package store

import (
	"context"
	"errors"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
	"vpn-panel/internal/models"
)

var ErrAdminExists = errors.New("администратор уже зарегистрирован")

type UserStore struct {
	pool *pgxpool.Pool
}

func NewUserStore(pool *pgxpool.Pool) *UserStore {
	return &UserStore{pool: pool}
}

func (s *UserStore) HasAdmin(ctx context.Context) (bool, error) {
	var n int
	err := s.pool.QueryRow(ctx,
		`SELECT COUNT(*) FROM users WHERE role = 'admin'`,
	).Scan(&n)
	return n > 0, err
}

func (s *UserStore) CreateAdmin(ctx context.Context, email, passwordHash string) (*models.User, error) {
	has, err := s.HasAdmin(ctx)
	if err != nil {
		return nil, err
	}
	if has {
		return nil, ErrAdminExists
	}

	var u models.User
	err = s.pool.QueryRow(ctx, `
		INSERT INTO users (email, password_hash, role)
		VALUES ($1, $2, 'admin')
		RETURNING id, email, password_hash, role, created_at
	`, email, passwordHash).Scan(
		&u.ID, &u.Email, &u.PasswordHash, &u.Role, &u.CreatedAt,
	)
	if err != nil {
		return nil, err
	}
	return &u, nil
}

func (s *UserStore) GetByEmail(ctx context.Context, email string) (*models.User, error) {
	var u models.User
	err := s.pool.QueryRow(ctx, `
		SELECT id, email, password_hash, role, created_at
		FROM users WHERE email = $1
	`, email).Scan(&u.ID, &u.Email, &u.PasswordHash, &u.Role, &u.CreatedAt)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return &u, nil
}

func (s *UserStore) CountUsers(ctx context.Context) (int, error) {
	var n int
	err := s.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users`).Scan(&n)
	return n, err
}

func (s *UserStore) GetAdminID(ctx context.Context) (uuid.UUID, bool, error) {
	var id uuid.UUID
	err := s.pool.QueryRow(ctx,
		`SELECT id FROM users WHERE role = 'admin' LIMIT 1`,
	).Scan(&id)
	if errors.Is(err, pgx.ErrNoRows) {
		return uuid.Nil, false, nil
	}
	if err != nil {
		return uuid.Nil, false, err
	}
	return id, true, nil
}