using AmtScanner.Api.Data;
using AmtScanner.Api.Models;
using Microsoft.EntityFrameworkCore;

namespace AmtScanner.Api.Services;

/// <summary>
/// 认证服务实现
/// </summary>
public class AuthService : IAuthService
{
    private readonly AppDbContext _context;
    private readonly IJwtService _jwtService;

    public AuthService(AppDbContext context, IJwtService jwtService)
    {
        _context = context;
        _jwtService = jwtService;
    }

    public async Task<(User? user, string? accessToken, string? refreshToken, string? error)> LoginAsync(string userName, string password)
    {
        // 查找用户
        var user = await _context.Users
            .FirstOrDefaultAsync(u => u.UserName == userName && !u.IsDeleted);

        if (user == null)
        {
            return (null, null, null, "用户名或密码错误");
        }

        // 验证密码
        if (!BCrypt.Net.BCrypt.Verify(password, user.PasswordHash))
        {
            return (null, null, null, "用户名或密码错误");
        }

        // 检查用户状态
        if (user.Status != "1")
        {
            return (null, null, null, "用户已被禁用");
        }

        // 获取用户角色
        var roles = await GetUserRolesAsync(user.Id);

        // 生成 Token
        var accessToken = _jwtService.GenerateAccessToken(user, roles);
        var refreshToken = _jwtService.GenerateRefreshToken();

        // 保存 RefreshToken 到用户
        user.RefreshToken = refreshToken;
        user.RefreshTokenExpiryTime = _jwtService.GetRefreshTokenExpiryTime();
        await _context.SaveChangesAsync();

        return (user, accessToken, refreshToken, null);
    }

    public async Task<(string? accessToken, string? refreshToken, string? error)> RefreshTokenAsync(string accessToken, string refreshToken)
    {
        // 从过期的 Token 中获取用户信息
        var principal = _jwtService.GetPrincipalFromExpiredToken(accessToken);
        if (principal == null)
        {
            return (null, null, "无效的 Token");
        }

        var userIdClaim = principal.FindFirst("userId")?.Value;
        if (string.IsNullOrEmpty(userIdClaim) || !int.TryParse(userIdClaim, out var userId))
        {
            return (null, null, "无效的 Token");
        }

        // 查找用户
        var user = await _context.Users
            .FirstOrDefaultAsync(u => u.Id == userId && !u.IsDeleted);

        if (user == null)
        {
            return (null, null, "用户不存在");
        }

        // 验证 RefreshToken
        if (user.RefreshToken != refreshToken || user.RefreshTokenExpiryTime <= DateTime.UtcNow)
        {
            return (null, null, "RefreshToken 无效或已过期");
        }

        // 获取用户角色
        var roles = await GetUserRolesAsync(user.Id);

        // 生成新的 Token
        var newAccessToken = _jwtService.GenerateAccessToken(user, roles);
        var newRefreshToken = _jwtService.GenerateRefreshToken();

        // 更新 RefreshToken
        user.RefreshToken = newRefreshToken;
        user.RefreshTokenExpiryTime = _jwtService.GetRefreshTokenExpiryTime();
        await _context.SaveChangesAsync();

        return (newAccessToken, newRefreshToken, null);
    }

    public async Task<bool> LogoutAsync(int userId)
    {
        var user = await _context.Users.FindAsync(userId);
        if (user == null)
        {
            return false;
        }

        // 清除 RefreshToken
        user.RefreshToken = null;
        user.RefreshTokenExpiryTime = null;
        await _context.SaveChangesAsync();

        return true;
    }

    public async Task<User?> GetUserByIdAsync(int userId)
    {
        return await _context.Users
            .FirstOrDefaultAsync(u => u.Id == userId && !u.IsDeleted);
    }

    public async Task<List<string>> GetUserRolesAsync(int userId)
    {
        return await _context.UserRoles
            .Where(ur => ur.UserId == userId)
            .Join(_context.Roles, ur => ur.RoleId, r => r.Id, (ur, r) => r)
            .Where(r => r.Enabled)
            .Select(r => r.RoleCode)
            .ToListAsync();
    }

    public async Task<(List<User> users, int total)> GetUsersAsync(int current, int size, string? userName = null, string? status = null)
    {
        var query = _context.Users.Where(u => !u.IsDeleted);

        // 按用户名筛选
        if (!string.IsNullOrEmpty(userName))
        {
            query = query.Where(u => u.UserName.Contains(userName));
        }

        // 按状态筛选
        if (!string.IsNullOrEmpty(status))
        {
            query = query.Where(u => u.Status == status);
        }

        var total = await query.CountAsync();
        var users = await query
            .OrderByDescending(u => u.CreatedAt)
            .Skip((current - 1) * size)
            .Take(size)
            .ToListAsync();

        return (users, total);
    }
}