using Mws.Application.Common;
using Mws.Application.Permissions;
using Mws.Domain.Documents;
using Mws.Domain.Projects;

namespace Mws.Application.Documents;

internal static class DocumentAccess
{
    public static async Task EnsureDocumentPermissionAsync(
        IUnitOfWork uow, Guid userId, Guid projectId, PermissionAction action, CancellationToken ct)
    {
        var member = await uow.Projects.GetMemberAsync(projectId, userId, ct)
            ?? throw new NotFoundException("Project not found");

        if (!await HasDocumentPermissionAsync(uow, member, action, ct))
        {
            throw new ForbiddenException("You do not have permission to access documents in this project");
        }
    }

    public static async Task<bool> HasDocumentPermissionAsync(
        IUnitOfWork uow, ProjectMember member, PermissionAction action, CancellationToken ct)
    {
        if (member.Role == MemberRole.Owner)
        {
            return true;
        }

        var permission = await uow.Projects.GetMemberPermissionAsync(member.ProjectId, member.UserId, ProjectPermissionScreens.Documents, ct);

        return action switch
        {
            PermissionAction.View => permission?.CanView ?? false,
            PermissionAction.Create => permission?.CanCreate ?? false,
            PermissionAction.Edit => permission?.CanEdit ?? false,
            PermissionAction.Delete => permission?.CanDelete ?? false,
            _ => false,
        };
    }

    public static async Task<Document> GetDocumentForUserAsync(IUnitOfWork uow, Guid userId, Guid documentId, CancellationToken ct)
    {
        var doc = await uow.Documents.GetByIdAsync(documentId, ct)
            ?? throw new NotFoundException("Document not found");

        var member = await uow.Projects.GetMemberAsync(doc.ProjectId, userId, ct);

        if (member is null)
        {
            throw new NotFoundException("Document not found");
        }

        if (!await HasDocumentPermissionAsync(uow, member, PermissionAction.View, ct))
        {
            throw new ForbiddenException("You do not have permission to view this document");
        }

        return doc;
    }

    public static async Task DeleteDescendantsAsync(IUnitOfWork uow, Guid parentId, CancellationToken ct)
    {
        var children = await uow.Documents.GetChildrenAsync(parentId, ct);
        foreach (var child in children)
        {
            await DeleteDescendantsAsync(uow, child.Id, ct);
            uow.Documents.Remove(child);
        }
    }
}