package bloom_test

import (
	"fmt"
	"math/rand"
	"time"
	
	"github.com/p9c/p9/pkg/bloom"
	"github.com/p9c/p9/pkg/chainhash"
	"github.com/p9c/p9/pkg/wire"
)

// This example demonstrates how to create a new bloom filter, add a transaction hash to it, and check if the filter
// matches the transaction.
func ExampleNewFilter() {
	rand.Seed(time.Now().UnixNano())
	tweak := rand.Uint32()
	// Create a new bloom filter intended to hold 10 elements with a 0.01% false positive rate and does not include any
	// automatic update functionality when transactions are matched.
	filter := bloom.NewFilter(10, tweak, 0.0001, wire.BloomUpdateNone)
	// Create a transaction hash and add it to the filter. This particular trasaction is the first transaction in block
	// 310,000 of the main bitcoin block chain.
	txHashStr := "fd611c56ca0d378cdcd16244b45c2ba9588da3adac367c4ef43e808b280b8a45"
	txHash, e := chainhash.NewHashFromStr(txHashStr)
	if e != nil {
		fmt.Println(e)
		return
	}
	filter.AddHash(txHash)
	// Show that the filter matches.
	matches := filter.Matches(txHash[:])
	fmt.Println("Filter Matches?:", matches)
	// Output:
	// Filter Matches?: true
}