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 KhatmController : ControllerBase
{
    private readonly AppDbContext _db;

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

    [HttpGet("items")]
    public async Task<IActionResult> GetItems()
    {
        var items = await _db.KhatmItems
            .OrderBy(k => k.Id)
            .Select(k => new KhatmItemDto
            {
                Id = k.Id,
                Title = k.Title,
                Url = k.Url,
                Points = k.Points
            })
            .ToListAsync();

        return Ok(items);
    }

    [HttpPost("save")]
    public async Task<IActionResult> SaveSelections([FromBody] KhatmSaveRequest request)
    {
        var user = await _db.Users.FindAsync(request.UserId);
        if (user == null)
        {
            return NotFound(new { message = "کاربر یافت نشد." });
        }

        foreach (var selection in request.Selections)
        {
            var existing = await _db.UserKhatmSelections
                .FirstOrDefaultAsync(ks => ks.UserId == request.UserId && ks.KhatmItemId == selection.KhatmItemId);

            if (existing != null)
            {
                existing.IsSelected = selection.IsSelected;
                existing.LastModified = DateTime.UtcNow;
            }
            else
            {
                _db.UserKhatmSelections.Add(new UserKhatmSelection
                {
                    UserId = request.UserId,
                    KhatmItemId = selection.KhatmItemId,
                    IsSelected = selection.IsSelected,
                    LastModified = DateTime.UtcNow
                });
            }
        }

        // Recalculate total score
        await RecalculateTotalScore(request.UserId);
        await _db.SaveChangesAsync();

        var totalScore = await _db.UserTotalScores
            .Where(ts => ts.UserId == request.UserId)
            .Select(ts => ts.TotalPoints)
            .FirstOrDefaultAsync();

        return Ok(new KhatmSaveResponse
        {
            Success = true,
            TotalScore = totalScore
        });
    }

    private async Task RecalculateTotalScore(int userId)
    {
        var quizPoints = await _db.UserQuizAttempts
            .Where(qa => qa.UserId == userId)
            .Select(qa => (int?)qa.TotalQuizPoints)
            .FirstOrDefaultAsync() ?? 0;

        var khatmPoints = await _db.UserKhatmSelections
            .Where(ks => ks.UserId == userId && ks.IsSelected)
            .SumAsync(ks => ks.KhatmItem.Points);

        int total = quizPoints + khatmPoints;

        var totalScore = await _db.UserTotalScores
            .FirstOrDefaultAsync(ts => ts.UserId == userId);

        if (totalScore != null)
        {
            totalScore.TotalPoints = total;
        }
    }
}