package exec

import (
	"database/sql"
	"errors"
	"reflect"

	"git.gdulai.com/gdulai/simpleorm"
	"git.gdulai.com/gdulai/simpleorm/schema"
	log "gitlab.com/gdulai/simpleloglvl"
)

type Update[T any] struct {
	target   schema.Table
	toUpdate T
}

func NewUpdate[T any](orm *simpleorm.ORM, toUpdate T) (Update[T], error) {
	table, ok := orm.Cache().Get(reflect.TypeFor[T]().Name())
	if !ok {
		return Update[T]{}, errors.New("Failed to get table from schema cache")
	}

	return Update[T]{target: *table, toUpdate: toUpdate}, nil
}

func (u Update[T]) Execute(conn *simpleorm.DBConnection) error {
	return u.execute(conn, nil)
}

func (u Update[T]) execute(conn *simpleorm.DBConnection, tx *sql.Tx) error {
	dml, err := u.target.GetUpdateDML()
	if err != nil {
		return err
	}

	params := prepareParams(u.toUpdate, u.target)

	pkCols, err := getPk(u.toUpdate, u.target)
	if err != nil {
		return err
	}
	// Put the pks back at the end
	for _, pk := range pkCols {
		params = append(params, pk)
	}

	log.LogDebug("%s [%s]", dml, params)

	var stmt *sql.Stmt
	if tx != nil {
		stmt, err = tx.Prepare(dml)
	} else {
		stmt, err = conn.Prepare(dml)
	}
	defer stmt.Close()

	result, err := stmt.Exec(params...)
	if err != nil {
		return err
	} else {
		rowsAffected, _ := result.RowsAffected()
		log.LogInfo("Updated %s row", rowsAffected)
	}
	return nil
}