package hdkeychain_test

import (
	"fmt"
	
	"github.com/p9c/p9/pkg/chaincfg"
	"github.com/p9c/p9/pkg/util/hdkeychain"
)

// This example demonstrates how to generate a cryptographically random seed then use it to create a new master node
// (extended key).
func ExampleNewMaster() {
	// Generate a random seed at the recommended length.
	seed, e := hdkeychain.GenerateSeed(hdkeychain.RecommendedSeedLen)
	if e != nil {
		return
	}
	// Generate a new master node using the seed.
	key, e := hdkeychain.NewMaster(seed, &chaincfg.MainNetParams)
	if e != nil {
		return
	}
	// Show that the generated master node extended key is private.
	fmt.Println("Private Extended Key?:", key.IsPrivate())
	// Output:
	// Private Extended Key?: true
}

// This example demonstrates the default hierarchical deterministic wallet layout as described in BIP0032.
func Example_defaultWalletLayout() {
	// The default wallet layout described in BIP0032 is:
	//
	// Each account is composed of two keypair chains: an internal and an external one. The external keychain is used to
	// generate new public addresses, while the internal keychain is used for all other operations (change addresses,
	// generation addresses, ..., anything that doesn't need to be communicated).
	//
	//   * m/iH/0/k
	//
	//   corresponds to the k'th keypair of the external chain of account number i of the HDW derived from master m.
	//
	//   * m/iH/1/k
	//
	//   corresponds to the k'th keypair of the internal chain of account number i of the HDW derived from master m.
	//
	// Ordinarily this would either be read from some encrypted source and be decrypted or generated as the NewMaster
	// example shows, but for the purposes of this example, the private extended key for the master node is being hard
	// coded here.
	master := "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"
	// Start by getting an extended key instance for the master node. This gives the path: m
	masterKey, e := hdkeychain.NewKeyFromString(master)
	if e != nil {
		return
	}
	// Derive the extended key for account 0.  This gives the path: m/0H
	acct0, e := masterKey.Child(hdkeychain.HardenedKeyStart + 0)
	if e != nil {
		return
	}
	// Derive the extended key for the account 0 external chain.  This gives the path:   m/0H/0
	acct0Ext, e := acct0.Child(0)
	if e != nil {
		return
	}
	// Derive the extended key for the account 0 internal chain.  This gives the path: m/0H/1
	acct0Int, e := acct0.Child(1)
	if e != nil {
		return
	}
	// At this point, acct0Ext and acct0Int are ready to derive the keys for the external and internal wallet chains.
	// Derive the 10th extended key for the account 0 external chain. This gives the path: m/0H/0/10
	acct0Ext10, e := acct0Ext.Child(10)
	if e != nil {
		return
	}
	// Derive the 1st extended key for the account 0 internal chain.  This gives the path:   m/0H/1/0
	acct0Int0, e := acct0Int.Child(0)
	if e != nil {
		return
	}
	// Get and show the address associated with the extended keys for the main bitcoin	network.
	acct0ExtAddr, e := acct0Ext10.Address(&chaincfg.MainNetParams)
	if e != nil {
		return
	}
	acct0IntAddr, e := acct0Int0.Address(&chaincfg.MainNetParams)
	if e != nil {
		return
	}
	fmt.Println("Account 0 External Address 10:", acct0ExtAddr)
	fmt.Println("Account 0 Internal Address 0:", acct0IntAddr)
	// Output:
	// Account 0 External Address 10: aV29NZpQZkh7ByDPhP4NR7nzx56crLAvTF
	// Account 0 Internal Address 0: aUWmaTQVFwTV6wwQYvyyQRAvWeQmAorqAV
}

// This example demonstrates the audits use case in BIP0032.
func Example_audits() {
	// The audits use case described in BIP0032 is://
	//
	// In case an auditor needs full access to the list of incoming and outgoing payments, one can share all account
	// public extended keys. This will allow the auditor to see all transactions from and to the wallet, in all
	// accounts, but not a single secret key.
	//
	//   * N(m/*)
	//
	//   corresponds to the neutered master extended key (also called the master public extended key) Ordinarily this
	//   would either be read from some encrypted source and be decrypted or generated as the NewMaster example shows, but
	//   for the purposes of this example, the private extended key for the master node is being hard coded here.
	master := "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"
	// Start by getting an extended key instance for the master node. This gives the path:
	//
	//   m
	masterKey, e := hdkeychain.NewKeyFromString(master)
	if e != nil {
		return
	}
	// Neuter the master key to generate a master public extended key.  This gives the path:   N(m/*)
	masterPubKey, e := masterKey.Neuter()
	if e != nil {
		return
	}
	// Share the master public extended key with the auditor.
	fmt.Println("Audit key N(m/*):", masterPubKey)
	// Output:
	// Audit key N(m/*): xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EGMcet8
}