using Data.SeaHavenIndustries;
using Data.SeaHavenIndustries.Enums;
using Microsoft.EntityFrameworkCore;
using SeaHaven.DataServices.Helpers;
using SeaHaven.DataServices.Interfaces;

namespace SeaHaven.DataServices.Implementation
{
    public class CompletionDocTemplateDataService : ICompletionDocTemplateDataService
    {
        private static readonly LifecycleStatus[] OpenStatuses = Enum.GetValues<LifecycleStatus>()
            .Where(status => !LifecycleStatusSets.Terminal.Contains(status))
            .ToArray();

        private readonly ApplicationDbContext _context;

        public CompletionDocTemplateDataService(ApplicationDbContext context)
        {
            _context = context;
        }

        public async Task<CompletionDocTemplateRow?> ResolveForWorkOrderAsync(string? trade, WorkOrderType? workOrderType)
        {
            if (!string.IsNullOrWhiteSpace(trade))
            {
                var byTrade = await _context.CompletionDocTemplates
                    .AsNoTracking()
                    .Where(t => t.IsActive && t.IsDeleted != true && t.ServiceKey == trade)
                    .OrderBy(t => t.WorkOrderType == workOrderType ? 0 : 1)
                    .ThenBy(t => t.Name)
                    .ThenBy(t => t.Id)
                    .Select(MapRow)
                    .FirstOrDefaultAsync();

                if (byTrade != null)
                    return byTrade;
            }

            if (!workOrderType.HasValue)
                return null;

            return await _context.CompletionDocTemplates
                .AsNoTracking()
                .Where(t => t.IsActive && t.IsDeleted != true && t.WorkOrderType == workOrderType)
                .OrderBy(t => t.Name)
                .ThenBy(t => t.Id)
                .Select(MapRow)
                .FirstOrDefaultAsync();
        }

        public async Task<IReadOnlyList<CompletionDocTemplateDetailRow>> ListAsync(
            string? search,
            string? serviceKey,
            WorkOrderType? workOrderType,
            CancellationToken cancellationToken)
        {
            var query = _context.CompletionDocTemplates
                .AsNoTracking()
                .Where(t => t.IsActive && t.IsDeleted != true);

            if (!string.IsNullOrWhiteSpace(serviceKey))
                query = query.Where(t => t.ServiceKey == serviceKey);

            if (workOrderType.HasValue)
                query = query.Where(t => t.WorkOrderType == null || t.WorkOrderType == workOrderType);

            if (!string.IsNullOrWhiteSpace(search))
            {
                var term = search.Trim().ToLower();
                query = query.Where(t => t.Name.ToLower().Contains(term));
            }

            return await ProjectDetail(query).ToListAsync(cancellationToken);
        }

        public async Task<CompletionDocTemplateDetailRow?> GetDetailAsync(int id, CancellationToken cancellationToken)
        {
            var query = _context.CompletionDocTemplates
                .AsNoTracking()
                .Where(t => t.Id == id && t.IsDeleted != true);

            return await ProjectDetail(query).FirstOrDefaultAsync(cancellationToken);
        }

        public Task<CompletionDocTemplate?> GetTrackedForEditAsync(int id, CancellationToken cancellationToken)
            => _context.CompletionDocTemplates
                .Include(t => t.Procedures)
                .FirstOrDefaultAsync(t => t.Id == id && t.IsDeleted != true, cancellationToken);

        public async Task<int> CreateAsync(CompletionDocTemplate template, CancellationToken cancellationToken)
        {
            template.CreatedDate = DateTime.UtcNow;
            await _context.CompletionDocTemplates.AddAsync(template, cancellationToken);
            await _context.SaveChangesAsync(cancellationToken);
            return template.Id;
        }

        public async Task SaveEditAsync(
            CompletionDocTemplate template,
            IReadOnlyList<CompletionDocTemplateProcedure>? replacementProcedures,
            CancellationToken cancellationToken)
        {
            if (replacementProcedures != null)
            {
                // Explicit removal: the context forces Restrict on every FK before the
                // procedure cascade is configured, so orphan deletion is not relied on.
                _context.CompletionDocTemplateProcedures.RemoveRange(template.Procedures.ToList());
                foreach (var procedure in replacementProcedures)
                {
                    procedure.CompletionDocTemplateId = template.Id;
                    _context.CompletionDocTemplateProcedures.Add(procedure);
                }
            }

            template.LastModificationTime = DateTime.UtcNow;
            await _context.SaveChangesAsync(cancellationToken);
        }

        public async Task<bool> DeleteAndUnlinkServicesAsync(
            int id,
            string? deleterUserId,
            CancellationToken cancellationToken)
        {
            var template = await _context.CompletionDocTemplates
                .FirstOrDefaultAsync(t => t.Id == id && t.IsDeleted != true, cancellationToken);
            if (template == null)
                return false;

            var now = DateTime.UtcNow;
            template.IsDeleted = true;
            template.DeletionTime = now;
            template.DeleterUserId = deleterUserId;

            var linkedServices = await _context.Services
                .Where(s => s.CompletionDocTemplateId == id)
                .ToListAsync(cancellationToken);
            foreach (var service in linkedServices)
            {
                service.CompletionDocTemplateId = null;
                service.LastModificationTime = now;
            }

            await _context.SaveChangesAsync(cancellationToken);
            return true;
        }

        public async Task<IReadOnlyList<int>> GetOpenLinkedWorkOrderIdsAsync(
            int templateId,
            int? accountId,
            CancellationToken cancellationToken)
        {
            var workOrders = WorkOrderBoardQueryFilters.ApplyBaseScope(_context.workOrders.AsNoTracking());
            if (accountId.HasValue)
                workOrders = WorkOrderBoardQueryFilters.ApplyAccountScope(workOrders, accountId.Value);

            var linkedServiceIds = _context.Services
                .Where(s => s.CompletionDocTemplateId == templateId)
                .Select(s => (int?)s.Id);

            // Shared status filter so legacy rows without a LifecycleStatus are read
            // through their legacy status text (a legacy "completed" row is not open).
            workOrders = WorkOrderBoardQueryFilters.ApplyStatusFilter(workOrders, OpenStatuses);

            return await workOrders
                .Where(w => w.ServiceId != null && linkedServiceIds.Contains(w.ServiceId))
                .OrderBy(w => w.Id)
                .Select(w => w.Id)
                .ToListAsync(cancellationToken);
        }

        private IQueryable<CompletionDocTemplateDetailRow> ProjectDetail(IQueryable<CompletionDocTemplate> templates)
            => from t in templates
               join u in _context.Users on t.createdby equals u.Id into creators
               from creator in creators.DefaultIfEmpty()
               orderby t.Name, t.Id
               select new CompletionDocTemplateDetailRow(
                   t.Id,
                   t.Name,
                   t.ServiceKey,
                   t.WorkOrderType,
                   t.TemplateUrl,
                   t.IsActive,
                   t.ExtraSafetyNote,
                   t.CreatedDate,
                   t.LastModificationTime,
                   creator != null ? creator.FirstName : null,
                   creator != null ? creator.LastName : null,
                   t.Procedures
                       .OrderBy(p => p.SortOrder)
                       .ThenBy(p => p.Id)
                       .Select(p => new CompletionDocTemplateProcedureRow(p.Id, p.SortOrder, p.Name, p.Description))
                       .ToList());

        private static readonly System.Linq.Expressions.Expression<Func<CompletionDocTemplate, CompletionDocTemplateRow>> MapRow =
            t => new CompletionDocTemplateRow(t.Id, t.Name, t.ServiceKey, t.WorkOrderType, t.TemplateUrl, t.IsActive);
    }
}