package operator

import (
	"context"
	"database/sql"

	"amadan.net/rastrillo/rastrillo/migrate"
)

func VerifyLedger(ctx context.Context, c *sql.Conn, set *migrate.Set) error {
	if c == nil || set == nil {
		return ErrRefused
	}
	expected := map[string]string{}
	for _, m := range set.All() {
		if m.Fn != nil {
			return ErrRefused
		}
		expected[m.ID] = migrate.Checksum(m.SQL)
	}
	rows, e := c.QueryContext(ctx, "SELECT id,checksum FROM rastrillo_migrations LIMIT 1001")
	if e != nil {
		return ErrRefused
	}
	for rows.Next() {
		var id, sum string
		if rows.Scan(&id, &sum) != nil || expected[id] == "" || expected[id] != sum {
			rows.Close()
			return ErrRefused
		}
		delete(expected, id)
	}
	if rows.Err() != nil || rows.Close() != nil || len(expected) != 0 {
		return ErrRefused
	}
	return nil
}