package types

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"strconv"
	"time"

	sdk "github.com/cosmos/cosmos-sdk/types"
)

const (
	// ModuleName is the name of the staking module
	ModuleName = "staking"

	// StoreKey is the string store representation
	StoreKey = ModuleName

	// QuerierRoute is the querier route for the staking module
	QuerierRoute = ModuleName

	// RouterKey is the msg router key for the staking module
	RouterKey = ModuleName
)

var (
	// Keys for store prefixes
	// Last* values are constant during a block.
	LastValidatorPowerKey = []byte{0x11} // prefix for each key to a validator index, for bonded validators
	LastTotalPowerKey     = []byte{0x12} // prefix for the total power

	ValidatorsKey             = []byte{0x21} // prefix for each key to a validator
	ValidatorsByConsAddrKey   = []byte{0x22} // prefix for each key to a validator index, by pubkey
	ValidatorsByPowerIndexKey = []byte{0x23} // prefix for each key to a validator index, sorted by power

	DelegationKey                    = []byte{0x31} // key for a delegation
	UnbondingDelegationKey           = []byte{0x32} // key for an unbonding-delegation
	UnbondingDelegationByValIndexKey = []byte{0x33} // prefix for each key for an unbonding-delegation, by validator operator
	RedelegationKey                  = []byte{0x34} // key for a redelegation
	RedelegationByValSrcIndexKey     = []byte{0x35} // prefix for each key for an redelegation, by source validator operator
	RedelegationByValDstIndexKey     = []byte{0x36} // prefix for each key for an redelegation, by destination validator operator

	UnbondingQueueKey    = []byte{0x41} // prefix for the timestamps in unbonding queue
	RedelegationQueueKey = []byte{0x42} // prefix for the timestamps in redelegations queue
	ValidatorQueueKey    = []byte{0x43} // prefix for the timestamps in validator queue

	HistoricalInfoKey = []byte{0x50} // prefix for the historical info
)

// gets the key for the validator with address
// VALUE: staking/Validator
func GetValidatorKey(operatorAddr sdk.ValAddress) []byte {
	return append(ValidatorsKey, operatorAddr.Bytes()...)
}

// gets the key for the validator with pubkey
// VALUE: validator operator address ([]byte)
func GetValidatorByConsAddrKey(addr sdk.ConsAddress) []byte {
	return append(ValidatorsByConsAddrKey, addr.Bytes()...)
}

// Get the validator operator address from LastValidatorPowerKey
func AddressFromLastValidatorPowerKey(key []byte) []byte {
	return key[1:] // remove prefix bytes
}

// get the validator by power index.
// Power index is the key used in the power-store, and represents the relative
// power ranking of the validator.
// VALUE: validator operator address ([]byte)
func GetValidatorsByPowerIndexKey(validator Validator) []byte {
	// NOTE the address doesn't need to be stored because counter bytes must always be different
	return getValidatorPowerRank(validator)
}

// get the bonded validator index key for an operator address
func GetLastValidatorPowerKey(operator sdk.ValAddress) []byte {
	return append(LastValidatorPowerKey, operator...)
}

// get the power ranking of a validator
// NOTE the larger values are of higher value
func getValidatorPowerRank(validator Validator) []byte {
	consensusPower := sdk.TokensToConsensusPower(validator.Tokens)
	consensusPowerBytes := make([]byte, 8)
	binary.BigEndian.PutUint64(consensusPowerBytes, uint64(consensusPower))

	powerBytes := consensusPowerBytes
	powerBytesLen := len(powerBytes) // 8

	// key is of format prefix || powerbytes || addrBytes
	key := make([]byte, 1+powerBytesLen+sdk.AddrLen)

	key[0] = ValidatorsByPowerIndexKey[0]
	copy(key[1:powerBytesLen+1], powerBytes)

	operAddrInvr := sdk.CopyBytes(validator.OperatorAddress)

	for i, b := range operAddrInvr {
		operAddrInvr[i] = ^b
	}

	copy(key[powerBytesLen+1:], operAddrInvr)

	return key
}

// parse the validators operator address from power rank key
func ParseValidatorPowerRankKey(key []byte) (operAddr []byte) {
	powerBytesLen := 8
	if len(key) != 1+powerBytesLen+sdk.AddrLen {
		panic("Invalid validator power rank key length")
	}

	operAddr = sdk.CopyBytes(key[powerBytesLen+1:])

	for i, b := range operAddr {
		operAddr[i] = ^b
	}

	return operAddr
}

// GetValidatorQueueKey returns the prefix key used for getting a set of unbonding
// validators whose unbonding completion occurs at the given time and height.
func GetValidatorQueueKey(timestamp time.Time, height int64) []byte {
	heightBz := sdk.Uint64ToBigEndian(uint64(height))
	timeBz := sdk.FormatTimeBytes(timestamp)
	timeBzL := len(timeBz)
	prefixL := len(ValidatorQueueKey)

	bz := make([]byte, prefixL+8+timeBzL+8)

	// copy the prefix
	copy(bz[:prefixL], ValidatorQueueKey)

	// copy the encoded time bytes length
	copy(bz[prefixL:prefixL+8], sdk.Uint64ToBigEndian(uint64(timeBzL)))

	// copy the encoded time bytes
	copy(bz[prefixL+8:prefixL+8+timeBzL], timeBz)

	// copy the encoded height
	copy(bz[prefixL+8+timeBzL:], heightBz)

	return bz
}

// ParseValidatorQueueKey returns the encoded time and height from a key created
// from GetValidatorQueueKey.
func ParseValidatorQueueKey(bz []byte) (time.Time, int64, error) {
	prefixL := len(ValidatorQueueKey)
	if prefix := bz[:prefixL]; !bytes.Equal(prefix, ValidatorQueueKey) {
		return time.Time{}, 0, fmt.Errorf("invalid prefix; expected: %X, got: %X", ValidatorQueueKey, prefix)
	}

	timeBzL := sdk.BigEndianToUint64(bz[prefixL : prefixL+8])
	ts, err := sdk.ParseTimeBytes(bz[prefixL+8 : prefixL+8+int(timeBzL)])
	if err != nil {
		return time.Time{}, 0, err
	}

	height := sdk.BigEndianToUint64(bz[prefixL+8+int(timeBzL):])

	return ts, int64(height), nil
}

// gets the key for delegator bond with validator
// VALUE: staking/Delegation
func GetDelegationKey(delAddr sdk.AccAddress, valAddr sdk.ValAddress) []byte {
	return append(GetDelegationsKey(delAddr), valAddr.Bytes()...)
}

// gets the prefix for a delegator for all validators
func GetDelegationsKey(delAddr sdk.AccAddress) []byte {
	return append(DelegationKey, delAddr.Bytes()...)
}

// gets the key for an unbonding delegation by delegator and validator addr
// VALUE: staking/UnbondingDelegation
func GetUBDKey(delAddr sdk.AccAddress, valAddr sdk.ValAddress) []byte {
	return append(
		GetUBDsKey(delAddr.Bytes()),
		valAddr.Bytes()...)
}

// gets the index-key for an unbonding delegation, stored by validator-index
// VALUE: none (key rearrangement used)
func GetUBDByValIndexKey(delAddr sdk.AccAddress, valAddr sdk.ValAddress) []byte {
	return append(GetUBDsByValIndexKey(valAddr), delAddr.Bytes()...)
}

// rearranges the ValIndexKey to get the UBDKey
func GetUBDKeyFromValIndexKey(indexKey []byte) []byte {
	addrs := indexKey[1:] // remove prefix bytes
	if len(addrs) != 2*sdk.AddrLen {
		panic("unexpected key length")
	}

	valAddr := addrs[:sdk.AddrLen]
	delAddr := addrs[sdk.AddrLen:]

	return GetUBDKey(delAddr, valAddr)
}

// gets the prefix for all unbonding delegations from a delegator
func GetUBDsKey(delAddr sdk.AccAddress) []byte {
	return append(UnbondingDelegationKey, delAddr.Bytes()...)
}

// gets the prefix keyspace for the indexes of unbonding delegations for a validator
func GetUBDsByValIndexKey(valAddr sdk.ValAddress) []byte {
	return append(UnbondingDelegationByValIndexKey, valAddr.Bytes()...)
}

// gets the prefix for all unbonding delegations from a delegator
func GetUnbondingDelegationTimeKey(timestamp time.Time) []byte {
	bz := sdk.FormatTimeBytes(timestamp)
	return append(UnbondingQueueKey, bz...)
}

// GetREDKey returns a key prefix for indexing a redelegation from a delegator
// and source validator to a destination validator.
func GetREDKey(delAddr sdk.AccAddress, valSrcAddr, valDstAddr sdk.ValAddress) []byte {
	key := make([]byte, 1+sdk.AddrLen*3)

	copy(key[0:sdk.AddrLen+1], GetREDsKey(delAddr.Bytes()))
	copy(key[sdk.AddrLen+1:2*sdk.AddrLen+1], valSrcAddr.Bytes())
	copy(key[2*sdk.AddrLen+1:3*sdk.AddrLen+1], valDstAddr.Bytes())

	return key
}

// gets the index-key for a redelegation, stored by source-validator-index
// VALUE: none (key rearrangement used)
func GetREDByValSrcIndexKey(delAddr sdk.AccAddress, valSrcAddr, valDstAddr sdk.ValAddress) []byte {
	REDSFromValsSrcKey := GetREDsFromValSrcIndexKey(valSrcAddr)
	offset := len(REDSFromValsSrcKey)

	// key is of the form REDSFromValsSrcKey || delAddr || valDstAddr
	key := make([]byte, len(REDSFromValsSrcKey)+2*sdk.AddrLen)
	copy(key[0:offset], REDSFromValsSrcKey)
	copy(key[offset:offset+sdk.AddrLen], delAddr.Bytes())
	copy(key[offset+sdk.AddrLen:offset+2*sdk.AddrLen], valDstAddr.Bytes())

	return key
}

// gets the index-key for a redelegation, stored by destination-validator-index
// VALUE: none (key rearrangement used)
func GetREDByValDstIndexKey(delAddr sdk.AccAddress, valSrcAddr, valDstAddr sdk.ValAddress) []byte {
	REDSToValsDstKey := GetREDsToValDstIndexKey(valDstAddr)
	offset := len(REDSToValsDstKey)

	// key is of the form REDSToValsDstKey || delAddr || valSrcAddr
	key := make([]byte, len(REDSToValsDstKey)+2*sdk.AddrLen)
	copy(key[0:offset], REDSToValsDstKey)
	copy(key[offset:offset+sdk.AddrLen], delAddr.Bytes())
	copy(key[offset+sdk.AddrLen:offset+2*sdk.AddrLen], valSrcAddr.Bytes())

	return key
}

// GetREDKeyFromValSrcIndexKey rearranges the ValSrcIndexKey to get the REDKey
func GetREDKeyFromValSrcIndexKey(indexKey []byte) []byte {
	// note that first byte is prefix byte
	if len(indexKey) != 3*sdk.AddrLen+1 {
		panic("unexpected key length")
	}

	valSrcAddr := indexKey[1 : sdk.AddrLen+1]
	delAddr := indexKey[sdk.AddrLen+1 : 2*sdk.AddrLen+1]
	valDstAddr := indexKey[2*sdk.AddrLen+1 : 3*sdk.AddrLen+1]

	return GetREDKey(delAddr, valSrcAddr, valDstAddr)
}

// GetREDKeyFromValDstIndexKey rearranges the ValDstIndexKey to get the REDKey
func GetREDKeyFromValDstIndexKey(indexKey []byte) []byte {
	// note that first byte is prefix byte
	if len(indexKey) != 3*sdk.AddrLen+1 {
		panic("unexpected key length")
	}

	valDstAddr := indexKey[1 : sdk.AddrLen+1]
	delAddr := indexKey[sdk.AddrLen+1 : 2*sdk.AddrLen+1]
	valSrcAddr := indexKey[2*sdk.AddrLen+1 : 3*sdk.AddrLen+1]

	return GetREDKey(delAddr, valSrcAddr, valDstAddr)
}

// GetRedelegationTimeKey returns a key prefix for indexing an unbonding
// redelegation based on a completion time.
func GetRedelegationTimeKey(timestamp time.Time) []byte {
	bz := sdk.FormatTimeBytes(timestamp)
	return append(RedelegationQueueKey, bz...)
}

// GetREDsKey returns a key prefix for indexing a redelegation from a delegator
// address.
func GetREDsKey(delAddr sdk.AccAddress) []byte {
	return append(RedelegationKey, delAddr.Bytes()...)
}

// GetREDsFromValSrcIndexKey returns a key prefix for indexing a redelegation to
// a source validator.
func GetREDsFromValSrcIndexKey(valSrcAddr sdk.ValAddress) []byte {
	return append(RedelegationByValSrcIndexKey, valSrcAddr.Bytes()...)
}

// GetREDsToValDstIndexKey returns a key prefix for indexing a redelegation to a
// destination (target) validator.
func GetREDsToValDstIndexKey(valDstAddr sdk.ValAddress) []byte {
	return append(RedelegationByValDstIndexKey, valDstAddr.Bytes()...)
}

// GetREDsByDelToValDstIndexKey returns a key prefix for indexing a redelegation
// from an address to a source validator.
func GetREDsByDelToValDstIndexKey(delAddr sdk.AccAddress, valDstAddr sdk.ValAddress) []byte {
	return append(GetREDsToValDstIndexKey(valDstAddr), delAddr.Bytes()...)
}

// GetHistoricalInfoKey returns a key prefix for indexing HistoricalInfo objects.
func GetHistoricalInfoKey(height int64) []byte {
	return append(HistoricalInfoKey, []byte(strconv.FormatInt(height, 10))...)
}