Errors);
            }

            var followUp = await _followUpDataService.GetByIdAsync(id);
            if (followUp == null)
                throw new InvalidOperationException($"Follow-Up with ID {id} not found");

            if (dto.Reason != null) followUp.Reason = dto.Reason;
            if (dto.ScheduleDate.HasValue) followUp.ScheduleDate = dto.ScheduleDate.Value;
            if (dto.ScheduleStartTime.HasValue) followUp.ScheduleStartTime = dto.ScheduleStartTime.Value;
            if (dto.Status != null) followUp.Status = dto.Status;
            if (dto.EmployeeId.HasValue) followUp.EmployeeId = dto.EmployeeId;
            if (dto.WorkOrderId.HasValue) followUp.WorkOrderId = dto.WorkOrderId;
            if (dto.AccountId.HasValue) followUp.AccountId = dto.AccountId;
            if (dto.LocationId.HasValue) followUp.LocationId = dto.LocationId;

            followUp.LastModificationTime = DateTime.UtcNow;
            if (int.TryParse(userId, out int userIdInt))
                followUp.LastModifierUserId = userIdInt;

            await _followUpDataService.UpdateAsync(followUp);
            return MapToDTO(followUp);
        }

        public async Task DeleteFollowUpAsync(int id, string userId)
        {
            var followUp = await _followUpDataService.GetByIdAsync(id);
            if (followUp == null)
                throw new InvalidOperationException($"Follow-Up with ID {id} not found");

            followUp.IsDeleted = true;
            followUp.DeleterUserId = userId;
            followUp.DeletionTime = DateTime.UtcNow;

            await _followUpDataService.UpdateAsync(followUp);
        }

        public async Task<bool> FollowUpExistsAsync(int id)
        {
            return await _followUpDataService.ExistsAsync(id);
        }

        public async Task<int> GetTotalFollowUpCountAsync()
        {
            return await _followUpDataService.CountAsync();
        }

        public async Task<PagedResult<FollowUpListRowDTO>> GetFollowUpListAsync(
            int page,
            int pageSize,
            string? search,
            string? status,
            CancellationToken cancellationToken)
        {
            status = string.IsNullOrWhiteSpace(status) ? "Open" : status;

            var items = await _followUpDataService.GetListPagedAsync(page, pageSize, search, status, cancellationToken);
            var totalCount = await _followUpDataService.GetListTotalAsync(search, status, cancellationToken);

            return new PagedResult<FollowUpListRowDTO>
            {
                Items = items.Select(MapToListRow).ToList(),
                TotalCount = totalCount,
                Page = page,
                PageSize = pageSize
            };
        }

        public async Task<FollowUpDetailDTO?> GetFollowUpDetailAsync(int id, CancellationToken cancellationToken)
        {
            var followUp = await _followUpDataService.GetDetailByIdAsync(id, cancellationToken);
            if (followUp == null)
                return null;

            var createdByName = await _followUpDataService.GetUserNameAsync(followUp.createdby, cancellationToken);

            return new FollowUpDetailDTO
            {
                Id = followUp.Id,
                Reason = followUp.Reason,
                ScheduleDate = followUp.ScheduleDate,
                ScheduleStartTime = followUp.ScheduleStartTime,
                EmployeeId = followUp.EmployeeId,
                WorkOrderId = followUp.WorkOrderId,
                AccountId = followUp.AccountId,
                LocationId = followUp.LocationId,
                AccountName = followUp.Account?.Name ?? "",
                AssignedTo = followUp.Employee != null
                    ? $"{followUp.Employee.FirstName} {followUp.Employee.LastName}"
                    : "",
                LocationName = followUp.Location?.Name ?? "",
                WorkOrderNumber = "",
                InternalWONumber = "",
                Status = followUp.Status,
                CreatedDate = followUp.CreatedDate,
                CreatedById = followUp.createdby,
                CreatedByName = createdByName
            };
        }

        public async Task<int> CreateOpenFollowUpAsync(FollowUpCreateRequestDTO dto, string userId, CancellationToken cancellationToken)
        {
            var followUp = new FollowUps
            {
                Reason = dto.Reason,
                ScheduleDate = dto.ScheduleDate,
                ScheduleStartTime = dto.ScheduleStartTime,
                EmployeeId = dto.EmployeeId,
                WorkOrderId = dto.WorkOrderId,
                AccountId = dto.AccountId,
                LocationId = dto.LocationId,
                Status = "Open",
                createdby = userId
            };

            var created = await _followUpDataService.AddAsync(followUp, cancellationToken);
            return created.Id;
        }

        public async Task UpdateFollowUpFieldsAsync(int id, FollowUpUpdateRequestDTO dto, CancellationToken cancellationToken)
        {
            var followUp = await _followUpDataService.GetByIdForUpdateAsync(id, cancellationToken);
            if (followUp == null)
                throw new KeyNotFoundException($"Follow-Up with ID {id} not found");

            followUp.Reason = dto.Reason;
            followUp.ScheduleDate = dto.ScheduleDate;
            followUp.ScheduleStartTime = dto.ScheduleStartTime;
            followUp.EmployeeId = dto.EmployeeId;
            followUp.WorkOrderId = dto.WorkOrderId;
            followUp.AccountId = dto.AccountId;
            followUp.LocationId = dto.LocationId;

            await _followUpDataService.UpdateAsync(followUp, cancellationToken);
        }

        public Task<bool> SetFollowUpStatusAsync(int id, string status, CancellationToken cancellationToken)
        {
            return _followUpDataService.SetStatusAsync(id, status, cancellationToken);
        }

        public Task<bool> RemoveFollowUpAsync(int id, CancellationToken cancellationToken)
        {
            return _followUpDataService.RemoveByIdAsync(id, cancellationToken);
        }

        private static FollowUpListRowDTO MapToListRow(FollowUps followUp)
        {
            return new FollowUpListRowDTO
            {
                Id = followUp.Id,
                Reason = followUp.Reason,
                ScheduleDate = followUp.ScheduleDate,
                ScheduleStartTime = followUp.ScheduleStartTime,
                EmployeeId = followUp.EmployeeId,
                WorkOrderId = followUp.WorkOrderId,
                AccountId = followUp.AccountId,
                LocationId = followUp.LocationId,
                AccountName = followUp.Account?.Name ?? "",
                AssignedTo = followUp.Employee != null
                    ? $"{followUp.Employee.FirstName} {followUp.Employee.LastName}"
                    : "",
                LocationName = followUp.Location?.Name ?? "",
                WorkOrderNumber = "",
                InternalWONumber = "",
                Status = followUp.Status,
                CreatedDate = followUp.CreatedDate,
                CreatedById = null,
                CreatedByName = ""
            };
        }

        private FollowUpDTO MapToDTO(FollowUps followUp)
        {
            return new FollowUpDTO
            {
                Id = followUp.Id,
                Reason = followUp.Reason,
                ScheduleDate = followUp.ScheduleDate,
                ScheduleStartTime = followUp.ScheduleStartTime,
                Status = followUp.Status,
                EmployeeId = followUp.EmployeeId,
                EmployeeName = followUp.Employee != null ? $"{followUp.Employee.FirstName} {followUp.Employee.LastName}" : null,
                WorkOrderId = followUp.WorkOrderId,
                AccountId = followUp.AccountId,
                AccountName = followUp.Account?.Name,
                LocationId = followUp.LocationId,
                LocationName = followUp.Location?.Name,
                CreatedDate = followUp.CreatedDate
            };
        }
    }
}