package gov

import (
	"bytes"
	"fmt"
	"time"

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

const (
	// Default period for deposits & voting
	DefaultPeriod time.Duration = 86400 * 2 * time.Second // 2 days
)

// GenesisState - all staking state that must be provided at genesis
type GenesisState struct {
	StartingProposalID uint64                `json:"starting_proposal_id"`
	Deposits           []DepositWithMetadata `json:"deposits"`
	Votes              []VoteWithMetadata    `json:"votes"`
	Proposals          []Proposal            `json:"proposals"`
	DepositParams      DepositParams         `json:"deposit_params"`
	VotingParams       VotingParams          `json:"voting_params"`
	TallyParams        TallyParams           `json:"tally_params"`
}

// DepositWithMetadata (just for genesis)
type DepositWithMetadata struct {
	ProposalID uint64  `json:"proposal_id"`
	Deposit    Deposit `json:"deposit"`
}

// VoteWithMetadata (just for genesis)
type VoteWithMetadata struct {
	ProposalID uint64 `json:"proposal_id"`
	Vote       Vote   `json:"vote"`
}

func NewGenesisState(startingProposalID uint64, dp DepositParams, vp VotingParams, tp TallyParams) GenesisState {
	return GenesisState{
		StartingProposalID: startingProposalID,
		DepositParams:      dp,
		VotingParams:       vp,
		TallyParams:        tp,
	}
}

// get raw genesis raw message for testing
func DefaultGenesisState() GenesisState {
	minDepositTokens := sdk.TokensFromTendermintPower(10)
	return GenesisState{
		StartingProposalID: 1,
		DepositParams: DepositParams{
			MinDeposit:       sdk.Coins{sdk.NewCoin(sdk.DefaultBondDenom, minDepositTokens)},
			MaxDepositPeriod: DefaultPeriod,
		},
		VotingParams: VotingParams{
			VotingPeriod: DefaultPeriod,
		},
		TallyParams: TallyParams{
			Quorum:    sdk.NewDecWithPrec(334, 3),
			Threshold: sdk.NewDecWithPrec(5, 1),
			Veto:      sdk.NewDecWithPrec(334, 3),
		},
	}
}

// Checks whether 2 GenesisState structs are equivalent.
func (data GenesisState) Equal(data2 GenesisState) bool {
	b1 := msgCdc.MustMarshalBinaryBare(data)
	b2 := msgCdc.MustMarshalBinaryBare(data2)
	return bytes.Equal(b1, b2)
}

// Returns if a GenesisState is empty or has data in it
func (data GenesisState) IsEmpty() bool {
	emptyGenState := GenesisState{}
	return data.Equal(emptyGenState)
}

// ValidateGenesis
func ValidateGenesis(data GenesisState) error {
	threshold := data.TallyParams.Threshold
	if threshold.IsNegative() || threshold.GT(sdk.OneDec()) {
		return fmt.Errorf("Governance vote threshold should be positive and less or equal to one, is %s",
			threshold.String())
	}

	veto := data.TallyParams.Veto
	if veto.IsNegative() || veto.GT(sdk.OneDec()) {
		return fmt.Errorf("Governance vote veto threshold should be positive and less or equal to one, is %s",
			veto.String())
	}

	if !data.DepositParams.MinDeposit.IsValid() {
		return fmt.Errorf("Governance deposit amount must be a valid sdk.Coins amount, is %s",
			data.DepositParams.MinDeposit.String())
	}

	return nil
}

// InitGenesis - store genesis parameters
func InitGenesis(ctx sdk.Context, k Keeper, data GenesisState) {
	err := k.setInitialProposalID(ctx, data.StartingProposalID)
	if err != nil {
		// TODO: Handle this with #870
		panic(err)
	}
	k.setDepositParams(ctx, data.DepositParams)
	k.setVotingParams(ctx, data.VotingParams)
	k.setTallyParams(ctx, data.TallyParams)
	for _, deposit := range data.Deposits {
		k.setDeposit(ctx, deposit.ProposalID, deposit.Deposit.Depositor, deposit.Deposit)
	}
	for _, vote := range data.Votes {
		k.setVote(ctx, vote.ProposalID, vote.Vote.Voter, vote.Vote)
	}
	for _, proposal := range data.Proposals {
		switch proposal.Status {
		case StatusDepositPeriod:
			k.InsertInactiveProposalQueue(ctx, proposal.DepositEndTime, proposal.ProposalID)
		case StatusVotingPeriod:
			k.InsertActiveProposalQueue(ctx, proposal.VotingEndTime, proposal.ProposalID)
		}
		k.SetProposal(ctx, proposal)
	}
}

// ExportGenesis - output genesis parameters
func ExportGenesis(ctx sdk.Context, k Keeper) GenesisState {
	startingProposalID, _ := k.peekCurrentProposalID(ctx)
	depositParams := k.GetDepositParams(ctx)
	votingParams := k.GetVotingParams(ctx)
	tallyParams := k.GetTallyParams(ctx)
	var deposits []DepositWithMetadata
	var votes []VoteWithMetadata
	proposals := k.GetProposalsFiltered(ctx, nil, nil, StatusNil, 0)
	for _, proposal := range proposals {
		proposalID := proposal.ProposalID
		depositsIterator := k.GetDeposits(ctx, proposalID)
		defer depositsIterator.Close()
		for ; depositsIterator.Valid(); depositsIterator.Next() {
			var deposit Deposit
			k.cdc.MustUnmarshalBinaryLengthPrefixed(depositsIterator.Value(), &deposit)
			deposits = append(deposits, DepositWithMetadata{proposalID, deposit})
		}
		votesIterator := k.GetVotes(ctx, proposalID)
		defer votesIterator.Close()
		for ; votesIterator.Valid(); votesIterator.Next() {
			var vote Vote
			k.cdc.MustUnmarshalBinaryLengthPrefixed(votesIterator.Value(), &vote)
			votes = append(votes, VoteWithMetadata{proposalID, vote})
		}
	}

	return GenesisState{
		StartingProposalID: startingProposalID,
		Deposits:           deposits,
		Votes:              votes,
		Proposals:          proposals,
		DepositParams:      depositParams,
		VotingParams:       votingParams,
		TallyParams:        tallyParams,
	}
}