using System.Security.Claims;
using SharepointToolbox.Web.Core.Models;
using SharepointToolbox.Web.Infrastructure.Persistence;

namespace SharepointToolbox.Web.Services.Auth;

public class UserService : IUserService
{
    private readonly UserRepository _repo;

    public UserService(UserRepository repo) { _repo = repo; }

    public async Task<AppUser> ProvisionAsync(ClaimsPrincipal principal)
    {
        var email = principal.FindFirstValue(ClaimTypes.Email)
                    ?? principal.FindFirstValue("preferred_username")
                    ?? throw new InvalidOperationException("OIDC token has no email claim.");

        var display = principal.FindFirstValue("name")
                      ?? principal.FindFirstValue(ClaimTypes.Name)
                      ?? email;

        var existing = await _repo.FindByEmailAsync(email);
        if (existing is not null)
        {
            existing.LastLogin = DateTimeOffset.UtcNow;
            existing.DisplayName = display;
            await _repo.UpsertAsync(existing);
            return existing;
        }

        // First user ever → Admin; subsequent → TechN0
        var all = await _repo.LoadAsync();
        var role = all.Count == 0 ? UserRole.Admin : UserRole.TechN0;

        var user = new AppUser
        {
            Email       = email,
            DisplayName = display,
            Role        = role,
            CreatedAt   = DateTimeOffset.UtcNow,
            LastLogin   = DateTimeOffset.UtcNow
        };
        await _repo.UpsertAsync(user);
        return user;
    }

    public Task<AppUser?> GetByEmailAsync(string email) => _repo.FindByEmailAsync(email);

    public Task<IReadOnlyList<AppUser>> GetAllAsync() => _repo.LoadAsync();

    public async Task UpdateRoleAsync(string userId, UserRole role)
    {
        var users = (await _repo.LoadAsync()).ToList();
        var user  = users.FirstOrDefault(u => u.Id == userId)
                    ?? throw new KeyNotFoundException($"User {userId} not found.");
        user.Role = role;
        await _repo.UpsertAsync(user);
    }

    public Task DeleteAsync(string userId) => _repo.DeleteAsync(userId);
}