using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using backend.Data;
using backend.DTOs;
using backend.Models;

namespace backend.Controllers;

[ApiController]
[Route("api/[controller]")]
public class UserController : ControllerBase
{
    private readonly AppDbContext _db;

    public UserController(AppDbContext db)
    {
        _db = db;
    }

    [HttpPost("register")]
    public async Task<IActionResult> Register([FromBody] RegisterRequest request)
    {
        if (string.IsNullOrWhiteSpace(request.FullName) || string.IsNullOrWhiteSpace(request.Contact))
        {
            return BadRequest(new { message = "نام و شناسه الزامی هستند." });
        }

        if (request.Contact.Length < 5)
        {
            return BadRequest(new { message = "شناسه باید حداقل ۵ کاراکتر باشد." });
        }

        // Check if contact already exists
        var existingUser = await _db.Users.FirstOrDefaultAsync(u => u.Contact == request.Contact);
        if (existingUser != null)
        {
            return Conflict(new { message = "این شناسه قبلاً ثبت شده است. لطفاً با کد رهگیری وارد شوید." });
        }

        // Generate unique tracking code
        string trackingCode;
        do
        {
            trackingCode = GenerateTrackingCode();
        } while (await _db.Users.AnyAsync(u => u.TrackingCode == trackingCode));

        var user = new User
        {
            FullName = request.FullName.Trim(),
            Contact = request.Contact.Trim(),
            TrackingCode = trackingCode
        };

        _db.Users.Add(user);

        // Save the user first so that user.Id is populated by the database
        await _db.SaveChangesAsync();

        // Create initial total score record with the now-populated user.Id
        var totalScore = new UserTotalScore
        {
            UserId = user.Id,
            TotalPoints = 0
        };
        _db.UserTotalScores.Add(totalScore);

        await _db.SaveChangesAsync();

        return Ok(new RegisterResponse
        {
            UserId = user.Id,
            TrackingCode = trackingCode
        });
    }

    [HttpPost("login")]
    public async Task<IActionResult> Login([FromBody] LoginRequest request)
    {
        if (string.IsNullOrWhiteSpace(request.TrackingCode))
        {
            return BadRequest(new { message = "کد رهگیری الزامی است." });
        }

        var user = await _db.Users
            .Include(u => u.QuizAttempt)
            .Include(u => u.KhatmSelections)
            .FirstOrDefaultAsync(u => u.TrackingCode == request.TrackingCode.Trim());

        if (user == null)
        {
            return NotFound(new { message = "کد رهگیری نامعتبر است." });
        }

        return Ok(new LoginResponse
        {
            UserId = user.Id,
            FullName = user.FullName,
            Contact = user.Contact,
            IsQuizCompleted = user.QuizAttempt != null,
            KhatmSelections = user.KhatmSelections
                .Where(ks => ks.IsSelected)
                .Select(ks => ks.KhatmItemId)
                .ToList()
        });
    }

    [HttpGet("{userId}/score")]
    public async Task<IActionResult> GetScore(int userId)
    {
        var totalScore = await _db.UserTotalScores
            .FirstOrDefaultAsync(ts => ts.UserId == userId);

        if (totalScore == null)
        {
            return NotFound(new { message = "کاربر یافت نشد." });
        }

        return Ok(new UserScoreResponse
        {
            TotalScore = totalScore.TotalPoints
        });
    }

    private static string GenerateTrackingCode()
    {
        var random = new Random();
        return random.Next(1000, 10000).ToString();
    }
}