using System.Security.Claims;
using Data.SeaHavenIndustries;
using Data.SeaHavenIndustries.Enums;
using SeaHaven.DataServices.Interfaces;
using SeaHaven.Services.Constants;
using SeaHaven.Services.DTOs;
using SeaHaven.Services.Exceptions;
using SeaHaven.Services.Helpers;
using SeaHaven.Services.Interfaces;

namespace SeaHaven.Services.Implementation
{
    public sealed class CompletionDocTemplateService : ICompletionDocTemplateService
    {
        private readonly ICompletionDocTemplateDataService _templateData;
        private readonly ITeamPermissionOverrideDataService _permissionUsers;
        private readonly ITeamPermissionPolicy _permissionPolicy;
        private readonly IWorkOrderAccountResolver _accountResolver;

        public CompletionDocTemplateService(
            ICompletionDocTemplateDataService templateData,
            ITeamPermissionOverrideDataService permissionUsers,
            ITeamPermissionPolicy permissionPolicy,
            IWorkOrderAccountResolver accountResolver)
        {
            _templateData = templateData;
            _permissionUsers = permissionUsers;
            _permissionPolicy = permissionPolicy;
            _accountResolver = accountResolver;
        }

        public async Task<IReadOnlyList<CompletionDocTemplateDetailDto>> ListAsync(
            string? search,
            string? serviceKey,
            WorkOrderType? workOrderType,
            CancellationToken cancellationToken)
        {
            var rows = await _templateData.ListAsync(
                search,
                serviceKey,
                WorkOrderCatalogType.For(workOrderType),
                cancellationToken);
            return rows.Select(Map).ToList();
        }

        public async Task<CompletionDocTemplateDetailDto?> GetAsync(int id, CancellationToken cancellationToken)
        {
            var row = await _templateData.GetDetailAsync(id, cancellationToken);
            return row == null ? null : Map(row);
        }

        public async Task<CompletionDocTemplateLinkedWorkOrdersDto> GetLinkedWorkOrdersAsync(
            ClaimsPrincipal user,
            int id,
            CancellationToken cancellationToken)
        {
            var accountId = _accountResolver.ResolveAccountFilter(user);

            if (await _templateData.GetDetailAsync(id, cancellationToken) == null)
                throw NotFound();

            var ids = await _templateData.GetOpenLinkedWorkOrderIdsAsync(id, accountId, cancellationToken);
            return new CompletionDocTemplateLinkedWorkOrdersDto { Count = ids.Count, WorkOrderIds = ids.ToList() };
        }

        public async Task<CompletionDocTemplateDetailDto> CreateAsync(
            ClaimsPrincipal user,
            CompletionDocTemplateCreateDto request,
            CancellationToken cancellationToken)
        {
            var actorId = await EnsureAllowedAsync(
                user,
                TeamPermissionKeys.CreateCompletionDocTemplates,
                "You do not have permission to create completion document templates.",
                cancellationToken);

            var input = Validate(request);
            var entity = new CompletionDocTemplate
            {
                Name = input.Name,
                ExtraSafetyNote = input.ExtraSafetyNote,
                ServiceKey = input.ServiceKey ?? "",
                WorkOrderType = request.WorkOrderType,
                TemplateUrl = input.TemplateUrl ?? "",
                IsActive = request.IsActive ?? true,
                createdby = actorId,
                Procedures = (input.Procedures ?? new List<CompletionDocTemplateProcedure>()).ToList()
            };

            var id = await _templateData.CreateAsync(entity, cancellationToken);
            return await GetSavedAsync(id, cancellationToken);
        }

        public async Task<CompletionDocTemplateDetailDto> UpdateAsync(
            ClaimsPrincipal user,
            int id,
            CompletionDocTemplateCreateDto request,
            CancellationToken cancellationToken)
        {
            await EnsureAllowedAsync(
                user,
                TeamPermissionKeys.EditCompletionDocTemplates,
                "You do not have permission to edit completion document templates.",
                cancellationToken);

            var input = Validate(request);
            var entity = await _templateData.GetTrackedForEditAsync(id, cancellationToken) ?? throw NotFound();

            entity.Name = input.Name;
            entity.ExtraSafetyNote = input.ExtraSafetyNote;
            if (input.ServiceKey != null)
                entity.ServiceKey = input.ServiceKey;
            if (request.WorkOrderTypeSpecified)
                entity.WorkOrderType = request.WorkOrderType;
            if (input.TemplateUrl != null)
                entity.TemplateUrl = input.TemplateUrl;
            if (request.IsActive.HasValue)
                entity.IsActive = request.IsActive.Value;

            await _templateData.SaveEditAsync(entity, input.Procedures, cancellationToken);
            return await GetSavedAsync(id, cancellationToken);
        }

        public async Task DeleteAsync(ClaimsPrincipal user, int id, CancellationToken cancellationToken)
        {
            var actorId = await EnsureAllowedAsync(
                user,
                TeamPermissionKeys.DeleteCompletionDocTemplates,
                "You do not have permission to delete completion document templates.",
                cancellationToken);

            if (!await _templateData.DeleteAndUnlinkServicesAsync(id, actorId, cancellationToken))
                throw NotFound();
        }

        private async Task<string> EnsureAllowedAsync(
            ClaimsPrincipal user,
            string permissionKey,
            string deniedMessage,
            CancellationToken cancellationToken)
        {
            var userId = user?.FindFirstValue(ClaimTypes.NameIdentifier);
            var permissionUser = string.IsNullOrWhiteSpace(userId)
                ? null
                : await _permissionUsers.GetUserAsync(userId, cancellationToken);

            if (permissionUser is null
                || !_permissionPolicy.IsAllowed(permissionUser.RoleName, permissionKey, permissionUser.Overrides))
            {
                throw new WorkOrderBoardValidationException("Forbidden", deniedMessage);
            }

            return userId!;
        }

        private async Task<CompletionDocTemplateDetailDto> GetSavedAsync(int id, CancellationToken cancellationToken)
        {
            var row = await _templateData.GetDetailAsync(id, cancellationToken) ?? throw NotFound();
            return Map(row);
        }

        private sealed record ValidatedInput(
            string Name,
            string? ExtraSafetyNote,
            string? ServiceKey,
            string? TemplateUrl,
            IReadOnlyList<CompletionDocTemplateProcedure>? Procedures);

        private static ValidatedInput Validate(CompletionDocTemplateCreateDto request)
        {
            if (request == null || string.IsNullOrWhiteSpace(request.Name))
                throw new WorkOrderBoardValidationException("TitleRequired", "Document Title is required.");

            var extraSafetyNote = string.IsNullOrWhiteSpace(request.ExtraSafetyNote)
                ? null
                : request.ExtraSafetyNote.Trim();
            if (extraSafetyNote?.Length > CompletionDocTemplate.ExtraSafetyNoteMaxLength)
            {
                throw new WorkOrderBoardValidationException(
                    "InvalidValue",
                    $"Extra safety note must be {CompletionDocTemplate.ExtraSafetyNoteMaxLength} characters or fewer.");
            }

            var templateUrl = request.TemplateUrl?.Trim();
            if (!string.IsNullOrEmpty(templateUrl)
                && (!Uri.TryCreate(templateUrl, UriKind.Absolute, out var uri)
                    || (uri.Scheme != Uri.UriSchemeHttp && uri.Scheme != Uri.UriSchemeHttps)))
            {
                throw new WorkOrderBoardValidationException("InvalidValue", "TemplateUrl must be an absolute http(s) URL.");
            }

            // Blank procedure names and descriptions are allowed: authors may keep a
            // placeholder step and fill it in later.
            List<CompletionDocTemplateProcedure>? procedures = null;
            if (request.Procedures != null)
            {
                procedures = new List<CompletionDocTemplateProcedure>(request.Procedures.Count);
                foreach (var procedure in request.Procedures)
                {
                    var name = procedure?.Name?.Trim() ?? "";
                    if (name.Length > CompletionDocTemplateProcedure.NameMaxLength)
                    {
                        throw new WorkOrderBoardValidationException(
                            "InvalidValue",
                            $"Procedure name must be {CompletionDocTemplateProcedure.NameMaxLength} characters or fewer.");
                    }

                    procedures.Add(new CompletionDocTemplateProcedure
                    {
                        SortOrder = procedures.Count,
                        Name = name,
                        Description = procedure?.Description ?? ""
                    });
                }
            }

            return new ValidatedInput(
                request.Name.Trim(),
                extraSafetyNote,
                request.ServiceKey?.Trim(),
                templateUrl,
                procedures);
        }

        private static WorkOrderBoardValidationException NotFound()
            => new("NotFound", "Template not found.");

        private static CompletionDocTemplateDetailDto Map(CompletionDocTemplateDetailRow row)
        {
            var createdByName = string.Join(
                " ",
                new[] { row.CreatedByFirstName, row.CreatedByLastName }
                    .Where(part => !string.IsNullOrWhiteSpace(part))
                    .Select(part => part!.Trim()));

            return new CompletionDocTemplateDetailDto
            {
                Id = row.Id,
                Name = row.Name,
                ServiceKey = row.ServiceKey,
                WorkOrderType = row.WorkOrderType,
                TemplateUrl = row.TemplateUrl,
                IsActive = row.IsActive,
                ExtraSafetyNote = row.ExtraSafetyNote,
                Procedures = row.Procedures
                    .Select(p => new CompletionDocTemplateProcedureDto
                    {
                        Id = p.Id,
                        Name = p.Name,
                        Description = p.Description,
                        SortOrder = p.SortOrder
                    })
                    .ToList(),
                CreatedAt = AsUtc(row.CreatedAt),
                UpdatedAt = AsUtc(row.UpdatedAt),
                CreatedByName = createdByName.Length == 0 ? null : createdByName
            };
        }

        // Audit timestamps are written as DateTime.UtcNow; the store drops the kind.
        private static DateTime? AsUtc(DateTime? value)
            => value.HasValue ? DateTime.SpecifyKind(value.Value, DateTimeKind.Utc) : null;
    }
}