package db

import (
	"context"
	"database/sql"

	"github.com/pkg/errors"
	"github.com/uptrace/bun"
)

type deleter[T any] struct {
	q *bun.DeleteQuery
}

type systemType interface {
	isSystem() bool
}

func DeleteItem[T any](tx bun.Tx) *deleter[T] {
	return &deleter[T]{
		tx.NewDelete().
			Model((*T)(nil)),
	}
}

func (d *deleter[T]) Where(query string, args ...any) *deleter[T] {
	d.q = d.q.Where(query, args...)
	return d
}

func (d *deleter[T]) Delete(ctx context.Context) error {
	_, err := d.q.Exec(ctx)
	if err != nil {
		if err == sql.ErrNoRows {
			return nil
		}
	}
	return errors.Wrap(err, "bun.DeleteQuery.Exec")
}

func DeleteByID[T any](tx bun.Tx, id int) *deleter[T] {
	return DeleteItem[T](tx).Where("id = ?", id)
}

func DeleteWithProtection[T systemType](ctx context.Context, tx bun.Tx, id int) error {
	deleter := DeleteByID[T](tx, id)
	item, err := GetByID[T](tx, id).GetFirst(ctx)
	if err != nil {
		return errors.Wrap(err, "GetByID")
	}
	if item == nil {
		return errors.New("record not found")
	}
	if (*item).isSystem() {
		return errors.New("record is system protected")
	}
	return deleter.Delete(ctx)
}