package with

import (
	"context"
	"database/sql"
)

type SQLKV struct {
	db *sql.DB
}

func KV(ctx context.Context, db *sql.DB, foo func(SQLKV) error) error {
	if _, err := db.ExecContext(ctx, `
		CREATE TABLE IF NOT EXISTS with_kv(
			k TEXT PRIMARY KEY
			, v TEXT
		)
	`); err != nil {
		return err
	}

	return foo(SQLKV{db: db})
}

func (kv SQLKV) Get(ctx context.Context, k string) ([]byte, error) {
	row := kv.db.QueryRowContext(ctx, `
		SELECT v FROM with_kv WHERE k=$1
	`, k)

	var v []byte
	if err := row.Scan(&v); err != nil {
		return nil, err
	}

	return v, row.Err()
}

func (kv SQLKV) Set(ctx context.Context, k string, v []byte) error {
	_, err := kv.db.ExecContext(ctx, `
		INSERT INTO with_kv
		(k, v) VALUES ($1, $2)
		ON CONFLICT DO UPDATE
		SET v=$2 WHERE k=$1
	`, k, v)
	return err
}