package pgUtils

import (
	"context"
	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/matchsystems/werr"
)

type PgxQuerier interface {
	Query(ctx context.Context, sql string, args ...any) (pgx.Rows, error)
}

// Query executes query on a provided querier and tries to parse db response
// Works only with structs
//
// Usage:
//
//	type User struct {
//	  Id   int    `db:"id"`
//	  Name string `db:"name"`
//	}
//
//	db := pgx.Connect(context.Background(), "<url>")
//	users, err := pgUtils.Query[User](context.Background(), db, "SELECT id, name FROM users")
func Query[T any](ctx context.Context, db PgxQuerier, query string, args ...any) (out []T, err error) {
	rows, err := db.Query(ctx, query, args)
	if err != nil {
		return nil, err
	}
	entities, err := pgx.CollectRows(rows, pgx.RowToStructByNameLax[T])
	if err != nil {
		return nil, werr.Wrapf(err, "failed to parse query results")
	}
	return entities, nil
}

// Tx creates new transaction. Cancels it if returned not nil err
func Tx(ctx context.Context, db *pgxpool.Pool, exec func(ctx context.Context, tx pgx.Tx) error) error {
	tx, err := db.Begin(ctx)
	if err != nil {
		return err
	}
	err = exec(ctx, tx)
	if err != nil {
		_ = tx.Rollback(ctx)
		return err
	}
	return tx.Commit(ctx)
}