// Adds a coin.Transaction to the pool, or updates an existing one's timestamps
// Returns an error if txn is invalid, and whether the transaction already
// existed in the pool.
func (self *UnconfirmedTxnPool) RecordTxn(bc *coin.Blockchain,
	t coin.Transaction, addrs map[coin.Address]byte, maxSize int,
	burnFactor uint64) (error, bool) {
	if err := VerifyTransaction(bc, &t, maxSize, burnFactor); err != nil {
		return err, false
	}
	if err := bc.VerifyTransaction(t); err != nil {
		return err, false
	}

	// Update if we already have this txn
	ut, ok := self.Txns[t.Hash()]
	if ok {
		now := util.Now()
		ut.Received = now
		ut.Checked = now
		self.Txns[ut.Txn.Hash()] = ut
		return nil, true
	}

	// Add txn to index
	self.Txns[t.Hash()] = self.createUnconfirmedTxn(&bc.Unspent, t, addrs)
	// Add predicted unspents
	uxs := coin.CreateExpectedUnspents(t)
	for i, _ := range uxs {
		self.Unspent.Add(uxs[i])
	}

	return nil, false
}

// Adds a coin.Transaction to the pool, or updates an existing one's timestamps
// Returns an error if txn is invalid, and whether the transaction already
// existed in the pool.
func (self *UnconfirmedTxnPool) RecordTxn(bc *coin.Blockchain,
	t coin.Transaction, addrs map[cipher.Address]byte, maxSize int,
	burnFactor uint64) (error, bool) {
	if err := VerifyTransaction(bc, &t, maxSize, burnFactor); err != nil {
		return err, false
	}
	if err := bc.VerifyTransaction(t); err != nil {
		return err, false
	}

	// Update if we already have this txn
	h := t.Hash()
	ut, ok := self.Txns[h]
	if ok {
		now := util.Now()
		ut.Received = now
		ut.Checked = now
		self.Txns[h] = ut
		return nil, true
	}

	// Add txn to index
	self.Txns[h] = self.createUnconfirmedTxn(&bc.Unspent, t, addrs)
	// Add predicted unspents
	self.Unspent[h] = coin.CreateUnspents(bc.Head().Head, t)

	return nil, false
}

// Adds a coin.Transaction to the pool, or updates an existing one's timestamps
// Returns an error if txn is invalid, and whether the transaction already
// existed in the pool.
func (self *UnconfirmedTxnPool) InjectTxn(bc *coin.Blockchain,
	t coin.Transaction) (error, bool) {

	if err := t.Verify(); err != nil {
		return err, false
	}

	if err := VerifyTransactionFee(bc, &t); err != nil {
		return err, false
	}
	if err := bc.VerifyTransaction(t); err != nil {
		return err, false
	}

	// Update if we already have this txn
	h := t.Hash()
	ut, ok := self.Txns[h]
	if ok {
		now := util.Now()
		ut.Received = now
		ut.Checked = now
		self.Txns[h] = ut
		return nil, true
	}

	// Add txn to index
	self.Txns[h] = self.createUnconfirmedTxn(&bc.Unspent, t)
	// Add predicted unspents
	self.Unspent[h] = coin.CreateUnspents(bc.Head().Head, t)

	return nil, false
}

func assertValidUnspent(t *testing.T, bc *coin.Blockchain,
	unspent *coin.UnspentPool, tx coin.Transaction) {
	expect := bc.TxUxOut(tx, coin.BlockHeader{})
	assert.NotEqual(t, len(expect), 0)
	assert.Equal(t, len(expect), len(unspent.Arr))
	for _, ux := range expect {
		assert.True(t, unspent.Has(ux.Hash()))
	}
}

// Performs additional transaction verification at the unconfirmed pool level.
// This checks tunable parameters that should prevent the transaction from
// entering the blockchain, but cannot be done at the blockchain level because
// they may be changed.
func VerifyTransaction(bc *coin.Blockchain, t *coin.Transaction, maxSize int,
	burnFactor uint64) error {
	if t.Size() > maxSize {
		return errors.New("Transaction too large")
	}
	if fee, err := bc.TransactionFee(t); err != nil {
		return err
	} else if burnFactor != 0 && t.OutputHours()/burnFactor > fee {
		return errors.New("Transaction fee minimum not met")
	}
	return nil
}

// Performs additional transaction verification at the unconfirmed pool level.
// This checks tunable parameters that should prevent the transaction from
// entering the blockchain, but cannot be done at the blockchain level because
// they may be changed.
func VerifyTransactionFee(bc *coin.Blockchain, t *coin.Transaction) error {
	fee, err := bc.TransactionFee(t)
	if err != nil {
		return err
	}

	//calculate total number of coinhours
	var total uint64 = t.OutputHours() + fee
	//make sure at least half the coin hours are destroyed
	if fee < total/BurnFactor {
		return errors.New("Transaction coinhour fee minimum not met")
	}
	return nil
}

// Checks all unconfirmed txns against the blockchain. maxAge is how long
// we'll hold a txn regardless of whether it has been invalidated.
// checkPeriod is how often we check the txn against the blockchain.
func (self *UnconfirmedTxnPool) Refresh(bc *coin.Blockchain, checkPeriod int) {
	now := time.Now().Unix()
	toRemove := make([]cipher.SHA256, 0)
	for k, t := range self.Txns {
		if now-t.Checked >= int64(checkPeriod) {
			if bc.VerifyTransaction(t.Txn) == nil {
				t.Checked = now
				self.Txns[k] = t
			} else {
				toRemove = append(toRemove, k)
			}
		}
	}
	self.removeTxns(toRemove)
}

// Checks all unconfirmed txns against the blockchain. maxAge is how long
// we'll hold a txn regardless of whether it has been invalidated.
// checkPeriod is how often we check the txn against the blockchain.
func (self *UnconfirmedTxnPool) Refresh(bc *coin.Blockchain,
	checkPeriod, maxAge time.Duration) {
	now := util.Now()
	toRemove := make([]coin.SHA256, 0)
	for k, t := range self.Txns {
		if now.Sub(t.Received) >= maxAge {
			toRemove = append(toRemove, k)
		} else if now.Sub(t.Checked) >= checkPeriod {
			if bc.VerifyTransaction(t.Txn) == nil {
				t.Checked = now
				self.Txns[k] = t
			} else {
				toRemove = append(toRemove, k)
			}
		}
	}
	self.removeTxns(bc, toRemove)
}

func assertValidUnspent(t *testing.T, bc *coin.Blockchain,
	unspent TxnUnspents, tx coin.Transaction) {
	expect := coin.CreateUnspents(bc.Head().Head, tx)
	assert.NotEqual(t, len(expect), 0)
	sum := 0
	for _, uxs := range unspent {
		sum += len(uxs)
	}
	assert.Equal(t, len(expect), sum)
	uxs := unspent[tx.Hash()]
	for _, ux := range expect {
		found := false
		for _, u := range uxs {
			if u.Hash() == ux.Hash() {
				found = true
				break
			}
		}
		assert.True(t, found)
	}
}