using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using LingAdmin.API.Data;
using LingAdmin.API.Models;
using LingAdmin.API.DTOs;
using LingAdmin.API.Services;
using Dapr.Client;

namespace LingAdmin.API.Controllers;

[ApiController]
[Route("api/[controller]")]
public class AuthController : ControllerBase
{
    private readonly AppDbContext _context;
    private readonly IPasswordHasher _passwordHasher;
    private readonly ITokenService _tokenService;
    private readonly DaprClient _daprClient;
    private readonly ILogger<AuthController> _logger;

    public AuthController(
        AppDbContext context,
        IPasswordHasher passwordHasher,
        ITokenService tokenService,
        DaprClient daprClient,
        ILogger<AuthController> logger)
    {
        _context = context;
        _passwordHasher = passwordHasher;
        _tokenService = tokenService;
        _daprClient = daprClient;
        _logger = logger;
    }

    [HttpPost("register")]
    public async Task<ActionResult<ApiResponse<UserDto>>> Register(RegisterDto registerDto)
    {
        try
        {
            // Validate input
            if (string.IsNullOrWhiteSpace(registerDto.Email) || 
                string.IsNullOrWhiteSpace(registerDto.Password))
            {
                return BadRequest(ApiResponse<UserDto>.Error("Email and password are required", 400));
            }

            // Check if user already exists
            if (await _context.Users.AnyAsync(u => u.Email == registerDto.Email))
            {
                return BadRequest(ApiResponse<UserDto>.Error("User with this email already exists", 400));
            }

            // Create new user
            var user = new User
            {
                Name = registerDto.Name,
                Email = registerDto.Email,
                Role = registerDto.Role,
                Status = "Active",
                PasswordHash = _passwordHasher.HashPassword(registerDto.Password),
                CreatedAt = DateTime.UtcNow
            };

            _context.Users.Add(user);
            await _context.SaveChangesAsync();

            // Publish user created event
            await _daprClient.PublishEventAsync("pubsub", "user-created", new
            {
                userId = user.Id,
                email = user.Email,
                name = user.Name,
                timestamp = DateTime.UtcNow
            });

            _logger.LogInformation("User registered successfully: {Email}", user.Email);

            var userDto = MapToUserDto(user);
            return CreatedAtAction(nameof(GetProfile), new { id = user.Id }, ApiResponse<UserDto>.Success(userDto));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error during user registration");
            return StatusCode(500, ApiResponse<UserDto>.Error("Internal server error", 500));
        }
    }

    [HttpPost("login")]
    public async Task<ActionResult<ApiResponse<LoginResponseDto>>> Login(LoginDto loginDto)
    {
        try
        {
            // Find user by email
            var user = await _context.Users.FirstOrDefaultAsync(u => u.Email == loginDto.Email);
            if (user == null)
            {
                return Unauthorized(ApiResponse<LoginResponseDto>.Error("Invalid email or password", 401));
            }

            // Verify password
            if (!_passwordHasher.VerifyPassword(loginDto.Password, user.PasswordHash))
            {
                return Unauthorized(ApiResponse<LoginResponseDto>.Error("Invalid email or password", 401));
            }

            // Check if user is active
            if (user.Status != "Active")
            {
                return Unauthorized(ApiResponse<LoginResponseDto>.Error("User account is not active", 401));
            }

            // Update last login time
            user.LastLoginAt = DateTime.UtcNow;
            await _context.SaveChangesAsync();

            // Generate token
            var token = _tokenService.GenerateToken(user);

            // Publish login event
            await _daprClient.PublishEventAsync("pubsub", "user-login", new
            {
                userId = user.Id,
                email = user.Email,
                timestamp = DateTime.UtcNow
            });

            _logger.LogInformation("User logged in successfully: {Email}", user.Email);

            var response = new LoginResponseDto
            {
                Token = token,
                User = MapToUserDto(user)
            };

            return Ok(ApiResponse<LoginResponseDto>.Success(response));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error during user login");
            return StatusCode(500, ApiResponse<LoginResponseDto>.Error("Internal server error", 500));
        }
    }

    [HttpGet("profile/{id}")]
    public async Task<ActionResult<ApiResponse<UserDto>>> GetProfile(int id)
    {
        try
        {
            var user = await _context.Users.FindAsync(id);
            if (user == null)
            {
                return NotFound(ApiResponse<UserDto>.Error("User not found", 404));
            }

            return Ok(ApiResponse<UserDto>.Success(MapToUserDto(user)));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error retrieving user profile");
            return StatusCode(500, ApiResponse<UserDto>.Error("Internal server error", 500));
        }
    }

    [HttpPost("change-password/{id}")]
    public async Task<ActionResult<ApiResponse<object>>> ChangePassword(int id, ChangePasswordDto changePasswordDto)
    {
        try
        {
            var user = await _context.Users.FindAsync(id);
            if (user == null)
            {
                return NotFound(ApiResponse<object>.Error("User not found", 404));
            }

            // Verify current password
            if (!_passwordHasher.VerifyPassword(changePasswordDto.CurrentPassword, user.PasswordHash))
            {
                return BadRequest(ApiResponse<object>.Error("Current password is incorrect", 400));
            }

            // Update password
            user.PasswordHash = _passwordHasher.HashPassword(changePasswordDto.NewPassword);
            await _context.SaveChangesAsync();

            // Publish password changed event
            await _daprClient.PublishEventAsync("pubsub", "user-password-changed", new
            {
                userId = user.Id,
                email = user.Email,
                timestamp = DateTime.UtcNow
            });

            _logger.LogInformation("Password changed successfully for user: {Email}", user.Email);

            return Ok(ApiResponse<object>.Success(new { message = "Password changed successfully" }));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error changing password");
            return StatusCode(500, ApiResponse<object>.Error("Internal server error", 500));
        }
    }

    private UserDto MapToUserDto(User user)
    {
        return new UserDto
        {
            Id = user.Id,
            Name = user.Name,
            Email = user.Email,
            Role = user.Role,
            Status = user.Status,
            CreatedAt = user.CreatedAt,
            LastLoginAt = user.LastLoginAt
        };
    }
}