package types

import (
	"math/big"

	abci "github.com/tendermint/tendermint/abci/types"
	"github.com/tendermint/tendermint/crypto"
)

// status of a validator
type BondStatus byte

// staking constants
const (
	Unbonded  BondStatus = 0x00
	Unbonding BondStatus = 0x01
	Bonded    BondStatus = 0x02

	// default bond denomination
	DefaultBondDenom = "stake"

	// Delay, in blocks, between when validator updates are returned to Tendermint and when they are applied.
	// For example, if this is 0, the validator set at the end of a block will sign the next block, or
	// if this is 1, the validator set at the end of a block will sign the block after the next.
	// Constant as this should not change without a hard fork.
	// TODO: Link to some Tendermint docs, this is very unobvious.
	ValidatorUpdateDelay int64 = 1
)

//BondStatusToString for pretty prints of Bond Status
func BondStatusToString(b BondStatus) string {
	switch b {
	case 0x00:
		return "Unbonded"
	case 0x01:
		return "Unbonding"
	case 0x02:
		return "Bonded"
	default:
		panic("improper use of BondStatusToString")
	}
}

// PowerReduction is the amount of staking tokens required for 1 unit of Tendermint power
var PowerReduction = NewIntFromBigInt(new(big.Int).Exp(big.NewInt(10), big.NewInt(6), nil))

// TokensToTendermintPower - convert input tokens to potential tendermint power
func TokensToTendermintPower(tokens Int) int64 {
	return (tokens.Div(PowerReduction)).Int64()
}

// TokensFromTendermintPower - convert input power to tokens
func TokensFromTendermintPower(power int64) Int {
	return NewInt(power).Mul(PowerReduction)
}

// nolint
func (b BondStatus) Equal(b2 BondStatus) bool {
	return byte(b) == byte(b2)
}

// validator for a delegated proof of stake system
type Validator interface {
	GetJailed() bool              // whether the validator is jailed
	GetMoniker() string           // moniker of the validator
	GetStatus() BondStatus        // status of the validator
	GetOperator() ValAddress      // operator address to receive/return validators coins
	GetConsPubKey() crypto.PubKey // validation consensus pubkey
	GetConsAddr() ConsAddress     // validation consensus address
	GetTokens() Int               // validation tokens
	GetBondedTokens() Int         // validator bonded tokens
	GetTendermintPower() int64    // validation power in tendermint
	GetCommission() Dec           // validator commission rate
	GetMinSelfDelegation() Int    // validator minimum self delegation
	GetDelegatorShares() Dec      // total outstanding delegator shares
	GetDelegatorShareExRate() Dec // tokens per delegator share exchange rate
}

// validator which fulfills abci validator interface for use in Tendermint
func ABCIValidator(v Validator) abci.Validator {
	return abci.Validator{
		Address: v.GetConsPubKey().Address(),
		Power:   v.GetTendermintPower(),
	}
}

// properties for the set of all validators
type ValidatorSet interface {
	// iterate through validators by operator address, execute func for each validator
	IterateValidators(Context,
		func(index int64, validator Validator) (stop bool))

	// iterate through bonded validators by operator address, execute func for each validator
	IterateBondedValidatorsByPower(Context,
		func(index int64, validator Validator) (stop bool))

	// iterate through the consensus validator set of the last block by operator address, execute func for each validator
	IterateLastValidators(Context,
		func(index int64, validator Validator) (stop bool))

	Validator(Context, ValAddress) Validator            // get a particular validator by operator address
	ValidatorByConsAddr(Context, ConsAddress) Validator // get a particular validator by consensus address
	TotalBondedTokens(Context) Int                      // total bonded tokens within the validator set
	TotalTokens(Context) Int                            // total token supply

	// slash the validator and delegators of the validator, specifying offence height, offence power, and slash fraction
	Slash(Context, ConsAddress, int64, int64, Dec)
	Jail(Context, ConsAddress)   // jail a validator
	Unjail(Context, ConsAddress) // unjail a validator

	// Delegation allows for getting a particular delegation for a given validator
	// and delegator outside the scope of the staking module.
	Delegation(Context, AccAddress, ValAddress) Delegation
}

//_______________________________________________________________________________

// delegation bond for a delegated proof of stake system
type Delegation interface {
	GetDelegatorAddr() AccAddress // delegator AccAddress for the bond
	GetValidatorAddr() ValAddress // validator operator address
	GetShares() Dec               // amount of validator's shares held in this delegation
}

// properties for the set of all delegations for a particular
type DelegationSet interface {
	GetValidatorSet() ValidatorSet // validator set for which delegation set is based upon

	// iterate through all delegations from one delegator by validator-AccAddress,
	//   execute func for each validator
	IterateDelegations(ctx Context, delegator AccAddress,
		fn func(index int64, delegation Delegation) (stop bool))
}

//_______________________________________________________________________________
// Event Hooks
// These can be utilized to communicate between a staking keeper and another
// keeper which must take particular actions when validators/delegators change
// state. The second keeper must implement this interface, which then the
// staking keeper can call.

// TODO refactor event hooks out to the receiver modules

// event hooks for staking validator object
type StakingHooks interface {
	AfterValidatorCreated(ctx Context, valAddr ValAddress)                       // Must be called when a validator is created
	BeforeValidatorModified(ctx Context, valAddr ValAddress)                     // Must be called when a validator's state changes
	AfterValidatorRemoved(ctx Context, consAddr ConsAddress, valAddr ValAddress) // Must be called when a validator is deleted

	AfterValidatorBonded(ctx Context, consAddr ConsAddress, valAddr ValAddress)         // Must be called when a validator is bonded
	AfterValidatorBeginUnbonding(ctx Context, consAddr ConsAddress, valAddr ValAddress) // Must be called when a validator begins unbonding

	BeforeDelegationCreated(ctx Context, delAddr AccAddress, valAddr ValAddress)        // Must be called when a delegation is created
	BeforeDelegationSharesModified(ctx Context, delAddr AccAddress, valAddr ValAddress) // Must be called when a delegation's shares are modified
	BeforeDelegationRemoved(ctx Context, delAddr AccAddress, valAddr ValAddress)        // Must be called when a delegation is removed
	AfterDelegationModified(ctx Context, delAddr AccAddress, valAddr ValAddress)
	BeforeValidatorSlashed(ctx Context, valAddr ValAddress, fraction Dec)
}