using Connected.Interop;
using Connected.Middleware;
using Connected.Security.Identity;
using Connected.Security.Membership;
using Connected.Security.Permissions;
using Connected.ServiceModel;
using Microsoft.Extensions.Logging;
using System.Collections.Immutable;

namespace Connected.Security.Authorization.Middleware;

internal class RoleAuthorizationMiddleware : MiddlewareComponent, IAuthorizationMiddleware
{
	public RoleAuthorizationMiddleware(IRoleService roleService, IUserService userService, ILogger<RoleAuthorizationMiddleware> logger, IMembershipService membershipService)
	{
		RoleService = roleService;
		UserService = userService;
		Logger = logger;
		MembershipService = membershipService;
	}

	public string Id => "Roles";
	private IRoleService RoleService { get; }
	private IUserService UserService { get; }
	private ILogger<RoleAuthorizationMiddleware> Logger { get; }
	private IMembershipService MembershipService { get; }

	public Task<AuthorizationProviderResult> Authorize(IPermission permission, AuthorizationArgs e, Dictionary<string, object> state)
	{
		if (state["roles"] is not List<int> roles)
			return Task.FromResult(AuthorizationProviderResult.NotHandled);

		if (!TypeConversion.TryConvert(permission.Evidence, out int evidence))
			return Task.FromResult(AuthorizationProviderResult.NotHandled);

		if (roles.Contains(evidence))
		{
			return permission.Value switch
			{
				PermissionValue.NotSet => Task.FromResult(AuthorizationProviderResult.NotHandled),
				PermissionValue.Allow => Task.FromResult(AuthorizationProviderResult.Success),
				PermissionValue.Deny => Task.FromResult(AuthorizationProviderResult.Fail),
				_ => throw new NotSupportedException(),
			};
		}

		return Task.FromResult(AuthorizationProviderResult.NotHandled);
	}

	public async Task<AuthorizationProviderResult> PreAuthorize(AuthorizationArgs e, Dictionary<string, object> state)
	{
		var roles = await ResolveImplicitRoles(e);

		state.Add("roles", roles);

		if (e.User > 0)
		{
			var list = await MembershipService.Query(new MembershipQueryArgs { User = (int)e.User });

			if (list is not null && list.Any())
				roles.AddRange(list.Select(f => f.Role));
		}

		if (await RoleService.Select(new NameArgs { Name = Roles.FullControl }) is IRole fullControl && roles.Contains(fullControl.Id))
			return AuthorizationProviderResult.Success;

		return AuthorizationProviderResult.NotHandled;
	}

	public async Task<ImmutableList<IPermissionSchemaDescriptor>> QueryDescriptors()
	{
		if (await RoleService.Query() is not ImmutableList<IRole> roles)
			return ImmutableList<IPermissionSchemaDescriptor>.Empty;

		var result = new List<IPermissionSchemaDescriptor>();

		foreach (var role in roles)
		{
			result.Add(new PermissionSchemaDescriptor
			{
				Title = role.Name,
				Id = role.Id.ToString()
			});
		}

		return result.ToImmutableList();
	}

	private async Task<List<int>> ResolveImplicitRoles(AuthorizationArgs e)
	{
		var result = new List<int>();

		if (await RoleService.Select(Roles.Everyone) is IRole everyone)
			result.Add(everyone.Id);

		if (e.User == 0)
		{
			if (await RoleService.Select(Roles.Anonymous) is IRole anonymous)
				result.Add(anonymous.Id);
		}
		else
		{
			if (e.User is null || await UserService.Select(e.User) is null)
			{
				if (await RoleService.Select(Roles.Anonymous) is IRole anonymous)
					result.Add(anonymous.Id);

				Logger.LogWarning("Authenticated user not found. Request will be treated as anonymous {user}.", e.User);

				return result;
			}

			if (await RoleService.Select(Roles.Authenticated) is IRole authenticated)
				result.Add(authenticated.Id);
		}

		return result;
	}
}