using System.Security.Claims;
using Backend.Data;
using Backend.Dtos;
using Backend.Models;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace Backend.Controllers;

[ApiController]
[Route("api/todos")]
[Authorize]
public class TodosController(AppDbContext db) : ControllerBase
{
    private Guid CurrentUserId()
    {
        var sub = User.FindFirstValue("sub")
            ?? throw new InvalidOperationException("Authenticated request missing 'sub' claim");
        return Guid.Parse(sub);
    }

    [HttpGet]
    public async Task<ActionResult<IEnumerable<TodoDto>>> List()
    {
        var userId = CurrentUserId();
        var todos = await db.Todos
            .Where(t => t.UserId == userId)
            .OrderByDescending(t => t.CreatedAt)
            .Select(t => new TodoDto(t.Id, t.Title, t.Completed, t.CreatedAt))
            .ToListAsync();
        return Ok(todos);
    }

    [HttpPost]
    public async Task<ActionResult<TodoDto>> Create([FromBody] CreateTodoRequest body)
    {
        if (!ModelState.IsValid) return ValidationProblem(ModelState);

        var userId = CurrentUserId();
        var todo = new Todo
        {
            UserId = userId,
            Title = body.Title,
            Completed = false,
            CreatedAt = DateTimeOffset.UtcNow
        };
        db.Todos.Add(todo);
        await db.SaveChangesAsync();

        var dto = new TodoDto(todo.Id, todo.Title, todo.Completed, todo.CreatedAt);
        return CreatedAtAction(nameof(List), new { id = todo.Id }, dto);
    }

    [HttpPatch("{id:long}")]
    public async Task<ActionResult<TodoDto>> Update(long id, [FromBody] UpdateTodoRequest body)
    {
        var userId = CurrentUserId();
        var todo = await db.Todos.FirstOrDefaultAsync(t => t.Id == id && t.UserId == userId);
        if (todo is null) return NotFound();

        if (body.Completed.HasValue) todo.Completed = body.Completed.Value;
        await db.SaveChangesAsync();

        return Ok(new TodoDto(todo.Id, todo.Title, todo.Completed, todo.CreatedAt));
    }

    [HttpDelete("{id:long}")]
    public async Task<IActionResult> Delete(long id)
    {
        var userId = CurrentUserId();
        var affected = await db.Todos
            .Where(t => t.Id == id && t.UserId == userId)
            .ExecuteDeleteAsync();
        return affected == 0 ? NotFound() : NoContent();
    }
}