using AutoMapper;
using MediatR;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using mws.backend.dotnet.application.Common;
using mws.backend.dotnet.application.Permissions;
using mws.backend.dotnet.application.Users;
using mws.backend.dotnet.domain.Users;
using mws.backend.dotnet.infrastructure.Persistence;

namespace mws.backend.dotnet.api.Controllers;

[ApiController]
[Route("api/users")]
[Authorize]
public class UsersController(ISender sender, AppDbContext db, IPermissionService permissions, IMapper mapper) : ControllerBase
{
    [HttpGet]
    public async Task<ActionResult<PagedResult<UserDto>>> GetAll(
        [FromQuery] string? q, [FromQuery] bool? isActive, [FromQuery] int page = 1, [FromQuery] int pageSize = 20, CancellationToken ct = default)
    {
        var filter = new UserListFilter(q, isActive);
        return Ok(await sender.Send(new GetUsersQuery(User.GetUserId(), filter, page, pageSize), ct));
    }

    [HttpPost]
    public async Task<ActionResult<UserDto>> Create([FromBody] CreateUserRequest request, CancellationToken ct)
    {
        return Ok(await sender.Send(new CreateUserCommand(User.GetUserId(), request), ct));
    }

    [HttpPut("{id:guid}")]
    public async Task<ActionResult<UserDto>> Update(Guid id, [FromBody] UpdateUserRequest request, CancellationToken ct)
    {
        return Ok(await sender.Send(new UpdateUserCommand(User.GetUserId(), id, request), ct));
    }

    [HttpDelete("{id:guid}")]
    public async Task<IActionResult> Delete(Guid id, CancellationToken ct)
    {
        await sender.Send(new DeleteUserCommand(User.GetUserId(), id), ct);
        return NoContent();
    }

    [HttpPost("{id:guid}/reset-password")]
    public async Task<IActionResult> ResetPassword(Guid id, [FromBody] ResetPasswordRequest request, CancellationToken ct)
    {
        await sender.Send(new ResetPasswordCommand(User.GetUserId(), id, request), ct);
        return NoContent();
    }

    [HttpGet("list")]
    public async Task<ActionResult<List<UserDto>>> GetList([FromQuery] string? q, CancellationToken ct)
    {
        var query = db.Users.AsQueryable();
        if (!string.IsNullOrWhiteSpace(q))
        {
            var lower = q.Trim().ToLower();
            query = query.Where(u => u.Username.ToLower().Contains(lower) || u.DisplayName.ToLower().Contains(lower));
        }

        var users = await query.OrderBy(u => u.DisplayName).ToListAsync(ct);
        return Ok(mapper.Map<List<UserDto>>(users));
    }

    [HttpGet("{id:guid}/roles")]
    public async Task<ActionResult<UserRoleDetailDto>> GetUserRoles(Guid id, CancellationToken ct)
    {
        await permissions.EnsureAsync(User.GetUserId(), "permissions", PermissionAction.View, ct);

        var user = await db.Users
            .Include(u => u.UserRoles)
            .ThenInclude(ur => ur.Role)
            .FirstOrDefaultAsync(u => u.Id == id, ct);

        if (user is null) return NotFound("User not found");

        var allRoles = await db.Roles.Include(r => r.Permissions).OrderBy(r => r.Name).ToListAsync(ct);
        var assignedRoleIds = user.UserRoles.Select(ur => ur.RoleId).ToHashSet();

        var assigned = allRoles.Where(r => assignedRoleIds.Contains(r.Id)).ToList();
        var unassigned = allRoles.Where(r => !assignedRoleIds.Contains(r.Id)).ToList();

        return Ok(new UserRoleDetailDto
        {
            UserId = user.Id,
            Username = user.Username,
            DisplayName = user.DisplayName,
            AssignedRoles = mapper.Map<List<RoleDto>>(assigned),
            UnassignedRoles = mapper.Map<List<RoleDto>>(unassigned)
        });
    }

    [HttpPost("{id:guid}/roles")]
    public async Task<IActionResult> AssignRole(Guid id, [FromBody] AssignRoleRequest req, CancellationToken ct)
    {
        await permissions.EnsureAsync(User.GetUserId(), "permissions", PermissionAction.Edit, ct);

        var user = await db.Users.Include(u => u.UserRoles).FirstOrDefaultAsync(u => u.Id == id, ct);
        if (user is null) return NotFound("User not found");

        if (!user.UserRoles.Any(ur => ur.RoleId == req.RoleId))
        {
            user.UserRoles.Add(new UserRole { UserId = id, RoleId = req.RoleId });
            await db.SaveChangesAsync(ct);
        }

        return NoContent();
    }

    [HttpDelete("{id:guid}/roles/{roleId:guid}")]
    public async Task<IActionResult> UnassignRole(Guid id, Guid roleId, CancellationToken ct)
    {
        await permissions.EnsureAsync(User.GetUserId(), "permissions", PermissionAction.Edit, ct);

        var ur = await db.UserRoles.FirstOrDefaultAsync(x => x.UserId == id && x.RoleId == roleId, ct);
        if (ur != null)
        {
            db.UserRoles.Remove(ur);
            await db.SaveChangesAsync(ct);
        }

        return NoContent();
    }

    [HttpGet("{id:guid}/permissions")]
    public async Task<ActionResult<List<MenuItemDto>>> GetUserPermissions(Guid id, CancellationToken ct)
    {
        await permissions.EnsureAsync(User.GetUserId(), "permissions", PermissionAction.View, ct);

        var roleIds = await db.UserRoles.Where(ur => ur.UserId == id).Select(ur => ur.RoleId).ToListAsync(ct);
        var permissionsList = await db.RolePermissions.Where(p => roleIds.Contains(p.RoleId)).ToListAsync(ct);

        var merged = permissionsList.GroupBy(p => p.Screen).ToDictionary(
            g => g.Key,
            g => new
            {
                CanView = g.Any(p => p.CanView),
                CanCreate = g.Any(p => p.CanCreate),
                CanEdit = g.Any(p => p.CanEdit),
                CanDelete = g.Any(p => p.CanDelete),
            }
        );

        var res = ScreenCatalog.Screens.Select(s =>
        {
            merged.TryGetValue(s.Key, out var p);
            return new MenuItemDto
            {
                Key = s.Key,
                Label = s.Label,
                Path = s.Path,
                CanView = p?.CanView ?? false,
                CanCreate = p?.CanCreate ?? false,
                CanEdit = p?.CanEdit ?? false,
                CanDelete = p?.CanDelete ?? false,
            };
        }).ToList();

        return Ok(res);
    }
}